pca9539d NXP Semiconductors, pca9539d Datasheet - Page 5

• Manufacturer Part Number: pca9539d
• Description: 16-bit I2c And Smbus, Low Power I/o Port With Interrupt And Reset
• Manufacturer: NXP Semiconductors

NOTE: At Power-on Reset, all registers return to default values.
Philips Semiconductors
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 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 V
2006 Sep 21
16-bit I
I/O port with interrupt and reset
WRITE CONFIGURATION
DD
SHIFT REGISTER
to a maximum of 5.5 V.
SHIFT REGISTER
SHIFT REGISTER
READ PULSE
2
WRITE PULSE
C-bus and SMBus low power
DATA FROM
DD
DATA FROM
DATA FROM
POLARITY
or V
WRITE
PULSE
PULSE
SS
.
CONFIGURATION
REGISTER
C
D
K
FF
Q
Q
Figure 4. Simplified schematic of I/Os
REGISTER
OUTPUT
C
D
PORT
K
FF
Q
Q
5
INPUT PORT
INVERSION
REGISTER
REGISTER
POLARITY
C
C
D
D
K
K
FF
FF
Q
Q
Q
Q
Q1
Q2
OUTPUT PORT
REGISTER DATA
V
I/O PIN
V
INPUT PORT
REGISTER DATA
POLARITY
REGISTER DATA
DD
SS
TO INT
PCA9539
Product data sheet
SU02203