STM32 Industrial Input Output Expansion Board User Manual

The dual-channel digital isolators provide galvanic isolation
between user and power interfaces. They offer robustness to noise
and high-speed input/output switching time.

High-side Switches (IPS1025H-32 and IPS1025HQ-32):

The high-side switches on the board feature overcurrent and
overtemperature protection for safe output load control. They have
an application board operating range of 8 to 33 V and 0 to 2.5 A.
Ensure compatibility with STM32 Nucleo development boards.

High-side Current Limiter (CLT03-2Q3):

The high-side current limiter can be configured for both
high-side and low-side applications. It offers galvanic isolation
between process and login sides, with important features like 60 V
and reverse input plugin capability.

FAQ:

Q: What should I do if the side switches get heated?

A: Care must be taken while touching the IC or adjoining areas
on the boards, particularly with higher loads. If the switches get
heated, reduce the load current or contact our online support
portal for assistance.

Q: What do the LEDs on the board indicate?

A: The green LED corresponding to each output indicates when a
switch is ON, while red LEDs indicate overload and overheating
diagnostics.

“`

View Fullscreen

UM3483
User manual
Getting started with the X-NUCLEO-ISO1A1 industrial input/output expansion board for STM32 Nucleo
Introduction
The X-NUCLEO-ISO1A1 evaluation board is designed to expand the STM32 Nucleo board and provide micro-PLC functionality with isolated industrial input and output. Isolation between logic and process side components is provided by the UL1577 certified digital isolators STISO620 and STISO621. Two current-limited high-side inputs from the process side are realized through the CLT03-2Q3. Protected outputs with diagnostics and smart driving features are provided by one each of the high-side switches IPS1025H/HQ and IPS1025H-32/ HQ-32 which can drive capacitive, resistive, or inductive loads up to 5.6 A. Two X-NUCLEO-ISO1A1 boards can be stacked together on top of an STM32 Nucleo board via ST morpho connectors with the appropriate selection of jumpers on the expansion boards to avoid conflict in GPIO interfaces. Rapid evaluation of the onboard ICs is facilitated by the X-NUCLEO-ISO1A1 using the X-CUBE-ISO1 software package. Provision for ARDUINO® connections is provided on the board.
Figure 1. X-NUCLEO-ISO1A1 expansion board

Notice:

For dedicated assistance, submit a request through our online support portal at www.st.com/support.

UM3483 – Rev 1 – May 2025 For further information, contact your local STMicroelectronics sales office.

www.st.com

UM3483
Safety and compliance information

Safety and compliance information

The side switches IPS1025HQs may get heated with high load current. Care must be taken while touching the IC or adjoining areas on the boards. particularly with higher loads.

1.1

Compliance information (Reference)

Both CLT03-2Q3 and IPS1025H are designed to meet common industrial requirements, including IEC61000-4-2, IEC61000-4-4, and IEC61000-4-5 standards. For a more detailed evaluation of these components, refer to the single-product evaluation boards available at www.st.com. The X-NUCLEO-ISO1A1 serves as an excellent tool for initial assessments and rapid prototyping, providing a robust platform for developing industrial applications with STM32 Nucleo boards. Additionally, the board is RoHS compliant and comes with a free comprehensive development firmware library and examples compatible with STM32Cube firmware.

UM3483 – Rev 1

page 2/31

Component diagram

The different components on the board are shown here, with description.

U1 – CLT03-2Q3: Input current limiter

U2, U5 – STISO620: ST digital isolator unidirectional

U6, U7 – STISO621: ST digital isolator bidirectional.

U3 – IPS1025HQ-32: high-side switch (package: 48-VFQFN Exposed Pad)

U4 – IPS1025H-32: high-side switch (package: PowerSSO-24).

U8 – LDO40LPURY: Voltage regulator

Figure 2. Different ST ICs and their position

UM3483
Component diagram

UM3483 – Rev 1

page 3/31

UM3483
Overview

Overview

The X-NUCLEO-ISO1A1 is an industrial I/O evaluation board with two inputs and outputs. It is designed to be operated with an STM32 Nucleo board such as NUCLEO-G071RB. Compatible with the ARDUINO® UNO R3 layout, it features the STISO620 dual-channel digital isolator and IPS1025H-32 and IPS1025HQ-32 high-side switches. The IPS1025H-32 and IPS1025HQ-32 are single high-side switch ICs capable of driving capacitive, resistive, or inductive loads. The CLT03-2Q3 provides protection and isolation in industrial operating conditions and offers an ‘energy-less’ status indication for each of the two input channels, featuring minimal power consumption. It is designed for situations that require compliance with IEC61000-4-2 standards. The STM32 MCU on board the controls and monitors all the devices via GPIOs. Each input and output have an LED indication. In addition, there are two programmable LEDs for customizable indications. The X-NUCLEO-ISO1A1 enables rapid evaluation of the onboard ICs by performing a basic set of operations in conjunction with the X-CUBE-ISO1 software package. The key features of the constituent components are given below.

