PCA9555 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2017. All rights reserved.
Product data sheet Rev. 10 — 8 November 2017 5 of 34
NXP Semiconductors
PCA9555
16-bit I
2
C-bus and SMBus I/O port with interrupt
5.2 Pin description
[1] HVQFN and HWQFN package die supply ground is connected to both the V
SS
pin and the exposed center
pad. The V
SS
pin must be connected to supply ground for proper device operation. For enhanced thermal,
electrical, and board-level performance, the exposed pad needs to be soldered to the board using a
corresponding thermal pad on the board, and for proper heat conduction through the board thermal vias
need to be incorporated in the PCB in the thermal pad region.
Table 3. Pin description
Symbol Pin Description
SO24, SSOP24,
TSSOP24
HVQFN24,
HWQFN24
INT
1 22 interrupt output (open-drain)
A1 2 23 address input 1
A2 3 24 address input 2
IO0_0 4 1 port 0 input/output
IO0_1 5 2
IO0_2 6 3
IO0_3 7 4
IO0_4 8 5
IO0_5 9 6
IO0_6 10 7
IO0_7 11 8
V
SS
12 9
[1]
supply ground
IO1_0 13 10 port 1 input/output
IO1_1 14 11
IO1_2 15 12
IO1_3 16 13
IO1_4 17 14
IO1_5 18 15
IO1_6 19 16
IO1_7 20 17
A0 21 18 address input 0
SCL 22 19 serial clock line
SDA 23 20 serial data line
V
DD
24 21 supply voltage
