LT3430 Datasheet, PDF (1/28 Pages) Linear Technology – High Voltage, 3A, 200kHz Step-Down Switching Regulator

FEATURES
s _{Wide Input Range: 5.5V to 60V}
s _{3A Peak Switch Current}
s _{Small Thermally Enhanced 16-Pin TSSOP Package}
s _{Constant 200kHz Switching Frequency}
s _{Saturating Switch Design: 0.1Ω}
s _{Peak Switch Current Maintained Over}
Full Duty Cycle Range
s _{Effective Supply Current: 2.5mA}
s _{Shutdown Current: 30µA}
s _{1.2V Feedback Reference Voltage}
s _{Easily Synchronizable}
s _{Cycle-by-Cycle Current Limiting}
U
APPLICATIO S
s _{Industrial and Automotive Power Supplies}
s _{Portable Computers}
s _{Battery Chargers}
s _{Distributed Power Systems}
Final Electrical Specifications
LT3430
High Voltage, 3A,
200kHz Step-Down
Switching Regulator
DESCRIPTIO
August 2002
The LT^®3430 is a 200kHz monolithic buck switching regu-
lator that accepts input voltages up to 60V. A high efficiency
3A, 0.1Ω switch is included on the die along with all the nec-
essary oscillator, control and logic circuitry. A current mode
architecture provides fast transient response and excellent
loop stability.
Special design techniques and a new high voltage process
achieve high efficiency over a wide input range. Efficiency
is maintained over a wide output current range by using the
output to bias the circuitry and by utilizing a supply boost
capacitor to saturate the power switch. Patented circuitry
maintains peak switch current over the full duty cycle range.
A shutdown pin reduces supply current to 30µA and a SYNC
pin can be externally synchronized from 228kHz to 700kHz
with a logic level input.
The LT3430 is available in a thermally enhanced 16-pin
TSSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
5V, 2A Buck Converter
MMSD914TI
V_IN
5.5V*
TO 60V
6
BOOST
3, 4
2, 5
V_IN
SW
4.7µF 100V
CERAMIC^†
LT3430
15
OFF ON
SHDN
10
BIAS
14
SYNC
GND
1, 8, 9, 16
12
FB
V_C
11
220pF
3.3k
0.68µF
22µH
30BQ060
+
15.4k
4.99k
V_OUT
5V
2A
100µF 10V
SOLID
TANTALUM
Efficiency vs Load Current
100
V_OUT = 5V
L = 27µH
90
V_IN = 12V
80
V_IN = 42V
70
60
0.022µF
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
†_{UNITED CHEMI-CON}
3430 TA01
50
0
0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
3430 TA02
sn3430 3430is
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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