Design DocumentAnalog

DC424A - LTC3701 2-Phase Dual-Output Switching Regulator Controller Demonstration Circuit

User guide for the DC424A demo board featuring the LTC3701 controller, providing dual outputs of 2.5V and 1.8V at 1.6A from a 2.5V to 9.8V input range.

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Overview

Demonstration Circuit DC424A showcases the LTC3701, a 2-phase, dual-output switching regulator controller. The circuit provides 2.5V and 1.8V outputs with 1.6A current capability each, operating from an input range of 2.5V to 9.8V. By operating the two channels 180 degrees out of phase, the design reduces peak input ripple current and EMI. The switching frequency is internally set to 550kHz but can be synchronized to an external clock from 300kHz to 750kHz. This document provides a performance summary, quick start setup procedures, schematic diagrams, and a full Bill of Materials including components from Linear Technology, Fairchild, and Murata.

Use Cases

Battery-powered systems
Point-of-load power supplies
Distributed power architectures
Noise-sensitive applications
Handheld electronics

Topics

LTC3701

DC424A

2-phase switching regulator

dual-output controller

step-down converter

Linear Technology

synchronous buck

EMI reduction

FDC638P

Sanyo 6TPA47M

Referenced Parts

FDC638P

Fairchild

P-MOSFET, FDC638P, TSOP-6 FAIRCHILD, FDC638P

6TPA47M

Sanyo

CAP., POSCAP, 47uF, 6.3V, C SIZE SANYO, 6TPA47M

LMK325BJ106MN

Taiyo Yuden

CAP., X7R, 10uF, 10V, 20%, 1210 TAIYO TUDEN, LMK325BJ106MN

04025C102MAT

AVX

CAP., X7R, 1nF, 50V, 20% 0402 AVX, 04025C102MAT

04025C221MAT

AVX

CAP., X7R, 220pF, 50V, 20% 0402 AVX, 04025C221MAT

06035C103MAT

AVX

CAP., X7R, 10nF, 50V, 20% 0603 AVX, 06035C103MAT

MBRM120LT3

Onsemi

DIODE, MBRM120LT3, POWERMITE ON SEMI., MBRM120LT3

CJ06-000M

American Alumina Corp

RES., CHIP, 0, 1/16W, 0603 AAC, CJ06-000M

CR05-1003FM

American Alumina Corp

RES., CHIP, 100K, 1/16W, 1% 0402 AAC, CR05-1003FM

CR05-103JM

American Alumina Corp

RES., CHIP, 10K, 1/16W, 5% 0402 AAC, CR05-103JM

CR05-1693FM

American Alumina Corp

RES., CHIP, 169K, 1/16W, 1% 0402 AAC, CR05-1693FM

CR05-7872FM

American Alumina Corp

RES., CHIP, 78.7K, 1/16W, 1% 0402 AAC, CR05-7872FM

2802S-03G1

Comm Con

JUMPER, 0.079, 3PIN COMM CON, 2802S-03G1

CCIJ2MM-138G

Comm Con

SHUNT COMM CON, CCIJ2MM-138G

LR1206-01-R030-F

IRC

RES., CHIP, 0.03, 1/4W, 1% 1206 IRC, LR1206-01-R030-F

LTC3701EGN

Linear Technology

LTC3701 2-phase, dual-output switching regulator controller

2308-2-00-44

Mill-Max

TURRET, TEST PIN, .061 MILL-MAX 2308-2-00-44

2501-2

Mill-Max

TURRET, TEST PIN, .095 MILL-MAX 2501-2

JMK107BJ105MA

Taiyo Yuden

CAP., X5R, 1uF, 6.3V, 20%, 0603 TAIYO YUDEN, JMK107BJ105MA

LMK107BJ684MA

Taiyo Yuden

CAP., 0.68uF, 10V, 20% 0603 TAIYO TUDEN, LMK107BJ684MA

A915AY-4R7M

Toko

INDUCTOR, 4.7uH, TOKO, A915AY-4R7M

CR05-100JM

American Alumina Corp

RES., CHIP, 10, 1/16W, 5% 0402 AAC, CR05-100JM

CR05-8062FM

American Alumina Corp

RES., CHIP, 80.6K, 1/16W, 1%, 0402 AAC, CR05-8062FM

CR16-105JM

American Alumina Corp

RES., CHIP, 1M, 1/16W, 5% 0603 AAC, CR16-105JM

LQH55DN4R7M01

Murata

maximum output current can be increased to 2A if Murata LQH55DN4R7M01 inductors are used

