PSD312B-90JI
| Part Number | PSD312B-90JI |
|---|---|
| Manufacturer | STMicroelectronics / Waferscale Integration (WSI) |
| Category | Integrated Circuits (ICs) > Memory / Programmable Peripheral ICs |
| Description | Programmable System Peripheral (PSD) IC with 512Kb EPROM, 16Kb SRAM, and Programmable Logic, 90ns, PLCC-44, Obsolete. |
| Stock Status | In Stock |
| Origin | Original Factory |
Product Overview
The PSD312B‑90JI is a programmable system peripheral (PSD) IC for microcontroller expansion. It integrates 512Kb EPROM, 16Kb SRAM, PAD programmable address decoder and up to 19 configurable I/O ports. Compatible with 8‑bit/16‑bit MCUs (8051, 68HC11, Z80), it cuts component count and PCB size for legacy embedded systems. This part is Obsolete (End‑of‑Life) from original manufacturer.
Core Advantages
Highly Integrated Memory Architecture
Combines EPROM program storage and SRAM data memory in one chip, eliminating separate memory chips and discrete decoding circuits.
Flexible Microcontroller Interface
Supports 8‑bit / 16‑bit multiplexed & non‑multiplexed MCU buses, no extra glue logic required for connection.
Built‑in Programmable Logic (PAD)
Programmable Address Decoder enables flexible address mapping, internal memory control and external chip‑select output generation.
Robust Industrial‑Grade Reliability
90ns EPROM access time, 70ns PLD propagation delay, industrial‑grade temperature range for harsh operating environments.
Key Specifications
| Brand | STMicroelectronics / WSI |
|---|---|
| RoHS Status | Non‑RoHS Original, Lead‑Free Available Options |
| EDA / CAD | PCB Footprint & 3D Model Available upon Request |
| Warranty | 1‑Year Standard Quality Warranty |
| Package / Case | PLCC‑44 |
| Mounting Type | Surface Mount (SMD / SMT / Socketable) |
| Surface Marking / Silkscreen | PSD312B‑90JI Marking |
| EPROM Size | 512 Kb (64K x 8 / 32K x 16) |
| SRAM Size | 16 Kb (2K x 8) |
| Speed / Access Time | 90 ns (EPROM access time); 70ns PLD propagation delay |
| Operating Supply Voltage | 4.5V to 5.5V (5V Standard Power Supply) |
| Programmable I/O Lines | Up to 19 Configurable I/O Ports |
| Operating Temperature | -40°C to +85°C (Industrial Grade) |
| Lifecycle | Obsolete (End‑of‑Life) |
| Programmable Security | Built‑in security feature for EPROM code protection |
| Bus Compatibility | 8‑bit / 16‑bit multiplexed & non‑multiplexed MCU bus |
Typical Applications
- 8‑bit and 16‑bit Microcontroller Support Systems (8051, 68HC11, Z80 systems)
- Industrial Process Control, Automation Equipment, and PLC Modules
- Telecommunication Equipment, Routers, and Data Acquisition Systems
- Medical Instrumentation and Commercial Embedded Boards
- Legacy System Maintenance, Retrofits, and Avionics Electronics
Order & Shipping Info
| Minimum Order Quantity (MOQ) | 1 Piece |
|---|---|
| Shipping Time | Shipped within 1‑2 business days |
| Delivery Time | 3‑7 working days worldwide |
| Shipping Methods | DHL, UPS, FedEx, EMS |
| Payment Methods | T/T (Bank Transfer), PayPal, Credit Card, Western Union |
Technical Support
For datasheet, sample requests, stock check, or bulk pricing, please use the Quick Inquiry form. We will reply within 24 hours.
Frequently Asked Questions
Q1: What memory capacity does the PSD312B‑90JI integrate?
A: It integrates 512Kb EPROM and 16Kb SRAM. EPROM supports 64K×8 (8‑bit) and 32K×16 (16‑bit) bus modes.
Q2: What access speed does the PSD312B‑90JI support?
A: 90ns EPROM access time; internal PLD propagation delay is 70ns. Suffix “-90” stands for EPROM speed rating.
Q3: What package type is used for PSD312B‑90JI?
A: 44‑pin PLCC‑44 package, supports SMD or socket mounting. Suffix “JI” means PLCC‑44 industrial‑temperature variant.
Q4: What do suffixes in PSD312B‑90JI part number mean?
A: 90=90ns EPROM speed; J=PLCC‑44 package; I=‑40~+85°C industrial range. “B” indicates SRAM‑equipped version.
Q5: Are there compatible or substitute parts for PSD312B‑90JI?
A: Family variants: PSD312B‑120JI (120ns), PSD302B‑90JI (smaller memory). PSD312R‑90JI is pin‑compatible but without SRAM. Check datasheet before substitution.
Q6: What is the difference between PSD312B and PSD312R series?
A: PSD312B includes 16Kb SRAM; PSD312R is SRAM‑less. They share identical EPROM, I/O, package and timing specs.
Q7: Does PSD312B‑90JI support 8‑bit and 16‑bit MCU bus?
A: Yes. It works with 8‑bit/16‑bit multiplexed & non‑multiplexed MCU buses, no extra glue logic required.
Q8: Is PSD312B‑90JI still in production?
A: No, it is Obsolete (End‑of‑Life). We supply surplus original stock for legacy repair & retrofitting projects.
Q9: How can I request datasheets, programming details, or volume price quotes?
A: Datasheets, CAD files, stock status and bulk pricing can be requested via our Quick Inquiry form.

