LTC1430A
High Power Step-Down
Switching Regulator Controller
DESCRIPTIO
FEATURES
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High Power 5V to 1.xV-3.xV Switching Controller: The LTC 1430A is a high power, high efficiency switching
Can Exceed 10A Output regulator controller optimized for 5V to 1.xV-3.xV applica-
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Maximum Duty Cycle > 90% Permits 3.3V to 2.xV tions. It includes a precision internal reference and an inter-
Conversion Using a Low Power 5V Supply nal feedback system that can provide output regulation of
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All N-Channel External MOSFETs 1% over temperature, load current and line voltage shifts.
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Fixed Frequency OperationSmall L The LTC1430A uses a synchronous switching architecture
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Excellent Output Regulation: 1% Over Line, Load with two N-channel output devices, eliminating the need for
and Temperature Variations a high power, high cost P-channel device. Additionally, it
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High Efficiency: Over 95% Possible senses output current across the drain-source resistance
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No Low Value Sense Resistor Needed of the upper N-channel FET, providing an adjustable cur-
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Outputs Can Drive External FETs with Up to rent limit without an external low value sense resistor.
10,000pF Gate Capacitance
The LTC1430A includes a fixed frequency PWM oscillator
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Quiescent Current: 350m A Typ, 1m A in Shutdown
for low output ripple under virtually all operating condi-
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Fast Transient Response
tions. The 200kHz free-running clock frequency can be
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Adjustable or Fixed 3.3V Output
externally adjusted from 100kHz to above 500kHz. The
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Available in 8-Lead SO and 16-Lead GN
LTC1430As maximum duty cycle is typically 93.5% com-
and SO Packages
pared to 88% for the LTC1430. This permits 3.3V to 2.xV
conversion using a low power 5V supply. The LTC1430A
features low 350m A quiescent current, allowing greater
APPLICATI S
than 90% efficiency operation in converter designs from
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1A to greater than 50A output current. Shutdown mode
Power Supply for Pentium II and AMD-K6
drops the LTC1430A supply current to 1m A. For new
Microprocessors
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designs, refer to the LTC3830.
High Power 5V to 3.xV Regulators
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, LTC and LT are registered trademarks of Linear Technology Corporation.
Local Regulation for Dual Voltage Logic Boards
Pentium is a registered trademark of Intel Corporation.
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Low Voltage, High Current Battery Regulation AMD-K6 is a registered trademark of Advanced Micro Devices, Inc.
TYPICAL APPLICATI
Typical 5V to 3.3V, 10A Application Efficiency
100
5V
T = 25C
A
PV = 5V
+
C CC
IN
90
MBR0530T1
+ V = 3.3V
220m F OUT
100W 1m F
4
80
PV PV 16k 0.1m F
CC2 CC1 Q1A, Q1B
2 IN PARALLEL
+ V G1
CC
70
4.7m F 0.1m F
0.1m F
SS I 2.7m H/15A
MAX
1k
0.01m F
3.3V
LTC1430A I
FB
60
10A
+
C
OUT
NC FREQSET G2 Q2
330m F
6
50
SHUTDOWN SHDN PGND
COMP
GND
40
C1
+
0.1 1 10
R SENSE
220pF C
1430 TA01
7.5k LOAD CURRENT (A)
FB NC
C
C SENSE 1430 TA02
Q1A, Q1B, Q2: MOTOROLA MTD20N03HL
4700pF
C : AVX-TPSE227M010R0100
IN
C : AVX-TPSE337M006R0100
OUT
1
EFFICIENCY (%)
UO
UO
ULTC1430A
(Note 1)
ABSOLUTEXAI U RATI GS
Supply Voltage Junction Temperature........................................... 150 C
V ....................................................................... 9V Operating Temperature Range
CC
PV .............................................................. 13V LTC1430AC ............................................. 0 C to 70 C
CC1, 2
Input Voltage LTC1430AI ........................................ 40 C to 85 C
I ......................................................... 0.3V to 18V Storage Temperature Range ................ 65 C to 150 C
FB
All Other Inputs ...................... 0.3V to (V + 0.3V) Lead Temperature (Soldering, 10 sec)................. 300 C
CC
PACKAGE/ORDER I FOR ATIO
ORDER ORDER
TOP VIEW
PART NUMBER PART NUMBER
G1 1 16 G2
TOP VIEW
PV 2 15 PV
CC2
CC1 LTC1430ACGN
LTC1430ACS8
G1 1 8 G2
PGND 3 14 V
CC
LTC1430AIGN
PV V /PV
2 7
CC1 CC CC2 GND 4 13 I
FB
LTC1430ACS
GND 3 6 COMP
SENSE 5 12 I
MAX
FB 4 5 SHDN FB 6 11 FREQSET
+
SENSE 7 10 COMP
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO SHDN 8 9 SS
T = 150 C, q = 150 C/W
JMAX JA
1430A
GN PACKAGE S PACKAGE
16-LEAD PLASTIC SSOP 16-LEAD PLASTIC SO
T = 150 C, q = 130 C/W (GN)
JMAX JA
T = 150 C, q = 110 C/W (S)
JMAX JA
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
V = 5V, T = 25 C (Note 2) unless otherwise noted.
CC A
LTC1430AC LTC1430AI
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
V Supply Voltage l 48 4 8 V
CC
PV PV , PV Voltage l 313 3 13 V
CC CC1 CC2
V Output Voltage Figure 1 3.30 3.30 V
OUT
+
V Feedback Voltage SENSE and SENSE Floating , l 1.25 1.265 1.28 1.23 1.265 1.29 V
FB
V = 2.5V
COMP
D V Output Load Regulation Figure 1, I = 0A to 10A 5 5 mV
OUT OUT
Output Line Regulation Figure 1, V = 4.75V to 5.25V 1 1 mV
CC
I Supply Current (V Only) Figure 2, V = V l 350 700 350 700 m A
VCC CC SHDN CC
V = 0V 1 10 1 10 m A
SHDN
I Supply Current (PV ) Figure 2, PV = 5V, V = V (Note 3) 1.5 1.5 mA
PVCC CC CC SHDN CC
V = 0V 0.1 0.1 m A
SHDN
f Internal Oscillator Frequency FREQSET Floating l 140 200 260 130 200 300 kHz
OSC
2
U WU
U W W W