PSD303B-70M

Overview

The PSD303B-70M is a field-programmable microcontroller peripheral from the PSD3XX family, manufactured by STMicroelectronics. It integrates up to 1 Mbit of UV EPROM and optional 16 Kbit SRAM with two programmable logic arrays (PAD A and PAD B). The device supports bus access times as fast as 70 ns and features 19 individually configurable I/O pins for port expansion or address decoding. It operates on a single 5 V supply (±10%) and is available in TQFP-44 packaging. The architecture eliminates external glue logic by providing chip-select generation, address latching, and security locking capabilities.

Feature Summary

• Integrates high-performance user-configurable blocks of EPROM, programmable logic, and optional SRAM into a single component.
• Provides a powerful microcontroller interface that replaces discrete glue logic, supporting both multiplexed and non-multiplexed buses.
• Features two programmable logic arrays capable of decoding up to 1 MB of address space without paging.
• Includes built-in security mechanisms to lock the device and its PAD decoding configuration.

Applications

• Telecommunications equipment such as cellular phones, digital PBX systems, and FAX machines.
• Portable industrial equipment including industrial control units, measurement meters, and data recorders.
• Medical instrumentation devices like hearing aids and diagnostic monitoring tools.
• Computer peripherals for notebooks and palm-top computers, handling fixed disk or modem interfaces.

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official selector guide to confirm package type and speed grade. Confirm end-of-life status prior to design finalization. Ensure compatibility with the target microcontroller's bus protocol using the provided software suite. Check for alternative packages if surface-mount constraints vary.

Selection Notes

Select this part when interfacing with 8-bit or 16-bit microcontrollers requiring expanded address space and custom logic. Choose the 1 Mbit EPROM variant for large code storage needs. Consider the ZPSD variants if lower power consumption is critical. Verify that the 44-pin package fits the PCB layout requirements.

Part Context

This component belongs to the PSD3XX family of low-cost field-programmable microcontroller peripherals. It is designed to enhance standard microcontroller systems by adding memory and programmable logic. The family includes variations with different memory sizes and voltage ranges, such as the ZPSD series for low-power applications.

Replacement Considerations

Direct replacements within the same family include PSD313B-70M or ZPSD303B-70M depending on memory and power requirements. Verify pinout compatibility and logic configuration equivalence before substitution.