PCA9539 查看數據表（PDF） - Philips Electronics

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PCA9539

16-bit I2C and SMBus, low power I/O port with interrupt and reset

Philips Electronics 

Philips Semiconductors

16-bit I2C and SMBus, low power I/O port

with interrupt and reset

Product data sheet

PCA9539

SIMPLIFIED SCHEMATIC OF I/Os

DATA FROM

SHIFT REGISTER

DATA FROM

SHIFT REGISTER

WRITE CONFIGURATION

PULSE

WRITE PULSE

CONFIGURATION

REGISTER

DQ

FF

CK Q

READ PULSE

Q1

DQ

FF

CK Q

OUTPUT

Q2

PORT

REGISTER

INPUT PORT

REGISTER

DQ

FF

CK Q

DATA FROM

SHIFT REGISTER

WRITE

POLARITY

PULSE

DQ

FF

CK Q

POLARITY

INVERSION

REGISTER

NOTE: At Power-on Reset, all registers return to default values.

Figure 4. Simplified schematic of I/Os

I/O port

When an I/O is configured as an input, FETs Q1 and Q2 are off,

creating a high impedance input. The input voltage may be raised

above VDD to a maximum of 5.5 V.

If the I/O is configured as an output, then either Q1 or Q2 is on,

depending on the state of the Output Port register. Care should be

exercised if an external voltage is applied to an I/O configured as an

output because of the low impedance path that exists between the

pin and either VDD or VSS.

OUTPUT PORT

REGISTER DATA

VDD

ESD PROTECTION DIODE

I/O PIN

ESD PROTECTION DIODE

VSS

INPUT PORT

REGISTER DATA

TO INT

POLARITY

REGISTER DATA

SU02203

2004 Sep 30

5

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