Renesas 71V321L35JG

Overview

71V321L35JG from Renesas Electronics (formerly IDT) is a high-speed 3.3V 2K × 8 dual-port static RAM with interrupt logic and BUSY arbitration, supporting independent asynchronous access on left/right ports, 35 ns max read cycle time, 2V data retention, and industrial-grade operation (–40°C to +85°C) in 52-pin PLCC package. It enables interprocessor communication in real-time embedded systems requiring deterministic memory coherency.

For engineers reviewing the 71V321L35JG datasheet, 71V321L35JG pinout, 71V321L35JG application, or 71V321L35JG equivalent, key selection considerations include dual-port arbitration timing (tBDD ≤ 45 ns), low-power standby current (ISB3 = 0.2 mA typ.), interrupt mailbox addressing (7FEh/7FFh), and TTL-compatible 3.3V single-supply operation.

Technical Context

The 71V321L35JG implements fully asynchronous dual-port architecture with separate address/control/I/O buses per port, enabling concurrent read/write operations without clock synchronization. Its on-chip arbitration logic uses address and chip-enable matching (not R/W state) to assert BUSYL/BUSYR outputs, preventing simultaneous writes to identical addresses.

Interrupt functionality relies on dedicated mailbox addresses: right-port write to 7FFh sets INTR; left-port write to 7FEh sets INTL. Both flags are cleared by reading the same address with OE active. BUSY and INT outputs are totem-pole, eliminating external pull-ups.

Key Specifications

Pinout & Package

71V321L35JG is housed in a 52-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead configuration, body size ≈ 19.05 mm × 19.05 mm × 4.32 mm, lead pitch 1.27 mm, and RoHS-compliant green finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-35AXC and AS7C3256B-35JC, the 71V321L35JG uniquely integrates address-matching arbitration and dual interrupt mailboxes in a compact 52-pin PLCC, delivering deterministic inter-CPU communication without external glue logic or firmware overhead.

Availability

71V321L35JG is available at Aetrix Electronics and suitable for real-time multi-processor communication, industrial PLC buffering, avionics data acquisition, and medical imaging frame buffering requiring stable component supply across extended product lifecycles.

Supply support for 71V321L35JG 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 71V321L35JG belongs to Renesas' legacy dual-port SRAM family originally developed by IDT, designed specifically for deterministic interprocessor communication in hard real-time embedded systems requiring hardware arbitration and low-latency signaling.

FAQ

What is the maximum operating frequency supported by the 71V321L35JG?

The 71V321L35JG does not operate on a clock signal-it is fully asynchronous. Its performance is defined by access timing parameters: maximum read cycle time (tRC) is 35 ns, corresponding to an effective throughput of up to ~28.6 MHz for consecutive accesses. Actual system bandwidth depends on address/control setup/hold times and bus turnaround overhead, not a fixed clock frequency. The 71V321L35JG achieves this timing across its full industrial temperature range without derating.

Does the 71V321L35JG require external pull-up resistors on BUSY or INT pins?

No. The 71V321L35JG features totem-pole output drivers on BUSYL, BUSYR, INTL, and INTR pins, as confirmed in the functional block diagram and pin descriptions. These outputs actively drive both HIGH and LOW logic levels, eliminating the need for external pull-up resistors-reducing component count, PCB area, and potential signal integrity issues in high-density layouts.

How does the 71V321L35JG handle simultaneous access to the same memory address from both ports?

When both ports attempt access to the same address, the 71V321L35JG's hardware arbitration asserts the BUSY flag (BUSYL or BUSYR) on the later-arriving port based on address and chip-enable timing. Writes on the BUSY-asserted side are internally gated and ignored; reads return indeterminate data unless tBDD delay is observed. This ensures deterministic resolution without software intervention, with tBDD ≤ 45 ns guaranteeing recovery before next valid access.

Can the 71V321L35JG retain data during complete power loss?

The 71V321L35JG supports data retention at V_CC ≥ 2.0 V (typical 2V battery), consuming ≤500 µA (max) in retention mode. It does not retain data at 0 V-full power loss results in memory wipe. For true zero-power retention, supplemental battery backup circuitry with voltage monitoring and automatic switchover must be implemented externally, as the 71V321L35JG lacks built-in power-fail detection or switching logic.

What are the valid interrupt mailbox addresses for the 71V321L35JG?

The 71V321L35JG uses two fixed interrupt mailbox addresses: writing to address 7FEh (hex) via the right port sets the left-port interrupt flag (INTL), and writing to 7FFh (hex) via the left port sets the right-port flag (INTR). Flags are cleared by reading the same address with OE enabled (OEL or OER low). These locations are part of the main memory array and remain accessible as general SRAM when interrupts are unused.