1.5MHz 2A Synchronous Step-Down Regulator Dropout TD6817(B)
General
Description

The TD6817/TD6817B is a high efficiency monolithic
synchronous buck regulator using a constant frequency,
current mode architecture. The device is available in an
adjustable version and fixed output voltages of 1.5V and
1.8V. Supply current during operation is only 20mA and
drops to ≤1mA in shutdown. The 2.5V to 5.5V input
voltage range makes the TD6817/TD6817B ideally
suited for single Li-Ion battery-powered applications.
100% duty cycle provides low dropout operation,
extending battery life in portable systems.Automatic
Burst Mode operation increases efficiency at light loads,
further extending battery life.
Switching frequency is internally set at 1.5MHz, allowing
the use of small surface mount inductors and capacitors.
The internal synchronous switch increases efficiency and
eliminates the need for an external Schottky diode. Low
output voltages are easily supported with the 0.6V
feedback reference voltage. The TD6817/TD6817B is
available in TSOT23-5 package.

Package
Types

Features

.
High Efficiency: Up to 96%
.
High Efficiency at light loads
.
Very Low Quiescent Current: Only 20uA During
Operation
.
2A Output Current
.
2.5V to 5.5V Input Voltage Range
.
1.5MHz Constant Frequency Operation
.
No Schottky Diode Required
.
Low Dropout Operation: 100% Duty Cycle
.
0.6V Reference Allows Low Output Voltages
.
Shutdown Mode Draws ≤1uA Supply Current
.
Current Mode Operation for Excellent Line and Load
Transient Response
.
Overtemperature Protected
.
TSOT23-5 Package
is
Available
Applications

.
Cellular Telephones
.
Personal Information Appliances
.
Wireless and DSL Modems
.
Digital Still Cameras
.
MP3 Players
.
Portable Instruments
SOT235/
SOT236

Figure
1.
Package
Types
of
TD6817/TD6817B

December,
20,
2009
Techcode
Semiconductor
Limited