1.

General description

maximum capacitance of 400 pF on the higher voltage side. The SDA and SCL pins are

over-voltage tolerant and are high-impedance when the PCA9519 is unpowered.

The port B drivers are compliant with SMBus I/O levels, while port A uses a current

sensing mechanism to detect the input or output LOW signal which prevents bus lock-up.

The port A uses a 1 mA current source for pull-up and a 200

Ω pull-down driver. This

results in a LOW on port A accommodating smaller voltage swings. The output pull-down

on the port A internal buffer LOW is set for approximately 0.2 V, while the input threshold

of the internal buffer is set about 50 mV lower than that of the output voltage LOW. When

the port A I/O is driven LOW internally, the LOW is not recognized as a LOW by the input.

This prevents a lock-up condition from occurring. The output pull-down on the port B

2.5 V. The enable (EN) pin can also be used to turn the drivers on and off under system

control. Caution should be observed to only change the state of the EN pin when the bus

is idle.

2.

Features

400 pF on port B of the device

port B

PCA9519

Rev. 01 — 22 June 2006

Objective data sheet