s Very Low Standby Current: 10µA
s Available in Space-Saving 8-Lead MSOP Package
s High Output Currents
s Wide VIN Range: 2.8V to 20V Operation
s VOUT Range: 1.23V to 18V
s High Efficiency: Over 93% Possible
s ±2% Output Accuracy
s Very Low Dropout Operation: 100% Duty Cycle
s Current Mode Operation for Excellent Line and
Load Transient Response
s Defeatable Burst ModeTM Operation
s Short-Circuit Protected
s Optional Programmable Soft-Start
s Micropower Shutdown: IQ = 2µA
s Cellular Telephones and Wireless Modems
s 1- to 4-Cell Lithium-Ion-Powered Applications
s Portable Instruments
s Battery-Powered Equipment
s Battery Chargers
Final Electrical Specifications
Low Quiescent Current
High Efficiency Step-Down
The LTC®1771 is a high efficiency current mode step-
down DC/DC controller that draws as little as 10µA DC
supply current to regulate the output at no load while
maintaining high efficiency for loads up to several amps.
The LTC1771 drives an external P-channel power MOSFET
using a current mode, constant off-time architecture. An
external sense resistor is used to program the operating
current level. Current mode control provides short-circuit
protection, excellent transient response and controlled
start-up behavior. Burst Mode operation enables the
LTC1771 to maintain high efficiency down to extremely
low currents. Shutdown mode further reduces the supply
current to a mere 2µA. For low noise applications, Burst
Mode operation can be easily disabled with the MODE pin.
Wide input supply range of 2.8V to 18V (20V maximum)
and 100% duty cycle operation for low dropout make the
LTC1771 ideal for a wide variety of battery-powered appli-
cations where maximizing battery life is important.
The LTC1771’s availability in both 8-lead MSOP and SO
packages provides for a minimum area solution.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
4.5V TO 18V
+ COUT 2A
Figure 1. High Efficiency Step-Down Converter
VIN = 5V
90 VIN = 10V
80 VIN = 15V
VOUT = 3.3V
40 RSENSE = 0.05Ω
LOAD CURRENT (mA)
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.