Renesas 71V321S55PFI8

Overview

71V321S55PFI8 from Renesas Electronics is a high-speed 3.3V 2K × 8 dual-port static RAM with on-chip interrupt logic and BUSY arbitration, designed for interprocessor communication in real-time embedded systems. It supports independent asynchronous access from left and right ports, delivers 55 ns read/write cycle time, consumes ≤55 mA dynamic current (typ.), and operates across –40°C to +85°C industrial temperature range.

For engineers reviewing the 71V321S55PFI8 datasheet, 71V321S55PFI8 pinout, 71V321S55PFI8 application, or 71V321S55PFI8 equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 45 ns), interrupt flag behavior (INTL/INTR at addresses 7FEh/7FFh), battery-backed data retention capability (2V, L-version only), and compatibility with 64-pin TQFP layout constraints.

Technical Context

The 71V321S55PFI8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port-enabling concurrent read/write operations without external 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 memory locations.

Interrupt functionality is implemented via dedicated mailbox addresses: writing to 7FFh (hex) on the left port asserts INTR on the right port; reading 7FEh (hex) on the left port clears INTL. All interrupt timing parameters-including tINS and tINR (≤45 ns max)-are specified under industrial temperature and 3.3V ±0.3V supply conditions.

Key Specifications

Pinout & Package

71V321S55PFI8 is packaged in a 64-pin TQFP (PNG64), measuring 10 mm × 10 mm × 1.4 mm, with exposed pad for thermal dissipation and standard JEDEC-compliant footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-55AXC, the 71V321S55PFI8 integrates arbitration and interrupt logic-reducing BOM count and layout complexity-while IDT71V321S55PFGI offers identical functionality in a mechanically distinct but electrically interchangeable package.

Availability

71V321S55PFI8 is available at Aetrix Electronics and suitable for industrial PLC communication modules, real-time motor control systems, telecom line card buffers, avionics data acquisition units, and dual-CPU embedded instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for 71V321S55PFI8 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 71V321S55PFI8 belongs to Renesas' legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in hard real-time systems where hardware arbitration and low-latency signaling are critical.

FAQ

What is the maximum operating temperature range for the 71V321S55PFI8?

The 71V321S55PFI8 is rated for industrial temperature operation from –40°C to +85°C. This specification is guaranteed across all AC and DC electrical parameters, including 55 ns access time, BUSY arbitration delays (tBDD ≤ 45 ns), and interrupt timing (tINS/tINR ≤ 45 ns), making it suitable for deployment in demanding environments such as factory automation and outdoor telecom equipment.

Does the 71V321S55PFI8 support battery backup data retention?

No-the 71V321S55PFI8 is the "S" (standard power) variant and does not support battery backup data retention. Only the "L" (low-power) versions-such as 71V321L55PFI8-specify VDR ≥ 2.0 V and ICCDR ≤ 500 µA for data retention at 2V. The 71V321S55PFI8 retains data only while powered within its 3.0 V–3.6 V operating range.

How does BUSY arbitration work on the 71V321S55PFI8?

BUSY arbitration on the 71V321S55PFI8 activates when both ports attempt access to the same memory address simultaneously. BUSYL and BUSYR are totem-pole outputs that go LOW to stall the later-arriving access. The device uses address and chip-enable signals-not R/W state-to detect contention, and tBDD (BUSY disable to valid data) is guaranteed ≤ 45 ns, ensuring predictable resolution timing for real-time systems.

What are the interrupt mailbox addresses for the 71V321S55PFI8?

The 71V321S55PFI8 uses fixed SRAM addresses for hardware interrupts: writing to address 7FFh (hex) on the left port asserts the INTR flag on the right port; writing to 7FEh (hex) on the right port asserts the INTL flag on the left port. Clearing is performed by reading those same addresses with appropriate CE/OE/RW settings, as defined in Truth Table II of the datasheet.

Is the 71V321S55PFI8 pin-compatible with other speed grades in the same package?

Yes-the 71V321S55PFI8 is pin-compatible with all other 71V321S variants in the 64-pin TQFP (PNG64) package, including 71V321S25PFGI and 71V321S35PFGI. Electrical pin functions, voltage levels, and timing interfaces are identical; only access time (25/35/55 ns) and associated AC parameters differ-allowing drop-in replacement for timing margin optimization or cost trade-offs.