ANALOG DEVICES LT7182S Dual Channel Poly Phase Step Down Silent Switcher
DESCRIPTION
Demonstration Circuit 2836A is a dual-output PolyPhase® DC/DC synchronous step-down regulator with 4V to 20V input range featuring LT®7182S. Each output can supply 6A continuous/9A maximum transient load current. LT7182S is a dual 6A monolithic step-down regulator. The second-generation Silent Switcher® structure is incorporated into LT7182S to minimize EMI and reduce PCB layout sensitivity. It also integrates digital power system management function, allowing for programmability and telemetry with a PMBus/I2C compliant serial interface. Please see the T7182S data sheet for more detailed information.
The demonstration circuit 2836A runs at 1 MHz to minimize solution size. The peak efficiency at 12V input is 83.2% for 1.2V rail and 91.1% for 3.3V rail. The IC temperature rise is 70°C when both channels run at full load, 6A each, at 1MHz.
The demo board has EMI filters installed for both chan-nels. The conducted and radiated EMI performances of the board (with EMI filters) are shown in Figure 2. The red lines in Figure 2 are the CISPR25 CLASS 5 limit.
DC2836A powers up to default settings and produces power based on configuration resistors 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 your 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 EEPROM, view telemetry of voltage, current, temperature and fault status.
GUI Download
The software can be downloaded from: LTpowerPlay
The LT7182S 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 DC2836A.
For more details and instructions of LTpowerPlay, please refer to the LTpowerPlay GUI for the LT7182S Quick Start Guide.
Design files for this circuit board are available.
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
| SYMBOL | PARAMETER | CONDITIONS | MIN | TYP | MAX | UNITS |
| VIN | Input Voltage Range | 4* | 20 | V | ||
| VOUT0 | Output0 Voltage | 1.2 | V | |||
| IOUT0 | Maximum Output0 Current | 9 | A | |||
| VOUT1 | Output1 Voltage | 3.3 | V | |||
| IOUT1 | Maximum Output1 Current | 9 | A | |||
| fSW | Switching Frequency | 0.925 | 1 | 1.075 | MHz | |
| EFE | Efficiency at DC | VIN = 12V, IOUT0 = 3A, IOUT1 = 0A VIN = 12V, IOUT1 = 3A, IOUT0 = 0A | 83.2
91.1 |
%
% |
||
*The DC2836A minimum VIN is limited by U3 (LTC4413) and U4 (LT1761) that provide VPULLUP signal. LT7182S is capable of a minimum VIN of 1.5V with separate 3V ≤ EXTVCC ≤ 5.5V. For more details, refer to the LT7182S data sheet.
QUICK START PROCEDURE
DC2836A is easy to set up to evaluate the performance of the LT7182S. Refer to Figure 3 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 5 for the proper scope technique.
- Set an input power supply that is capable of 20V/18A. Then turn off the supply.
- With power off, connect the supply to the input terminals VEMI and GND. Set default jumper position: SW1: ON; SW2: ON
- Turn on the power at the input.
NOTE: Make sure that the input voltage never exceeds 20V. - Check for the proper output voltages of 1.2V ±0.5%(1.194V ~ 1.206V) and 3.3V ±0.5% (3.283V ~ 3.317V). Turn off the power at the input.
- Once the proper output voltage is established, connect variable loads capable of sinking 6A at 1.2V and 3.3V to the output terminals VOUT0/VOUT1 and GND. Set the current for 0A.
- If efficiency measurements are desired, ammeters can be put in series with the output loads to measure the DC2836A’s output currents.
- Voltmeters can be placed across the output terminals to get accurate output voltage measurements.
- 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 volt-age, efficiency and other desired parameters.
- Connect the dongle and control the output voltages from the GUI. See Lthe TpowerPlay GUI for the LT7182S Quick Start Guide for details.
