Datasheet LT1676 (Analog Devices)

LT1676 Wide Input Range, High Efficiency, Step-Down Switching Regulator
U FEATURES DESCRIPTIO
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Wide Input Range: 7.4V to 60V
The LT®1676 is a wide input range, high efficiency Buck ■ 700mA Peak Switch Current Rating (step-down) switching regulator. The monolithic die in- ■
Adaptive Switch Drive Maintains Efficiency at High
cludes all oscillator, control and protection circuitry. The
Load Without Pulse Skipping at Light Load
part can accept input voltages as high as 60V and contains ■ True Current Mode Control an output switch rated at 700mA peak current. Current ■ 100kHz Fixed Operating Frequency mode control offers excellent dynamic input supply rejec- ■ Synchronizable to 250kHz tion and short-circuit protection. ■ Low Supply Current in Shutdown: 30µA The LT1676 contains several features to enhance effi- ■ Available in 8-Pin SO and PDIP Packages ciency. The internal control circuitry is normally powered via the VCC pin, thereby minimizing power drawn directly
U
from the V
APPLICATIO S
IN supply (see Applications Information). The action of the LT1676 switch circuitry is also load depen- ■ Automotive DC/DC Converters dent. At medium to high loads, the output switch circuitry ■ Telecom 48V Step-Down Converters maintains high rise time for good efficiency. At light loads, ■ Cellular Phone Battery Charger Accessories rise time is deliberately reduced to avoid pulse skipping ■ IEEE 1394 Step-Down Converters behavior. The available SO-8 package and 100kHz switching fre- quency allow for minimal PC board area requirements. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO
VIN
Efficiency vs VIN and ILOAD
8V TO 50V 5 90 VIN 1 2 SHDN V 80 CC 220µH* 3 5V VSW + 70 + 400mA 39µF 100µF MBR160 36.5k 63V LT1676 10V 1% 60 7 FB 6 8 50 SYNC VC EFFICIENCY (%) 2200pF 40 VIN = 12V 12.1k 1% VIN = 24V GND 22k 100pF 30 VIN = 36V V 4 IN = 48V 20 *65T #30 ON MAGNETICS 1676 F01 1 10 100 1000 MPP #55030 ILOAD (mA) 1676 TA01
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