LT3430-1_15 Datasheet, PDF (1/28 Pages) Linear Technology – High Voltage, 3A, 200kHz/100kHz Step-Down Switching Regulators

FEATURES
■ _{Wide Input Range: 5.5V to 60V}
■ _{3A Peak Switch Current over All Duty Cycles}
■ _{Constant Switching Frequency:}
200kHz (LT3430)
100kHz (LT3430-1)
■ _{0.1Ω Switch Resistance}
■ _{Current Mode}
■ _{Effective Supply Current: 2.5mA}
■ _{Shutdown Current: 30µA}
■ _{1.2V Feedback Reference Voltage}
■ _{Easily Synchronizable}
■ _{Cycle-by-Cycle Current Limiting}
■ _{Small, 16-Pin Thermally Enhanced TSSOP Package}
APPLICATIONS
■ _{Industrial and Automotive Power Supplies}
■ _{Portable Computers}
■ _{Battery Chargers}
■ _{Distributed Power Systems}
LT3430/LT3430-1
High Voltage, 3A,
200kHz/100kHz Step-Down
Switching Regulators
DESCRIPTION
The LT^®3430/LT3430-1 are monolithic buck switching
regulators that accept input voltages up to 60V. A high ef-
ficiency 3A, 0.1Ω switch is included on the die along with
all the necessary 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 with
a logic level input from 228kHz to 700kHz for the LT3430
or from 125kHz to 250kHz for the LT3430-1.
The LT3430/LT3430-1 are available in a thermally enhanced
16-pin TSSOP package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
*US Patent # 6498466
TYPICAL APPLICATION
5V, 2A Buck Converter
MMSD914TI
V_IN
5.5V*
TO 60V
4.7µF
100V
OFF ON
BOOST
V_IN
SW
LT3430**
SHDN
BIAS
SYNC
FB
GND
V_C
0.68µF
22µH
30BQ060
+
15.4k
V_OUT
5V
2A
100µF 10V
SOLID
TANTALUM
4.99k
3.3k
0.022µF
220pF
3430 TA01
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
** SEE LT3430-1 CIRCUIT IN APPLICATIONS INFORMATION SECTION
Efficiency vs Load Current
100
V_OUT = 5V
90
V_IN = 12V
80
V_IN = 42V
70
60
LT3430-1 L = 68µH
LT3430 L =27µH
50
0
0.5
1.0
1.5
2.0
2.5
LOAD CURRENT (A)
3430 TA02
34301fa
1