3.1

Dual-channel digital isolator

The STISO620 and STISO621 are dual-channel digital isolators based on the ST thick oxide galvanic isolation technology.

The devices provide two independent channels in the opposite direction (STISO621) and in the same direction (STISO620) with Schmitt trigger input as shown in Figure 3, providing robustness to noise and high-speed input/ output switching time.

It is designed to operate within a wide ambient temperature range from -40 ºC to 125 ºC, making it suitable for various environmental conditions. The device boasts a high common-mode transient immunity exceeding 50 kV/µs, ensuring robust performance in electrically noisy environments. It supports supply levels ranging from 3 V to 5.5 V and provides level translation between 3.3 V and 5 V. The isolator is engineered for low-power consumption and features pulse width distortions of less than 3 ns. It offers 6 kV (STISO621) and 4 kV (STISO620) galvanic isolation, enhancing safety and reliability in critical applications. The product is available in both SO-8 narrow and wide package options, providing flexibility in design. Additionally, it has received safety and regulatory approvals, including UL1577 certification.

Figure 3. ST digital isolators

UM3483 – Rev 1

page 4/31

UM3483
Overview

3.2

High-side switches IPS1025H-32 and IPS1025HQ-32

The X-NUCLEO-ISO1A1 embeds the IPS1025H-32 and IPS1025HQ-32 intelligent power switch (IPS), featuring overcurrent and overtemperature protection for safe output load control.

The board is designed to meet application requirements in terms of galvanic isolation between user and power interfaces using ST’s new technology STISO620 and STISO621 ICs. This requirement is satisfied by a dualchannel digital isolator based on the ST thick oxide galvanic isolation technology.

The system utilizes two STISO621 bidirectional isolators, labeled as U6 and U7, to facilitate the forward transmission of signals to the device, as well as to handle the FLT pins for feedback diagnostic signals. Each high-side switch generates two fault signals, necessitating the inclusion of an additional unidirectional isolator, designated as U5, which is digital isolator STISO620. This configuration ensures that all diagnostic feedback is accurately isolated and transmitted, maintaining the integrity and reliability of the system’s fault detection and signaling mechanisms.

The industrial outputs on the board are based on the IPS1025H-32 and IPS1025HQ-32 single high-side

switch, which features:

Operating range up to 60 V

Low-power dissipation (RON = 12 m)

Fast decay for inductive loads

Smart driving of capacitive loads

Undervoltage lockout

Overload and overtemperature protection

PowerSSO-24 and QFN48L 8x6x0.9mm package

Application board operating range: 8 to 33 V/0 to 2.5 A

Extended voltage operating range (J3 open) up to 60 V

5 kV galvanic isolation

Supply rail reverse polarity protection

EMC compliance with IEC61000-4-2, IEC61000-4-3, IEC61000-4-4, IEC61000-4-5, IEC61000-4-8

Compatible with STM32 Nucleo development boards

Equipped with Arduino® UNO R3 connectors

CE certified:

EN 55032:2015 + A1:2020

EN 55035:2017 + A11:2020.

Green LED corresponding to each output indicates when a switch is ON. Also Red LEDs indicates overload and overheating diagnostics.

UM3483 – Rev 1

page 5/31

UM3483
Overview

3.3

High-side current limiter CLT03-2Q3

The X-NUCLEO-ISO1A1 board has two input connectors for any industrial digital sensors, such as proximity, capacitive, optical, ultrasonic, and touch sensors. Two of the inputs are intended for isolated lines with optocouplers on the outputs. Each input then feeds directly into one of the two independent channels in CLT03-2Q3 current limiters. The channels in the current limiter immediately limit the current as per the standard and proceed to filter and regulate the signals to deliver appropriate outputs for the isolated lines destined for the GPIO ports of a logic processor, such as a microcontroller in a programmable logic controller (PLC). The board also includes jumpers to enable test pulses through any of the channels to verify normal operation.

Isolator STISO620 (U2) is used for Galvanic isolation between process and login side.

Important features:

The 2 isolated channel input current limiter can be configured for both high-side and low-side applications

60 V and reverse input plugin capable

No power supply required

Safety test pulse

High EMI robustness thanks to integrated digital filter

IEC61131-2 type 1 and type 3 compliant

RoHS compliant

The input side of the CLT03-2Q3 current limiter is characterized by certain voltage and current ranges that delimit ON and OFF regions, as well as transition regions between these logical high and low states. The device enters Fault Mode when the input voltage exceeds 30 V.

