
February 2013
2009 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FT7521 Rev. 1.0.8
FT7521
—
Re
set
Ti
mer
with
Fi
x
ed
De
lay
and
Rese
t
Pulse
FT7521
Reset Timer with Fixed Delay and Reset Pulse
Features
Fixed Reset Delay: 7.5 Seconds
One Input Reset Pin
Open-Drain Output Pin with Fixed 400ms Pulse
1.8 V to 5.0 V Operation (T
A=-40°C to +85°C)
1.7 V to 5.0 V Operation (T
A=-25°C to +85°C)
1.65 V to 5.00 V Operation (T
A=0°C to +85°C)
<1 A I
CCQ Consumption
Zero-Second Test-Mode Enable
Integrated Pull-Up Resistor on /SRO
Applications
Cell Phones
Portable Media Players
Tablets
Mobile Devices
Consumer Medical
Description
The FT7521 is a timer for resetting a mobile device
where long reset times are needed. The long delay
helps avoid unintended resets caused by accidental key
presses. It has a fixed delay of 7.5 ±20% seconds. The
DSR pin enables Test Mode operation by immediately
forcing /RST1 LOW for factory testing.
The FT7521 has one input for single-button resetting
capability. The device has a single open-drain output
with 0.5 mA pull-down drive.
FT7521 draws minimal ICC current when inactive and
functions over a power supply range of 1.65 V to 5.0 V.
Open-Drain Output
Oscillator
Digital Logic &
Counter
Voltage
Reference
/SR0
DSR
/RST1
VCC
TEST
RPU
Figure 1.
Block Diagram
Ordering Information
Part Number
Operating
Temperature Range
Package
Packing
Method
FT7521L6X
-40
C to +85C
6-
Lead, MicroPak 1.0 x 1.45 mm, JEDEC MO-252
5000 Units on
Tape and Reel
FT7521FHX
6-
Lead, MicroPak2 1.0 x 1.0 mm Body, .35 mm Pitch