LTC3870

1

3870fb

For more information www.linear.com/LTC3870

Typical applicaTion

FeaTures

DescripTion

PolyPhase Step-Down

Slave Controller for Digital

Power System Management

ler specially designed for multiphase operation with the

LTC3880familydigitalpowersystemmanagementDC/DC

controllers. It provides a small and cost effective solution

for supplying very large currents by cascading it with a

master controller. A peak current mode architecture pro-

vides the LTC3870 with excellent current sharing from

phase to phase and from chip to chip.

CoherentlyworkingwiththeLTC3880family,theLTC3870

all programmable features as well as fault protection.

The constant switching frequency can be synchronized

to an external clock from the master controller from

100kHz to 1MHz.

Load Transient Response of a

2-Phase Master (3880)/Slave

(3870) Converter

applicaTions

n

LTC3880 Family Phase Extender Supporting

LTC3880/3880-1, LTC3883/3883-1, LTC3886,

LTC3887 Master Controllers

n

Cascade with Multiple Chips for Very Large Current

Applications

n

Accurate PolyPhase Current Sharing

n

n

n

Wide Output Voltage Range : 0.5V to 14V

n

Wide SYNC Frequency Range: 100kHz to 1MHz

n

Pin Programmable of CCM/DCM Operation

n

Pin Programmable of Phase-Shift Control

n

Integrated Powerful N-Channel MOSFET Gate Drivers

n

Available in a 28-Pin (4mm

× 5mm) QFN Package

n

High Power Distributed Power Systems

n

Telecom Systems

n

Industrial Applications

L

, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks

of Linear Technology Corporation. All other trademarks are the property of their respective

owners. Protected by U.S. Patents including 5481178, 5705919, 5929620, 6144194, 6177787,

6580258, 5408150

+

+

4.7µF

BOOST0

SW0

BG0

BOOST1

TG0

TG1

SW1

BG1

FREQ

* REFER TO LTC3880 DATA SHEET

FOR MASTER SETUP

LTC3870

PHASMD

MODE0

MODE1

SGND

RUN0

SYNC

RUN1

FAULT0

FAULT1

PGND

0.1µF

0.1µF

1.0µH

0.56µH

0.2µF

0.2µF

RUN0

GPIO0

GPIO1

RUN1

SYNC

3.3V

LTC3880*

1.8V

2.15k

1.74k

100k

530µF

530µF

30A

40A

3870 TA01a

50µs/DIV

3870 TA01b

10A/DIV

10A/DIV

100mV/DIV

AC-COUPLED

10A/DIV

0A TO 10A TO 0A