NOTE: When measuring the output or input voltage rip-ple, do not use the long ground lead on the oscilloscope probe. See Figure 4 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. VOUT1 = 3.3V
QUICK START PROCEDURE
QUICK START PROCEDURE
Connecting a PC to DC2836A
You can use a PC to reconfigure the power management features of the LT7182S, such as: nominal VOUT, margin set points, OV/UV limits, temperature fault limits, sequencing parameters, the fault log, fault responses, GPIOs and other functionalities. The DC1613A dongle may be plugged win hen VIN is present.
LTpowerPlay SOFTWARE GUI
LTpowerPlay is a powerful Windows-based development environment that supports Linear Technology power system management ICs and μModules. The software supports a variety of tasks. You can use LTpowerPlay to evaluate Linear Technology ICs by connecting to a demo board system. LTpowerPlay can also be used in an offline mode (with no hardware present) in order 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 LTC Digital Power Products visit the LTpowerPlay Help menu. Online hel isp also available through the LTpowerPlay.
LTpowerPlay QUICK START PROCEDURE
The following procedure describes how to use LTpowerPlay to monitor and change the settings of LT7182S.
- Download and install the LTPowerPlay GUI: LTpowerPlay | Analog Devices
- Launch the LTpowerPlay GUI.
- The GUI should automatically identify the DC2836A. The system tree on the left hand side should look like this:
- A green message box shows for a few seconds in the lower left hand corner, confirming that LT7182S is communicating:
- In the Toolbar, click the R (RAM to PC) icon to read the RAM from the LT7182S. This reads the configu-ration from the RAM of LT7182S and loads it into the GUI.
- If you want to change the output voltage to a differ-ent value, like 1.5V. In the Config tab, type in 1.5 in the VOUT_COMMAND box, like this:
- The GUI should automatically identify the DC2836A. The system tree on the left hand side should look like this:
Then, click the W (PC to RAM) icon to write these register values to the LT7182S. After finishing this step, you will see the output voltage will change to 1.5V.
If the write is successful, you will see the following message:
You can save the changes to the NVM. In the toolbar, click the RAM to NVM button, as follows:
Save the demo board configuration to a (*.proj) file. Click the Save icon and save the file. Name it whatever you want.
PARTS LIST
| ITEM | QTY | REFERENCE | PART DESCRIPTION | MANUFACTURER/PART NUMBER |
Required Circuit Components
| 1 | 3 | C5, C6, C8 | CAP., 10µF, X6S, 10V, 10%, 0603 | MURATA, ZRB18AC81A106KE01L |
| 2 | 1 | C7 | CAP., 1µF, X7R, 16V, 10%, 0603 | MURATA, GRM188R71C105KA12D |
