ACSEVB-MC16
MC Package Generic Evaluation Board User Guide
DESCRIPTION
Generic evaluation boards offer a method for quickly evaluating Allegro current sensors in a lab environment without needing a custom circuit board. This document describes the use of the MC current sensor evaluation board. This evaluation board (ACSEVB-MC16, TED-0004115) is intended for use with any MC package (16-pin SOICW Allegro current sensor).
FEATURES
· Enhanced thermal performance:
6-layer PCB with 2 oz copper weight on all layers Nonconductive filled via-in-pad used High performance FR4 material with 180°C glass
transition temperature
· Flexible instrument connection:
Standard Keystone test points, SMA/SMB connector or 2-pin headers options are provided
· Sensor integrated current loop resistance can be measured directly on the evaluation board; voltage drop can be measured for approximating power loss in the package
EVALUATION BOARD CONTENTS
· Bare printed circuit board without populated components
NOTE: It is up to the user to assemble the board with the desired current sensor. This board does not come populated with an Allegro current sensor.
· Recommended bill of materials (BOM) for all compatible current sensors are listed in the Bill of Materials section.
Table of Contents
Description .......................................................................... 1 Features ............................................................................. 1 Evaluation Board Contents.................................................... 1 Using the Evaluation Board ................................................... 2 Performance Data ................................................................ 3 Schematic ........................................................................... 4 Layout ................................................................................ 5 Bill of Materials .................................................................... 6 Related Links and Application Support.................................... 7 Revision History................................................................... 8
0
Figure 1: MC Evaluation Board
Figure 2: SOIC-W Package (MC Package)
MC-Allegro-Current-Sensor-UM MCO-0001430
August 17, 2023
USING THE EVALUATION BOARD
Evaluation Board Components
1. U1 is an MC package footprint (Pin 1 is on bottom left side, see the small white dot)
2. U1 pins allow the option to connect: RPU: Pull-up resistor to VCC RPD: Pull-down resistor to GND C: decoupling or load capacitor to GND All passive components are 0603 package size
3. Keystone 5005 test points (e.g., Digikey #36-5005-ND)
4. Standard SMB/SMA connector (e.g., Digikey #1868-1429ND)
5. 2-pin 100 mil header connector option (note: either SMB or header can be assembled)
6. Primary current cables mounting positions (positive current flow direction is left to right)
7. 2-pin 100 mil header connector for voltage drop measurement across the integrated current loop of the current sensor
8. RB1, RB2, RB3, and RB4: rubber bumper mounting positions (e.g., Digikey #SJ61A6-ND)
Evaluation Board Procedure
CONNECTING TO THE EVALUATION BOARD
The best way to connect measurement instruments to the evaluation board is to use SMB/SMA or 2-pin headers connectors along with coaxial cables. This configuration will be most resilient to external coupling, and it is preferred way for measurement, e.g., high speed dI/dt transients.
Keystone test points are a convenient way to connect any instrument, but is it recommended for DC setups only.
4 3
6
2 7
6 1
Top view
5 8
Bottom view
Figure 3: MC Current Sensor Evaluation Board Reference Image
2
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
EVALUATION BOARD PERFORMANCE DATA
Thermal Rise vs. Primary Current
Self-heating due to the flow of current in the package IP conductor should be considered during the design of any current sensing system. The sensor, printed circuit board (PCB), and contacts to the PCB will generate heat and act as a heat sink as current moves through the system. The thermal response is highly dependent on PCB layout, copper thickness, cooling techniques, and the profile of the injected current. The current profile includes peak current value, current on-time, and duty cycle. Placing vias under the copper pads of the Allegro current sensor evaluation board minimize the current path resistance and improves heatsinking to the PCB, while vias outside of the pads limit the current path to the top of the PCB trace and have worse heatsinking under the part (see Figure 4 and Figure 5 below). The ACSEVB-MC16 does include vias in pad and is recommended to improve thermal performance.
Figure 4: Vias Under Copper Pads Example
The plot in Figure 6 shows the measured rise in steady-state die temperature of the MC package versus DC continuous current at an ambient temperature, TA, of 25 °C for two board designs: filled vias under copper pads and no vias under copper pads.
Note: Using in-pad vias has better thermal performance that no in-pad vias, and this is the design the ACSEVB-MC16 uses.
