Renesas 70261L25PFI

Overview

70261L25PFI from IDT (now Renesas) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, designed for real-time inter-processor communication in embedded systems requiring simultaneous, asynchronous access to shared memory. It operates at 25 ns max access time, supports industrial temperature (−40°C to +85°C), consumes only 1 mW standby power, and features independent left/right ports with full hardware arbitration.

For engineers reviewing the 70261L25PFI datasheet, 70261L25PFI pinout, 70261L25PFI application, or 70261L25PFI equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 30 ns), interrupt mailbox addressing (3FFE/3FFF), semaphore flag control via A0–A2, and compatibility with 5 V ±10% TTL-level bus interfaces in master/slave cascaded configurations.

Technical Context

The 70261L25PFI implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port - enabling concurrent read/write operations to any memory location without external logic. Its on-chip arbitration uses BUSY flag signaling (push-pull, not open-drain) and priority set-up time (tAPS = 5 ns) to resolve contention when both ports access identical addresses.

Interrupt generation is triggered by writes to dedicated mailbox addresses (3FFE for INTL, 3FFF for INTR), while eight semaphore flags are accessed via CE = VIH/SEM = VIL mode using A0–A2 as semaphore index. All timing parameters - including tAA (25 ns), tRC (25 ns), and tPD (25 ns) - are specified over the full industrial temperature range and 5 V ±10% supply.

Key Specifications

Pinout & Package

70261L25PFI is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VCC and GND pins must be individually decoupled per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-25AC and 70V25L25PF, the 70261L25PFI uniquely delivers hardware-accelerated inter-processor coordination - reducing firmware complexity and eliminating timing-critical software arbitration, while maintaining full 5 V TTL compatibility and industrial temperature operation.

Availability

70261L25PFI is available at Aetrix Electronics and suitable for industrial PLC communication, avionics flight control interfaces, and medical imaging data buffering requiring stable component supply, long-term lifecycle support, and guaranteed industrial-grade qualification.

Supply support for 70261L25PFI 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

IDT (Integrated Device Technology), now part of Renesas Electronics, specializes in high-performance timing, memory, and interface solutions for real-time embedded systems.

The IDT70261 family was engineered specifically for deterministic inter-processor communication in safety-critical and latency-sensitive applications - delivering hardware-enforced memory coherency without software overhead.

FAQ

What is the maximum operating temperature range for the 70261L25PFI?

The 70261L25PFI is rated for industrial temperature operation from −40°C to +85°C. This specification is validated across all AC and DC electrical parameters in the datasheet, including access time (tAA ≤ 25 ns), standby current (ISB3 ≤ 5 µA), and interrupt timing (tINS ≤ 20 ns). The 70261L25PFI maintains full functionality without derating throughout this range.

Does the 70261L25PFI support true simultaneous read/write to the same memory address?

Yes - the 70261L25PFI implements true dual-ported SRAM cells that allow concurrent access to identical addresses. When contention occurs, on-chip arbitration asserts BUSY on the lower-priority port, stalling its write until the higher-priority access completes. This behavior is guaranteed by tAPS = 5 ns setup time and tBDD ≤ 30 ns disable-to-valid-data timing in the 70261L25PFI.

How are the interrupt mailboxes configured on the 70261L25PFI?

The 70261L25PFI uses fixed addresses 3FFE_H (for INTL) and 3FFF_H (for INTR) as interrupt mailboxes. Writing to 3FFF_H from the left port asserts INTR; reading 3FFF_H from the right port clears it. Similarly, 3FFE_H controls INTL. These locations remain functional as general SRAM if interrupts are unused. The 70261L25PFI requires no configuration registers to enable this behavior.

Can the 70261L25PFI be used in a 32-bit data path configuration?

Yes - the 70261L25PFI supports 32-bit expansion via master/slave cascading. One device is configured as master (M/S = H) providing BUSY output, while others operate as slaves (M/S = L) accepting BUSY input. This arrangement enables full-speed, error-free 32-bit-or-wider word systems without discrete logic, as documented in the 70261L25PFI functional description and pin configuration diagrams.

What is the standby power consumption of the 70261L25PFI in full shutdown mode?

In full standby mode (ISB3), where both ports are disabled with CMOS-level inputs (CE > VCC − 0.2 V, SEM > VCC − 0.2 V), the 70261L25PFI draws only 0.2 mA typical (5 µA max) at VCC = 5.0 V. This ultra-low quiescent current enables energy-efficient operation in battery-backed or always-on industrial systems - a key differentiator versus the 70261S variant (15 mA ISB3).