20-668-0030

Overview

The Digi 20-668-0030 is the Rabbit RIO intelligent I/O expansion chip, designed to offload peripheral processing from host microcontrollers. Operating at clock speeds up to 40 MHz with a 3.0–3.6 VDC supply, it provides 5.0 VDC tolerant I/Os and an 8 mA output drive capability. The device features four fixed digital inputs and eight independent functional channels, each containing four ports for a total of up to 32 configurable lines. These channels support bi-directional I/O, PWM, PPM, TRIAC generation, input capture, counters, and quadrature decoding. Communication with the host CPU is facilitated via SPI or 8-bit parallel interfaces within a 64-pin TQFP package.

Feature Summary

• Intelligent I/O processor that reduces host CPU load by handling peripheral tasks independently
• Configurable channels supporting multiple modes including PWM, PPM, TRIAC signals, and quadrature decoding
• 5V tolerant I/Os with pin-pair protection suitable for H-bridge drivers and high-current applications
• Flexible CPU interface options allowing integration with any microcontroller possessing SPI or parallel port capabilities

Applications

• Industrial automation and control systems requiring extensive I/O expansion
• Motor control applications utilizing quadrature decoding and PWM outputs
• Machine control designs needing push-pull protection for sink and source drivers
• Systems demanding higher drive current operations through multi-pin signal output

Procurement Notes

Verify the specific revision level and packaging configuration when ordering the 20-668-0030 component. Confirm compatibility with the host microcontroller's interface protocol, whether SPI or 8-bit parallel, prior to implementation. Ensure power supply rails strictly adhere to the 3.0–3.6 VDC operating voltage range to maintain reliable performance. Check for updated documentation regarding the 64-pin TQFP footprint dimensions during the PCB layout phase.

Selection Notes

Select the 20-668-0030 when a design requires significant I/O expansion without burdening the main processor. It is appropriate for applications needing specialized peripherals like quadrature decoders or TRIAC generators. Consider this chip if the system operates on a 3.3 V core but requires 5 V tolerant inputs. Evaluate the need for up to 32 configurable lines against the available SPI or parallel bus resources on the target CPU.

Part Context

The 20-668-0030 is part of the Rabbit RIO family of intelligent I/O expansion chips manufactured by Digi International. It complements other Rabbit Semiconductor products such as the RCM3000 series modules and BL2100 series single-board computers. This chip serves as a dedicated peripheral processor, often used in conjunction with RabbitCore modules to handle complex I/O tasks in industrial environments.

Replacement Considerations

The 20-101-1187 is listed as a two-pack variant of the same Rio I/O chip. No direct cross-manufacturer replacements are documented in the provided datasheet. Verify mechanical and electrical compatibility before substituting with generic I/O expanders.