1 Features
• Configurable IEC 61131-2 eight Type 1/3 or four
Type 2 Isolated Digital Inputs
• Low Power and Heat Dissipation
– Selectable input current limit
– Fieldside LED drivers using input current
• Configurable sinking or sourcing type inputs
• Wire-break detection in sink mode
• Integrated field-side power loss detection
• 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): 75kV/μs
• VCC1 Logic supply voltage range: 1.71V to 5.5V
• AVCC field supply voltage range (sink mode): 8.5V
to 36V
• AVCC field supply voltage range (source mode):
13V to 36V
• 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
EN IEC 60747-17 (VDE 0884-17)
– 3000-VRMS Isolation for 1 Minute per UL 1577
– IEC 62368-1, IEC 61010-1 Certifications
– 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 24V
digital input receiver, configurable to IEC 61131-2
Type 1, and 3 characteristics or four-channel
Type 2 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 either
sourcing or sinking type digital inputs with minimal
hardware change. Both serial SPI and parallel output
modes are available. Wire-break detection, fieldside
supply monitoring and built-in CRC across barriers
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
1.71V to 5.5V, supporting 1.8V, 2.5-V, 3.3V, and 5V
controllers. Field side output voltage range supported
is 8.5V to 36V in sink mode and 13V to 36V in
source mode. ISO1228 supports up to 1.5Mbps data
rates passing a minimum pulse width of 667ns for
high-speed operation.