User Guide for ANALOG DEVICES models including: DC3158A, Evaluation Board, DC3158A Evaluation Board
LT3041 Datasheet and Product Info | Analog Devices
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DocumentDocumentUser Guide | DC3158A
UG-2059
Evaluating the LT3041 20 V, 1 A, Ultra-Low Noise, Ultra-High PSRR Linear Regulator with VIOC Control
FEATURES
Input voltage range: 3.8 V to 20 V Resistor-programmed 3.32 V output voltage Maximum output current: 1 A BNC connectors for noise and PSRR measurement Resistor programmed power-good Resistor-programmable current limit, current monitoring, and UV-
LO VIOC to manage power dissipation and PSRR Thermally enhanced, 14-lead, 3 mm × 4 mm, DFN package
EVALUATION KIT CONTENTS
DC3158A evaluation board
EQUIPMENT NEEDED
A DC power supply Multimeters for voltage and current measurements Electronic or resistive loads
DOCUMENTS NEEDED
LT3041 data sheet
EVALUATION BOARD PHOTOGRAPH
Figure 1. DC3158A Evaluation Board Photograph
GENERAL DESCRIPTION The DC3158A evaluation board features the LT3041, a 20 V, 1 A, ultra-low noise and ultra-high power-supply rejection ratio (PSRR), low-dropout (LDO) linear regulator that incorporates voltage input-to-output control (VIOC) tracking. VIOC allows control of the upstream switching converter to maintain a constant voltage across the LT3041 and, therefore, minimizes power dissipation and maintains PSRR. The DC3158A operates over an input voltage range of 3.8 V to 20 V. The LT3041 delivers a maximum output current of 1 A. In addition to featuring ultra-low noise and ultra-high PSRR, the regulator offers programmable power-good functionality and a programmable current limit. Current monitoring is also achieved by sensing the ILIM pin voltage. Built-in protection includes reverse-battery protection, reverse-current protection, internal current limit with foldback and thermal limit with hysteresis. For full details on the LT3041, see the LT3041 data sheet, which must be consulted with this user guide when using the DC3158A evaluation board. The LT3041 of the DC3158A features a 14-lead, 3 mm × 4 mm, plastic DFN package with an exposed pad on the bottom side of the IC. Proper board layout is essential for maximum thermal performance. Design files are available on the DC3158A evaluation board page.
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS.
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User Guide
TABLE OF CONTENTS
Features................................................................ 1 Evaluation Kit Contents......................................... 1 Equipment Needed................................................1 Documents Needed...............................................1 Evaluation Board Photograph................................1 General Description...............................................1 Performance Summary..........................................3 Quick Start Procedure........................................... 4 Printed Circuit Board (PCB) Layout.......................5
REVISION HISTORY
10/2022--Revision 0: Initial Version
DC3158A
Best PSRR Performance: PCB Layout for Input Traces......................................................5
Best AC Performance: PCB Layout for Output Capacitor C2.........................................6
Evaluation Board Schematic................................. 7 Ordering Information..............................................8
Bill of Materials................................................... 8 Notes.................................................................. 9
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DC3158A
PERFORMANCE SUMMARY
Specifications are at TA = 25°C, unless otherwise noted.
Table 1. Performance Summary
Parameter
Symbol
Test Conditions/Comments
Min
Typ
Max
Unit
INPUT VOLTAGE RANGE
OUTPUT VOLTAGE SHUTDOWN INPUT CURRENT
VIN
Output current (IOUT) = 150 mA, VOUT = 3.3 V 3.8
IOUT = 1 A, VOUT = 3.3 V
3.8
20
V
5.81
V
VOUT
VIN = 5 V, IOUT = 1 A, R3 = 33.2 k
3.25
3.32
3.39
V
IIN
JP1 = off, R4 = open, VIN = 6 V
18
A
1 The maximum power dissipation and, consequently, the maximum input voltage for a 1 A load current is set by the 60°C temperature rise of the LT3041 on the evaluation board. Higher input voltages can be reached if larger copper area or forced-air cooling is applied. In addition, consider the effect of ambient temperature and the maximum junction temperature that may occur. The LT3041 limits output current at higher input-to-output voltage differentials. See the LT3041 data sheet for more information.
