Datasheet
© 2008 Microchip Technology Inc. DS22103A-page 5
MCP23018/MCP23S18
1.1 Pin Descriptions
TABLE 1-1: I
2
C PINOUT DESCRIPTION (MCP23018)
Pin
Name
28L
PDIP/
SOIC
24L
QFN
24L
SSOP
Pin
Type
Standard Function
GPB0 3 24 2 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB1 4 1 3 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB2 5 2 4 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB3 6 3 5 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB4 7 4 6 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB5 8 5 7 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB6 9 6 8 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPB7 10 7 9 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
V
DD
11 8 10 P Power
V
SS
1 23 1 P Ground
SCL 12 9 11 I Serial clock input
SDA 13 10 12 I/O Serial data I/O
ADDR 15 11 13 I Hardware address pin allows up to 8 slave devices on the bus
RESET 16 12 14 I Hardware reset
INTB 18 13 15 O Interrupt output for port B. Can be configured as active high, active low, or
open drain.
INTA 19 14 16 O Interrupt output for port A. Can be configured as active high, active low, or
open drain.
GPA0 20 15 17 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA1 21 16 18 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA2 22 17 19 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA3 23 18 20 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA4 24 19 21 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA5 25 20 22 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA6 26 21 23 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
GPA7 27 22 24 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be
enabled for interrupt on change, and/or internal pull-up resistor.
NC 2, 14,
17, 28
— — Not connected
EP — 25 — Exposed Thermal Pad (EP). Do not electrically connect, or connect to V
SS.