LT1956EFE-5 Datasheet, PDF (1/28 Pages) Linear Technology – High Voltage, 1.5A, 500kHz Step-Down

FEATURES
s _{Wide Input Range: 5.5V to 60V}
s _{1.5A Peak Switch Current}
s _{Small 16-Pin SSOP or Thermally Enhanced}
TSSOP Package
s _{Saturating Switch Design: 0.2Ω}
s _{Peak Switch Current Maintained Over}
Full Duty Cycle Range
s _{Constant 500kHz Switching Frequency}
s _{Effective Supply Current: 2.5mA}
s _{Shutdown Current: 25µA}
s _{1.2V Feedback Reference (LT1956)}
s _{5V Fixed Output (LT1956-5)}
s _{Easily Synchronizable}
s _{Cycle-by-Cycle Current Limiting}
U
APPLICATIO S
s _{High Voltage, Industrial and Automotive}
s _{Portable Computers}
s _{Battery-Powered Systems}
s _{Battery Chargers}
s _{Distributed Power Systems}
LT1956/LT1956-5
High Voltage, 1.5A,
500kHz Step-Down
Switching Regulators
DESCRIPTIO
The LT^®1956/LT1956-5 are 500kHz monolithic buck
switching regulators with an input voltage capability up to
60V. A high efficiency 1.5A, 0.2Ω switch is included on the
die along with all the necessary oscillator, control and logic
circuitry. A current mode architecture provides fast tran-
sient response and good 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 25µA and
the device can be externally synchronized from 580kHz to
700kHz with a logic level input.
The LT1956/LT1956-5 are available in fused-lead 16-pin
SSOP and thermally enhanced TSSOP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*U.S. PATENT NO. 6,498,466
TYPICAL APPLICATIO
5V Buck Converter
MMSD914TI
V_IN
12V
(TRANSIENTS
TO 60V)
2.2µF^†
100V
CERAMIC
6
BOOST
4
2
V_IN
SW
LT1956-5
15
SHDN
10
BIAS
14
SYNC
12
FB
GND
V_C
1, 8, 9, 16 11
220pF
4.7k
0.1µF
10µH
10MQ060N
V_OUT
5V
1A
22µF
6.3V
CERAMIC
4700pF
†_{UNITED CHEMI-CON THCS50EZA225ZT}
1956 TA01
Efficiency vs Load Current
100
V_IN = 12V
L = 18µH
90
80
V_OUT = 5V
V_OUT = 3.3V
70
60
50
0
0.25 0.50 0.75 1.00 1.25
LOAD CURRENT (A)
1956 TA02
1956f
1