LTC3870-1
PolyPhase Step-Down
Slave Controller for Digital
Power System Management
Fea T Descrip T
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LTC3887-1 Phase Extender The LTC 3870-1 is a PolyPhase step-down slave control-
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Operates with Power Blocks, DrMOS or External ler specially designed for multiphase operation with LTC's
Gate Drivers and MOSFETs digital power system management DC/DC controllers. It
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Cascade with Multiple Chips for Very Large Current provides a small and cost effective solution for supply-
Applications ing very large currents by cascading it with a LTC3887-1
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Accurate PolyPhase Current Sharing controller. A peak current mode architecture provides the
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EXTV Capable of 5V to 14V Input LTC3870-1 with excellent current sharing from phase to
CC
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Wide V Range: 4.5V to 60V phase and from chip to chip.
IN
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Wide Output Voltage Range : 0.5V to 14V
Coherently working with the LTC3887-1, the LTC3870-1
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Wide SYNC Frequency Range: 100kHz to 1MHz
2
does not require additional I C addresses, and it supports
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Pin Programmable CCM/DCM Operation
all programmable features as well as fault protection.
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Pin Programmable Phase-Shift Control
The constant switching frequency can be synchronized
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Available in a 24-Pin (4mm 4mm) QFN Package
to an external clock from the LTC3887-1 over a range of
100kHz to 1MHz.
L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks
a T
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,
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6580258, 5408150
High Power Distributed Power Systems
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Telecom Systems
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Industrial Applications
Typical a T
Load Transient Response of a
2-Phase Master (3887-1)/Slave
V
IN
7V TO 14V (3870-1) Converter
22F
4.7F
V INTV
IN CC I
LOAD
20A/DIV
V V
CC0 CC1
10A TO 20A TO 10A
LTC3870-1
I LTC38871
V L
V
OUT0 OUT1
(CH0)
1.0H 0.56H
3.3V, 30A
1.8V, 40A
10A/DIV
DrMOS PWM0 PWM1 DrMOS
I LTC38701
L
2.15k 1.74k
530F 530F
(CH0)
0.2F 0.2F
10A/DIV
I + I + V
OUT
SENSE0 SENSE1
200mV/DIV
I - I -
SENSE0 SENSE1
ACCOUPLED
38701 TA01b
100s/DIV
EXTV
LTC3887-1 CC
V = 12V
RUN0 RUN0 IN
RUN1 RUN1 V = 1.8V
82.5k
3.3V OUT
V + GPIO0 FAULT0 FREQ
SENSE0
GPIO1 FAULT1 PHASMD
1.8V
V + I I I
SENSE1 TH0 TH0 LIM
I I MODE0
TH1 TH1
SYNC SYNC MODE1
GND
* REFER TO LTC3887-1 DATA SHEET
FOR MASTER SETUP
38701 TA01a
38701f
1
For more information www.linear.com/LTC3870-1
ion pplica
ions pplica
ion uresLTC3870-1
a Te Maxi Mu M r a T p in c F T
(Note 1)
TOP VIEW
V ............................................................. 0.3V to 65V
IN
V , V .................................................... 0.3V to 6V
CC0 CC1
I +, I , I +, I ....... 0.3V to 15V
SENSE0 SENSE0 SENSE1 SENSE1
24 23 22 21 20 19
INTV , RUN0/RUN1 .................................. 0.3V to 6V
CC
+
I 1 18 V
SENSE0 CC0
EXTV .................................................... 0.3V to 14V
CC
I 2 17 V
SENSE0 IN
MODE0/MODE1,
RUN0 GND
3 25 16
GND
FREQ, PHASMD, I ........................0.3V to INTV
RUN1 4 15 EXTV
LIM CC CC
FAULT0/FAULT1, I /I , SYNC .............. 0.3V to 3.6V I 5 14 INTV
SENSE1 CC
TH0 TH1
+
I 6 13 V
INTV , EXTV Peak Current (Note 7) ...............100mA SENSE1 CC1
CC CC
Operating Junction 7 8 9 10 11 12
Temperature Range ............................ 40C to 125C
Storage Temperature Range .................. 65C to 150C
UF PACKAGE
24-LEAD (4mm 4mm) PLASTIC QFN
T = 125C, = 46.9C/W, = 4.5C/W
JMAX JA JC_BOT
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
o r Der i n F Ma T
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3870EUF-1#PBF LTC3870EUF-1#TRPBF 38701 24-Lead (4mm 4mm) Plastic QFN 40C to 125C
LTC3870IUF-1#PBF LTC3870IUF-1#TRPBF 38701 40C to 125C
24-Lead (4mm 4mm) Plastic QFN
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: