Renesas 71321LA25JGI8

Overview

IDT71321LA25JGI8 from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM with interrupt and BUSY arbitration logic, designed as a MASTER device for interprocessor communication in real-time embedded systems. It features 25 ns max access time, industrial temperature range (–40°C to +85°C), 5 V ±10% supply, battery-backed data retention at 2 V, and dual independent asynchronous ports supporting simultaneous read/write operations.

For engineers reviewing the IDT71321LA25JGI8 datasheet, IDT71321LA25JGI8 pinout, IDT71321LA25JGI8 application, or IDT71321LA25JGI8 equivalent, key selection criteria include its MASTER arbitration capability, low 1 µA standby current (LA version), 2K × 8 memory width scalability with SLAVE IDT71421 devices, and integrated interrupt flags for mailbox-style inter-processor signaling.

Technical Context

The IDT71321LA25JGI8 implements on-chip port arbitration logic that resolves contention when both ports access the same address, asserting open-drain BUSYL/BUSYR outputs to inhibit writes - critical for deterministic dual-CPU shared-memory systems. Its interrupt logic uses dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR) to signal cross-port events without software polling.

It supports fully asynchronous operation per port, with separate CE/OE/R/W controls, and automatic power-down via chip enable. The LA variant enables battery backup with 2 V data retention and ultra-low 100–4000 µA retention current depending on grade, distinguishing it from SA versions.

Key Specifications

Pinout & Package

Package: 52-pin STQFP (PPG52), 10 mm × 10 mm × 1.4 mm body, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C1371DV33-250BZI, IDT71321LA25JGI8 delivers integrated hardware arbitration and mailbox interrupts at 5 V, reducing BOM count and design complexity for deterministic inter-CPU communication; versus IDT71421LA25JGI8, it provides the essential MASTER functionality required to initiate and resolve contention - making it irreplaceable in standalone dual-processor topologies.

Availability

IDT71321LA25JGI8 is available at Aetrix Electronics and suitable for industrial automation, avionics subsystems, and medical imaging equipment requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for IDT71321LA25JGI8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and power management ICs for communications, computing, and industrial markets.

IDT71321LA25JGI8 belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware arbitration, interrupt signaling, and battery-backed data retention.

FAQ

What is the function of BUSYL and BUSYR on IDT71321LA25JGI8?

BUSYL and BUSYR are open-drain arbitration outputs on IDT71321LA25JGI8 that assert LOW when port contention occurs (i.e., both ports access the same address). They require external 270 Ω pull-up resistors and are used to inhibit writes on the contending port - a hardware mechanism ensuring deterministic memory access in dual-CPU systems. Unlike IDT71421, IDT71321LA25JGI8 drives these signals; they are inputs on SLAVE devices.

Does IDT71321LA25JGI8 support battery backup, and what voltage is required?

Yes, IDT71321LA25JGI8 supports battery backup with guaranteed data retention at 2.0 V (VDR), as specified in the LA variant datasheet. At VCC = 2.0 V and TA = +25°C, it draws ≤1500 µA (commercial) or ≤4000 µA (industrial) retention current. This enables direct connection to a lithium coin cell for nonvolatile state preservation during main power loss.

How do the interrupt flags INTL and INTR work on IDT71321LA25JGI8?

INTL and INTR are open-drain interrupt outputs on IDT71321LA25JGI8 triggered by writes to dedicated mailbox addresses: writing to 7FE_H sets INTL, and writing to 7FF_H sets INTR. Each flag is cleared by reading its respective address (7FE_H clears INTL; 7FF_H clears INTR). These hardware-signaled events eliminate polling overhead and provide sub-25 ns latency for interprocessor messaging.

Can IDT71321LA25JGI8 operate as a standalone dual-port RAM without a SLAVE device?

Yes, IDT71321LA25JGI8 functions fully as a standalone 2K × 8 dual-port SRAM with both ports independently accessible. Its MASTER arbitration logic, BUSY outputs, and interrupt flags remain active and usable without any SLAVE device. The SLAVE (IDT71421) is optional and only required when expanding data bus width beyond 8 bits - e.g., to 16-bit or wider configurations.

What package and pin count does IDT71321LA25JGI8 use?

IDT71321LA25JGI8 is packaged in a 52-pin STQFP (PPG52) with 10 mm × 10 mm footprint and 1.4 mm height. This lead-free, RoHS-compliant package features perimeter gull-wing leads and is distinct from the 64-pin TQFP variants - confirmed by the "JGI8" suffix in the part number and the PPG52 pin diagram in the official datasheet (DSC-2691/17).