ANALOG DEVICES EVAL-LT7170-AZ Silent Switcher Step-Down Regulator User Guide
- June 1, 2024
- Analog Devices
Table of Contents
ANALOG DEVICES EVAL-LT7170-AZ Silent Switcher Step-Down Regulator
General Description
Evaluation kit EVAL-LT7170-AZ is a single-phase monolithic DC/DC synchronous step-down regulator with a 2.9V or 1.5V with EXTVCC to 16V input range featuring LT®7170. The output can supply up to 20A continuous load current. The Silent Switcher® regulator structure is incorporated into the LT7170 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 LT7170 data sheet for more detailed information. The EVAL-LT7170-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-LT7170-AZ has EMI filters installed for improved conducted and radiated EMI performances, which are shown in Figure 5. The red lines in Figure 5 are the CISPR32 limit for industrial application requirement. The figure shows that the circuit passes the test with a wide margin.
The EVAL-LT7170-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.
GUI Download
The software can be downloaded from LTpowerPlay. The LT7170 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-
LT7170-AZ. For more details and instructions of the LTpowerPlay, refer to
LTpowerPlay GUI for the LT7170 Quick Start Guide.
Performance Summary
- Specifications are at TA = 25°C
PARAMETER| SYMBOL| CONDITIONS| MIN TYP
MAX| UNITS
---|---|---|---|---
Input Voltage Range
| ****
VIN
| EXTVCC = 0V| 2.9 16| ****
V
3V ≤ EXTVCC ≤ 5.5V| 1.5 16
Default Output Voltage| VOUT| | 1.0| V
Maximum Continuous Output Current| IOUT| | 20| A
Switching Frequency| fSW| | 0.925 1
1.075| MHz
Efficiency| Eff| VIN = 12V, IOUT = 10A| 87.1| %
Quick Start Procedure
The EVAL-LT7170-AZ is easy to set up to evaluate the performance of the
LT7170. 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.
-
Set an input power supply that is capable of 16V/10A. Then turn off the supply.
-
With power off, connect the supply to the input terminals VEMI and GND. Set the default jumper position: SW1: ON.
-
Turn on the power at the input.
NOTE: Make sure that the input voltage never exceeds 16V. -
Check for the proper output voltages of 1.0V ±0.25% (0.997V~1.003V). Turn off the power at the input.
-
Once the proper output voltage is established, connect variable loads capable of sinking 20A 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-LT7170-AZ’s output current and in series with the power supply to measure the input current.
- Voltmeters can be placed across the output terminals (VSENSE+, VSENSE-) to get accurate output voltage measurements.
- Voltmeters can be placed across the input terminals (VIN_SENSE, GND) to get accurate input voltage measurements.
- To achieve the best efficiency and accuracy, remove R11/R16 and populate R21/R22 only on the bottom layer of the board.
-
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. -
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.
-
Connect the dongle and control the output voltages from the GUI. See the LTpowerPlay GUI for the LT7170 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. 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.
Connecting a PC to EVAL-LT7170-AZ
Use a PC to reconfigure the power management features of the LT7170, such as
VOUT, current limit, switching frequency, OV/UV limits, control loop
compensation, 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-LT7170-AZ.
EVAL-LT7170-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 μModule®
regulators. 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
program or 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 LT7170.
- Download and install the LTPowerPlay GUI: LTpowerPlay | Analog Devices.
- Launch the LTpowerPlay GUI.
- The GUI should automatically identify the EVAL-LT7170-AZ. The system tree on the left-hand side should look like the image below:
- A green message box shows for a few seconds in the lower left-hand corner, confirming that LT7170 is communicating:
- In the toolbar, click the R (RAM to PC) icon to read the RAM from the LT7170. This reads the configuration from the RAM of the LT7170 and loads it into the GUI.
- 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:
- Then, click the W (PC to RAM) icon to write the register values to the LT7170. After finishing this step, the output voltage changes to 1.5V.
- If the write is successful, the following message will appear.
- To save the changes to NVM in the tool bar, click the RAM to NVM button.
