Datasheet LTC3870 (Analog Devices)

LTC3870 PolyPhase Step-Down Slave Controller for Digital Power System Management
FeaTures DescripTion
n
LTC3880 Family Phase Extender Supporting
The LTC®3870 is a PolyPhase® step-down slave control-
LTC3880/3880-1, LTC3883/3883-1, LTC3886,
ler specially designed for multiphase operation with the
LTC3887 Master Controllers
LTC3880 family digital power system management DC/DC n
Cascade with Multiple Chips for Very Large Current
controllers. It provides a small and cost effective solution
Applications
for supplying very large currents by cascading it with a n
Accurate PolyPhase Current Sharing
master controller. A peak current mode architecture pro- n
EXTVCC Capable of 5V to 14V Input
vides the LTC3870 with excellent current sharing from n Wide VIN Range: 4.5V to 60V phase to phase and from chip to chip. n Wide Output Voltage Range : 0.5V to 14V Coherently working with the LTC3880 family, the LTC3870 n Wide SYNC Frequency Range: 100kHz to 1MHz does not require additional I2C addresses, and it supports n Pin Programmable of CCM/DCM Operation all programmable features as well as fault protection. n Pin Programmable of Phase-Shift Control The constant switching frequency can be synchronized n Integrated Powerful N-Channel MOSFET Gate Drivers to an external clock from the master controller from n Available in a 28-Pin (4mm × 5mm) QFN Package 100kHz to 1MHz.
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 n High Power Distributed Power Systems n Telecom Systems n Industrial Applications
Typical applicaTion Load Transient Response of a 2-Phase Master (3880)/Slave
VIN
(3870) Converter
4.7µF VIN INTVCC TG0 TG1 ILOAD VOUT0 VOUT1 10A/DIV 1.0µH BOOST0 BOOST1 30A 0.1µF 0.1µF 0.56µH 40A 0A TO 10A TO 0A SW0 SW1 + 530µF BG0 BG1 + 530µF 2.15k 1.74k IL_3880(CH1) PGND EXTV 10A/DIV 0.2µF CC 0.2µF LTC3870 IL_3870(CH1) I + + SENSE0 ISENSE1 10A/DIV I – – SENSE0 ISENSE1 V LTC3880* OUT1 100mV/DIV RUN0 RUN0 AC-COUPLED 3.3V RUN1 RUN1 V + SENSE0 GPIO0 FAULT0 100k GPIO1 FAULT1 FREQ 50µs/DIV 3870 TA01b 1.8V ITH0 I PHASMD TH0 V V IN = 12V SENSE1 I I TH1 I LIM TH1 VOUT1 = 1.8V MODE0 SYNC SYNC MODE1 * REFER TO LTC3880 DATA SHEET SGND FOR MASTER SETUP 3870 TA01a 3870fb For more information www.linear.com/LTC3870 1