2004 California Micro Devices Corp. All rights reserved.
09/21/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Tel: 408.263.3214
Fax: 408.263.7846
www.calmicro.com
1
CM2500-05
CMOS Multiplexer for Keypad Switches
Features
Functionally equivalent to a five-diode pair network
Up to 60% space saving vs. discrete solution
Flexibility in design with "separate" outputs
100k
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
Applications
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
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.
Simplified Block Schematic
Simplified Module Schematic
(One channel pair only)
IN
IN
IN
IN
IN
B
B
B
B
B
A
A
A
A
A
GND
IN1
IN2
IN3
IN4
IN5
VCC
OUTA OUT1 OUT2 OUT3 OUT4 OUT5 OUTB
R
R
R
R
R
R
R
R
R
R
R
R
IN
GND
A
B
N1
N2
2004 California Micro Devices Corp. All rights reserved.
2
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Tel: 408.263.3214
Fax: 408.263.7846
www.calmicro.com
09/21/04
CM2500-05
Ordering Information
Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.
PIN DESCRIPTIONS
PINS
NAME
DESCRIPTION
1
NC
No internal connection.
2
OUTA
Combined "Functional OR" output of IN1, IN2 and IN3.
3
VCC
Positive supply voltage.
4
IN1
Input 1 from switch to be multiplexed.
5
IN2
Input 2 from switch to be multiplexed.
6
IN3
Input 3 from switch to be multiplexed.
7
IN4
Input 4 from switch to be multiplexed.
8
IN5
Input 5 from switch to be multiplexed.
9
NC
No internal connection.
10
GND
Negative supply voltage.
11
OUTB
Combined "Functional OR" output of IN4 and IN5.
12
OUT5
Output 5 to keypad interface lines.
13
OUT4
Output 4 to keypad interface lines.
14
OUT3
Output 3 to keypad interface lines.
15
OUT2
Output 2 to keypad interface lines.
16
OUT1
Output 1 to keypad interface lines.
PACKAGE / PINOUT DIAGRAM
Note: This drawing is not to scale.
Bottom View
16-Lead QFN Package
IN1
VCC
OUTA
NC
NC
GND
OUTB
OUT5
OUT1
OUT2
OUT3
OUT4
IN2
IN3
IN4
IN5
4
3
2
1
9
10
11
12
5
6
7
8
16
15
14
13
QFN16
3 X 3
PART NUMBERING INFORMATION
Pads
Package
Standard Finish
Lead-free Finish
Ordering Part
Number
1
Part Marking
Ordering Part
Number
1
Part Marking
16
QFN-16
CM2500-05QF
CM250005QF
CM2500-05QE
CM250005QE
2004 California Micro Devices Corp. All rights reserved.
09/21/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Tel: 408.263.3214
Fax: 408.263.7846
www.calmicro.com
3
CM2500-05
Specifications
Note 1: Equivalent to discharging a 100pF capacitor via a 1.5k
resistor (Human body model).
Note 1: Operating Characteristics are over Standard Operating Conditions unless otherwise specified.
ABSOLUTE MAXIMUM RATINGS
PARAMETER
RATING
UNITS
ESD Protection (HBM, All Pins, See Note 1)
+2000
V
V
CC
[GND - 0.5] to +6.0
V
V
I
(Inputs and Outputs)
[GND - 0.5] to [VCC + 0.5]
V
Storage Temperature Range
-65 to +150
C
Operating Temperature Range - Junction
-40 to +150
C
DC Package Power rating
0.5
W
STANDARD (RECOMMENDED) OPERATING CONDITIONS
SYMBOL
PARAMETER
MIN
TYP
MAX
UNITS
V
CC
Supply Voltage
1.5
5.5
V
V
I
DC Input Voltage
0
-
V
CC
V
T
AMB
Ambient Operating Temperature Range
-40
-
85
C
ELECTRICAL OPERATING CHARACTERISTICS
(NOTE 1)
Supply Pins (V
BUS
= 4.1V to 5.5V; V
CC
= 1.65V to 3.6V)
SYM-
BOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
I
CC
Supply quiescent current
All inputs/outputs floating
0.1
10.0
A
R
OUT
OUTx Pull-up Resistance
50
100
150
k
R
IN2.7
INx Pull-up Resistance
VCC=2.7V, PIN at GND
50
100
150
k
R
IN1.8
INx Pull-up Resistance
VCC=1.8V, PIN at GND
100
240
500
k
V
D
Voltage Drop (OUTx to GND)
