www.fairchildsemi.com
FAN2508, FAN2509
50 mA CMOS LDO Regulators
wide variety of external capacitors, and the compact SOT23-5
surface-mount package. The FAN2508/09 family of products
offer significant improvements over older BiCMOS designs
and are pin-compatible with many popular devices. The
output is thermally protected against overload.
Features
• Ultra Low Power Consumption
• 50 mV dropout voltage at 50 mA
• 25 µA ground current at 50 mA
• Enable/Shutdown Control
• SOT23-5 package
The FAN2508 and FAN2509 devices are distinguished by
the assignment of pin 4:
• Thermal limiting
• 300 mA peak current
FAN2508: pin 4 – ADJ, allowing the user to adjust the
output voltage over a wide range using an external voltage
divider.
Applications
• Cellular Phones and accessories
• PDAs
• Portable cameras and video recorders
• Laptop, notebook and palmtop computers
FAN2508-XX: pin 4 – BYP, to which a bypass capacitor
may be connected for optimal noise performance. Output
voltage is fixed, indicated by the suffix XX.
Description
FAN2509-XX: pin 4 – ERR, a flag which indicates that the
output voltage has dropped below the specified minimum
due to a fault condition.
The FAN2508/09 family of micropower low-dropout voltage
regulators utilize CMOS technology to offer a new level of
cost-effective performance in GSM and TDMA cellular
handsets, Laptop and Notebook portable computers, and
other portable devices. Features include extremely low
power consumption and low shutdown current, low dropout
voltage, exceptional loop stability able to accommodate a
The standard fixed output voltages available are 2.5V, 2.6V,
2.7V, 2.8V, 2.85V, 3.0V, and 3.3V. Custom output voltage are
also available: please contact your local Fairchild Sales
Office for information.
Block Diagrams
EN
EN
V
IN
V
IN
BYP
Bandgap
Bandgap
p
p
Error
Error
Amplifier
Amplifier
V
OUT
V
OUT
ADJ
Thermal
Sense
Thermal
Sense
GND
GND
FAN2508
FAN2508-XX
EN
V
IN
ERR
Bandgap
p
Error
Amplifier
V
OUT
Thermal
Sense
GND
FAN2509-XX
REV. 1.0.1 12/18/00