MC Package Comparison
140
Change in Die Temperature from Room Temperature [°C]
120
100
80
60
40
20
0
0
20
40
60
80
100
120
140
DC Continuous Current [A]
Via Outside Pad
Via In Pad
Figure 6: MC Package Comparison with and without In-Pad Vias
The thermal capacity of the MC package should be verified
by the end user in the application's specific conditions. The maximum junction temperature, TJ(max) (165), should not be exceeded. Measuring the temperature of the top of the package is
a close approximation of the die temperature.
Figure 5: No Vias Under Copper Pads Example
3
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
SCHEMATIC
0
1
2
3
V0
7
STSE
7
4ES STUV.
S:W S:0
3[126`20 SSSSSSSS::::::::WWWW0000
::::::::SSSSSSSEEEEEEESE0000000113[8220 0080000002113[2
::::::::SSSSSSSSEEEEEEEE800000000123[21
SS::W0
S:TZ 01
4ES
;5ÿ3?=aCA
6
Z55
Z55
Z55
Z55
6
LXF8 :8 :SE8
:SE8
LXY8 58 3;6
LXF01 :01 :SE01
:SE01
LXY01 501 3;6
LXF00 :00 :SE00
:SE00
LXY00 500 3;6
LXF01 :01 :SE01
:SE01
LXY01 501 3;6
5
Z55
Z55
Z55
Z55
5
LXF02 :02 :SE02
:SE02
LXY02 502 3;6
LXF03 :03 :SE03
:SE03
LXY03 503 3;6
LXF02 :02 :SE02
:SE02
LXY02 502 3;6
LXF0[ :0[ :SE0[
:SE0[
LXY0[ 50[ 3;6
4
>_ALAXTN575U5]4]/]T<0JBBC^I?G@=I?<=?G5CO5XI?YF=AN5NCONC5=FIICOA0NCON?I0@=N
4
b?^?0 HLF6G0X?O LHF6G1X?O LHF6G2X?O HLF6G3X?O
0
b?^?1 4STZUb.7\/TbU\U
1
.3:=?3X=C?ÿ\XEC04
.@ABC7$%&'()*+%,-
K43@@JBDCACC777.275/1465011E7111FF12GA3>0?H0IC72I7<3.L=.>/<@ÿ4GQ4?CI0=7R12N1A71@2J38O072022ÿ0:3;543>CCA0L?CPM@0N@?O70 899
ÿ
ÿ
ÿ
ÿÿ!"
#!"
2
3
Figure 7: MC Generic Evaluation Board Schematic
4
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
LAYOUT
TopLayer (Scale 2:1)
Int1 (Scale 2:1)
65mm
85mm
Figure 8: MC Generic Evaluation Board Top Layer (left) and Interior Layer 1
The MC current sensor evaluation board features test points that allow the current sensor integrated current loop resistance to be measured directly from the evaluation board. The voltage drop sensing is routed in the first internal layer (as to not reduce isolation spec of the package). As a consequence, the voltage drop will include the parasitic resistance of the vias between the top layer and the first interior layer.
Int2 (Scale 2:1)
Int3 (Scale 2:1)
Figure 9: MC Generic Evaluation Board Interior Layer 2 (left) and Interior Layer 3
Int4 (Scale 2:1)
BottomLayer (Scale 2:1)
Figure 10: MC Generic Evaluation Board Interior Layer 4 (left) and Bottom Layer
5
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
BILL OF MATERIALS
Components listed are based on the typical application circuit given in the respective device datasheet.
