LTC3370_15 Datasheet, PDF (1/24 Pages) Linear Technology – 4-Channel 8A Configurable Buck DC/DCs

LTC3370
4-Channel 8A Configurable
Buck DC/DCs
Features
Description
n _{8 × 1A 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 _{Zero Current In Shutdown (All Channels Off)}
n _{63µA 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 _{PGOODALL Pin Indicates All Enabled Bucks Are in}
Regulation
n _{32-Lead 5mm × 5mm QFN Package}
Applications
n _{General Purpose Multichannel Power Supplies:}
Automotive, Industrial, Distributed Power Systems
The LTC^®3370 is a highly flexible multioutput power
supply IC. The device includes four synchronous buck
converters, 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 power configu-
rations via pin programmable C1-C3 pins. The common
buck switching frequency may be programmed with an
external resistor, synchronized to an external oscillator,
or set to a default internal 2MHz clock.
The operating mode for all DC/DCs may be programmed
via the PLL/MODE pin for Burst Mode or forced continuous
mode operation. A PGOODALL output indicates when all
enabled DC/DCs are within a specified percentage of their
final output value.
To reduce input noise, the buck converters are phased
in 90° steps. Precision enable pin thresholds facilitate
reliable power-up sequencing. The LTC3370 is available
in a 32-lead 5mm × 5mm QFN package.
L, LT, LTC, LTM, 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
649k
V_OUT2
1.5V/2A
2.25V TO 5.5V
2.2µH
715k
649k
2.7V TO 5.5V
V_INA
V_CC
V_INE
V_INB
V_INF
SWA
SWE
SWB
SWF
FB1
FB2
EN1
EN2
LTC3370
V_INC
V_IND
SWC
SWD
V_ING
V_INH
SWG
SWH
FB2
FB4
EN2
EN4
2.25V TO 5.5V
2.2µH
806k
649k
2.5V TO 5.5V
2.2µH
665k
309k
PLL/MODE TEMP
RT
PGOODALL
402k C1 C2 C3 GND
3370 TA01a
V_OUT3
1.8V/2A
V_OUT4
2.5V/2A
Buck Efficiency vs I_LOAD
100
90
80
70
60
Burst Mode OPERATION
50
V_IN = 3.3V
V_OUT = 1.8V
40
f _OSC = 1MHz
L = 3.3µH
30
1A BUCK
20
2A BUCK
10
3A BUCK
4A BUCK
0
1
10
100
1000 4000
LOAD CURRENT (mA)
3370 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
3370f
For more information www.linear.com/LTC3370
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