SC18IS600_601_3

© NXP B.V. 2006. All rights reserved.

Product data sheet

Rev. 03 — 13 December 2006

7 of 28

NXP Semiconductors

SC18IS600/601

6.2.1.2

Open-drain output configuration

The open-drain output configuration turns off all pull-ups and only drives the pull-down

transistor of the pin when the pin latch contains a logic 0. To be used as a logic output, a

pin configured in this manner must have an external pull-up, typically a resistor tied to

The open-drain pin configuration is shown in Figure 6.

An open-drain pin has a Schmitt-triggered input that also has a glitch suppression circuit.

6.2.1.3

Input-only configuration

The input-only pin configuration is shown in Figure 7. It is a Schmitt-triggered input that

also has a glitch suppression circuit.

6.2.1.4

Push-pull output configuration

The push-pull output configuration has the same pull-down structure as both the

open-drain and the quasi-bidirectional output modes, but provides a continuous strong

pull-up when the pin latch contains a logic 1. The push-pull mode may be used when

more source current is needed from a pin output.

The push-pull pin configuration is shown in Figure 8.

A push-pull pin has a Schmitt-triggered input that also has a glitch suppression circuit.

Fig 6.

Open-drain output configuration

002aab883

pin latch data

GPIO pin

glitch rejection

input data

Fig 7.

Input-only configuration

002aab884

GPIO pin

glitch rejection

input data