Renesas 71V321SA25PF

Overview

71V321SA25PF from Renesas Electronics (formerly IDT) is a high-speed, 3.3V, 2K × 8 dual-port static RAM with on-chip interrupt logic and BUSY arbitration for interprocessor communication. It supports fully asynchronous access from independent left/right ports, delivers 25 ns max read cycle time, operates across commercial temperature range (0°C to +70°C), and features TTL-compatible I/O with 325 mW typical active power consumption - used in real-time embedded control systems requiring concurrent memory access.

For engineers reviewing the 71V321SA25PF datasheet, 71V321SA25PF pinout, 71V321SA25PF application, or 71V321SA25PF equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 30 ns), interrupt flag behavior (INTL/INTR set/clear via dedicated mailbox addresses 7FEh/7FFh), 2V data retention capability (L-version only), and compatibility with 64-pin TQFP layout constraints.

Technical Context

The 71V321SA25PF implements hardware-based port arbitration using totem-pole BUSYL/BUSYR outputs that assert when both ports simultaneously access the same address - enabling stall-based conflict resolution without external logic. Its interrupt subsystem uses fixed SRAM locations (7FEh for INTL, 7FFh for INTR) as mailbox registers, where write operations from one port trigger flags readable by the other.

It supports four standby modes (ISB1–ISB4) controlled by CE and SEM inputs, achieving as low as 0.2 mA full-standby current (ISB3) under CMOS-level input conditions. The device requires no external pull-ups on BUSY/INT pins due to internal totem-pole drivers, and its 3.3V-only supply eliminates level-shifting needs in modern digital systems.

Key Specifications

Pinout & Package

71V321SA25PF is packaged in a 64-pin TQFP (PNG64), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). Pin assignments are symmetric for left/right ports, supporting identical PCB layout for both sides of dual-port interface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-25AXC and 71V3556SA25PFG, the 71V321SA25PF uniquely delivers 2K × 8 density with fully integrated hardware arbitration and interrupt mailbox logic in a compact 64-pin footprint - making it optimal for space-constrained, low-latency dual-processor designs where external logic minimization is critical.

Availability

71V321SA25PF is available at Aetrix Electronics and suitable for industrial PLC communication modules, real-time signal processing bridges, redundant controller synchronization systems, and legacy system memory expansion projects requiring stable component supply and long-term lifecycle support.

Supply support for 71V321SA25PF 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

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

The 71V321SA25PF belongs to Renesas' legacy dual-port SRAM product line, originally developed by IDT, designed specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware-enforced memory coherency.

FAQ

What is the maximum operating frequency supported by the 71V321SA25PF?

The 71V321SA25PF does not specify a clock frequency; it is an asynchronous SRAM. Its 25 ns access time (tAA, tACE) supports effective bus rates up to ~40 MHz when interfaced with controllers having compatible setup/hold timing. Actual throughput depends on system-level bus protocol and control signal timing margins.

Does the 71V321SA25PF support battery backup operation?

The 71V321SA25PF is the 'S' (standard power) variant and does not support battery backup data retention. Only the 'L' (low-power) versions like 71V321L25PF guarantee 2V data retention. The 'S' version draws higher standby current and lacks the internal circuitry for sub-3V retention.

How do the INTL and INTR interrupt flags function in the 71V321SA25PF?

In the 71V321SA25PF, INTL asserts when the right port writes to address 7FEh, and INTR asserts when the left port writes to 7FFh. Both flags remain active until cleared by a read access to their respective addresses with OE and CE asserted - enabling hardware-triggered, low-latency interprocessor signaling without polling.

Can BUSYL and BUSYR be tied together externally for system-wide busy indication?

Yes - BUSYL and BUSYR are totem-pole outputs and may be wire-OR'd externally to generate a single system BUSY signal. This is commonly used to stall both processors during contention. No pull-up resistors are required, and the combined signal asserts when either port detects address collision.

What is the meaning of the 'A' suffix in 71V321SA25PF?

The 'A' in 71V321SA25PF denotes the process/temperature grade: 'A' indicates commercial temperature range (0°C to +70°C). The 'S' specifies standard power consumption, '25' is the 25 ns speed grade, and 'PF' identifies the 64-pin TQFP package (PNG64).