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QUICK START PROCEDURE
The DC3158A evaluation board is simple to set up to evaluate the performance of the LT3041. Refer to Figure 2 for the proper measurement equipment setup and take the following steps:
1. Connect a load between the VOUT and GND terminals. 2. With power off, connect the input power supply to the VIN and
GND terminals. 3. Ensure that the shunt of JP1 is in the ON position. 4. With the load turned down, turn the input power supply on, and
ensure that the voltage is between 3.8 V and 20 V. 5. Vary VIN from 3.8 V to 20 V and vary the load current from 0 A
to 1 A. Note the following when setting VIN and the load current: An input voltage that is too close to the programmed output
voltage (too low) may cause dropout operation and a loss of output-voltage regulation. The amount of output current combined with an input voltage that is too high above the output may increase power dissipation to an unacceptable level.
DC3158A
The LT3041 limits output current at higher input-to-output voltage differentials (refer to the LT3041 data sheet for more information).
6. Refer to Application Note 83 and Application Note AN159 for measuring the output noise and PSRR. Note that, J1 and J2 are Bayonet NeillConcelman (BNC) connectors that are used for noise and PSRR measurements.
7. With JP1 in the ON position, R1 and R2 can be used to set an accurate undervoltage lockout (UVLO) threshold.
8. Change to a suitable ILIM resistor (R7) to program a current limit and provide output current monitoring at the resistor or pin.
9. Refer to the data sheet for the usage of the VIOC terminal. 10. In addition, change the PGFB divider resistors (R5 and R6) if
the SET resistor (R3) is changed. Monitor power good at the PG terminal.
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Figure 2. Proper Measurement Equipment Setup for DC3158A
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PRINTED CIRCUIT BOARD (PCB) LAYOUT
BEST PSRR PERFORMANCE: PCB LAYOUT FOR INPUT TRACES
For applications using the LT3041 for post-regulating switching converters, placing a capacitor directly at the LT3041 input results in AC current (at the switching frequency) flowing near the LT3041. Without careful attention to PCB layout, this relatively high-frequency switching current generates an electromagnetic field (EMF) that couples to the LT3041 output, degrading its effective PSRR. Highly dependent on the PCB, the switching preregulator, and the input capacitor size, among other factors, the PSRR degradation can easily be 30 dB at 1 MHz. This degradation is present even if the LT3041 is desoldered from the board because it effectively degrades the PSRR of the PCB itself. While negligible for conventional low PSRR LDO regulators, the ultra-high PSRR of the LT3041 requires careful attention to higher-order parasitics to realize the full performance offered by the regulator.
The LT3041 evaluation board alleviates this degradation in PSRR by using a specialized layout technique. The VIN input trace and its corresponding return path (GND) are highlighted in red in Figure 3 and Figure 4. Figure 4 also shows the location of the C1 input capacitor. Normally, when AC voltages are applied to the inputs of the board, AC current flows on the input and return paths, thus generating an electromagnetic field (EMF). This EMF couples to the C2 and C3 output capacitors and the related traces, making the PSRR appear worse than it actually is. With the input trace directly above the return path, the EMFs are in opposite directions, and consequently, cancel each other out. Making sure that these traces exactly overlap each other maximizes the cancellation effect and thus provides the maximum PSRR offered by the regulator.
