CM2500-05
CMOS Multiplexer for Keypad Switches
Features
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Functionally equivalent to a five-diode pair network
Up to 60% space saving vs. discrete solution
Flexibility in design with "separate" outputs
100kΩ pull-up resistors on outputs
Voltage drop of less than 10mV under light loads
16-lead QFN package - 3mm x 3mm, 0.5mm pitch
Lead-free version available
Product Description
The CM2500-05 is a CMOS multiplexer for keypad
switches. The device is functionally equivalent to a
five-diode pair network. However, each channel in this
network has virtually no voltage drop from input to out-
put under light load. All inputs and outputs have an
internal pull up to V
CC
.
This device is particularly well suited for portable elec-
tronics (e.g. mobile handsets, PDAs, notebook com-
puters) because of its small package format. This
product is ideal for converting the logic of keypad
switches where each switch pulls two sense lines low.
The keypad multiplexer channels are set up in series
on the keypad sense lines such that it will interface
directly to the CPU chipset.
The CM2500-05 is available in a space-saving, low-
profile 16-lead QFN package. This presents a 60%
saving in space when compared with a discrete imple-
mentation. The CM2500-05 is available with optional
lead-free finishing.
Applications
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Enables more keys from current keyboard control-
ler without extra I/O from chipset
Keypad switches in mobile electronics
Roller pad or joystick in mobile electronic products
Wireless Handsets
MP3 Players
Digital Cameras
Simplified Block Schematic
(One channel pair only)
Simplified Module Schematic
GND
IN1
IN2
IN3
IN4
IN5
VCC
A
R
R
R
R
R
IN
IN
IN
IN
IN
IN
A
B
B
A
B
A
B
A
B
A
B
N1
N2
R
R
R
R
R
R
R
GND
OUTA OUT1 OUT2 OUT3 OUT4 OUT5 OUTB
©
2004 California Micro Devices Corp. All rights reserved.
09/21/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
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Tel: 408.263.3214
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Fax: 408.263.7846
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www.calmicro.com
1
CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
