ANALOG DEVICES EVAL-LT7171-AZ Silent Switcher Step-Down Regulator User Guide

ANALOG DEVICES EVAL-LT7171-AZ Silent Switcher Step-Down Regulator

Specifications

• Product Name: EVAL-LT7171-AZ
• Model: LT7171
• Output Voltage: 1.0V
• Switching Frequency: 1MHz
• Maximum Continuous Output Current: 40A

Product Usage Instructions

1. Set up the input power supply capable of 16V/10A.
2. Turn off the power supply.
3. Connect the supply to the input terminals VEMI and GND with default jumper position SW1: ON.

Measurement Equipment Setup

When measuring input or output voltage ripple, avoid a long ground lead on the oscilloscope probe.

1. Turn on the input power supply (ensure voltage does not exceed 16V).
2. For efficiency measurements, use ammeters in series with the output load and power supply.
3. Use voltmeters across output sense turrets for accurate output voltage measurements.
4. Use voltmeters across input sense turrets for accurate input voltage measurements.
5. For best efficiency accuracy, populate R58 and R59 only. For best output voltage accuracy, populate R27 and R28 only.
6. Adjust the load and/or input within the operating range to observe output voltage regulation, ripple voltage, efficiency, and other parameters.

FAQ

Q: What is the default output voltage of EVAL-LT7171-AZ?

A: The default output voltage is 1.0V.

Q: What is the maximum continuous output current supported by EVAL-LT7171-AZ?

A: The maximum continuous output current is 40A.

Q: Where can I download the GUI software for EVAL-LT7171-AZ?

A: The software can be downloaded from LTpowerPlay.

Q: How many LT7171 IC parallel operations can be evaluated on EVAL-LT7171-AZ?

A: EVAL-LT7171-AZ reserves two locations for evaluations, up to a total of four LT7171 IC parallel operations.

General Description

• Evaluation kit EVAL-LT7171-AZ has two single-phase monolithic DC/DC synchronous step-down regulators with a 2.9V to 16V input range featuring LT®7171. The output can supply up to 40A continuous load current. The Silent Switcher® structure is incorporated into the LT7171 to minimize EMI and reduce PCB layout sensitivity. It also integrates digital power system management functionality, allowing for programmability and telemetry with a PMBus/I2C compliant serial interface. Refer to the LT7171 data sheet for more detailed information.
• The EVAL-LT7171-AZ evaluation board is designed for 1.0V output with a switching frequency set at 1MHz. The controlled on-time valley current-mode control with 25ns typical minimum on-time enables a high switching frequency at a low output voltage with excellent transient response in a small overall solution size.
• The EVAL-LT7171-AZ powers up to default settings and produces power based on the NVM configuration without the need for any serial bus communication. This allows easy evaluation of the DC/DC converter. To fully explore the power system management features of the part, download the GUI software LTpowerPlay® onto the PC and use ADI’s I2C/SMBus/PMBus dongle DC1613A to connect to the board. LTpowerPlay allows the user to reconfigure the part on the fly, and store the configuration in NVM, view telemetry of voltage, current, temperature, and fault status. The NVM can be programmed up to three times.
• The EVAL-LT7171-AZ reserves two locations for evaluations, up to a total of four LT7171 IC parallel operations. For a detailed parallel configuration, refer to the LT7171 data sheet.

GUI Download

• The software can be downloaded from LTpowerPlay.
• The LT7171 data sheet gives a complete description of the part, operation, and application information. The data sheet must be read in conjunction with this demo manual for EVAL-LT7171-AZ.
• For more details and instructions of the LTpowerPlay, refer to LTpowerPlay GUI for the LT7171 Quick Start Guide.

Performance Summary Specifications are at TA = 25°C

PARAMETER| SYMBOL| CONDITIONS| MIN                   TYP MAX..| UNITS
---|---|---|---|---
Input Voltage Range| VIN| | 2.9 16| V
Default Output Voltage| VOUT| | 1.0| V
Maximum Continuous Output Current| IOUT| Two Phases| 40| A
Switching Frequency| fSW| | 0.925                    1 1.075| MHz
Efficiency| Eff| VIN = 12V, IOUT = 20A| 87.5| %

Setup and Operation
The EVAL-LT7171-AZ is easy to set up to evaluate the performance of the LT7171. See Figure 1 for proper measurement equipment setup, and follow the procedure below:
NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. See Figure 2 for the proper scope technique.

