May 2002
LM2612
400mA Sub-miniature, Programmable, Step-Down DC-DC
Converter for Ultra Low-Voltage Circuits
General Description
Key Specifications
n Operates from a single LiION cell (2.8V to 5.5V)
n Pin programmable output voltage (1.05V, 1.3V, 1.5V and
1.8V)
The LM2612 step-down DC-DC converter is optimized for
powering ultra-low voltage circuits from a single Lithium-Ion
cell. It provides up to 400mA (300mA for B grade), over an
input voltage range of 2.8V to 5.5V. Pin programmable out-
put voltages of 1.05V, 1.3V, 1.5V or 1.8V allow adjustment
for MPU voltage options without board redesign or external
feedback resistors.
n 400mA maximum load capability (300mA for B grade)
±
n
2% PWM mode DC output voltage precision
n 2mV typ PWM mode output voltage ripple
n 150 µA typ PFM mode quiescent current
n 0.1µA typ shutdown mode current
n Internal synchronous rectification for high PWM mode
efficiency (91% at 2.8VIN, 1.8VOUT
n 600kHz PWM mode switching frequency
n SYNC input for PWM mode frequency synchronization
from 500kHz to 1MHz
The device has three pin-selectable modes for maximizing
battery life in mobile phones and similar portable applica-
tions. Low-noise PWM mode offers 600kHz fixed-frequency
operation to reduce interference in RF and data acquisition
applications during full-power operation. In PWM mode, in-
ternal synchronous rectification provides high efficiency
(91% typ. at 1.8VOUT). A SYNC input allows synchronizing
the switching frequency in a range of 500kHz to 1MHz to
)
avoid noise from intermodulation with system frequencies. Features
Low-current hysteretic PFM mode reduces quiescent current
n Sub-miniature 10-pin micro SMD package
to 150 µA (typ.) during system standby. Shutdown mode
turns the device off and reduces battery consumption to
0.1µA (typ.). Additional features include soft start and current
overload protection.
n Only three tiny surface-mount external components
required
n Uses small ceramic capacitors.
n Internal soft start
n Current overload protection
n No external compensation required
The LM2612 is available in a 10 pin micro SMD packge. This
package uses National’s wafer level chip-scale micro SMD
technology and offers the smallest possible size. Only three
small external surface-mount components, an inductor and
two ceramic capacitors are required.
Applications
n Mobile Phones
n Hand-Held Radios
n Battery Powered Devices
Typical Application Circuit
20007102
© 2002 National Semiconductor Corporation
DS200071
www.national.com