| 3 | 2 | C14, C22 | CAP., 0.1µF, X7R, 25V, 10%, 0402 | MURATA, GRM155R71E104KE14 |
| 4 | 4 | C15, C23, C55, C56 | CAP., 100µF, X5R, 6.3V, 10%, 1206 | MURATA, GRM31CR60J107KE39L |
| 5 | 2 | C17, C25 | CAP., 10µF, X5R, 10V, 10%, 0603 | MURATA, GRM188R61A106KAALD |
| 6 | 2 | C36, C37 | CAP., 1µF, X5R, 35V, 10%, 0402 | MURATA, GRM155R6YA105KE11D |
| 7 | 2 | C53, C54 | CAP., 4.7µF, X6S, 25V, 10%, 0603 | MURATA, GRM188C81E475KE11D |
| 8 | 1 | L1 | IND., 0.47µH, 21.2A, 3.4mΩ | COILCRAFT, XGL4030-471MEC |
| 9 | 1 | L2 | IND., 1.2µH, 12.2A, 9.4mΩ | COILCRAFT, XGL4030-122MEC |
| 10 | 6 | R2, R3, R4, R7, R8, R9 | RES., 10k, 1%, 1/10W, 0603 | VISHAY, CRCW060310K0FKEA |
| 11 | 1 | R19 | RES., 51.1k, 1%, 1/10W, 0603 | VISHAY, CRCW060351K1FKEA |
| 12 | 1 | R20 | RES., 107k, 1%, 1/10W, 0603 | VISHAY, CRCW0603107KFKEA |
| 13 | 1 | R21 | RES., 80.6k, 1%, 1/10W, 0603 | VISHAY, CRCW060380K6FKEA |
| 14 | 1 | U1 | IC, REGULATOR, LQFN-40 | ANALOG DEVICES, LT7182SRV#PBF |
Additional Demo Board Circuit Components
| 1 | 1 | C1 | CAP., 1µF, X5R, 50V, 10%, 0603 | MURATA, GRM188R61H105KAALD |
| 2 | 1 | C2 | CAP., 0.01µF, X7R, 25V, 10%, 0603 | TDK, C1608X7R1E103K080AA |
| 3 | 1 | C3 | CAP., 100µF, ALUM, 35V | PANASONIC, EEHZK1V101XP |
| 4 | 1 | C4 | CAP., 4.7µF, X7R, 10V, 10%, 0805 | TDK, C2012X7R1A475K085AC |
| 5 | 1 | C57 | CAP., 10µF, X6S, 10V, 10%, 0603 | MURATA, ZRB18AC81A106KE01L |
| 6 | 0 | C16, C24 | CAP., OPTION, 7343 | |
| 7 | 0 | C19, C20, C27, C28 | CAP., OPTION, 0603 | |
| 8 | 2 | C29, C30 | CAP., 0.01µF, X5R, 25V, 10%, 0603 | AVX, 06033D103KAT2A |
| 9 | 1 | C31 | CAP., 0.1µF, X7R, 10V, 20%, 0603 | AVX, 0603ZC104MAT2A |
| 10 | 2 | C32, C33 | CAP., 1µF, X5R, 10V, 10%, 0603 | MURATA, GRM188R61A105KA61D |
| 11 | 2 | C34, C35 | CAP., 0.01µF, X5R, 50V, 10%, 0603 | AVX, 06035D103KAT2A |
| 12 | 4 | C38, C39, C40, C41 | CAP., 0.1µF, X7R, 50V, 10%, 0402 | MURATA, GCM155R71H104KE02D |
| 13 | 2 | C42, C44 | CAP., 10µF, X5R, 50V, 10%, 1210 | TDK, C3225X5R1H106K250AB |
| 14 | 1 | C43 | CAP., 1µF, X5R, 50V, 10%, 0603 | TAIYO YUDEN, UMK107ABJ105KAHT |
| 15 | 3 | C50, C51, C52 | CAP., 4.7µF, X5R, 25V, 10%, 0603 | MURATA, GRM188R61E475KE15D |
| 16 | 0 | D1, D2 | DIODE, OPTION, SOD-323 | |
| 17 | 2 | D4, D5 | LED, GREEN, DIFFUSED, 0603 | BROADCOM INC., HSMG-C190 |
| 18 | 3 | D6, D7, D8 | LED, RED, DIFFUSED, 0603 | BROADCOM INC., HSMH-C190 |
| 19 | 1 | FB1 | FERRITE BEAD, 100Ω, 1812 | WURTH ELEKTRONIK, 74279226101 |
| 20 | 1 | L3 | IND., 0.47µH, 6.8A, 14mΩ | WURTH ELEKTRONIK, 744373240047 |
| 21 | 2 | Q2, Q3 | MOSFET, N-CH, SOT-23-3 | VISHAY, 2N7002K-T1-GE3 |
| 22 | 1 | Q4 | MOSFET, N-CH, DPAK | VISHAY, SUD50N04-8M8P-4GE3 |
| ITEM | QTY | REFERENCE | PART DESCRIPTION | MANUFACTURER/PART NUMBER |
| 23 | 11 | R1, R11, R12, R14, R16, R18, R23, R25, R35, R38, R41 | RES., 0Ω, 1/10W, 0603 | VISHAY, CRCW06030000Z0EA |
