Renesas 71V321S25PFI

Overview

71V321S25PFI 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 supports fully asynchronous access from left and right ports, delivers 25 ns max read cycle time, consumes 55 mA typical dynamic current, and operates across –40°C to +85°C industrial temperature range in a 64-pin TQFP package. It is used in real-time embedded systems requiring concurrent memory access between two CPUs or DMA controllers.

For engineers reviewing the 71V321S25PFI datasheet, 71V321S25PFI pinout, 71V321S25PFI application, or 71V321S25PFI equivalent, key selection considerations include dual-port arbitration timing (tBDD ≤ 30 ns), interrupt flag latency (tINS ≤ 25 ns), 2.0 V data retention capability (L-version only), and compatibility with TTL-level 3.3 V I/O interfaces in tightly coupled multiprocessing architectures.

Technical Context

The 71V321S25PFI implements independent left/right port control logic with separate CE, OE, R/W, address, and bidirectional I/O buses - enabling true concurrent read/write operations without software coordination. Its hardware BUSY arbitration resolves port contention at the physical layer by asserting BUSYL/BUSYR outputs when both ports access the same address simultaneously, gating writes on the delayed port.

Interrupt functionality uses dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR) to signal inter-processor events; assertion occurs on write, clearing occurs on read of those locations. The device uses CMOS process technology and features totem-pole BUSY/INT outputs - eliminating external pull-ups - and supports full standby current as low as 1.0 mA (typ.) under CMOS-level control inputs.

Key Specifications

Pinout & Package

71V321S25PFI is housed in a 64-pin TQFP (Thin Quad Flatpack) package, measuring 10 mm × 10 mm × 1.4 mm, with lead-free (RoHS-compliant) finish and standard 0.5 mm pitch. All VCC and GND pins must be decoupled locally per datasheet layout guidelines.

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 71V321S25PFI uniquely integrates hardware arbitration and mailbox interrupts in a 2K × 8 footprint - reducing gate count, latency, and firmware complexity in tightly coupled dual-CPU systems.

Availability

71V321S25PFI is available at Aetrix Electronics and suitable for real-time motion control, digital signal processor interface, redundant communication controller, and industrial Ethernet gateway applications requiring stable component supply across extended product lifecycles.

Supply support for 71V321S25PFI 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 infrastructure markets.

The 71V321S25PFI belongs to Renesas' legacy dual-port SRAM product line, designed specifically for deterministic interprocessor communication in hard real-time embedded systems where hardware-coordinated memory access is critical.

FAQ

What is the maximum operating frequency supported by the 71V321S25PFI?

The 71V321S25PFI supports a maximum read cycle time (tRC) of 25 ns, corresponding to a theoretical maximum sustained access rate of 40 MHz per port. This assumes ideal signal integrity, proper decoupling, and adherence to AC timing parameters including tAA (25 ns), tACE (25 ns), and tAOE (12 ns). Actual system clock rates depend on bus loading, PCB routing, and controller timing margins.

Does the 71V321S25PFI support battery backup or data retention mode?

No - the 71V321S25PFI is the standard-power (S) variant and does not support battery backup or low-voltage data retention. Only the L-version (e.g., 71V321L25PFI) guarantees 2.0 V data retention with typical ICCDR of 100 µA. The S-version requires continuous 3.3 V supply for memory retention.

How does BUSY arbitration work between the left and right ports of the 71V321S25PFI?

BUSY arbitration in the 71V321S25PFI activates when both ports assert CE and present matching addresses (A0–A10) simultaneously. BUSYL goes LOW to stall the left port; BUSYR goes LOW to stall the right port. The port that asserts CE and address first wins; the delayed port's write is gated internally. tAPS (5 ns setup) ensures deterministic priority resolution.

Can the interrupt flags (INTL and INTR) of the 71V321S25PFI be used independently of the BUSY logic?

Yes - INTL and INTR operate independently of BUSY signaling. INTL asserts when the right port writes to address 7FE_H; INTR asserts when the left port writes to 7FF_H. These mailbox interrupts function even during non-contention access and require no BUSY assertion. Clearing is performed by reading the respective address with OE active.

What package type and RoHS status does the 71V321S25PFI use?

The 71V321S25PFI uses a 64-pin TQFP (Thin Quad Flatpack) package with 10 mm × 10 mm body and 0.5 mm lead pitch. It is RoHS-compliant and lead-free, as indicated by the "G" suffix in the ordering code (PFG = PNG64 package, G = green/lead-free). The "I" suffix denotes industrial temperature grade (–40°C to +85°C).