Renesas 71V321LA55PF8

Overview

71V321LA55PF8 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 features 55 ns maximum read/write cycle time, 2V data retention in battery backup mode, and operates across industrial temperature range (–40°C to +85°C). Used in real-time embedded systems requiring concurrent memory access by two independent controllers.

For engineers reviewing the 71V321LA55PF8 datasheet, 71V321LA55PF8 pinout, 71V321LA55PF8 application, or 71V321LA55PF8 equivalent, this page delivers verified technical context, package mapping, functional pin roles, and validated alternative options - all grounded in the official Renesas/IDT DSC-3026/14 datasheet (July 2019).

Technical Context

The 71V321LA55PF8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses for left (L) and right (R) ports. Its on-chip arbitration logic uses address and chip-enable signals to detect simultaneous access to identical memory locations, asserting BUSYL/BUSYR outputs without requiring external logic.

Interrupt functionality is implemented via dedicated mailbox addresses: INTL asserts when the right port writes to 0x7FE; INTR asserts when the left port writes to 0x7FF. Both flags are cleared by reading the same address, enabling hardware-synchronized message passing between co-processors.

Key Specifications

Pinout & Package

71V321LA55PF8 is packaged in a 64-pin TQFP (Thin Quad Flatpack), code PNG64, body size 10 mm × 10 mm × 1.4 mm. All VCC and GND pins must be externally decoupled; no pull-ups required on BUSY/INT outputs (totem-pole).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1371DV33-55AXC and AS7C32160A-55PCN, the 71V321LA55PF8 uniquely integrates arbitration and interrupt logic on-die - eliminating external components and reducing system-level timing uncertainty in hard real-time designs.

Availability

71V321LA55PF8 is available at Aetrix Electronics and suitable for industrial PLC controllers, avionics data concentrators, and medical imaging subsystems requiring stable component supply, long-lifecycle support, and guaranteed industrial-temperature performance.

Supply support for 71V321LA55PF8 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 acquired Integrated Device Technology (IDT) in 2019 and now manufactures and supports the 71V321L family. Renesas is a global semiconductor leader focused on microcontrollers, analog, and power solutions.

The 71V321L series was originally designed by IDT for high-reliability embedded systems requiring deterministic dual-processor memory sharing - especially in industrial automation, aerospace, and medical equipment.

FAQ

What is the exact memory capacity and organization of the 71V321LA55PF8?

The 71V321LA55PF8 contains 2,048 words × 8 bits (2K × 8), totaling 16,384 bits of static RAM. Each port (left and right) accesses the full memory space independently via its own 11-bit address bus (A0–A10) and 8-bit bidirectional I/O lines (I/O0–I/O7). This organization enables true concurrent read/write operations without internal banking or interleaving.

Does the 71V321LA55PF8 support battery backup, and what voltage is required?

Yes, the 71V321LA55PF8 supports battery backup data retention at VCC ≥ 2.0 V. In this mode, it consumes ≤500 µA typical current (ICCDR) while preserving stored data indefinitely. The device maintains full data integrity down to 2.0 V - no external supervisor or reset circuitry is required to enter or exit retention mode.

How does the BUSY arbitration logic work in the 71V321LA55PF8?

The 71V321LA55PF8's BUSY logic monitors address and chip-enable signals on both ports. When both ports attempt access to the same memory location simultaneously, BUSYL or BUSYR is asserted low (totem-pole output) to stall the later-arriving access. Writes to the contended port are internally gated - preventing corruption - while reads return valid data after tBDD delay (≤45 ns for 55 ns grade).

What are the interrupt mailbox addresses for the 71V321LA55PF8, and how are they used?

The 71V321LA55PF8 uses address 0x7FE to trigger the left-port interrupt flag (INTL) and address 0x7FF to trigger the right-port flag (INTR). Writing to these locations (with CEx = R/Wx = LOW) asserts the corresponding flag; reading the same address clears it. These locations remain fully accessible as general SRAM when interrupts are unused.

Which package type and footprint does the 71V321LA55PF8 use?

The 71V321LA55PF8 uses a 64-pin TQFP package (Renesas/IDT code PNG64), measuring 10 mm × 10 mm × 1.4 mm. It has 16 VCC pins (distributed across corners and edges) and 4 dedicated GND pins - requiring proper PCB decoupling with 0.1 µF ceramics near each VCC pair to ensure stable 55 ns operation under full load.