Renesas 70261S35PF8

Overview

70261S35PF8 from IDT (now Renesas) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 35 ns access time (max), 5 V ±10% supply, and industrial temperature range (–40°C to +85°C). It supports simultaneous independent read/write access from left and right ports and is used in real-time interprocessor communication, video frame buffers, and military avionics data exchange systems.

For engineers reviewing the 70261S35PF8 datasheet, 70261S35PF8 pinout, 70261S35PF8 application, or 70261S35PF8 equivalent, key selection considerations include its 100-pin TQFP package, BUSY/INT flag timing (tINS = 25 ns max), dual-port arbitration logic, and support for MASTER/SLAVE cascading to build 32-bit+ memory systems without external glue logic.

Technical Context

The 70261S35PF8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port - enabling concurrent access to any memory location. Its on-chip arbitration logic resolves contention via BUSY flag assertion (tBAA ≤ 20 ns) and supports both address-match and CE-controlled arbitration modes.

It integrates full hardware semaphore signaling across eight flags (addressed by A0–A2), interrupt generation via dedicated mailbox addresses (3FFE_H/3FFF_H), and byte-selectable I/O (UBL/LBL, UBR/LBR) for multiplexed bus compatibility. Power management includes four standby current modes (ISB1–ISB4), with ISB3 as low as 0.2 mA (typ.) under CMOS-level inputs.

Key Specifications

Pinout & Package

70261S35PF8 is housed in a 100-pin TQFP (PNG100) package with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VCC and GND pins must be connected per datasheet layout guidelines to ensure signal integrity and thermal stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-250BZXI, 70261S35PF8 offers native 5 V compatibility and proven industrial reliability, while IDT70V261S25PF8 provides identical functionality at reduced speed - making it ideal for legacy system refreshes where timing budgets allow relaxation.

Availability

70261S35PF8 is available at Aetrix Electronics and suitable for real-time interprocessor communication, video frame buffering, and military avionics data exchange requiring stable component supply across extended product lifecycles.

Supply support for 70261S35PF8 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 management, and high-performance memory solutions for industrial, automotive, and communications markets.

The IDT70261 family was designed specifically for deterministic, low-latency shared-memory architectures in safety-critical and real-time embedded systems - emphasizing hardware arbitration, interrupt signaling, and seamless MASTER/SLAVE scalability.

FAQ

What is the maximum access time specification for the 70261S35PF8?

The 70261S35PF8 has a maximum address access time (tAA) of 35 ns over the full industrial temperature range (–40°C to +85°C) and supply voltage (4.5 V to 5.5 V). This value is production-tested and guaranteed per datasheet Table 12b. The 70261S35PF8 achieves this timing without requiring external wait-state insertion in FPGA or microcontroller interfaces.

Does the 70261S35PF8 support true simultaneous read/write to the same memory location?

Yes - the 70261S35PF8 implements true dual-port SRAM cells that permit simultaneous access to the same address. When contention occurs, on-chip arbitration asserts BUSY on the later-arriving port (tBAA ≤ 20 ns), allowing the first port to complete its operation unimpeded. This behavior is confirmed in Functional Block Diagram and Truth Table IV of the 70261S35PF8 datasheet.

How is interrupt generation implemented in the 70261S35PF8?

The 70261S35PF8 uses dedicated SRAM addresses 3FFE_H (left port INTL) and 3FFF_H (right port INTR) as hardware mailboxes. A write to 3FFF_H by the left port asserts INTR; a read of 3FFF_H by the right port clears it. tINS ≤ 25 ns ensures interrupt latency remains bounded - critical for time-deterministic response in control loops.

Can the 70261S35PF8 be used in MASTER/SLAVE configurations for wider data buses?

Yes - the 70261S35PF8 supports cascaded MASTER/SLAVE operation via the M/S pin. When M/S = H, BUSY is an output (MASTER); when M/S = L, BUSY is an input (SLAVE). This allows multiple 70261S35PF8 devices to form error-free 32-bit or wider memory systems without external logic, as documented in the Functional Description section.

What are the standby current options for the 70261S35PF8 and how are they selected?

The 70261S35PF8 offers four standby current modes: ISB1 (20 mA typ., TTL inputs active), ISB2 (95 mA typ., one port active), ISB3 (0.2 mA typ., full CMOS standby), and ISB4 (90 mA typ., one port CMOS standby). Selection depends on CE and input voltage levels - ISB3 requires all inputs held > VCC – 0.2 V or < 0.2 V, as specified in Table 10.