PCA8550

Features:

•4-bit 2-to-1 multiplexer, 1-bit latch
•5-bit internal non-volatile register
•Override input forces all outputs to logic 0
•Internal non-volatile register write/readable via I2C bus
•Write-protect pin enables/disables I2C writes to register
•2.5V multiplexed outputs
•3.3V non-multiplexed output (latched)
•5V tolerant inputs
•Useful for 'jumperless' configuration of PC motherboards
•Designed for use in Pentium Pro/Pentium II^TM systems Pentium II is a registered trademark of Intel Corporation


Pinout




Specifications

In accordance with the Absolute Maximum Rating System (IEC 134) Voltages are referenced to GND (ground = 0V)

SYMBOL	PARAMETER	CONDITIONS	RATING	UNIT
VCC	DC supply voltage		0.5 to +4.6	V
VI	DC input voltage	Note 3	1.5 to VCC +1.5	V
VOUT	DC output voltage	Note 3	0.5 to VCC +0.5	V
Tstg	Storage temperature range		60 to +150

Description

The primary function of the 4-bit 2-to-1 I²C multiplexer PCA8550 is to select either a 4-bit input or data from a non-volatile register and drive this
value onto the output pins. One additional non-multiplexed register output of PCA8550 is also provided. The non-multiplexed output is latched to
prevent output value changes of PCA8550 during I²C writes to the non-volatile register. A write protect input is provided to enable/disable the ability
to write to the non-volatile register PCA8550. An "override" input feature forces all outputs to logic 0.