PSD835G2-90UI

Overview

The PSD835G2-90UI is a Flash Programmable System Device (PSD) designed for 8-bit microcontrollers, operating on a single 5 V ±10% supply. It integrates dual-bank flash memories comprising 4 Mbits of primary Flash and 256 Kbits of secondary Flash, alongside 64 Kbit of SRAM. The device features 52 reconfigurable I/O ports and an embedded PLD with over 3000 gates. It supports in-system programming via JTAG and allows concurrent read operations while erasing or writing the alternate memory bank.

Feature Summary

• Dual-bank Flash architecture: 4 Mbits primary and 256 Kbits secondary with concurrent operation capability
• Integrated 64 Kbit SRAM and PLD with over 3000 gates (CPLD/DPLD)
• 52 individually configurable I/O ports supporting multiple modes including MCU, PLD, and address output
• In-system programming (ISP) via built-in JTAG serial port

Applications

• Flash in-system programmable peripheral for 8-bit MCUs
• Memory expansion systems requiring separate program and data spaces
• Complex memory mapping applications using page registers
• Designs utilizing PLD logic for custom chip select decoding

Procurement Notes

Verify component status as obsolete. Confirm package details match the 80-LQFP specification. Ensure design compatibility with the 5 V supply requirement and 90 ns access time constraints before procurement.

Selection Notes

Select this part for 8-bit MCU designs needing large non-volatile storage and programmable logic. The 90 ns speed grade suits standard 5 V systems. Consider the 80-pin LQFP footprint for PCB layout planning.

Part Context

This component belongs to the PSD835G2 family of Flash PSDs from STMicroelectronics. It serves as a bridge between 8-bit microcontrollers and external memory/logic resources, consolidating Flash, SRAM, and PLD functions into a single interface.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.