1. Set an input power supply that is capable of 16V/10A. Then turn off the supply.

2. With power off, connect the supply to the input terminals VEMI and GND. Set the default jumper position: SW1: ON.

3. Turn on the power at the input.
   NOTE: Make sure that the input voltage never exceeds 16V.

4. Check for the proper output voltages of 1.0V ±0.25% (0.997V~1.003V). Turn off the power at the input.

5. Connect variable loads capable of sinking 40A at 1.0V to the output terminals VOUT and GND. Set the current to 0A.

   • If efficiency measurements are desired, ammeters can be put in series with the output load to measure the EVAL-LT7171-AZ’s output current and in series with the power supply to measure the input current.
   • Voltmeters can be placed across the output sense turrets (VSENSE+, VSENSE-) to get accurate output voltage measurements.
   • Voltmeters can be placed across the input sense turrets (VIN_SENSE, GND) to get accurate input voltage measurements.
   • To achieve the best efficiency measurement accuracy, populate R58 and R59 only. To achieve the best output voltage accuracy at the output terminal, populate R27 and R28 only.

6. Turn on the power at the input.
   NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high.

7. Once the proper output voltages are established again, adjust the load and/or input within the operating range and observe the output voltage regulation, ripple voltage, efficiency, and other desired parameters.

8. Connect the dongle and control the output voltages from the GUI. See the LTpowerPlay GUI for the LT7171 Quick Start Guide for details.

NOTE: When measuring the output or input voltage ripple, do not use the long ground lead on the oscilloscope probe. J6 can be used for measuring output voltage ripple. If using a probe is desired, see Figure 2 for the proper scope probe technique. Short, stiff leads need to be soldered to the (+) and (-) terminals of an output capacitor. The probe’s ground ring needs to touch the (-) lead, and the probe tip needs to touch the (+) lead.
NOTE: When evaluating a single IC, customers may remove the 0-ohm resistor connected to RUN and refer to the datasheet to adjust configuration resistors or registers if needed.
Connecting a PC to EVAL-LT7171-AZ
Use a PC to reconfigure the power management features of the LT7171, such as VOUT, current limit, switching frequency, OV/UV limits, temperature fault limits, sequencing parameters, the fault log, fault responses, and other functionalities. The DC1613A dongle may be plugged in when a VIN is present. Figure 3 shows a demo setup of connecting a PC to EVAL-LT7171-AZ.

Evaluation Board User Guide

EVAL-LT7171-AZ

Typical Performance Characteristics

LTpowerPlay Software GUI
LTpowerPlay is a powerful, Windows®-based development environment supporting Analog Devices’ Digital Power System Management (DPSM) ICs and μModules. The software supports a variety of different tasks. Use LTpowerPlay to evaluate Analog Devices’ ICs by connecting to an evaluation board system. LTpowerPlay can also be used in offline mode (with no hardware present) to build a multichip configuration file that can be saved and reloaded at a later time. LTpowerPlay provides unprecedented diagnostic and debug features. It becomes a valuable diagnostic tool during board bring-up to the program or to tweak the power management scheme in a system or to diagnose power issues when bringing up rails. LTpowerPlay utilizes the DC1613A USB-to-SMBus controller to communicate with one of many potential demo systems or a customer board. The software also provides an automatic update feature to keep the software current with the latest set of device drivers and documentation. The LTpowerPlay software can be downloaded from LTpowerPlay | Analog Devices.
To access technical support documents for Analog Devices’ Digital Power Products, visit the LTpowerPlay Help menu. Online help is also available through LTpowerPlay

LTpowerPlay Quick Start Procedure
The following procedure describes how to use LTpowerPlay to monitor and change the settings of LT7171.

1. Download and install the LTPowerPlay GUI: LTpowerPlay | Analog Devices.
2. Launch the LTpowerPlay GUI.
3. The GUI should automatically identify the EVAL-LT7171-AZ. The system tree on the left-hand side should look like the image below.
4. A green message box shows for a few seconds in the lower left-hand corner, confirming that LT7171 is communicating.
5. In the toolbar, click the R (RAM to PC) icon to read the RAM from the LT7171. This reads the configuration from the RAM of the LT7171 and loads it into the GUI.
6. To change the output voltage to a different value, like 1.5V, in the Config tab, type in 1.5 in the VOUT_COMMAND box under the Voltage tab, as shown below.
7. Select U1 in the left window and repeat Step 6 for changes such as VOUT_COMMAND, VOUT_MAX, VOUT_RANGE, etc.
8. Then, click the W (PC to RAM) icon to write the register values to the LT7171. After finishing this step, the output voltage changes to 1.5V.
9. If the write is successful, the following message will appear.
10. To save the changes to NVM in the toolbar, click the RAM to NVM button.
11. Save the evaluation board configuration to a (*.proj) file. Click the Save icon and save the file with a new name.

