1 Features
• Eight Configurable IEC 61131-2 Type 1, 2, 3
Isolated Digital Inputs
• Low Power and Heat Dissipation
– Selectable Input Current Limit
– Field Side LED Drivers Using Input Current
• Supports Sourcing and Sinking Type Inputs
• Wire-break Detection in Sink Mode
• Integrated Field Supply Voltage Monitor
• Programmable Glitch Filters
• Built in CRC check across Barrier
• Serial SPI and Parallel Output Options
– Supports SPI Daisy Chaining
– Supports SPI Burst Mode
• Integrated IEC ESD and Surge Protection
• High CMTI(Typ): 75 kV/μs
• VCC1 Logic Supply Voltage Range: 1.71 V to 5.5 V
• AVCC Field Supply Voltage Range (Sink mode):
8.5 V to 36 V
• AVCC Field Supply Voltage Range (Source mode):
13 V to 36 V
• Ambient Temperature Range: –40°C to 125°C
• Small Footprint 38-SSOP Package
• Safety-related certifications:
– 4242-VPK VIOTM and 637-VPK VIORM per DIN V
VDE V 0884-11
– 3000-VRMS Isolation for 1 Minute per UL 1577
– IEC 62368-1, IEC 61010-1 and GB
4943.1-2011Certifications
– All Certifications Planned

2 Applications
• Programmable Logic Controllers (PLC)
– Digital Input Modules
– Mixed Input Modules
• Motor Drive Digital Inputs
• Binary Input Modules
• CNC Control
• Industrial Transport Digital Inputs

3 Description
The ISO1228 is an eight-channel isolated 24-V digital
input receivers, configurable to IEC 61131-2 Type
1, 2, and 3 characteristics. The ISO1228 includes
resistor-programmable accurate current limit and
field side input-current-powered LED indication to
reduce system power dissipation and reduce board
temperatures. ISO1228 can be configured for both
sourcing and sinking type digital inputs with minimal
hardware change. Both serial SPI and parallel output
modes are available. Wire-break detection, field side
supply voltage monitoring and built-in CRC help
improve system reliability. In-built glitch filters and
integrated IEC-ESD and surge protection help to
achieve a robust design.
The ISO1228 operates over the logic supply range
of 1.71 V to 5.5 V, supporting 1.8-V, 2.5-V, 3.3-V,
and 5-V controllers. Field side output voltage range
supported is 8.5 V to 36 V in sink mode and 13 V
to 36 V in source mode. ISO1228 supports up to 1.5-
Mbps data rates passing a minimum pulse width of
667 ns for high-speed operation.