Figure 4. Input characteristics of CLT03-2Q3

UM3483 – Rev 1

page 6/31

Figure 5. Output operating region of CLT03-2Q3

UM3483
Overview

UM3483 – Rev 1

page 7/31

UM3483
Functional blocks

Functional blocks

The board is designed to operate with nominal 24V input which powers the process side circuitry. The logic component on the other side of isolators are powered by 5 V input to the X-NUCLEO board which is typically powered by a USB port of a PC.
Figure 6. Block diagram

4.1

Process side 5 V supply

A 5V supply is derived from 24V input with low drop regulator LDO40L with built in protection functions. The voltage regulator has a self-overheating turn-off feature. The output voltage can be adjusted and kept just below the 5V utilising a retorsion network feeback from output. The LDO has DFN6 (Wettable flanks), which make this IC suitable for board size optimization.

Figure 7. Process side 5 V supply

UM3483 – Rev 1

page 8/31

UM3483
Functional blocks

4.2

Isolator STISO621

The STISO621 digital isolator has 1-to-1 directionality, with 100MBPS data rate. It can withstand, 6KV galvanic isolation and high common-mode transient: >50 k V/s.

Figure 8. Isolator STISO621

4.3

Isolator STISO620

The STISO620 digital isolator has from 2-to-0 directionality, with 100MBPS data rate as the STISO621. It can withstand, 4KV galvanic isolation and has a Schmitt trigger input.

Figure 9. Isolator STISO620

UM3483 – Rev 1

page 9/31

UM3483
Functional blocks

4.4

Current limited digital input

The current limiter IC CLT03-2Q3 has two isolated channels, where we can connect isolated inputs. The board has an input excitation LED indicator.

Figure 10. Current-limited digital input

4.5

High-side switch (with dynamic current control)

The high-side switches are available in two packages with identical features. In this board, both the packages, that is, POWER SSO-24 and 48-QFN(8*x6), are used. The details features are mentioned in the Overview section.

Figure 11. High-side switch

UM3483 – Rev 1

page 10/31

UM3483
Functional blocks

4.6

Jumper setting options

The control and status pins of the I/O devices are connected through jumpers to the MCU GPIO. The jumper selection allows connection of each control pin to one of two possible GPIOs. To simplify, these GPIOs are clubbed in two sets marked as default and alternate. The serigraphy on the boards includes bars that indicate the jumper positions for default connections. The standard firmware assumes that one of the sets, marked as default and alternate, is selected for a board. The figure below depicts the jumper information for routing control and status signals between the X-NUCLEO and suitable Nucleo boards through the Morpho connectors for various configurations.

Figure 12. Morpho connectors

Through this jumper connection, we can stack one more X-NUCLEO, which is fully functional.

UM3483 – Rev 1

page 11/31

Figure 13. MCU interface routing options

UM3483
Functional blocks

UM3483 – Rev 1

page 12/31

UM3483
Functional blocks

4.7

LED indicators

Two LEDs, D7 and D8 are provided on the board to have programmable LED indications. Refer to the software user manual for detailed information on various LED configurations and features, including power status and error states.

Figure 14. LED indicators

UM3483 – Rev 1

page 13/31

Board setup and configuration

UM3483
Board setup and configuration

5.1

Get started with the board

A detailed image is provided to help you become familiar with the board and its various connections. This image serves as a comprehensive visual guide, illustrating the layout and specific points of interest on the board. Terminal J1 is provided to connect 24V supply to power the process side of the board. Terminal J5 is also connected to the 24V DC input. However J5 is provided easy connection of external Loads and Sensors which are connected to Input terminal J5 and high side output terminal J12.

Figure 15. Different connecting ports of X-NUCLEO

UM3483 – Rev 1

page 14/31

UM3483
Board setup and configuration

5.2

System setup requirements

1. 24 V DC Power Supply: The 2$V input should have sufficient capability to drive the board along with external load. Ideally this should be short circuit protected externals.

2. NUCLEO-G071RB Board: The NUCLEO-G071RB board is a Nucleo development board. It serves as the main microcontroller unit for driving outputs, monitoring output health status, and fetching process side inputs.

3. X-NUCLEO-ISO1A1 Board: The Micro PLC board for evaluation of specific functionality of the devices. We can stack two X-NUCLEO as well.

4. USB-micro-B Cable: The USB-micro-B cable is used to connect the NUCLEO-G071RB board to a computer or a 5 V adapter. This cable is essential for flashing the binary file onto the mentioned Nucleo board and
subsequently powering it through any 5 V charger or adapter.

5. Wires to connect the Input Supply: Connecting wire for the load and inputs, it is highly recommended to use thick wires for the output high-side switches.

6. Laptop/PC: A laptop or PC has to be used to flash the test firmware onto the NUCLEO-G071RB board. This process only needs to be performed once when using the Nucleo board to test multiple X-NUCLEO boards.