DC3158A
Figure 4. Layer 4 of DC3158A
Figure 3. Layer 3 of DC3158A analog.com
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PRINTED CIRCUIT BOARD (PCB) LAYOUT BEST AC PERFORMANCE: PCB LAYOUT FOR OUTPUT CAPACITOR C2 For ultra-high PSRR performance, the LT3041 bandwidth is quite high (~750 kHz), making it close to the self-resonance frequency (~1.6 MHz) of the output capacitor. Therefore, it is important to avoid adding extra impedance (effective-series inductance (ESL) and effective-series resistance (ESR)) outside the feedback loop. To achieve this avoidance, minimize the effects of the PCB trace and solder inductance by Kelvin connecting the output sense pin (OUTS) and the SET pin capacitor (CSET) GND directly to the terminals of the output capacitor (C2) using a split capacitor technique, as shown in Figure 5 and Figure 6. With only small AC current flowing through these connections, the impact of the solder joint and/or PCB trace inductance on stability is eliminated. While the LT3041 is robust enough not to oscillate if the recommended layout is not followed, phase and gain margin and stability degrade.
Figure 5. C2 and CSET Connections for Best Performance
Figure 6. Split Pads for C2 on the Top Layer of DC3158A
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DC3158A
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EVALUATION BOARD SCHEMATIC
DC3158A
Figure 7. Evaluation Board Schematic
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ORDERING INFORMATION
BILL OF MATERIALS
Table 2. Bill of Materials
Item
Required Circuit Components 1 2 3 4 5
Quantity
1 2 1 1 1
Optional Evaluation Board Components
1
1
2
0
3
1
4
1
5
1
6
1
7
1
8
0
Hardware
1
7
2
2
3
1
4
1
5
4
DC3158A
Reference Designator
C1 C2, C3 C4 R3 U1
CIN
C5, C6 R7 R5 R6 R2 R4 R1
E1 to E7 J1, J2
JP1
XJP1
MP1 to MP4
Part Description
Manufacturer, Part Number
10 µF capacitor, X7R, 25 V, 10%, 1206 10 µF capacitors, X7S, 25 V, 10%, 1206 4.7 µF capacitor, X7R, 25 V, 10%, 1206 33.2 k resistor, 1%, 1/10 W, 0603 20 V, 1 A, ultra-low noise, ultra-high PSRR, linear regulator with VIOC control
KEMET, C1206C106K3RACAUTO Murata, GCM31CC71E106KA03L Murata, GCJ31CR71E475KA12L Vishay, CRCW060333K2FKEA Analog Devices, Inc., LT3041ADE#PBFES
22 µF capacitor, 35 V, 20%, 5 mm × 5.4 mm Capacitors, 1206, optional 0 , 1/10 W, 0603, AEC-Q200 453 k resistor, 1%, 1/10 W, 0603 49.9 k resistor, 1%,1/10 W, 0603 100 k resistor, 1%, 1/10 W, 0603 200 k resistor, 5%, 1/10 W, 0603 Resistor, 0603, optional
Sun Electronic Industries, 35CE22BSS
Vishay, CRCW06030000Z0EA Vishay, CRCW0603453KFKEA Vishay, CRCW060349K9FKEA Vishay, CRCW0603100KFKEA Vishay, CRCW0603200KJNEA
Test points, turret, 0.094" PBF
Connector, RF, BNC, receptacle, jack, 5-pin, straight, through-hole, 50
Connector, header, male, 2 × 3, 2 mm, vertical, straight, through-hole
Connector, shunt, female, 2 position, 2 mm
Standoff, nylon, snap-on, 6.4 mm
Mill-Max, 2501-2-00-80-00-00-07-0 Amphenol RF, 112404 Wurth Elektronik, 62000621121 Wurth Elektronik, 60800213421 Wurth Elektronik, 702931000
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ORDERING INFORMATION NOTES
DC3158A
ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of
functionality.
Legal Terms and Conditions By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the "Evaluation Board"), you are agreeing to be bound by the terms and conditions set forth below ("Agreement") unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you ("Customer") and Analog Devices, Inc. ("ADI"), with its principal place of business at Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal, temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term "Third Party" includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board. Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED "AS IS" AND ADI MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER'S POSSESSION OR USE OF THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI'S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby submits to the personal jurisdiction and venue of such courts. The United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement and is expressly disclaimed.
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Mixed-signal and digital signal processing ICs | Analog Devices
DC3158A Evaluation Board | Analog Devices