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LTC1430A
High Power Step-Down
Switching Regulator Controller
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The LTC
®
1430A is a high power, high efficiency switching
regulator controller optimized for 5V to 1.xV-3.xV applica-
tions. It includes a precision internal reference and an inter-
nal feedback system that can provide output regulation of
±1% over temperature, load current and line voltage shifts.
The LTC1430A uses a synchronous switching architecture
with two N-channel output devices, eliminating the need for
a high power, high cost P-channel device. Additionally, it
senses output current across the drain-source resistance
of the upper N-channel FET, providing an adjustable cur-
rent limit without an external low value sense resistor.
The LTC1430A includes a fixed frequency PWM oscillator
for low output ripple under virtually all operating condi-
tions. The 200kHz free-running clock frequency can be
externally adjusted from 100kHz to above 500kHz. The
LTC1430A’s maximum duty cycle is typically 93.5% com-
pared to 88% for the LTC1430. This permits 3.3V to 2.xV
conversion using a low power 5V supply. The LTC1430A
features low 350µA quiescent current, allowing greater
than 90% efficiency operation in converter designs from
1A to greater than 50A output current. Shutdown mode
drops the LTC1430A supply current to 1µA. For new
designs, refer to the LTC3830.
■
High Power 5V to 1.xV-3.xV Switching Controller:
Can Exceed 10A Output
■
Maximum Duty Cycle > 90% Permits 3.3V to 2.xV
Conversion Using a Low Power 5V Supply
■
All N-Channel External MOSFETs
■
Fixed Frequency Operation—Small L
■
Excellent Output Regulation: ±1% Over Line, Load
and Temperature Variations
■
High Efficiency: Over 95% Possible
■
No Low Value Sense Resistor Needed
■
Outputs Can Drive External FETs with Up to
10,000pF Gate Capacitance
■
Quiescent Current: 350µA Typ, 1µA in Shutdown
■
Fast Transient Response
■
Adjustable or Fixed 3.3V Output
■
Available in 8-Lead SO and 16-Lead GN
and SO Packages
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Efficiency
Typical 5V to 3.3V, 10A Application
+
C
IN
220µF
×4
C
OUT
330µF
×6
+
+
+
2.7µH/15A
PV
CC1
V
CC
FREQSET
SHDN
COMP
SS
PV
CC2
PGND
GND
G1
I
FB
I
MAX
G2NC
1430 TA01
SHUTDOWN
FB NC
Q1A, Q1B, Q2: MOTOROLA MTD20N03HL
C
IN
: AVX-TPSE227M010R0100
C
OUT
: AVX-TPSE337M006R0100
SENSE
+
LTC1430A
SENSE
–
16k
100Ω
R
C
7.5k
C
C
4700pF
C1
220pF
MBR0530T1
1k
0.1µF
1µF
0.01µF
0.1µF
4.7µF
0.1µF
3.3V
10A
Q1A, Q1B
2 IN PARALLEL
Q2
5V
LOAD CURRENT (A)
40
70
100
90
80
50
60
EFFICIENCY (%)
10
1430 TA02
0.1 1
T
A
= 25°C
PV
CC
= 5V
V
OUT
= 3.3V
, LTC and LT are registered trademarks of Linear Technology Corporation.
Pentium is a registered trademark of Intel Corporation.
AMD-K6 is a registered trademark of Advanced Micro Devices, Inc.
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Power Supply for Pentium
®
II and AMD-K6
®
Microprocessors
■
High Power 5V to 3.xV Regulators
■
Local Regulation for Dual Voltage Logic Boards
■
Low Voltage, High Current Battery Regulation