7. STM32CubeProgrammer (optional): The STM32CubeProgrammer is used to flash the binary after erasing the MCU chip. It is a versatile software tool designed for all STM32 microcontrollers, providing an efficient way to program and debug the devices. More information and the software can be found at STM32CubeProg STM32CubeProgrammer software for all STM32 – STMicroelectronics.

8. Software (optional): Install the ‘Tera Term’ software on your desktop to facilitate communication with the Nucleo board. This terminal emulator allows for easy interaction with the board during testing and debugging.
The software can be downloaded from Tera-Term.

5.3

Safety precautions and protective equipment

Applying a heavy load through the high-side switches may cause the board to overheat. A warning sign is placed near the IC to indicate this risk.

It has been observed that the board has reduced tolerance to relatively high voltage surges. Therefore, it is advised not to connect excessive inductive loads or apply increased voltage beyond the specified reference values. It is expected that the board should be handled by an individual with basic electrical knowledge.

5.4

Stacking of two X-NUCLEO board on Nucleo

The board is designed with a jumper configuration that enables the Nucleo to drive two X-NUCLEO boards, each with two outputs and two inputs. Additionally, the fault signal is configured separately. Please refer to the table below as well as the schematic described in the previous section to configure and route control and monitoring signal between the MCU and devices. Either Default or alternate jumper can used while using single X-Nucleo board. But the both the X-nucleo boards should have different jumper selection to avod clash incase they are stacked on top another.

Table 1. Jumper selection chart for the default and alternate configuration

PIN feature

Serigraphy on board

Schematic name

Jumper

Default configuration

Header setting

Name

IA.0 Input (CLT03)
IA.1

IA0_IN_L

J18

IA1_IN_L

J19

1-2(CN2PIN-18)
1-2(CN2PIN-36)

IA0_IN_1 IA1_IN_2

Alternate configuration

Header setting

Name

2-3(CN2PIN-38)

IA0_IN_2

2-3(CN2PIN-4)

IA1_IN_1

UM3483 – Rev 1

page 15/31

UM3483
Board setup and configuration

PIN feature

Serigraphy on board

Schematic name

Jumper

Default configuration

Header setting

Name

Alternate configuration

Header setting

Name

Output (IPS-1025)

QA.0 QA.1

QA0_CNTRL_ L

J22

QA1_CNTRL_ L

J20

1-2(CN2PIN-19)

QA0_CNTRL_ 2-3(CN1-

PIN-2)

1-2(CN1- PIN-1)

QA1_CNTRL_ 2

2-3(CN1PIN-10)

QA0_CNTRL_ 2
QA1_CNTRL_ 1

FLT1_QA0_L J21

1-2(CN1- PIN-4) FLT1_QA0_2

2-3(CN1PIN-15)

FLT1_QA0_1

Fault PIN configuration

FLT1_QA1_L J27 FLT2_QA0_L J24

1-2(CN1PIN-17)

FLT1_QA1_2

1-2(CN1- PIN-3) FLT2_QA0_2

2-3(CN1PIN-37)
2-3(CN1PIN-26)

FLT1_QA1_1 FLT2_QA0_1

FLT2_QA1_L J26

1-2(CN1PIN-27)

FLT2_QA1_1

2-3(CN1PIN-35)

FLT2_QA1_2

The image indicates the different views of the X-NUCLEO stacking. Figure 16. Stack of two X-NUCLEO boards

UM3483 – Rev 1

page 16/31

UM3483
How to set up the board (tasks)

How to set up the board (tasks)

Jumper connection Make sure all the jumpers are in the default state; a white bar indicates the default connection. As shown in Figure 2. The FW is configure d for default jumper selection. appropriate modifications are needed to use alternate jumper selections.
Figure 17. Jumper connection of X-NUCLEO-ISO1A1

1. Connect the Nucleo board via a micro-USB cable to the computer
2. Place the X-NUCLEO on top of Nucleo as shown in Figure 18
3. Copy the X-CUBE-ISO1.bin to the Nucleo disc, or refer to the software user manual for software debugging
4. Check the D7 LED on the stacked X-NUCLEO Board; it should blink 1 second ON and 2 seconds OFF as shown in Figure 5. You can also debug the X-CUBE-ISO1 firmware using STM32CubeIDE and other supported IDEs.Fig. 18 below shows LED indications with all Inputs as low followed by all high input to the board. Output mimics the corresponding input.

