PCA9557 View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

PCA9557

8-bit I2C and SMBus I/0 port with reset

Philips Electronics 

Philips Semiconductors

8-bit I2C and SMBus I/0 port with reset

Product data

PCA9557

SIMPLIFIED SCHEMATIC OF I/O1 TO I/O7

DATA FROM

SHIFT REGISTER

DATA FROM

SHIFT REGISTER

WRITE

CONFIGURATION

PULSE

WRITE PULSE

CONFIGURATION

REGISTER

DQ

FF

CK Q

DQ

FF

CK Q

OUTPUT

PORT

REGISTER

READ PULSE

INPUT PORT

REGISTER

DQ

FF

CK Q

DATA FROM

SHIFT REGISTER

WRITE POLARITY

PULSE

DQ

FF

CK Q

POLARITY

INVERSION

REGISTER

NOTE: On power–up or reset, all registers return to default values.

Figure 5. Simplified schematic of I/O1 to I/O7

OUTPUT PORT

REGISTER DATA

VDD

ESD PROTECTION DIODE

I/O1 TO I/O7

ESD PROTECTION DIODE

VSS

INPUT PORT

REGISTER DATA

POLARITY

REGISTER DATA

SW00796

2001 Dec 12

5

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