Renesas 71321SA45J8

Overview

IDT71321SA45J8 from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM with interrupt logic and on-chip arbitration, designed as the MASTER device in MASTER/SLAVE memory expansion systems. It features 45 ns maximum access time, TTL-compatible 5V ±10% operation, industrial temperature range (–40°C to +85°C), and dual independent asynchronous ports for interprocessor communication in real-time embedded control systems.

For engineers reviewing the IDT71321SA45J8 datasheet, IDT71321SA45J8 pinout, IDT71321SA45J8 application, or IDT71321SA45J8 equivalent, key selection criteria include BUSY arbitration timing (tBAA ≤ 30 ns), interrupt flag behavior (INTL/INTR set/reset via dedicated mailbox addresses), dual-port power-down modes (ISB3 ≤ 1.0 mA), and compatibility with IDT71421 SLAVE devices for 16-bit+ bus width expansion.

Technical Context

The IDT71321SA45J8 implements hardware-based port arbitration using address and chip-enable signals-no external logic required-to resolve simultaneous accesses to identical memory locations. Its BUSY output (open-drain, requires 270 Ω pull-up) asserts when contention occurs, blocking writes on the losing port until resolution.

Interrupt functionality uses fixed mailbox addresses (7FE_H for INTL, 7FF_H for INTR) with dedicated set/clear semantics per Truth Table II; both flags are active-high, edge-triggered only by write operations to those addresses, and remain asserted until explicitly cleared by read/write cycles to the same location.

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 CY7C024AV-45AXC and IDT71421SA45J8, the IDT71321SA45J8 uniquely integrates arbitration and interrupt logic in a MASTER configuration-enabling self-contained dual-processor communication without external logic, while maintaining pin- and timing-compatibility within the IDT71321/71421 family.

Availability

IDT71321SA45J8 is available at Aetrix Electronics and suitable for real-time industrial PLCs, avionics data acquisition systems, medical imaging controllers, and telecom baseband processors requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for IDT71321SA45J8 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 high-performance computing solutions.

IDT71321SA45J8 belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in hard real-time embedded systems where software-managed coherency is unacceptable.

FAQ

What is the function of the BUSY pin on IDT71321SA45J8?

The BUSY pin on IDT71321SA45J8 is an open-drain output that asserts low when port contention occurs-i.e., when both ports attempt simultaneous access to the same memory address. It requires a 270 Ω pull-up resistor and blocks write operations on the losing port until contention resolves. This hardware arbitration eliminates race conditions without software intervention, and IDT71321SA45J8 must be configured as MASTER in any system using BUSY logic.

How do the interrupt flags (INTL and INTR) operate in IDT71321SA45J8?

IDT71321SA45J8 uses fixed mailbox addresses: writing to 7FE_H sets INTL, and writing to 7FF_H sets INTR; reading or writing those same addresses clears the respective flag. Both flags are active-high, open-drain outputs requiring pull-ups. The interrupt behavior is strictly hardware-defined-no register programming is needed-and IDT71321SA45J8 guarantees tINS ≤ 45 ns from write to flag assertion.

Can IDT71321SA45J8 operate as a standalone dual-port RAM without a SLAVE device?

Yes, IDT71321SA45J8 functions fully as a standalone 2K × 8 dual-port SRAM with both ports independently accessible. Its MASTER designation refers to its capability to drive BUSY outputs and manage arbitration in expanded systems-not a requirement for basic operation. All control, timing, and electrical specifications in the datasheet apply identically whether used alone or with IDT71421 SLAVE devices.

What power supply requirements does IDT71321SA45J8 have?

IDT71321SA45J8 requires a single 5.0 V ±10% supply (4.5–5.5 V) with multiple dedicated VCC and GND pins distributed across the 52-pin STQFP package. It draws ≤110 mA dynamic current (ICC) and ≤1.0 mA in full standby (ISB3) at VCC = 5V. No battery backup is supported-only the LA variant offers 2V data retention, and IDT71321SA45J8 is SA (standard power) grade.

Which packages are available for IDT71321SA45J8?

IDT71321SA45J8 is offered exclusively in the 52-pin STQFP (PPG52) package: 10 mm × 10 mm body, 1.4 mm height, lead-free and RoHS-compliant. While the IDT71321/71421 family also supports PLCC, TQFP, and STQFP variants, the 'J8' suffix specifically denotes the PPG52 package-no other footprint options exist for this speed and version.