UM3483 – Rev 1

page 17/31

UM3483
How to set up the board (tasks)
Figure 18. LED indication pattern during normal board operation

UM3483 – Rev 1

page 18/31

UM3483 – Rev 1

Schematic diagrams

J1
1 2
Te rmina lBlock
24V DC Input

Figure 19. X-NUCLEO-ISO1A1 circuit schematic (1 of 4)
24V

C1 NM
P C Te s t P oint,
1

GND_EARTH

EARTH

R1 10R
C2 D1 S M15T33CA

C4 10UF

U8 3 VIN Vout 4
2 ENV Sense 5
1 GND ADJ 6
LDO40LPURY

BD1
R2 12K
R4 36K

5V TP10
1

C5 10UF

D2 Gre e n LED
R3

J5
1 2
input

D4 Gre e n LED
R10

D3 Gre e n LED
R5

IA.0H

IA.1H

GND

J6
1 2

24V
C15

GND

Field Side Connections GND
Figure 20. X-NUCLEO-ISO1A1 circuit schematic (2 of 4)

3V3

10nF

R7 0E

TP2

C25

C26

6 INATTL1 7 INA1 8 INB1

TP1 VBUF1 OUTP1 OUTN1 OUTN1_T
PD1

9 10 11 5 TAB1 12

10nF

O UTP 1 OUTN1
R9 0E

R38 220K
TP3

2 INATTL2 3 INA2 4 INB2

TP2 VBUF2 OUTP2 OUTN2 OUTN2_T
PD2

14 15 16 13 TAB2 1

C8 10nF O UTP 2
OUTN2

R37 220K

GND

1 2 3 4

VDD1 TxA TxB GND1

VDD2 RxA RxB
GND2

8 7 6 5

S T1S O620
Isolation Barrier

GND_Logic TP4
1

IA0_IN_L IA1_IN_L

R35 0E 0E R36

10nF

CLT03-2Q3

GND

GND_Logic

R7, R9

Can be replaced by a capacitor for test purpose

From Field Side

UM3483
Schematic diagrams
To STM32 Nucleo

GND

Input Current Limiter with Digital Isolation

page 19/31

UM3483 – Rev 1

Figure 21. X-NUCLEO-ISO1A1 circuit schematic (3 of 4)

High side Switch Section

C17

24V FLT2_QA0

QA.0

J12 1A 2A
OUTPUT

C16 24V

FLT2_QA1 QA.1

1 2 3 4 5 6 7 8 9 10 11 12

VCC NC NC FLT2 OUT OUT OUT OUT OUT OUT OUT OUT

GND IN
IPD FLT1 OUT OUT OUT OUT OUT OUT OUT OUT

24 23 22 21 20 19 18 17 16 15 14 13

IP S 1025HTR-32

GND
QA0_CNTRL_P
R14 220K

FLT1_QA0

J 10

3 pin jumpe r

Gre e n LED

2 D6

R15
C 11 0.47 µF

J 11

3 pin jumpe r

R16

10K

GND

0 2 1 13 42 41 17 18 19 20 21 22

VCC NC NC FLT2 OUT OUT OUT OUT OUT OUT OUT OUT

GND IN
IPD FLT1 OUT OUT OUT OUT OUT OUT OUT OUT

6 3 48 46 40 39 38 37 36 35 24 23

IP S 1025HQ-32

GND

QA1_CNTRL_P
R11 220K

FLT1_QA1

3 pin jumpe r

Gre e n LED

2 D5

R13

R12

C10

3 pin jumpe r

0.47 µF

10K

GND

3V3
C22 FLT1_QA0_L QA0_CNTRL_L

GND_Logic 3V3

FLT1_QA1_L C20
QA1_CNTRL_L

TP6

Isolation Section

U6
1 VDD1 2 RX1 3 TX1 4 GND1
S TIS O621

VDD2 8 TX2 7 RX2 6
GND2 5

5V
FLT1_QA0 QA0_CNTRL_P C23
R28 220K R29 220K

U7
1 VDD1 2 RX1 3 TX1 4 GND1
S TIS O621

VDD2 8 TX2 7 RX2 6
GND2 5

GND 5V

FLT1_QA1

QA1_CNTRL_P

C21

R30 220K R31 220K

TP7 1

GND_Logic 5V

FLT2_QA0

C18

FLT2_QA1

R33 220K R32 220K

GND

1 2 3 4

VDD1 TxA
TxB GND1

VDD2 RxA
RxB GND2

8 7 6 5

S T1S O620

GND 3V3

FLT2_QA0_L

C19

FLT2_QA1_L

GND_Logic

To Field

UM3483
Schematic diagrams

page 20/31

UM3483 – Rev 1

3V3 3V3

QA1_CNTRL_2 FLT2_QA0_2

C13

FLT1_QA0_1

FLT1_QA1_2

GND_Logic

R23 0E
FLT2_QA1_1

FLT2_QA1_2 FLT1_QA1_1

Figure 22. X-NUCLEO-ISO1A1 circuit schematic (4 of 4)

