LT1766 Datasheet, PDF (1/28 Pages) Linear Technology – Step-Down Switching Regulator

LT1766/LT1766-5
5.5V to 60V 1.5A, 200kHz
Step-Down Switching Regulator
FEATURES
s _{Wide Input Range: 5.5V to 60V}
s _{1.5A Peak Switch Current}
s _{Constant 200kHz Switching Frequency}
s _{Saturating Switch Design: 0.2Ω}
s _{Peak Switch Current Rating Maintained Over}
Full Duty Cycle Range
s _{Low Effective Supply Current: 2.5mA}
s _{Low Shutdown Current: 25µA}
s _{1.2V Feedback Reference Voltage (LT1766)}
s _{5V Fixed Output (LT1766-5)}
s _{Easily Synchronizable}
s _{Cycle-by-Cycle Current Limiting}
s _{Small 16-Pin SSOP and Thermally Enhanced}
TSSOP Packages
U
APPLICATIO S
s _{High Voltage, Industrial and Automotive}
s _{Portable Computers}
s _{Battery-Powered Systems}
s _{Battery Chargers}
s _{Distributed Power Systems}
DESCRIPTIO
The LT^®1766/LT1766-5 are 200kHz monolithic buck
switching regulators that accept input voltages 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 cir-
cuitry. A current mode control architecture delivers 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 25µA and the
device can be externally synchronized from 228kHz to
700kHz with logic level inputs.
The LT1766/LT1766-5 are available in a 16-pin fused-lead
SSOP package or a TSSOP package with exposed backside
for improved thermal performance.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*Patent # 6, 498, 466
TYPICAL APPLICATIO
5V Buck Converter
1N4148W
V_IN
5.5V*
TO 60V
6
BOOST
2.2µF^†
100V
4
V_IN
2
SW
LT1766
CERAMIC
15
OFF ON
SHDN
10
BIAS
14
SYNC
GND
1, 8, 9, 16
12
FB
V_C
11
220pF
2.2k
0.33µF
47µH
10MQ060N
+
15.4k
V_OUT
5V
1A
100µF 10V
SOLID
TANTALUM
4.99k
0.022µF
1766 TA01
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
†_{TDK C4532X7R2A225K}
Efficiency vs Load Current
100
V_OUT = 5V
L = 47µH
90
V_IN = 12V
V_IN = 42V
80
70
60
50
0
0.25 0.50 0.75 1.00 1.25
LOAD CURRENT (A)
1766 TA02
1766fa
1