Renesas 71V321L55TFI

Overview

71V321L55TFI from Renesas Electronics (formerly IDT) is a high-speed, low-power 2K × 8 dual-port static RAM with independent asynchronous left/right ports, on-chip interrupt logic, and BUSY arbitration. It operates at 3.3 V, supports 55 ns read/write cycle time, delivers 2 V data retention in battery backup mode, and targets interprocessor communication in industrial embedded systems.

For engineers reviewing the 71V321L55TFI datasheet, 71V321L55TFI pinout, 71V321L55TFI application, or 71V321L55TFI equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative parts, and supply-chain support details specific to the TQFP-64 industrial-grade variant.

Technical Context

The 71V321L55TFI implements fully asynchronous dual-port access with separate address, control, and I/O buses per port-enabling concurrent reads/writes without internal synchronization overhead. 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 is implemented via dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR), where write operations from one port set the opposite port's flag; flags are cleared by read accesses to those same locations. All control signals-including CE, OE, and R/W-are TTL-compatible and operate at 3.3 V only.

Key Specifications

Pinout & Package

71V321L55TFI is packaged in a 64-pin Thin Quad Flatpack (TQFP, package code PPG64), measuring 10 mm × 10 mm × 1.4 mm, with gull-wing leads and exposed thermal pad (not electrically connected). Pin numbering follows standard counter-clockwise orientation from top-left corner (pin 1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-55AXC and AS7C3256B-55TIN, the 71V321L55TFI uniquely integrates both BUSY arbitration and interrupt mailbox logic in a compact 2K × 8 form factor-reducing component count and eliminating timing-critical software coordination in tightly coupled dual-CPU systems.

Availability

71V321L55TFI is available at Aetrix Electronics and suitable for industrial PLCs, automotive ADAS modules, medical imaging subsystems, and telecom baseband units requiring stable component supply across extended product lifecycles.

Supply support for 71V321L55TFI 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 industrial, automotive, and infrastructure markets.

The 71V321L series was originally developed by IDT and continues under Renesas as a purpose-built dual-port SRAM family targeting deterministic interprocessor communication in resource-constrained real-time systems.

FAQ

What is the maximum operating frequency supported by the 71V321L55TFI?

The 71V321L55TFI does not specify a maximum clock frequency because it is an asynchronous SRAM. Its timing is governed by absolute delays: 55 ns maximum read cycle time (tRC), 55 ns write cycle time (tWC), and 55 ns address access time (tAA). These values define the minimum interval between successive valid accesses-not a clock rate. System designers must ensure setup/hold times (e.g., tAS = 0 ns, tDH = 0 ns) are met relative to control edges.

Does the 71V321L55TFI require external pull-up resistors on its interrupt pins?

No, the 71V321L55TFI's INTL and INTR pins are open-drain outputs and require external pull-up resistors to VCC (3.3 V) for proper logic-level assertion. This is explicitly stated in the datasheet's Truth Table II and functional description. Failure to add pull-ups will prevent interrupt flags from reaching VIH (≥2.0 V), causing missed notifications in the receiving processor.

Can the 71V321L55TFI be used in battery backup mode with a 2.0 V lithium cell?

Yes, the 71V321L55TFI guarantees data retention down to VCC = 2.0 V, with typical retention current of 100 µA at that voltage. A standard CR2032 coin cell (nominal 3.0 V, ~220 mAh capacity) can sustain the 71V321L55TFI in retention mode for over 2 years. The device enters retention automatically when CE is deasserted and VCC drops within specification-no additional control signals are needed.

How does BUSY arbitration work when both ports access the same address simultaneously?

When both ports drive matching addresses (A0–A10) and their respective CE signals go active within the arbitration priority setup window (tAPS ≥ 5 ns), the 71V321L55TFI asserts BUSYL or BUSYR to stall the later-arriving access. The winning port proceeds; the stalled port's write is gated internally (no data corruption), and its BUSY output remains low until the winning operation completes. This hardware arbitration avoids software locks and guarantees atomicity.

Is the 71V321L55TFI pin-compatible with other speed grades in the same package?

Yes, all 71V321L variants in the 64-pin TQFP (PPG64) package-including 71V321L25TFI, 71V321L35TFI, and 71V321L55TFI-share identical pinouts, electrical characteristics, and functional behavior. Only access time and power consumption differ. This allows drop-in replacement during design validation or cost optimization without PCB revision.