CN1
1
3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

QA0_CNTRL_2

FLT1_QA0_2

10 12

QA1_CNTRL_1

14 B2

16 3V3

LOGIC_GND

3V3

FLT2_QA0_1

R24 0E

Le ft Ha nd S ide Conne ctor

GND_Logic

R34 0E

Morpho Connectors

CN2

D15

D14

R17 3V3

0E AGND

R26

R27

D13 11

D12 13

GND_Logic

D11 15

D10 17

D9′

R19 NM QA0_CNTRL_1 D9

GREEN LED

D8 RED LED

R20 NM

26 28

R21

34 36

GND_Logic

IA1_IN_1
IA0_IN_1 TP8
AGND IA1_IN_2 IA0_IN_2
GND_Logic

[ Note: Header PIN 1 and 2 to be shorted for All Default configuration. ]

2 FLT2_QA0_L

FLT2_QA0_2
J 24 3 pin jumpe r
QA0_CNTRL_L

QA0_CNTRL_1

FLT1_QA0_2

J 22

3 pin jumpe r

J 21

3 pin jumpe r

FLT1_QA0_L

FLT2_QA0_1

2 FLT1_QA1_L

FLT1_QA1_2
J 27 3 pin jumpe r

QA0_CNTRL_2 FLT2_QA1_1

FLT1_QA0_1 QA1_CNTRL_2

2 FLT2_QA1_L

J 26 3 pin jumpe r
2
QA1_CNTRL_L

J 20 3 pin jumpe r

FLT1_QA1_1

FLT2_QA1_2

QA1_CNTRL_1

2 IA1_IN_L
2 IA0_IN_L

IA1_IN_2 J 19 3 pin jumpe r
IA1_IN_1
IA0_IN_1 J 18 3 pin jumpe r
IA0_IN_2

MCU Interface Routing Options

CN6
1 2 3 4 5 6 7 8
NM

3V3
B2 3V3
LOGIC_GND

3V3
3V3 C24
AGND NM

D15 D14
D13 D12 D11 D10 D9′ D8

CN4

1 2 3 4 5 6 7 8

D0 D1 D2
D3 D4 D5
D6 D7

CN3
10 9 8 7 6 5 4 3 2 1
NM

CN5

1 2
3 4
5 6

A0 A1 A2 A3 A4 A5

Arduino Connectors

UM3483
Schematic diagrams

page 21/31

UM3483
Bill of materials

Bill of materials

Table 2. X-NUCLEO-ISO1A1 bill of materials

Item Q.ty

Ref.

1 1 BD1

2 2 C1, C3

3 2 C10, C11

C13, C18, C19,

C20, C21, C22, C23, C24, C25,

C26

5 2 C2, C15

6 2 C16, C17

7 1 C4

8 1 C5

9 4 C6, C7, C8, C9

10 2 CN1, CN2

11 1 CN3

12 2 CN4, CN6

13 1 CN5

14 1 D1, SMC

15 6

D2, D3, D4, D5, D6, D7

16 1 D8

17 2 HW1, HW2

18 1 J1

19 1 J2

20 1 J5

21 2 J6, J12

J8, J9, J10, J11,

J18, J19, J20, J21, J22, J24,

J26, J27

23 1 R1

24 8

R11, R14, R28, R29, R30, R31, R32, R33

Part/value 10OHM 4700pF
0.47uF

Description

Manufacturer

Ferrite Beads WE-CBF Würth Elektronik

Safety Capacitors 4700pF

Vishay

Multilayer Ceramic Capacitors

Würth Elektronik

Order code 7427927310 VY1472M63Y5UQ63V0
885012206050

100nF

Multilayer Ceramic Capacitors

Würth Elektronik

885012206046

1uF 100nF 10uF 10uF 10nF
465 VAC, 655 VDC 465 VAC, 655 VDC 5.1A 1.5kW(ESD) 20mA 20mA Jumper CAP 300VAC
300VAC 300VAC

Multilayer Ceramic Capacitors

Würth Elektronik

885012207103

Multilayer Ceramic Capacitors

Würth Elektronik

885382206004

Multilayer Ceramic Capacitors

Murata Electronics GRM21BR61H106KE43K

Multilayer Ceramic Capacitors, X5R

Murata Electronics GRM21BR61C106KE15K

Multilayer Ceramic Capacitors

Würth Elektronik

885382206002

Headers & Wire Housings

Samtec

SSQ-119-04-L-D

Headers & Wire Housings

Samtec

SSQ-110-03-L-S

8 Position Receptacle Connector

Samtec

SSQ-108-03-L-S

Headers & Wire Housings

Samtec

SSQ-106-03-L-S

ESD Suppressors / TVS Diodes

STMicroelectronics SM15T33CA

Standard LEDs SMD(Green)

Broadcom Limited ASCKCG00-NW5X5020302

Standard LEDs SMD(Red)

Broadcom Limited ASCKCR00-BU5V5020402

Jumper

Würth Elektronik

609002115121

Fixed Terminal Blocks Würth Elektronik

691214110002

Test Plugs & Test Jacks Keystone Electronics 4952

Fixed Terminal Blocks Würth Elektronik

691214110002

Fixed Terminal Blocks Würth Elektronik

691214110002

Headers & Wire Housings

Würth Elektronik

61300311121

10OHM 220 kOhms

Thin Film Resistors SMD

Vishay

Thick Film Resistors SMD

Vishay

TNPW080510R0FEEA RCS0603220KJNEA

UM3483 – Rev 1

page 22/31

UM3483
Bill of materials

Item Q.ty

Ref.

