Renesas 71V321L25TFG

Overview

71V321L25TFG 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 delivers 25 ns max access time, supports independent asynchronous reads/writes on left and right ports, and features battery-backed data retention down to 2V. It is used in real-time embedded systems requiring concurrent memory access between two processors or DMA engines.

For engineers reviewing the 71V321L25TFG datasheet, 71V321L25TFG pinout, 71V321L25TFG application, or 71V321L25TFG equivalent, key selection criteria include dual-port timing coordination, INT/BUSY flag behavior, 64-pin TQFP package compatibility, and low-power standby current (≤0.2 mA) under full CMOS-level disable conditions.

Technical Context

The 71V321L25TFG implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port. Its arbitration logic uses address and chip-enable matching (not R/W state) to assert BUSYL/BUSYR outputs, enabling hardware stall signaling during contention.

Interrupt functionality is implemented via dedicated mailbox addresses: writing to 0x7FF sets INTR (right port flag), writing to 0x7FE sets INTL (left port flag); clearing is performed by reading those same locations with OE and CE asserted. All interrupt timing parameters-including tINS and tINR-are specified at ≤25 ns (max) for the 25 ns speed grade.

Key Specifications

Pinout & Package

71V321L25TFG is housed in a 64-pin Thin Quad Flatpack (TQFP) with exposed pad, compliant with JEDEC MO-159AC. Pin 1 is located at bottom-left corner (marking dot adjacent), and pins are numbered counter-clockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-25AXC and AS7C3256B-25JCIN, the 71V321L25TFG uniquely integrates hardware arbitration and interrupt mailbox logic in a compact 2K × 8 form factor-reducing BOM count and PCB area while guaranteeing deterministic inter-core communication without external logic.

Availability

71V321L25TFG is available at Aetrix Electronics and suitable for industrial PLCs, medical imaging subsystems, avionics interfaces, and automated test equipment requiring stable component supply and long-lifecycle support.

Supply support for 71V321L25TFG 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 delivering microcontrollers, analog, power, and memory solutions for automotive, industrial, and IoT applications.

The 71V321L25TFG belongs to Renesas' legacy dual-port SRAM product line, originally developed by IDT, and was engineered specifically for deterministic, low-latency interprocessor communication in real-time embedded systems.

FAQ

What is the maximum operating frequency supported by the 71V321L25TFG?

The 71V321L25TFG does not specify a maximum clock frequency because it is an asynchronous SRAM. Its performance is defined by timing parameters: tRC (read cycle time) is 25 ns max, enabling effective throughput up to ~40 MHz in tightly controlled systems. Actual sustained bandwidth depends on bus protocol overhead and arbitration delays-not a fixed clock domain.

Does the 71V321L25TFG require external pull-up resistors on BUSY or INT pins?

No. The 71V321L25TFG features totem-pole BUSYL and BUSYR outputs (per datasheet Note 2), and INTL/INTR are compatible with open-drain configurations but do not require external pull-ups for standard operation. Pull-ups may be added only if interfacing with legacy 5V logic or specific interrupt controllers expecting active-low open-drain signaling.

Can the 71V321L25TFG operate with only one port active while the other is powered down?

Yes. The 71V321L25TFG supports asymmetric power management: when CEL = VIH and CER = VIL, only the right port remains active, drawing ISB2 current (25 mA typ. under TTL-level standby). Full CMOS-level disable (CE > VCC − 0.2 V) reduces that port's current to ≤0.2 mA, enabling true single-port low-power operation.

How is data integrity maintained during power transitions on the 71V321L25TFG?

Data integrity is preserved via 2V data retention capability (L version only). When VCC drops below 3.0 V but remains ≥2.0 V, and CE is held high, the 71V321L25TFG enters data retention mode with ICCDR ≤100 µA (typ.). This allows seamless holdover during brief interruptions-critical for medical and avionics applications where data loss is unacceptable.

What happens if both BUSYL and BUSYR are asserted simultaneously on the 71V321L25TFG?

Per datasheet Table II Note 2, BUSYL and BUSYR cannot be LOW simultaneously. The arbitration logic guarantees that only one BUSY output asserts at a time during address contention. If timing violations occur (e.g., tAPS not met), either BUSYL or BUSYR may go LOW-but never both-ensuring deterministic resolution and preventing deadlock in properly designed systems using the 71V321L25TFG.