1 Features

1• Eight Digital Sensor Inputs

– High Input Voltage up to 34 V

– Selectable Debounce Filters From 0 ms to

3 ms

– Flexible Input Current-Limited – 0.2 mA to 5.2

mA

– Field Inputs Protected to 15-kV ESD

• Single 5-V Supply

• Output Drivers for External Status LEDs

• Cascadable for More Inputs in Multiples of Eight on•

SPI-Compatible Interface

• Overtemperature Indicator

2 Applications

• Industrial PCs

• Digital I/O Cards

• High Channel Count Digital Input Modules

• Decentralized I/O Modules

3 Description

The SN65HVS885 is an eight channel, digital-input

serializer for high-channel density digital input

modules in industrial and building automation.

Operating from a 5-V supply the device accepts field

input voltages of up to 34 V. In combination with

galvanic isolators the device completes the interface

between the high voltage signals on the field-side and

the low-voltage signals on the controller side. Inputs

signals are current limited and then validated by

internal debounce filters.

With the addition of few external components, the

input switching characteristic can be configured in

accordance with IEC61131-2 for Type 1, 2 and 3

sensor switches.

Upon the application of load and clock signals, input

data is latched in parallel into the shift register and

afterwards clocked out serially.

Cascading of multiple devices is possible by

connecting the serial output of the leading device with

the serial input of the following device, enabling the

design of high-channel count input modules. Multiple

devices can be cascaded through a single serial port,

reducing both the isolation channels and controller inputs required.

Input status can be visually indicated via constant current LED outputs. The current limit on the inputs is

set by a single, external, precision resistor. An on•

chip temperature sensor provides diagnostic

information for graceful shutdown and system safety.

The SN65HVS885 is available in a 28-pin PWP

PowerPAD™ package, allowing for efficient heat

dissipation. The device is specified for operation at temperatures from –40°C to 125°C.