25 2 R12, R16

Part/value 10KOHM

26 1 R19

0Ohm

27 1 R2

12KOHM

28 2 R26, R27

150 OHM

29 4 R3, R13, R15

1KOHM

30 2 R35, R36

0Ohm

31 2 R37, R38

220 kOhms

32 1 R4

36KOHM

33 2 R5, R10

7.5KOHM

34 2
35 9
36 4 37 3 38 1 39 2 40 1
41 1 42 2 43 1

R6, R8

0Ohm

R7, R9, R17, R20, R21, R23, R24, R34
TP2, TP3, TP8, TP10
TP4, TP6, TP7

0Ohm

U1, QFN-16L

U2, U5, SO-8

U3, VFQFPN 48L 8.0 X 6.0 X .90 3.5A PITCH

U4, PowerSSO 24

3.5A

U6, U7, SO-8

U8, DFN6 3×3

Description
Thick Film Resistors SMD
Thick Film Resistors SMD
Thin Film Resistors SMD
Thin Film Chip Resistors
Thin Film Resistors SMD
Thick Film Resistors SMD
Thick Film Resistors SMD
Thick Film Resistors SMD
Thin Film Resistors SMD
Thick Film Resistors SMD

Manufacturer Bourns Vishay Panasonic Vishay Vishay Vishay Vishay Panasonic Vishay Vishay

Thick Film Resistors SMD

Vishay

Test Plugs & Test Jacks Harwin

Self-powered digital input current limiter

STMicroelectronics

Digital Isolators

STMicroelectronics

HIGH-SIDE SWITCH STMicroelectronics

Power Switch/Driver 1:1

N-Channel 5A

STMicroelectronics

PowerSSO-24

Digital Isolators

STMicroelectronics

LDO Voltage Regulators

STMicroelectronics

Order code CMP0603AFX-1002ELF CRCW06030000Z0EAHP ERA-3VEB1202V MCT06030C1500FP500 CRCW06031K00DHEBP CRCW06030000Z0EAHP RCS0603220KJNEA ERJ-H3EF3602V TNPW02017K50BEED CRCW06030000Z0EAHP
CRCW06030000Z0EAHP
S2761-46R S2761-46R CLT03-2Q3 STISO620TR IPS1025HQ-32
IPS1025HTR-32 STISO621 LDO40LPURY

UM3483 – Rev 1

page 23/31

UM3483
Board versions

Board versions

Table 3. X-NUCLEO-ISO1A1 versions

Finished good

Schematic diagrams

X$NUCLEO-ISO1A1A (1)

X$NUCLEO-ISO1A1A schematic diagrams

1. This code identifies the X-NUCLEO-ISO1A1 evaluation board first version.

Bill of materials X$NUCLEO-ISOA1A bill of materials

UM3483 – Rev 1

page 24/31

UM3483
Regulatory compliance information

Regulatory compliance information

Notice for US Federal Communication Commission (FCC)
For evaluation only; not FCC approved for resale FCC NOTICE – This kit is designed to allow: (1) Product developers to evaluate electronic components, circuitry, or software associated with the kit to determine whether to incorporate such items in a finished product and (2) Software developers to write software applications for use with the end product. This kit is not a finished product and when assembled may not be resold or otherwise marketed unless all required FCC equipment authorizations are first obtained. Operation is subject to the condition that this product not cause harmful interference to licensed radio stations and that this product accept harmful interference. Unless the assembled kit is designed to operate under part 15, part 18 or part 95 of this chapter, the operator of the kit must operate under the authority of an FCC license holder or must secure an experimental authorization under part 5 of this chapter 3.1.2.
Notice for Innovation, Science and Economic Development Canada (ISED)
For evaluation purposes only. This kit generates, uses, and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to Industry Canada (IC) rules. À des fins d’évaluation uniquement. Ce kit génère, utilise et peut émettre de l’énergie radiofréquence et n’a pas été testé pour sa conformité aux limites des appareils informatiques conformément aux règles d’Industrie Canada (IC).
Notice for the European Union
This device is in conformity with the essential requirements of the Directive 2014/30/EU (EMC) and of the Directive 2015/863/EU (RoHS).
Notice for the United Kingdom
This device is in compliance with the UK Electromagnetic Compatibility Regulations 2016 (UK S.I. 2016 No. 1091) and with the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Regulations 2012 (UK S.I. 2012 No. 3032).

