Renesas 70261S25PFI8

Overview

70261S25PFI8 from IDT (now Renesas) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 25 ns max access time over industrial temperature range (–40°C to +85°C), powered by single 5V ±10% supply, and packaged in 100-pin TQFP. It enables simultaneous asynchronous read/write access from independent left and right ports - used in real-time interprocessor communication, video frame buffers, and military/aerospace data acquisition systems.

For engineers reviewing the 70261S25PFI8 datasheet, 70261S25PFI8 pinout, 70261S25PFI8 application, or 70261S25PFI8 equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts - all grounded in the official IDT DSC3039/13 datasheet (July 2019) and Renesas product documentation.

Technical Context

The 70261S25PFI8 implements fully asynchronous dual-port architecture with separate address, control, and bidirectional I/O buses per port. Its on-chip arbitration logic resolves contention via BUSY flag assertion (M/S = H for master output; M/S = L for slave input), and supports semaphore signaling across eight flags addressed by A0–A2.

It integrates interrupt generation triggered by writes to dedicated mailbox addresses (3FFE_H for INTL, 3FFF_H for INTR), with tINS/tINR ≤ 20 ns. The device uses CMOS process, supports byte-selectable upper/lower I/O control (UBL/LBL, UBR/LBR), and enables 32-bit+ bus expansion via master/slave cascading with BUSY-driven synchronization.

Key Specifications

Pinout & Package

70261S25PFI8 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 externally decoupled 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 CY7C028V-25AC and 70V25S25PF8, the 70261S25PFI8 uniquely delivers hardware semaphore, BUSY arbitration, and mailbox interrupts in a fully asynchronous 5V package - making it irreplaceable in deterministic real-time interprocessor communication where software-managed locking introduces unacceptable jitter or latency.

Availability

70261S25PFI8 is available at Aetrix Electronics and suitable for real-time interprocessor communication, video frame buffering, radar signal processing, and military/aerospace data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 70261S25PFI8 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 (formerly Integrated Device Technology) is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

The IDT70261 family was designed specifically for high-reliability, low-latency dual-processor systems requiring hardware-enforced memory coherency - targeting avionics, medical imaging, and test equipment where deterministic timing is non-negotiable.

FAQ

What is the maximum operating temperature range for the 70261S25PFI8?

The 70261S25PFI8 is rated for industrial temperature operation from –40°C to +85°C, as confirmed in the "Maximum Operating Temperature and Supply Voltage" table (DSC3039/13, p.3). This qualification makes it suitable for deployment in harsh environments such as engine control units, outdoor base stations, and industrial PLCs where ambient thermal stress exceeds commercial-grade limits.

Does the 70261S25PFI8 support true simultaneous access to the same memory address?

Yes - the 70261S25PFI8 implements true dual-ported memory cells that permit simultaneous read/write access to identical addresses. When contention occurs, its on-chip arbitration logic asserts BUSY on the lower-priority port (per M/S configuration) and guarantees successful completion on the winning port, as detailed in Truth Table IV and the BUSY Timing section (DSC3039/13, pp.11,15).

How does the interrupt functionality work on the 70261S25PFI8?

The 70261S25PFI8 generates hardware interrupts via INTL and INTR outputs when the opposite port writes to dedicated mailbox addresses: 3FFE_H triggers INTL, and 3FFF_H triggers INTR. Clearing is performed by reading the same address. Timing parameters tINS and tINR are ≤20 ns (p.13), enabling sub-25 ns notification - critical for time-sensitive inter-processor messaging in the 70261S25PFI8.

Can the 70261S25PFI8 be used in a 32-bit data path configuration?

Yes - the 70261S25PFI8 supports 32-bit expansion using master/slave cascading. When configured with M/S = H (master), BUSY is an output; when M/S = L (slave), BUSY is an input. Connecting BUSY output of the master to BUSY input of the slave synchronizes write operations across devices, eliminating need for external logic - a capability explicitly documented in the "IDT MASTER/SLAVE Dual-Port RAM approach" (p.2).

What power-saving modes does the 70261S25PFI8 offer?

The 70261S25PFI8 provides three standby states: ISB1 (both ports disabled, TTL-level inputs, ≤25 mA), ISB2 (one port active, ≤105 mA), and ISB3 (full CMOS standby, ≤1.0 mA). These are controlled solely by CE pin state and input voltage levels - no command sequence required. The 5 mW typical standby power (p.1) is achieved in ISB3 mode, ideal for battery-buffered systems.