Table 1: Evaluation Board Bill of Materials
ACS37002 ASSEMBLY VARIANT (MC)
Pin
Terminal
Components
1, 2, 3, 4 5, 6, 7, 8
IP+ Terminals for current being sensed; fused internally
IP-
9
OCF
Overcurrent fault, open-drain, requires pull-up resistor
10
VCC
Device power supply terminal, connected to supply voltage
11
VREF
Zero current voltage reference
12
VOUT
Analog output representing the current flowing through IP, optional load capacitance or load resistance
13
VOC
Overcurrent fault operation point input, connected to resistor divider or external power source
14
GAIN_SEL_1
Gain selection bit 1, connected to high or GND
15
GND
Device ground terminal, connected to GND
16
GAIN_SEL_0
Gain selection bit 0, connected to high or GND
Table 2: Evaluation Board Bill of Materials
ACS724/25 ASSEMBLY VARIANT (MC)
Pin
Terminal
Components
1, 2, 3, 4 5, 6, 7, 8
IP+ Terminals for current being sensed; fused internally
IP-
9, 11, 14, 16
NC
No internal connection; recommended to be left unconnected in order to maintain high creepage
10
VCC
Device power supply terminal, connected to supply voltage
12
VOUT
Analog output representing the current flowing through IP, optional load capacitance or load resistance
13
FILTER
Terminal for external capacitor that sets bandwidth
15
GND
Device ground terminal, connected to GND
Table 3: Evaluation Board Bill of Materials
ACS37003 ASSEMBLY VARIANT (MC)
Pin
Terminal
Components
1, 2, 3, 4 5, 6, 7, 8
IP+ Terminals for current being sensed; fused internally
IP-
9, 10, 14, 15
OCF
Overcurrent fault, open-drain, requires pull-up resistor
11
VREF
Overcurrent fault operation point input, connected to resistor divider or external power source
12
VOUT
Analog output representing the current flowing through IP, optional load capacitance or load resistance
13
VREF
Zero current voltage reference
16
GND
Device ground terminal, connected to GND
6
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
RELATED LINKS AND APPLICATION SUPPORT
Table 4: Related Documentation and Application Support
Documentation
Summary
Location
Allegro Current Sensors Webpage
Product datasheet defining common electrical https://www.allegromicro.com/en/products/ characteristics and performance characteristics sense/current-sensor-ics
Allegro Current Sensor Package Documentation Schematic files, step files, package images
https://www.allegromicro.com/en/designsupport/packaging
An Effective Method for Characterizing System Bandwidth in Complex Current Sensor Applications
Application note describing methods used by Allegro to measure and quantify system bandwidth
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/an-effective-method-forcharacterizing-system-bandwidth-an296169
DC and Transient Current Capability/Fuse Characteristics of Surface Mount Current Sensor ICs
DC and Transient Current Capability/Fuse Characteristics of Surface Mount Current Sensor ICs
https://www.allegromicro.com/en/Insights-andInnovations/Technical-Documents/Hall-EffectSensor-IC-Publications/DC-and-TransientCurrent-Capability-Fuse-Characteristics.aspx
High-Current Measurement with Allegro Current Sensor IC and Ferromagnetic Core: Impact of Eddy Currents
Application note focusing on the effects of alternating current on current measurement
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/an296162_a1367_ current-sensor-eddy-current-core
Secrets of Measuring Currents Above 50 Amps
Application note regarding current measurement greater than 50 A
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/an296141-secrets-ofmeasuring-currents-above-50-amps
Allegro Hall-Effect Sensor ICs
Application note describing Hall-effect principles
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/allegro-hall-effect-sensorics
Hall-Effect Current Sensing in Electric and Hybrid Vehicles
Application note providing a greater understanding of hybrid electric vehicles and the contribution of Hall-effect sensing technology
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/hall-effect-currentsensing-in-electric-and-hybrid-vehicles
Hall-Effect Current Sensing in Hybrid Electric Vehicle (HEV) Applications
Application note providing a greater understanding of hybrid electric vehicles and the contribution of Hall-effect sensing technology
https://allegromicro.com/en/insightsand-innovations/technical-documents/ hall-effect-sensor-ic-publications/hall-effectcurrent-sensing-in-hybrid-electric-vehicle-hevapplications
Achieving Closed-Loop Accuracy in Open-Loop Current Sensors
Application note regarding current sensor IC solutions that achieve near closed-loop accuracy using open-loop topology
https://allegromicro.com/en/insights-andinnovations/technical-documents/hall-effectsensor-ic-publications/achieving-closed-loopaccuracy-in-open-loop-current-sensors
Allegro Current Sensor ICs Can Take the Heat! Unique Packaging Options for Every Thermal Budget
Application note regarding current sensors and https://www.allegromicro.com/-/media/files/ package selection based on thermal capabilities application-notes/an296190-current-sensor-
thermals.pdf
Explanation Of Error Specifications For Allegro Linear Hall-Effect-Based Current Sensor ICs And Techniques For Calculating Total System Error
Application note describing error sources and their effect on the current sensor output
https://www.allegromicro.com/-/media/files/ application-notes/an296181-acs72981-errorcalculation.pdf
7
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
Revision History
Number
Date
August 17, 2023
Initial release
Description
Copyright 2023, Allegro MicroSystems. Allegro MicroSystems reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro's products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro's product can reasonably be expected to cause bodily harm. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Copies of this document are considered uncontrolled documents.
8
Allegro MicroSystems 955 Perimeter Road Manchester, NH 03103-3353 U.S.A. www.allegromicro.com
Open-Close-Loop-Accuracy-ACS720
Packaging | Allegro MicroSystems