Renesas 71321LA20J8

Overview

IDT71321LA20J8 from Integrated Device Technology (IDT) 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 delivers 20 ns max read cycle time, supports 5 V ±10% TTL-compatible operation, enables battery-backed data retention at 2 V, and operates across –40°C to +85°C industrial temperature range.

For engineers reviewing the IDT71321LA20J8 datasheet, IDT71321LA20J8 pinout, IDT71321LA20J8 application, or IDT71321LA20J8 equivalent, key selection considerations include its master-mode arbitration capability, dual-interrupt flag support (INTL/INTR), low 1 µA full-standby current, and compatibility with SLAVE IDT71421 devices for 16-bit+ memory expansion without external logic.

Technical Context

The IDT71321LA20J8 implements fully asynchronous dual-port architecture with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention via BUSY output flags (BUSYL/BUSYR), triggered by address match detection - not R/W state - and governed by tAPS (5 ns priority setup time).

Interrupt functionality uses dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR) with set/reset timing of ≤25 ns (tINS/tINR). The LA variant integrates battery backup support, enabling 2 V data retention with ICCDR ≤1.5 mA (commercial) or ≤4 mA (industrial), while maintaining 200 µW typical standby power from backup supply.

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 CY7C1371D-200BAXI and IDT71421LA20J8, the IDT71321LA20J8 uniquely integrates master arbitration and interrupt logic in a single 5 V device - eliminating external components required by the Cypress part and avoiding the functional limitation of the SLAVE-only IDT71421LA20J8.

Availability

IDT71321LA20J8 is available at Aetrix Electronics and suitable for real-time industrial PLCs, avionics data loggers, and telecom line cards requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for IDT71321LA20J8 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 sensor signal conditioning solutions for communications, computing, and industrial markets.

The IDT71321LA20J8 belongs to IDT's high-speed dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in safety-critical and real-time embedded systems where hardware arbitration and low-latency memory access are mandatory.

FAQ

What is the function of BUSYL and BUSYR on the IDT71321LA20J8?

BUSYL and BUSYR are open-drain output flags on the IDT71321LA20J8 that assert low when port contention is detected - i.e., when both left and right ports attempt simultaneous access to the same memory address. These signals must be pulled up externally with 270 Ω resistors and are used to stall writes on the contending port, ensuring data integrity without software intervention.

Does the IDT71321LA20J8 support battery backup operation?

Yes, the IDT71321LA20J8 supports battery backup operation with guaranteed data retention down to 2.0 V. In this mode, it draws ≤1.5 mA (commercial grade) or ≤4 mA (industrial grade) from the backup source, enabling nonvolatile storage during main power failure - a key requirement for avionics and medical data recorders.

How does interrupt handling work in the IDT71321LA20J8?

The IDT71321LA20J8 uses dedicated mailbox addresses: writing to 7FE_H sets INTL (left-port interrupt), and writing to 7FF_H sets INTR (right-port interrupt). Clearing occurs when the corresponding port reads that address. Timing is hardware-accelerated with tINS/tINR ≤25 ns, enabling sub-microsecond interprocessor signaling without polling overhead.

Can the IDT71321LA20J8 be used as a standalone dual-port RAM without a SLAVE device?

Yes, the IDT71321LA20J8 functions as a complete standalone 2K × 8 dual-port SRAM. Its integrated arbitration logic, interrupt flags, and BUSY outputs operate independently. The SLAVE IDT71421LA20J8 is optional and only required when expanding data bus width beyond 8 bits - e.g., to 16 or 32 bits - in master/slave configurations.

What package type is used for the IDT71321LA20J8?

The IDT71321LA20J8 is packaged in a 52-pin STQFP (Surface-Mount Thin Quad Flat Package), designated PPG52, with dimensions of 10 mm × 10 mm × 1.4 mm. This RoHS-compliant, lead-free package offers excellent thermal performance and solderability for automated assembly in industrial-grade PCBs.