LTC1430A_15 Datasheet, PDF (1/24 Pages) Linear Technology – High Power Step-Down Switching Regulator Controller

LTC1430A
High Power Step-Down
Switching Regulator Controller
FEATURES
s _{High Power 5V to 1.xV-3.xV Switching Controller:}
Can Exceed 10A Output
s _{Maximum Duty Cycle > 90% Permits 3.3V to 2.xV}
Conversion Using a Low Power 5V Supply
s _{All N-Channel External MOSFETs}
s _{Fixed Frequency Operation—Small L}
s _{Excellent Output Regulation: ±1% Over Line, Load}
and Temperature Variations
s _{High Efficiency: Over 95% Possible}
s _{No Low Value Sense Resistor Needed}
s _{Outputs Can Drive External FETs with Up to}
10,000pF Gate Capacitance
s _{Quiescent Current: 350µA Typ, 1µA in Shutdown}
s _{Fast Transient Response}
s _{Adjustable or Fixed 3.3V Output}
s _{Available in 8-Lead SO and 16-Lead GN}
and SO Packages
APPLICATI S
s _{Power Supply for Pentium}^® _{II and AMD-K6}^®
Microprocessors
s _{High Power 5V to 3.xV Regulators}
s _{Local Regulation for Dual Voltage Logic Boards}
s _{Low Voltage, High Current Battery Regulation}
DESCRIPTIO
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.
, 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.
TYPICAL APPLICATI
+
4.7µF
Typical 5V to 3.3V, 10A Application
5V
+
100Ω
1µF
MBR0530T1
+ C_IN
220µF
×4
0.1µF
0.01µF
PV_CC2 PV_CC1
V_CC
G1
SS
I_MAX
LTC1430A I_FB
NC
FREQSET G2
SHUTDOWN
SHDN PGND
16k
0.1µF
Q1A, Q1B
2 IN PARALLEL
0.1µF _2.7µH/15A
1k
3.3V
Q2
+ C_OUT
10A
330µF
×6
COMP
GND
C1
220pF ^RC
SENSE⁺
7.5k
FB NC
C_C
SENSE^–
4700pF
1430 TA01
Q1A, Q1B, Q2: MOTOROLA MTD20N03HL
C_IN: AVX-TPSE227M010R0100
C_OUT: AVX-TPSE337M006R0100
Efficiency
100
T_A = 25°C
90
PV_CC = 5V
V_OUT = 3.3V
80
70
60
50
40
0.1
1
LOAD CURRENT (A)
10
1430 TA02
1