LTC3374A
High Accuracy 8-Channel
Parallelable 1A Buck DC/DCs
Fea T Descrip T
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8-Channel 1A Independent Step-Down DC/DCs The LTC 3374A is a multioutput power supply IC consisting
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Master-Slave Configurable for Up to 4A of Output of eight synchronous 1A buck converters, all powered from
Current with a Single Inductor independent 2.25V to 5.5V input supplies. An upgraded
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Independent V Supplies for Each DC/DC pin-compatible version of the LTC3374, the LTC3374A,
IN
(2.25V to 5.5V) has higher efficiency, improved output voltage accuracy
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All DC/DCs Have 0.8V to V Output Range and an added overvoltage (OV) indicator.
IN
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1% V Accuracy, for Buck 1 (1A to 4A)
FB
The DC/DCs may be used independently or in parallel to
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1% PGOOD Accuracy
achieve higher output currents of up to 4A with a shared
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Precision Enable Pin Thresholds for Autonomous
inductor. The common buck switching frequency may be
Sequencing
programmed with an external resistor, synchronized to an
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1MHz to 3MHz Programmable/Synchronizable
external oscillator, or set to a default internal 2MHz clock.
Oscillator Frequency (2MHz Default)
The operating mode for all DC/DCs may be programmed
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Die Temperature Monitor Output
via the MODE pin.
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Thermally Enhanced 38-Lead 5mm 7mm QFN and
To reduce input noise the buck converters are phased in
TSSOP Packages
n 90 steps. Precision enable pin thresholds simplify power-
Pin-Compatible with LTC3374
up sequencing. The LTC3374A is available in a 38-lead
5mm 7mm QFN package as well as a 38-lead exposed
a T
pad TSSOP package.
n L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
General Purpose Multichannel Power Supplies
of Linear Technology Corporation. All other trademarks are the property of their respective
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Industrial/Automotive/Communications owners.
Typical a T
Eight Synchronous 1A Buck Regulators
Buck Efficiency vs I
LOAD
BUCK 1
100
2.25V TO 5.5V V SW1 0.8V TO V
IN1 IN1
UP TO 1A
90
EN1 FB1
80
70
BUCK 2
60
V
SW2 0.8V TO V
2.25V TO 5.5V IN2
IN2
UP TO 1A
50 f = 1MHz
OSC
V V = 1.8V = 3.3V
OUT
IN
EN2 FB2
40
V = 1.8V
OUT
THE EIGHT BUCKS CAN
Burst Mode OPERATION
30
BE CONFIGURED IN 15
LTC3374A 1A BUCK, L = 4.7H, L DCR = 40m
DIFFERENT MASTER/SLAVE
20
2A BUCK, L = 2.2H, L DCR = 13m
COMBINATIONS
3A BUCK, L = 1.8H, L DCR = 10m
10
BUCK 8
4A BUCK, L = 1.0H, L DCR = 8m
2.25V TO 5.5V V
SW8 0.8V TO V
IN8 IN8
0
UP TO 1A
1m 10m 100m 1 4
EN8 FB8 LOAD CURRENT (A)
3374A TA01b
2.7V TO 5.5V V
CC
MODE
SYNC
PGOOD_ALL
RT TEMP
GND
3374A TA01a
3374af
1
For more information www.linear.com/LTC3374A
EFFICIENCY (%)
ion pplica
ions pplica
ion uresLTC3374A
a Te Maxi Mu M r a T (Note 1)
V , FB1-8, EN1-8, V , PGOOD_ALL, I .......................................................................2.6A
SW1-8
IN1-8 CC
SYNC, RT, TEMP .......................................... 0.3V to 6V Operating Junction Temperature Range
MODE .................. 0.3V to Lesser of (V + 0.3V) or 6V (Notes 2, 3) ............................................ 40C to 150C
CC
I ...............................................................5mA Storage Temperature Range .................. 65C to 150C
PGOOD_ALL
p in c F T
TOP VIEW
TOP VIEW
1 38 V
TEMP
CC
2 37 MODE
EN2
3 36 EN7
EN1
38 37 36 35 34 33 32
4 35 EN8
FB1
FB1 1 31 FB8
5 34 FB8
V 2 30 V V
IN1 IN8 IN1
SW1 3 29 SW8 6 33 V
SW1
IN8
SW2 4 28 SW7
7 32 SW8
SW2
V 5 27 V
IN2 IN7 8 31 SW7
V
IN2
FB2 6 26 FB7
39 9 30 V
FB2
IN7
GND
FB3 7 25 FB6
10 39 29 FB7
FB3
GND
V 8 24 V
IN3 IN6
11 28 FB6
V
IN3
SW3 9 23 SW6
12 27 V
SW3
IN6
SW4 10 22 SW5
13 26 SW6
SW4
21
V 11 V
IN4 IN5
14 25 SW5
V
IN4
FB4 12 20 FB5
15 24 V
FB4
IN5
13 14 15 16 17 18 19
16 23 FB5
EN4
17 22 EN5
EN3
18 21 EN6
PGOOD_ALL
19 20 RT
SYNC
UHF PACKAGE
38-LEAD (5mm 7mm) PLASTIC QFN
FE PACKAGE
T = 150C, = 34C/W
JMAX JA
38-LEAD PLASTIC TSSOP
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
T = 150C, = 25C/W
JMAX JA
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
o r Der i n F Ma Tion