LTC1702 查看數據表（PDF） - Linear Technology
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LTC1702 Datasheet PDF : 36 Pages
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LTC1702
Dual 550kHz Synchronous
2-Phase Switching Regulator Controller
FEATURES
■ Two Independent Controllers in One Package
■ Two Sides Run Out-of-Phase to Minimize CIN
■ All N-Channel External MOSFET Architecture
■ No External Current Sense Resistors
■ Excellent Output Regulation: 1% Total Output
Accuracy
■ 550kHz Switching Frequency Minimizes External
Component Size
■ 1A to 25A Output Current per Channel
■ High Efficiency over Wide Load Current Range
■ Quiescent Current Drops Below 100µA in Shutdown
■ Small 24-Pin Narrow SSOP Package
U
APPLICATIO S
■ Microprocessor Core and I/O Supplies
■ Multiple Logic Supply Generator
■ Distributed Power Applications
■ High Efficiency Power Conversion
, LTC and LT 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 5481178,
5847554, 6304066, 6307356, 6580258.
DESCRIPTIO
The LTC®1702 is a dual switching regulator controller opti-
mized for high efficiency with low input voltages. It includes
two complete, on-chip, independent switching regulator
controllers each designed to drive a pair of external N-channel
MOSFET devices in a voltage mode feedback, synchronous
buck configuration. The LTC1702 uses a constant-frequency,
true PWM design switching at 550kHz, minimizing external
component size and cost and maximizing load transient
performance. The synchronous buck architecture automati-
cally shifts to discontinuous and then to Burst ModeTM
operation as the output load decreases, ensuring maximum
efficiency over a wide range of load currents.
The LTC1702 features an onboard reference trimmed to
0.5% and can provide better than 1% regulation at the
converter outputs. Open-drain logic outputs indicate whether
either output has risen to within 5% of the final output voltage
and an optional latching FAULT mode protects the load if the
output rises 15% above the intended voltage. Each channel
can be enabled independently; with both channels disabled,
the LTC1702 shuts down and supply current drops below
100µA.
TYPICAL APPLICATIO
Dual Output High Power 3.3V/2.5V Logic Supply
COUT1, COUT2: PANASONIC EEFUE0G181R
CIN: KEMET TS10X337M010AS
D1, D2: MOTOROLA MBR0520LT1
D3, D4: MOTOROLA MBRS320T3
L1, L2: SUMIDA CEP125-1R0
Q1 TO Q8: FAIRCHILD FDS6670A
1µF
Q1
Q2
L1
1µH
VOUT1
2.5V
AT 15A
+
1µF
COUT1
180µF
D3
1.2k
Q3
Q4
×4
10k
820pF
1%
VIN
10k
PWRGD1
4.75k
1%
47k
680pF
27pF
VIN = 5V ±10%
D2
10Ω 10µF
1µF
1
24
1µF
PVCC
IMAX2
2
BOOST1
23
BOOST2
3
BG1
22
BG2
4
TG1
21
TG2
5
20
SW1
SW2
27k 6
19
IMAX1
7
LTC1702
PGND
18
PGOOD1
PGOOD2
8
FCB
17
FAULT
9
RUN/SS
1µF 10
COMP1
16
RUN/SS2
15
COMP2
11
SGND
14
FB2
12
FB1
13
VCC
+
D1
27k
CIN
330µF
×3
10µF
1µF
27pF
1702 TA01
1µF
Q5
Q6
L2
1µH
Q7
Q8
D4
VOUT2
3.3V/15A
1.6k
680pF
15.8k + COUT2
1%
180µF
1µF
×4
68k
3300pF
4.99k
1%
VIN
10k
PWRGD2
FAULT
1702fa
1
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