Bill of Materials

ITEM| QTY| REFERENCE| PART DESCRIPTION| MANUFACTURER/PART NUMBER
---|---|---|---|---
REQUIRED CIRCUIT COMPONNENTS
1| 4| C1, C3, C59, C63| CAP.,10µF, X6S, 10V, 10%, 0603| MURATA, ZRB18AC81A106KE01L

2

| ****

8

| C2, C5, C6, C40, C54, C60, C64, C65| ****

CAP., 0.1µF, X6S, 25V, 10%, 0201

| ****

Taiyo Yuden, TMK063C6104KP-F

3| 4| C7, C42, C61, C62| CAP., 1µF, X7S, 10V, 10%, 0402| MURATA, GCM155C71A105KE38D
4| 2| C11, C66| CAP., 4.7µF, X6S, 25V, 10%, 0603| MURATA, GRM188C81E475KE11D
5| 1| C8| CAP., 1µF, X7R, 25V, 10%, 0603| KEMET, C0603C105K3RACTU
6| 4| C17, C80, C81, C82| CAP., 100µF, X6S, 4V, 10%, 0805| MURATA, GRM31CR60J107KE39L

7

| ****

2

| ****

C19, C28

| CAP., 4.7pF, C0G/NP0, 50V, ±0.25pF, 0603| ****

MURATA, GRM1885C1H4R7CA01D

8| 4| C15, C43, C55, C56| CAP., 10µF, X7S, 4V, 20%, 0603| TDK, C1608X7S0G106M080AB
9| 4| C36, C44, C57, C58| CAP., 100µF, X6S, 4V, 20%, 0805| MURATA, GRM21BC80G107ME15L

10

| ****

2

| ****

C74, C75

| CAP., 470µF, ALUM. POLY., 2.5V, 20%, 3-TERM. 7343| ****

PANASONIC, EEFGX0E471L

11| 1| C47| CAP., 2200pF, C0G, 50V, 5%, 0603| MURATA, GCM1885C1H222JA16D

12

| ****

8

| C97, C105, C106, C107, C109, C110, C111, C112| ****

CAP., 10µF, X7S, 25V, 10%, 0805

| ****

MURATA, GRM21BC71E106KE11L

13| 2| L1, L2| IND., 0.22µH, 28.5A, 1.3mΩ| COILCRAFT, XGL6060‐221MEC
14| 1| R1| RES., 6.81kΩ, 1%, 1/10W,0603| PANASONIC, ERJ3EKF6811V
15| 3| R2, R9, R52| RES.,10kΩ,1%,1/10W,0603| PANASONIC, ERJ3EKF1002V

16

| ****

6

| R4, R7, R11, R37, R58, R59| ****

RES.,0Ω,1/10W,0603

| ****

VISHAY, CRCW06030000Z0EA

17| 2| R5, R8| RES.,4.7kΩ,1%,1/10W,0603| VISHAY, CRCW06034K70FKEA
18| 1| R14| RES.,1MΩ,1%,1/10W,0603| PANASONIC, ERJ3EKF1004V
19| 2| R19, R39| RES., 36.5kΩ, 1%, 1/10W, 0603| VISHAY, CRCW060336K5FKEA
20| 1| R20| RES., 6.65kΩ, 1%, 1/10W, 0603| VISHAY, CRCW06036K65FKEA
21| 1| R38| RES., 43.2kΩ, 1%, 1/10W, 0603| VISHAY, CRCW060343K2FKEA
22| 1| R40| RES., 11.8kΩ, 1%, 1/10W, 0603| VISHAY, CRCW060311K8FKEA
23| 1| R53| RES., 3.3KΩ, 5%, 1/10W, 0603| PANASONIC, ERJ3GEYJ332V
24| 2| U1, U2| IC, 20A, 16V REGULATOR, LQFN-30| ANALOG DEVICES, LT7171RV#TRPBF
ADDITIONAL EVALUATION BOARD CIRCUIT COMPONENTS
1| 1| C9| CAP., 4.7µF, X7S, 16V, 10%, 0603| MURATA, GRM188C71C475KE21D
2| 1| C108| CAP., 10µF, X7S, 25V, 10%, 0805| MURATA, GRM21BC71E106KE11L
3| 3| C18, C20, C21| CAP., 4.7µF, X5R, 25V, 10%, 0603| MURATA, GRM188R61E475KE15D
4| 1| C31| CAP., 0.1µF, X7R, 10V, 20%, 0603| AVX, 0603ZC104MAT2A
5| 3| C32, C34, C35| CAP., 1µF, X7R, 6.3V, 10%, 0402| MURATA, GRM155R70J105KA12D
---|---|---|---|---
6| 1| C38| CAP., 1µF, X7R, 50V, 10%, 0603| AVX, 06035C105KAT2A
7| 1| C39| CAP., 0.01µF, X7R, 25V, 10%, 0603| AVX, 06033C103K4Z2A

