LTC1702A
Dual 550kHz Synchronous
2-Phase Switching Regulator Controller
FEATURES
DESCRIPTIO
The LTC 1702A is a dual switching regulator controller
Pin Compatible with the LTC1702 with Improved
optimized for high efficiency with low input voltages. It
Current Limit Control
includes two complete, on-chip, independent switching regu-
Two Sides Run Out-of-Phase to Minimize C
IN
lator controllers each designed to drive a pair of external N-
No External Current Sense Resistors
channel MOSFETs in a voltage mode feedback, synchronous
Excellent Output Regulation: 1% Total Output
buck configuration. The LTC1702A uses a constant-fre-
Accuracy
quency, true PWM design switching at 550kHz, minimizing
Two Independent Controllers in One Package
external component size and cost and maximizing load
All N-Channel External MOSFET Architecture
transient performance. The synchronous buck architecture
550kHz Switching Frequency Minimizes External
automatically shifts to discontinuous and then to Burst
Component Size
Mode operation as the output load decreases, ensuring
1A to 25A Output Current per Channel
maximum efficiency over a wide range of load currents.
High Efficiency over Wide Load Current Range
Less Than 100A Shutdown Current
The LTC1702A features an onboard reference trimmed to
Small 24-Pin Narrow SSOP Package
0.5% and can provide better than 1% regulation at the
U
converter outputs. Open-drain logic outputs indicate whether
APPLICATIO S
either output has risen to within 5% of the final output voltage
and an optional latching FAULT mode protects the load if the
Microprocessor, DSP Core and I/O Supplies
output rises 15% above the intended voltage. Each channel
Multiple Logic Supply Generator
can be enabled independently; with both channels disabled,
Distributed Power Applications
the LTC1702A shuts down and supply current drops below
High Efficiency Power Conversion
100A.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners. Protected by U.S. Patents including 6144194.
TYPICAL APPLICATIO
Dual Output High Power 3.3V/2.5V Logic Supply
V = 5V 10%
IN
C , C : PANASONIC EEFUE0G181R
OUT1 OUT2
+
C
C : KEMET TS10X337M010AS IN
IN D1
10 10F
D2 330F
D1, D2: MOTOROLA MBR0520LT1
3
D3, D4: MOTOROLA MBRS320T3
1F
L1, L2: SUMIDA CEP125-1R0 11.8k
1 24
Q1 TO Q8: FAIRCHILD FDS6670A PV I
1F
CC MAX2
1F
1F
2 23 10F
BOOST1 BOOST2
3 22
BG1 BG2
Q1 Q2 Q5 Q6
4 21
L1 L2
TG1 TG2
1H 1H
V V
OUT1
5 20 OUT2
2.5V SW1 SW2 3.3V
AT 15A 11.8k AT 15A
6 19
D3 Q3 Q4 D4
Q7 Q8
I PGND
+
C MAX1
OUT1
1F LTC1702A
180F 7 18
1.2k 1.6k
PGOOD1 PGOOD2
4
8 17
+ C
OUT2
FCB FAULT
10k 820pF 15.8k
1F
180F
1% 680pF 1%
9 16
4
RUN/SS RUN/SS2
1F
10 15 1F
COMP1 COMP2
4.99k
4.75k
47k 68k
11 14
1%
1%
SGND FB2
V
V IN
IN
12 13
680pF 27pF
27pF 3300pF
FB1 V
CC
10k
10k
PWRGD2
PWRGD1
FAULT
1702 TA01
1702afa
1
U
ULTC1702A
ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION
(Note 1)
TOP VIEW
Supply Voltage
1 24 I
PV
V ........................................................................................... 7V CC MAX2
CC
2 23 BOOST2
BOOST1
BOOSTn............................................................... 15V
3 22 BG2
BG1
BOOSTn SWn .................................................... 7V
4 21 TG2
TG1
Input Voltage
5 20 SW2
SW1
SWn .......................................................... 1V to 8V
6 19 PGND
I
MAX1
All Other Inputs ......................... 0.3V to V + 0.3V
CC
7 18 PGOOD2
PGOOD1
Peak Output Current < 10s
8 17 FAULT
FCB
TGn, BGn ............................................................... 5A
9 16 RUN/SS2
RUN/SS1
Operating Temperature Range
10 15 COMP2
COMP1
LTC1702AC ............................................. 0C to 70C
11 14 FB2
SGND
LTC1702AI ........................................ 40C to 85C
12 13 V
FB1
CC
Storage Temperature Range ................. 65C to 150C
GN PACKAGE
24-LEAD NARROW PLASTIC SSOP
Lead Temperature (Soldering, 10 sec).................. 300C
T = 125C, = 100C/ W
JMAX JA
ORDER PART NUMBER
LTC1702ACGN
LTC1702AIGN
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: