500 mA PWM Step-Down DC-DC with
Synchronous Rectifier
ADP3051
GENERAL DESCRIPTION
FEATURES
Current mode control for simple loop compensation
Input voltage range: 2.7 V to 5.5 V
Output voltage range: 0.8 V to 5.5 V
Tri-Mode™ operation for high efficiency
550 kHz PWM operating frequency
High accuracy over line, load, and temperature
Micropower shutdown mode
The ADP3051 is a low noise, current mode, pulse width modu-
lator (PWM) step-down converter capable of supplying over
500 mA to output voltages as low as 0.8 V. This device integrates
a low resistance power switch and synchronous rectifier, provid-
ing excellent efficiency over the entire output voltage range and
eliminating the need for a large and costly external Schottky
rectifier. Its 550 kHz switching frequency permits the use of
small external components.
Space-saving MSOP-8 package
Current mode control and external compensation allow the
regulator to be easily optimized for a wide range of operating
conditions. The ADP3051 operates at a constant 550 kHz
frequency at medium to heavy loads; it smoothly transitions
into Tri-Mode operation to save power at light loads. A pin-
controlled micropower shutdown mode is also included.
APPLICATIONS
Li-ion powered handhelds
MP3 players
PDAs and palmtops
Consumer electronics
The ADP3051’s 2.7 V to 5.5 V input operating range makes it
ideal for both battery-powered applications as well as those with
3.3 V or 5 V supply buses. It is available in a space-saving, 8-lead
MSOP package.
TYPICAL APPLICATION CIRCUIT
ADP3051
V
1.8V
OUT
10µH
V
3.3V
IN
4
7
6
3
IN
SW
12.5kΩ
10kΩ
SHDN
10µF
5
COMP
FB
10µF
10kΩ
27pF
PGND
2
GND
270pF
8
Figure 1.
Rev. 0
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