Mobile I/O Expander and
Data Sheet
FEATURES
18-GPIO port expander or 10 × 8 keypad matrix
GPIOs configurable as GPIs, GPOs, and keypad rows or
columns
I
2
C interface with auto-increment
1.65 V to 3.6 V operation
Keypad lock capability
Open-drain interrupt output
Key press and key release interrupts
GPI interrupt with level programmability
Programmable pull-ups
Key event counter with overflow interrupt
275 μs debounce on the reset line and GPIs
1 μA typical idle current
55 μA typical polling current
4 mm × 4 mm LFCSP package
Small 2 mm x 2 mm WLCSP package, 0.4 mm pitch
Multiple I
2
C addresses available for the LFCSP package to
allow multiple port expanders on the same bus
APPLICATIONS
Keypad and I/O expander designed for QWERTY type phones
that require a large keypad matrix
FUNCTIONAL BLOCK DIAGRAM
18
17
19
21
23
22
20
24
CONTROL
REGISTERS
CONTROL
INTERFACE
R7
R6
R5
R4
R3
R2
R1
R0
C0
C1
C2
C3
C4
C5
C6
C7
C9
C8
GND
V
CC
SCL
SDA
RST
INT
3 4 5 6 7 8 9 10 11 12 13 14 15 161 2
ADP5587
08612-001
Figure 1.
GENERAL DESCRIPTION
The ADP5587 is an I/O port expander and keypad matrix
designed for QWERTY type phones that require a large keypad
matrix and expanded I/O lines. I/O expander ICs are used in
mobile platforms as a solution to the limited number of GPIOs
available in the main processor.
In its small 2 mm × 2 mm package, the ADP5587 contains
enough power to handle all key scanning and decoding and
to flag the processor of key presses and releases via the I
2
C
interface and interrupt. The ADP5587 frees the main micro-
processor from the need to monitor the keypad, thereby
minimizing current drain and increasing processor bandwidth.
The ADP5587 is also equipped with a buffer/FIFO and key
event counter to handle and keep track of up to 10 unprocessed
key or GPI events with overflow wrap and interrupt capability.
The ADP5587 has keypad lock capability with an option to
trigger or not trigger an interrupt at key presses and releases.
All communication to the main processor is done using one
interrupt line and two I
2
C-compatible interface lines. The
ADP5587 can be configured as a keypad matrix of up to 8 rows ×
10 columns (a maximum of 80 keys).
When the ADP5587 is used for smaller keypad matrices, unused
row and column pins can be reconfigured to act as general-
purpose inputs or outputs. R0 to R7 denote the row pins of the
matrix, whereas C0 to C9 denote the column pins. At power-up,
all rows and columns default to GPIs and must be programmed
to function as part of the keypad matrix or as GPOs.
Two options for I
2
C addresses exist for the LFCSP package to
reduce the chance of port contention and allow up to two
ADP5587 ICs to operate on the same I
2
C bus (see the Ordering
Guide).
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2009-2012 Analog Devices, Inc. All rights reserved.
