Saturating Switch Design: 0.2鈩?/div>
Peak Switch Current Rating Maintained Over
Full Duty Cycle Range
Low Effective Supply Current: 2.5mA
Low Shutdown Current: 25碌A(chǔ)
1.2V Feedback Reference Voltage (LT1766)
5V Fixed Output (LT1766-5)
Easily Synchronizable
Cycle-by-Cycle Current Limiting
Small 16-Pin SSOP and Thermally Enhanced
TSSOP Packages
The LT
廬
1766/LT1766-5 are 200kHz monolithic buck
switching regulators that accept input voltages up to 60V.
A high efficiency 1.5A, 0.2鈩?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 25碌A(chǔ) 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
APPLICATIO S
s
s
s
s
s
High Voltage, Industrial and Automotive
Portable Computers
Battery-Powered Systems
Battery Chargers
Distributed Power Systems
TYPICAL APPLICATIO
6
V
IN
5.5V*
TO 60V
BOOST
4
2.2碌F
鈥?/div>
100V
CERAMIC
OFF ON
15
14
V
IN
LT1766
SHDN
SYNC
GND
1, 8, 9, 16
2.2k
0.022碌F
5V Buck Converter
1N4148W
0.33碌F
SW
2
47碌H
10MQ060N
V
OUT
5V
1A
+
BIAS
FB
V
C
11
220pF
10
12
15.4k
4.99k
100碌F 10V
SOLID
TANTALUM
EFFICIENCY (%)
1766 TA01
*FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
鈥?/div>
TDK C4532X7R2A225K
U
Efficiency vs Load Current
100
V
OUT
= 5V
L = 47碌H
V
IN
= 12V
90
V
IN
= 42V
80
70
60
50
0
0.25
0.75
1.00
0.50
LOAD CURRENT (A)
1.25
1766 TA02
U
U
1766fa
1
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