VCC=2.7V, INx = GND
10
100
mV
V
IL
Maximum Low-level Input Voltage
V
CC
x 0.3
V
V
IH
Minimum High-level Input Voltage
V
CC
x 0.7
V
I
L
OUTx Leakage Current
INx floating
1.0
A
C
P
OUTx / INx Pin Capacitance
At 2.5 Volt bias, 1 MHz
15
p
F
2004 California Micro Devices Corp. All rights reserved.
4
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Tel: 408.263.3214
Fax: 408.263.7846
www.calmicro.com
09/21/04
CM2500-05
Applications Information
Figure 1. Typical Application for Extended 4X4 Keyboard
The CM2500-05 can be used with just about any key-
pad configuration. The diagram below gives an exam-
ple of an interface for a 4 column x 4 row
implementation. The outputs of the CM2500-05 have
been designed to interface with nearly any type of key-
board setup provided the same methodology is used.
Basically if any one of the switches 17 to 21 are closed,
it will pull down 2 row lines rather than 1. All outputs on
the CM2500-05 are open drain.
It follows in the above implementation that:
If SW17 is closed, row 1 and 2 are pulled low.
If SW18 is closed, row 1 and 3 are pulled low.
If SW19 is closed, row 1 and 4 are pulled low.
If SW20 is closed, row 2 and 3 are pulled low.
If SW21 is closed, row 2 and 4 are pulled low.
If SW17-SW21 are not closed, the standard scan
routine is in effect (i.e., one row is pulled low)
In larger keypad implementations, multiple CM2500-05
can be used to yield more switches.
OUTA
SW1
SW3
SW4
SW5
SW6
SW7
SW8
SW9
SW10
SW11
SW12
SW13
SW14
SW15
SW16
Row1
Row2
Row3
Row4
Col1
Col2
Col3
Col4
OUT1
OUT2
OUT3
OUT5
OUT4
OUTB
IN1
IN2
IN3
IN5
IN4
GND
CM2500-05
VCC
GPIO I
n
t
e
rf
ace Lines
SW2
SW17
SW18
SW19
SW20
SW21
VCC
2004 California Micro Devices Corp. All rights reserved.
09/21/04
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Tel: 408.263.3214
Fax: 408.263.7846
www.calmicro.com
5
CM2500-05
Mechanical Details
QFN-16 Mechanical Specifications
Dimensions for CM2500-05 devices supplied in 16-
lead QFN packages are presented below.
For complete information on the QFN-16 package, see
the California Micro Devices QFN Package Information
document.
* This is an approximate number which may vary.
Package Dimensions for 16-Lead QFN
PACKAGE DIMENSIONS
Package
QFN
Leads
16
Dim.
Millimeters
Inches
Min
Nom
Max
Min
Nom
Max
A
0.70
0.75
0.80
.028
.030
.031
A1
0.00
0.02
0.05
0.00
.001
.002
A3
0.20 REF
.008
b
0.20
0.25
0.30
.008
.010
.012
D
2.9
3.0
3.1
.114
.118
.122
D1
1.50 REF
.059 REF
D2
1.00
1.10
1.20
.039
.043
.047
E
2.9
3.0
3.1
.114
.118
.122
E1
1.50 REF
.059 REF
E2
1.00
1.10
1.20
.039
.043
.047
e
0.50 TYP.
.020 TYP.
L
0.30
0.40
0.50
.012
.016
.020
# per
tape and
reel
2500 pieces*
Controlling dimension: millimeters
Mechanical Package Diagrams
A3 A1
0.10 C
0.08 C
A
SIDE VIEW
D
E
0.15 C
0.15 C
BOTTOM VIEW
TOP VIEW
e
b
L
0.10
C A B
M
16X
D2
E2
DAP SIZE
1.8 X 1.8
E1
D1
Pin 1 Marking
PDF 
ZIP