©2008 Fairchild Semiconductor Corporation

1

www.fairchildsemi.com

FPF2123-FPF2125 Rev. F

tm

October 2008

FPF2123-FPF2125

IntelliMAX™ Advanced Load Management Products

Features

1.8 to 5.5V Input Voltage Range

Controlled Turn-On

0.15-1.5A Adjustable Current Limit

Undervoltage Lockout

Thermal Shutdown

<2 A Shutdown Current

Auto Restart

Fast Current limit Response Time

3 s to Moderate Over Currents

Fault Blanking

Reverse Current Blocking

RoHS Compliant

Applications

PDAs

Cell Phones

GPS Devices

MP3 Players

Digital Cameras

Peripheral Ports

Hot Swap Supplies

General Description

The FPF2123, FPF2124, and FPF2125 are a series of load

switches which provide full protection to systems and loads

which may encounter large current conditions. These devices

contain a 0.125

current-limited P-channel MOSFET which can

operate over an input voltage range of 1.8-5.5V. The current

limit is settable using an external resistor. Internally, current is

prevented from flowing when the MOSFET is off and the output

voltage is higher than the input voltage. Switch control is by a

logic input (ON) capable of interfacing directly with low voltage

control signals. Each part contains thermal shutdown protection

which shuts off the switch to prevent damage to the part when a

continuous over-current condition causes excessive heating.

When the switch current reaches the current limit, the parts

operate in a constant-current mode to prohibit excessive

currents from causing damage. For the FPF2123 and FPF2124

if the constant current condition still persists after 10ms, these

parts will shut off the switch. The FPF2123 has an auto-restart

feature which will turn the switch on again after 160ms if the ON

pin is still active. The FPF2124 does not have this auto-restart

feature so the switch will remain off after a current limit fault until

the ON pin is cycled. The FPF2125 will not turn off after a

current limit fault, but will rather remain in the constant current

mode indefinitely. The minimum current limit is 150mA.

These parts are available in a space-saving 5 pin SOT23

package

Typical Application Circuit

Ordering Information

Part

Current Limit

[A]

Current Limit

Blanking Time

[ms]

Auto-Restart

Time

[ms]

ON Pin

Activity

Top Mark

FPF2123

0.15 - 1.5

5/10/20

80/160/320

Active HI

2123

FPF2124

0.15 - 1.5

5/10/20

NA

Active HI

2124

FPF2125

0.15 - 1.5

Infinite

NA

Active HI

2125

OFF ON

ON

GND

FPF2123 - FPF2125

ISET

TO LOAD