LTC3870_15 Datasheet, PDF (1/22 Pages) Linear Technology – PolyPhase Step-Down Slave Controller for LTC3880/LTC3883 with Digital Power System Management

LTC3870
Features
PolyPhase Step-Down
Slave Controller for LTC3880/LTC3883
with Digital Power System Management
Description
n _{LTC3880/LTC3883 Phase Extender}
n _{Cascade with Multiple Chips for Very Large Current}
Applications
n _{Accurate PolyPhase Current Sharing}
n _{EXTVCC Capable of 5V to 14V Input}
n _{Wide VIN Range: 4.5V to 60V}
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}
Applications
n _{High Power Distributed Power Systems}
n _{Telecom Systems}
n _{Industrial Applications}
The LTC^®3870 is a PolyPhase^® step-down slave control-
ler specially designed for multiphase operation with the
LTC3880 and LTC3883 digital power system management
DC/DC controllers. It provides a small and cost effective
solution for supplying very large currents by cascading
it with a LTC3880 or LTC3883 controller. A peak current
mode architecture provides the LTC3870 with excellent
current sharing from phase to phase and from chip to chip.
Coherently working with the LTC3880 or LTC3883, the
LTC3870 does not require additional I²C addresses, and
it supports all programmable features as well as fault
protection. The constant switching frequency can be
synchronized to an external clock from the LTC3880 or
LTC3883 from 100 kHz to 1MHz.
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
Typical Application
V_IN
4.7µF
V_OUT0
30A
1.0µH
+ ^530µF
2.15k
0.2µF
0.1µF
LTC3880*
RUN0
3.3V
V_SENSE0+
RUN1
GPIO0
GPIO1
1.8V _VSENSE1
I_TH0
I_TH1
SYNC
* REFER TO LTC3880 DATA SHEET
FOR MASTER SETUP
V_IN
INTV_CC
TG0
TG1
BOOST0 BOOST1
SW0
SW1
BG0
BG1
PGND
EXTV_CC
LTC3870
II_{SSEENNSSEE00+–} II_{SSEENNSSEE11+–}
0.1µF
0.56µH
V_OUT1
40A
1.74k
0.2µF
+ ^530µF
RUN0
RUN1
FAULT0
FAULT1
I_TH0
I_TH1
SYNC
FREQ
PHASMD
I_LIM
MODE0
MODE1
SGND
100k
3870 TA01a
Load Transient Response of a
2-Phase Master (3880)/Slave
(3870) Converter
I_LOAD
10A/DIV
0A TO 10A TO 0A
I_{L_3880(CH1)}
10A/DIV
I_{L_3870(CH1)}
10A/DIV
V_OUT1
100mV/DIV
AC-COUPLED
V_IN = 12V
V_OUT1 = 1.8V
50µs/DIV
3870 TA01b
For more information www.linear.com/LTC3870
3870fa
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