8

| ****

1

| ****

C68

| CAP., 270µF, ALUM POLY HYB, 25V, 20%, 8×10.2mm| ****

PANASONIC, EEH-ZK1E271P

9| 1| C98| CAP., 1µF, X5R, 50V, 10%, 0603| TDK, CGA3E3X5R1H105K080AB
10| 1| D4| LED, GREEN, DIFFUSED, 0603| BROADCOM INC., HSMG-C190
11| 1| D6, D7| LED, RED, DIFFUSED, 0603| BROADCOM INC., HSMH-H190
12| 3| R3, R12, R26| RES., 866Ω, 1%, 1/10W, 0603| PANASONIC, ERJ3EKF8660V
13| 2| R6, R13| RES., 4.99kΩ, 1%, 1/10W, 0603| PANASONIC, ERJ3EKF4991V
14| 1| R10| RES., 49.9Ω, 1%, 1/10W, 0603| PANASONIC, ERJ3EKF49R9V
15| 1| R49| RES., 10mΩ, 1%, 3W, 6.3 X3.1mm| SUSUMU, KRL6432E-C-R010-F-T1
16| 1| Q1| MOSFET, N-CH, 25V, 70A, Power-SO8| NEXPERIA, PSMN5R4-25YLDX
17| 1| Q2| MOSFET, N-CH, 60V, 300mA, SOT-23-3| VISHAY, 2N7002K-T1-GE3
18| 1| U5| IC, EEPROM, 2Kb (256×8), TSSOP-8| MICROCHIP, 24LC025-I/ST
19| 1| U6| IC, 2.6A, 2.5V-5.5V IDEAL DIO, 10DFN| ANALOG DEVICES, LTC4413EDD#PBF

20

| ****

1

| ****

U7

| ****

IC, 200mA LDO, MSOP-8

| ANALOG DEVICES, LT3063EMS8E- 3.3#PBF
HARDWARE: FOR EVALUATION BOARD ONLY

1

| ****

6

| E1, E2, E3, E4, E18, E19| ****

TEST POINT, TURRET, 0.064″

| ****

MILL-MAX, 2308-2-00-80-00-00-07-0

2

| ****

10

| E5, E6, E7, E9, E10, E11, E12, E13, E14, E15| ****

TEST POINT, TURRET, 0.094″

| ****

MILL-MAX, 2501-2-00-80-00-00-07-0

3| 2| J1, J2| BANANA JACK, FEMALE| KEYSTONE, 575-4
4| 2| J3, J4| STUD, FASTENER, #10-32| PENNENGINEERING, KFH-032-10ET
5| 2| J5, J6| CONN., RF, BNC, RCPT| AMPHENOL RF, 112404
6| 1| J7| CONN., HDR, MALE, 2×6, 2mm| AMPHENOL, 98414-G06-12ULF
7| 1| JP1| CONN., HDR, MALE, 1×3, 2mm| WURTH ELEKTRONIK, 62000311121
8| 4| MP1, MP2, MP3, MP4| STANDOFF, NYLON, SNAP-ON, 0.625″| KEYSTONE, 8834

9

| ****

1

| ****

SW1

| SWITCH, SLIDE, DPDT, 0.3A, 6VDC, PTH| ****

C&K, JS202011CQN

10| 1| XJP1| CONN., SHUNT, FEMALE, 2-POS, 2mm| WURTH ELEKTRONIK, 60800213421

Schematic Diagram

NOTE: UNLESS OTHERWISE SPECIFIED.

1. ALL RESISTORS 0603.
2. ALL CAPACITORS 0603.

80A IF ALL FOUR PHASES POPULATED ON BOARD.

Revision History

ASSUMED BY ANALOG DEVICES FOR ITS USE, NOR FOR ANY INFRINGEMENTS OF PATENTS OR OTHER RIGHTS OF THIRD PARTIES THAT MAY RESULT FROM ITS USE. SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE. NO LICENCE, EITHER EXPRESSED OR IMPLIED, IS GRANTED UNDER ANY ADI PATENT RIGHT, COPYRIGHT, MASK WORK RIGHT, OR ANY OTHER ADI INTELLECTUAL PROPERTY RIGHT RELATING TO ANY COMBINATION, MACHINE, OR PROCESS WHICH ADI PRODUCTS ALL INFORMATION CONTAINED HEREIN IS PROVIDED “AS IS” WITHOUT REPRESENTATION OR WARRANTY. NO RESPONSIBILITY IS OR SERVICES ARE USED. TRADEMARKS AND REGISTERED TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS. analog.com.

References

• Mixed-signal and digital signal processing ICs | Analog Devices
• Document Feedback Form | Analog Devices
• Mixed-signal and digital signal processing ICs | Analog Devices

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