LTC3371_15 Datasheet, PDF (1/26 Pages) Linear Technology – 4-Channel 8A Configurable Buck DC/DCs with Watchdog and Power-On Reset

LTC3371
Features
4-Channel 8A Configurable
Buck DC/DCs with Watchdog
and Power-On Reset
Description
n _{8 × 1A Buck Power Stages Configurable as 2, 3 or 4}
Output Channels
n _{8 Unique Output Configurations (1A to 4A Per Channel)}
n _{Independent VIN Supplies for Each DC/DC (2.25V to 5.5V)}
n _{Low Total No Load Supply Current:}
n _{15µA In Shutdown (All Channels Off)}
n _{68µA One Channel Active in Burst Mode}^® _Operation
n _{18µA Per Additional Channel}
n _{Precision Enable Pin Thresholds for Autonomous}
Sequencing
n _{1MHz to 3MHz RT Programmable Frequency}
(2MHz Default) or PLL Synchronization
n _{Temp Monitor Indicates Die Temperature}
n _{CT Programmed Watchdog Timer}
n _{Independent RST Pins Indicate Buck in Regulation}
n _{Thermally Enhanced 38-Lead 5mm × 7mm QFN and}
TSSOP Packages
Applications
n _{General Purpose Multichannel Power Supplies:}
Automotive, Industrial, Distributed Power Systems
The LTC^®3371 is a highly flexible multioutput power supply
IC. The device includes four synchronous buck convert-
ers, configured to share eight 1A power stages, each of
which is powered from independent 2.25V to 5.5V inputs.
The DC/DCs are assigned to one of eight possible power
configurations via pin programmable C1-C3 pins. The
common buck switching frequency may be programmed
with an external resistor, synchronized to an external oscil-
lator, or set to a default internal 2MHz clock. The operating
mode for all DC/DCs may be programmed for Burst Mode
or forced continuous mode operation.
The CT pin programs the timing parameters of four inde-
pendent RST pins as well as the watchdog timer.
To reduce input noise, the buck converters are phased in
90° steps. Precision enable pin thresholds facilitate reli-
able power sequencing. The LTC3371 is available in low
profile 38-lead 5mm × 7mm QFN and TSSOP packages.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
Typical Application
V_OUT1 = 1.2V/2A
2.25V TO 5.5V
2.2µH
324k
645k
V_OUT2 = 1.5V/2A
2.25V TO 5.5V
2.2µH
412k
475k
2.7V TO 5.5V
V_INA
V_CC
V_INE
V_INB
V_INF
SWA
SWE
SWB
SWF
FB1
FB3
EN1
EN3
RST1
RST3
LTC3371
V_INC
V_IND
SWC
SWD
V_ING
V_INH
SWG
SWH
FB2
EN2
RST2
FB4
EN4
RST4
2.25V TO 5.5V
806k
649k
2.5V TO 5.5V
665k
309k
PLL/MODE TEMP
RT
WDI
CT
WDO
C1 C2 C3 GND
3371 TA01
V_OUT3 = 1.8V/2A
V_OUT4 = 2.5V/2A
Buck Efficiency vs I_LOAD
100
90
80
70
60
50
40
30 _{Burst Mode OPERATION}
20
V_IN = 3.3V
V_OUT = 1.8V
10 ^f OSC ^{= 1MHz}
L = 3.3µH
0
1
10
100
LOAD CURRENT (mA)
1A BUCK
2A BUCK
3A BUCK
4A BUCK
1000 4000
3371 TA01b
C3 C2 C1 BUCK1 BUCK2 BUCK3 BUCK4
0
0
0
2A 2A 2A 2A
0
0
1
3A 1A 2A 2A
0
1
0
3A 1A 1A 3A
0
1
1
4A 1A 1A 2A
1
0
0
3A
2A
–
3A
1
0
1
4A
–
2A 2A
1
1
0
4A
–
1A 3A
1
1
1
4A
–
–
4A
3371fa
For more information www.linear.com/LTC3371
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