- 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, C2, C5, C14| CAP., 0.1µF, X6S, 25V, 10%, 0201| TAIYO YUDEN,
TMK063C6104KP-F
2| 1| C3| CAP., 4.7µF, X6S, 25V, 10%, 0603| MURATA, GRM188C81E475KE11D
3| 2| C6, C8| CAP., 10µF, X6S, 10V, 10%, 0603| MURATA, ZRB18AC81A106KE01L
4| 1| C7| CAP., 2.2µF, X7S, 10V, 10%, 0402| TDK, C1005X7S1A225K050BC
6| 2| C17, C29, C36, C37| CAP., 100µF, X6S, 4V, 10%, 0805| MURATA,
GRM31CR60J107KE39L
7| 1| C19| CAP., 1µF, X6S, 16V, 10%, 0402| MURATA, GRM155C81C105KE11D
8| 2| C15, C16| CAP., 10µF, X7S, 4V, 20%, 0603| TDK, C1608X7S0G106M080AB
9| 1| L1| IND., 0.16µH, 20.5A, 1.2mΩ| COILCRAFT, XGL5050‐161MEC
10| 1| U1| IC, 20A, 16V REGULATOR, LQFN-24| ANALOG DEVICES, LT7170RV#TRPBF
ADDITIONAL EVALUATION BOARD CIRCUIT COMPONENTS
1| 1| C4| CAP., 100µF, ALUM, 35V, 20%| PANASONIC, EEHZK1V101XP
2| 0| C9, C10| CAP., OPTION, 7343|
3| 0| C11| CAP., OPTION, 0603|
4
| ****
6
| C12, C13, C22, C24, C30, C33| ****
CAP., 10µF, X7S, 25V, 10%, 0805
| ****
MURATA, GRM21BC71E106KE11L
5| 3| C18, C20, C21| CAP., 4.7µF, X5R, 25V, 10%, 0603| MURATA,
GRM188R61E475KE15D
6| 1| C23| CAP., 1µF, X5R, 25V, 10%, 0603| AVX, 06033D105KAT2A
7| 4| C25, C26, C27, C28| CAP., 1µF, X5R, 25V, 10%, 0402| MURATA,
GRM155R61E105KA12D
8| 1| C31| CAP., 0.1µF, X7R, 10V, 20%, 0603| AVX, 0603ZC104MAT2A
9| 3| C32, C34, C35| CAP., 1µF, X7R, 6.3V, 10%, 0402| MURATA,
GRM155R70J105KA12D
10| 1| C38| CAP., 1µF, X7R, 50V, 10%, 0603| AVX, 06035C105KAT2A
11| 2| C39, C40| CAP., 0.01µF, X7R, 25V, 10%, 0603| AVX, 06033C103K4Z2A
12| 1| C41| CAP., 10µF, X7R, 10V, 10%, 0805| AVX, 0805ZC106KAT2A
13| 1| C42| CAP., 1500pF, X7R, 25V, 10%, 0603| AVX, 06033C152KAT2A
14| 1| D1| LED, GREEN, DIFFUSED, 0603| BROADCOM INC., HSMG-C190
15| 1| D2| LED, RED, DIFFUSED, 0603| BROADCOM INC., HSMH-H190
16| 1| FB1| IND., 100Ω@100MHz, 8A, 6mΩ| WURTH ELEKTRONIK, 74279226101
17| 1| L2| IND., 1µH, 7.3A, 14mΩ| WURTH ELEKTRONIK, 74437336010
18| 1| Q1| MOSFET, N-CH, 25V, 70A, Power-SO8| NEXPERIA, PSMN5R4-25YLDX
19| 1| Q2| MOSFET, N-CH, 60V, 300mA, SOT-23-3| VISHAY, 2N7002K-T1-GE3
20| 4| R2, R5, R8, R9| RES., 10kΩ, 1%, 1/10W, 0603| VISHAY, CRCW060310K0FKEA
21| 2| R3, R12| RES., 866Ω, 1%, 1/10W, 0603| VISHAY, CRCW0603866RFKEA
---|---|---|---|---
22| 0| R4, R18| RES., OPTION, 0603|
23| 2| R6, R13| RES., 4.99kΩ, 1%, 1/10W, 0603| PANASONIC, ERJ3EKF4991V
24| 1| R7| RES., 10mΩ, 1%, 3W, 6.3 X3.1mm| SUSUMU, KRL6432E-C-R010-F-T1
25| 1| R10| RES., 49.9Ω, 1%, 1/10W, 0603| PANASONIC, ERJ3EKF49R9V
26| 3| R17, R20, R21| RES., 0Ω, 1/10W, 0603| VISHAY, CRCW06030000Z0EA
27| 1| R19| RES., 36.5kΩ, 1%, 1/10W, 0603| YAGEO RC0603FR‐0736K5L
28| 0| R21, R22| RES., OPTION, 0603|
29| 1| R14| RES., 1MΩ, 1%, 1/10W, 0603,| NIC, NRC06F1004TRF
30| 1| U2| IC, EEPROM, 2Kb (256×8), TSSOP-8| MICROCHIP, 24LC025-I/ST
31| 1| U3| IC, 2.6A, 2.5V-5.5V IDEAL DIO, 10DFN| ANALOG DEVICES,
LTC4413EDD#PBF
32| 1| U4| IC, 200mA LDO, MSOP-8| ANALOG DEVICES, LT3063EMS8E-3.3#PBF
HARDWARE: FOR EVALUATION BOARD ONLY
1| 5| E1, E2, E3, E4, E15| TEST POINT, TURRET, 0.064″| MILL-MAX,
2308-2-00-80-00-00-07-0
2
| ****
8
| E6, E7, E8, E9, E10, E11, E12, E13| ****
TEST POINT, TURRET, 0.094″
| ****
MILL-MAX, 2501-2-00-80-00-00-07-0
3| 4| J1, J2, J3, J4| BANANA JACK, FEMALE| KEYSTONE, 575-4
4| 1| J5| CONN., HDR, MALE, 2×6, 2mm| AMPHENOL, 98414-G06-12ULF
5| 2| J6, J7| CONN., BNC, 50Ω| AMPHENOL RF, 112404
6| 1| JP1| CONN., HDR, MALE, 1×3, 2mm| WURTH ELEKTRONIK, 62000311121
7
| ****
4
| MP1, MP2, MP3, MP4| ****
STANDOFF, NYLON, SNAP-ON, 0.50″
| ****
KEYSTONE, 8833
8
| ****
1
| ****
SW1
| SWITCH, SLIDE, DPDT, 0.3A, 6VDC, PTH| ****
C&K, JS202011CQN
9| 1| XJP1| CONN., SHUNT, FEMALE, 2-POS, 2mm| WURTH ELEKTRONIK, 60800213421
Schematic Diagram
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.
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