MBRS320

SMC Diode Solutions

(OPT) DIODE, MBRS320 SMC OPTIONAL

SI9803DY

Vishay Siliconix

(OPT) P-MOSFET, SI9803DY, SO-8 OPTIONAL

FDC638P	Fairchild	P-MOSFET, FDC638P, TSOP-6 FAIRCHILD, FDC638P
6TPA47M	Sanyo	CAP., POSCAP, 47uF, 6.3V, C SIZE SANYO, 6TPA47M
LMK325BJ106MN	Taiyo Yuden	CAP., X7R, 10uF, 10V, 20%, 1210 TAIYO TUDEN, LMK325BJ106MN
04025C102MAT	AVX	CAP., X7R, 1nF, 50V, 20% 0402 AVX, 04025C102MAT
04025C221MAT	AVX	CAP., X7R, 220pF, 50V, 20% 0402 AVX, 04025C221MAT
06035C103MAT	AVX	CAP., X7R, 10nF, 50V, 20% 0603 AVX, 06035C103MAT
MBRM120LT3	Onsemi	DIODE, MBRM120LT3, POWERMITE ON SEMI., MBRM120LT3
CJ06-000M	American Alumina Corp	RES., CHIP, 0, 1/16W, 0603 AAC, CJ06-000M
CR05-1003FM	American Alumina Corp	RES., CHIP, 100K, 1/16W, 1% 0402 AAC, CR05-1003FM
CR05-103JM	American Alumina Corp	RES., CHIP, 10K, 1/16W, 5% 0402 AAC, CR05-103JM
CR05-1693FM	American Alumina Corp	RES., CHIP, 169K, 1/16W, 1% 0402 AAC, CR05-1693FM
CR05-7872FM	American Alumina Corp	RES., CHIP, 78.7K, 1/16W, 1% 0402 AAC, CR05-7872FM
2802S-03G1	Comm Con	JUMPER, 0.079, 3PIN COMM CON, 2802S-03G1
CCIJ2MM-138G	Comm Con	SHUNT COMM CON, CCIJ2MM-138G
LR1206-01-R030-F	IRC	RES., CHIP, 0.03, 1/4W, 1% 1206 IRC, LR1206-01-R030-F
LTC3701EGN	Linear Technology	LTC3701 2-phase, dual-output switching regulator controller
2308-2-00-44	Mill-Max	TURRET, TEST PIN, .061 MILL-MAX 2308-2-00-44
2501-2	Mill-Max	TURRET, TEST PIN, .095 MILL-MAX 2501-2
JMK107BJ105MA	Taiyo Yuden	CAP., X5R, 1uF, 6.3V, 20%, 0603 TAIYO YUDEN, JMK107BJ105MA
LMK107BJ684MA	Taiyo Yuden	CAP., 0.68uF, 10V, 20% 0603 TAIYO TUDEN, LMK107BJ684MA
A915AY-4R7M	Toko	INDUCTOR, 4.7uH, TOKO, A915AY-4R7M
CR05-100JM	American Alumina Corp	RES., CHIP, 10, 1/16W, 5% 0402 AAC, CR05-100JM
CR05-8062FM	American Alumina Corp	RES., CHIP, 80.6K, 1/16W, 1%, 0402 AAC, CR05-8062FM
CR16-105JM	American Alumina Corp	RES., CHIP, 1M, 1/16W, 5% 0603 AAC, CR16-105JM
LQH55DN4R7M01	Murata	maximum output current can be increased to 2A if Murata LQH55DN4R7M01 inductors are used
MBRS320	SMC Diode Solutions	(OPT) DIODE, MBRS320 SMC OPTIONAL
SI9803DY	Vishay Siliconix	(OPT) P-MOSFET, SI9803DY, SO-8 OPTIONAL