PCA9557 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 7 — 10 December 2013 6 of 30
NXP Semiconductors
PCA9557
8-bit I
2
C-bus and SMBus I/O port with reset
[1] HVQFN16 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 the 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.
6. System diagram
V
SS
86
[1]
supply ground
IO2 9 7 input/output 2
IO3 10 8 input/output 3
IO4 11 9 input/output 4
IO5 12 10 input/output 5
IO6 13 11 input/output 6
IO7 14 12 input/output 7
RESET
15 13 active LOW reset input
V
DD
16 14 supply voltage
Table 3. Pin description
…continued
Symbol Pin Description
SO16, TSSOP16 HVQFN16
Fig 7. System diagram
002aad276
Q7
1.1 kΩ
RESET
1.6 kΩ
SCL
1.6 kΩ
SDA
1.1 kΩ
A2
or
1.1 kΩ
A1
or
1.1 kΩ
A0
or
I
2
C-BUS/SMBus
INTERFACE
LOGIC
Q6
Q5
Q4
Q3
Q2
Q1
Q0
INPUT
PORT
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
POLARITY
INVERSION
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
CONFIG.
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0
OUTPUT
PORT
1.1 kΩ
IO0
IO7
IO6
IO5
IO4
IO3
IO2
IO1
