1
LT1766/LT1766-5
1766fa
BOOST
V
IN
6
2
10
12
10MQ060N
15.4k
V
OUT
5V
1A
4
15
14
11
220pF
0.022µF
*
†
FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY
TDK C4532X7R2A225K
1, 8, 9, 16
LT1766
SHDN
SYNC
SW
BIAS
FB
V
C
GND
0.33µF
100µF 10V
SOLID
TANTALUM
47µH
1N4148W
4.99k
1766 TA01
2.2µF
†
100V
CERAMIC
V
IN
5.5V*
TO 60V
+
2.2k
ONOFF
5.5V to 60V 1.5A, 200kHz
Step-Down Switching Regulator
■
Wide Input Range: 5.5V to 60V
■
1.5A Peak Switch Current
■
Constant 200kHz Switching Frequency
■
Saturating Switch Design: 0.2Ω
■
Peak Switch Current Rating Maintained Over
Full Duty Cycle Range
■
Low Effective Supply Current: 2.5mA
■
Low Shutdown Current: 25µA
■
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
®
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.
■
High Voltage, Industrial and Automotive
■
Portable Computers
■
Battery-Powered Systems
■
Battery Chargers
■
Distributed Power Systems
, LTC and LT are registered trademarks of Linear Technology Corporation.
5V Buck Converter
Efficiency vs Load Current
LOAD CURRENT (A)
0
EFFICIENCY (%)
80
90
100
1.00
1766 TA02
70
60
50
0.25
0.50
0.75
1.25
V
IN
= 12V
V
IN
= 42V
V
OUT
= 5V
L = 47µH
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
*Patent # 6, 498, 466