UM3483 – Rev 1

page 25/31

Appendices
An example is described here for the easy use and handling of the board. Example – Digital input and Digital Output test case 1. Stack the X-NUCLEO Board onto the Nucleo board 2. Debug the code using a Micro- B Cable 3. Call this function in the main, “ST_ISO_APP_DIDOandUART” 4. Connect the 24V Power supply as shown in the image
Figure 23. Digital Input and Digital Output Implementation

UM3483

5. The input and the respective output follow the chart as mentioned in the chart below. Figure on the left corresponds to row 1 and figure on the right corresponds to row 4 of Table 4.

Case No.
1 2 3 4

D3 LED(IA.0) Input
0 V 24 V 0 V 24 V

Table 4. DIDO Logic Table

D4 LED(IA.1) Input
0 V 0 V 24 V 24 V

D6 LED(QA.0) Output
OFF ON OFF ON

D5 LED(QA.1) Output
OFF OFF ON ON

The demo serves as an easy start guide for quick hands-on experience. Users may also invoke additional functions for their specific needs.

UM3483 – Rev 1

page 26/31

Revision history
Date 05-May-2025

Table 5. Document revision history

Revision 1

Initial release.

Changes

UM3483

UM3483 – Rev 1

page 27/31

UM3483
Contents
Contents
1 Safety and compliance information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Compliance information (Reference) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Component diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 3 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3.1 Dual-channel digital isolator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2 High-side switches IPS1025H-32 and IPS1025HQ-32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.3 High-side current limiter CLT03-2Q3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Functional blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 4.1 Process side 5 V supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2 Isolator STISO621. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 Isolator STISO620 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.4 Current limited digital input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.5 High-side switch (with dynamic current control) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.6 Jumper setting options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.7 LED indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Board setup and configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 5.1 Get started with the board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.2 System setup requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.3 Safety precautions and protective equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5.4 Stacking of two X-NUCLEO board on Nucleo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6 How to set up the board (tasks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 7 Schematic diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 8 Bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 9 Board versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 10 Regulatory compliance information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 Appendices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 List of tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 List of figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

UM3483 – Rev 1

page 28/31

UM3483
List of tables

List of tables

Table 1. Table 2. Table 3. Table 4. Table 5.

Jumper selection chart for the default and alternate configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 X-NUCLEO-ISO1A1 bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 X-NUCLEO-ISO1A1 versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 DIDO Logic Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

UM3483 – Rev 1

page 29/31

UM3483
List of figures

List of figures

Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23.

X-NUCLEO-ISO1A1 expansion board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Different ST ICs and their position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 ST digital isolators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Input characteristics of CLT03-2Q3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Output operating region of CLT03-2Q3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Process side 5 V supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Isolator STISO621 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Isolator STISO620 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Current-limited digital input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 High-side switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Morpho connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 MCU interface routing options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 LED indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Different connecting ports of X-NUCLEO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Stack of two X-NUCLEO boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Jumper connection of X-NUCLEO-ISO1A1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 LED indication pattern during normal board operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 X-NUCLEO-ISO1A1 circuit schematic (1 of 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 X-NUCLEO-ISO1A1 circuit schematic (2 of 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 X-NUCLEO-ISO1A1 circuit schematic (3 of 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 X-NUCLEO-ISO1A1 circuit schematic (4 of 4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Digital Input and Digital Output Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

UM3483 – Rev 1

page 30/31

UM3483
IMPORTANT NOTICE READ CAREFULLY STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgment. Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or the design of purchasers’ products. No license, express or implied, to any intellectual property right is granted by ST herein. Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product. ST and the ST logo are trademarks of ST. For additional information about ST trademarks, refer to www.st.com/trademarks. All other product or service names are the property of their respective owners. Information in this document supersedes and replaces information previously supplied in any prior versions of this document.
© 2025 STMicroelectronics All rights reserved

UM3483 – Rev 1

page 31/31

Documents / Resources

ST STM32 Industrial Input Output Expansion Board [pdf] User Manual
UM3483, CLT03-2Q3, IPS1025H, STM32 Industrial Input Output Expansion Board, STM32, Industrial Input Output Expansion Board, Input Output Expansion Board, Output Expansion Board, Expansion Board

References

User Manual

STM32 Industrial Input Output Expansion Board User Manual

STM32 Industrial Input Output Expansion Board

Specifications:

Product Usage Instructions:

Dual-channel Digital Isolator (STISO620 and STISO621):

High-side Switches (IPS1025H-32 and IPS1025HQ-32):

High-side Current Limiter (CLT03-2Q3):

FAQ:

Q: What should I do if the side switches get heated?

Q: What do the LEDs on the board indicate?

Documents / Resources

References

Leave a comment

Cancel reply