| 24 | 5 | R5, R6, R37, R39, R56 | RES., 10k, 1%, 1/10W, 0603 | VISHAY, CRCW060310K0FKEA |
| 25 | 0 | R13, R15, R22, R24, R26, R27, R28, R33, R34, R36, R40, R42, R43, R49, R50, R62, R63, R67 | RES., OPTION, 0603 | |
| 26 | 0 | R29, R30 | RES., OPTION, 2512 | |
| 27 | 2 | R44, R45 | RES., 10Ω, 5%, 1/10W, 0603 | VISHAY, CRCW060310R0JNEA |
| 28 | 2 | R46, R61 | RES., 4.99k, 1%, 1/10W, 0603 | VISHAY, CRCW06034K99FKEA |
| 29 | 0 | R48 | RES., OPTION, 1206 | |
| 30 | 5 | R51, R52, R64, R65, R66 | RES., 866Ω, 1%, 1/10W, 0603 | VISHAY, CRCW0603866RFKEA |
| 31 | 1 | R53 | RES., 0Ω, 1W, 2010 | VISHAY, CRCW20100000Z0EFHP |
| 32 | 0 | R54 | RES., OPTION, 2010 | |
| 33 | 1 | R57 | RES., 0.01Ω, 1%, 1W, 2512 | VISHAY, WSL2512R0100FEA |
| 34 | 1 | U2 | IC, EEPROM, 2Kb (256×8), TSSOP-8 | MICROCHIP, 24LC025-I/ST |
| 35 | 1 | U3 | IC, IDEAL DIO, 10DFN | ANALOG DEVICES, LTC4413EDD#PBF |
| 36 | 1 | U4 | IC, LDO, TSOT23-5 | ANALOG DEVICES, LT1761ES5-3.3#PBF |
Hardware: For Demo Board Only
| 1 | 6 | E1, E2, J3-J6 | BANANA JACK, FEMALE | KEYSTONE, 575-4 |
| 2 | 13 | E12-E21, E40, E47, E48 | TEST POINT, TURRET, 0.094″ | MILL-MAX, 2501-2-00-80-00-00-07-0 |
| 3 | 6 | E41-E46 | TEST POINT, TURRET, 0.064″ | MILL-MAX, 2308-2-00-80-00-00-07-0 |
| 4 | 1 | J8 | CONN., HDR, MALE, 2×6, 2mm | AMPHENOL, 98414-G06-12ULF |
| 5 | 1 | J9 | CONN., HDR, MALE, 2×7, 2mm | MOLEX, 0877601416 |
| 6 | 1 | J10 | CONN., HDR, FEMALE, 2×7, 2mm | SULL. CONN. SOLU., NPPN072FJFN-RC |
| 7 | 3 | J11, J12, J13 | CONN., BNC, 50Ω | AMPHENOL RF, 112404 |
| 8 | 4 | JP1, JP2, JP3, JP4 | CONN., HDR, MALE, 1×3, 2mm | WURTH ELEKTRONIK, 62000311121 |
| 9 | 4 | MP1, MP2, MP3, MP4 | STANDOFF, NYLON, SNAP-ON, 0.50″ | KEYSTONE, 8833 |
| 10 | 2 | SW1, SW2 | SWITCH, SLIDE, DPDT, 0.3A, 6VDC, PTH | C&K, JS202011CQN |
| 11 | 4 | XJP1, XJP2, XJP3, XJP4 | CONN., SHUNT, FEMALE, 2 POS, 2mm | WURTH ELEKTRONIK, 60800213421 |
SCHEMATIC DIAGRAM
REVISION HISTORY
| REV | DATE | DESCRIPTION | PAGE NUMBER |
| 0 | 09/21 | Initial Release. | — |
| A | 07/24 | Updated Performance Summary Table. Updated the Title with Silent Switcher 2.
Updated the Efficiency and Power Loss vs Load Current Plots. |
1
1 2 |
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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.
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Documents / Resources
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ANALOG DEVICES LT7182S Dual Channel Poly Phase Step Down Silent Switcher [pdf] Owner's Manual LT7182S Dual Channel Poly Phase Step Down Silent Switcher, LT7182S, Dual Channel Poly Phase Step Down Silent Switcher, Poly Phase Step Down Silent Switcher, Step Down Silent Switcher, Down Silent Switcher, Silent Switcher |
