Renesas 70261L35PFI8

Overview

70261L35PFI8 from IDT (now Renesas) is a high-speed 16K × 16 dual-port static RAM with interrupt and semaphore support, operating at 35 ns access time in 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/right ports - used in real-time inter-processor communication, video frame buffers, and military avionics data exchange.

For engineers reviewing the 70261L35PFI8 datasheet, 70261L35PFI8 pinout, 70261L35PFI8 application, or 70261L35PFI8 equivalent, key selection criteria include bus arbitration timing (tBDD ≤ 35 ns), low standby current (ISB3 = 0.2 mA), interrupt mailbox addressing (3FFE/3FFF), and master/slave cascading capability for 32-bit+ systems.

Technical Context

The 70261L35PFI8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port. Its on-chip arbitration logic resolves contention via BUSY flag assertion (push-pull output) when both ports access the same memory location, with priority determined by tAPS (5 ns setup) and M/S pin configuration.

It integrates dedicated semaphore registers (8 flags, addressed by A0–A2), interrupt generation via write-triggered flags (INTL/INTR), and byte-selectable I/O (UBL/LBL, UBR/LBR) for multiplexed bus compatibility. Power management uses CE-controlled automatic power-down, achieving 0.2 mA full-standby current under CMOS-level inputs.

Key Specifications

Pinout & Package

70261L35PFI8 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 CY7C1362BV33-166BZXI and AS7C316000B-15JIN, the 70261L35PFI8 uniquely delivers integrated hardware arbitration, interrupt mailbox addressing, and industrial-temperature 5V operation - reducing BOM count and firmware complexity in safety-critical embedded systems.

Availability

70261L35PFI8 is available at Aetrix Electronics and suitable for industrial motion controllers, avionics data concentrators, and real-time video processing systems requiring stable component supply across extended product lifecycles.

Supply support for 70261L35PFI8 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, is a semiconductor company specializing in timing, memory interface, and RF solutions for communications, computing, and industrial markets.

The IDT70261 family was designed specifically for deterministic, low-latency inter-processor communication in real-time embedded systems - emphasizing hardware-accelerated arbitration, interrupt signaling, and industrial-grade reliability.

FAQ

What is the maximum operating frequency supported by the 70261L35PFI8?

The 70261L35PFI8 does not operate at a clock frequency but supports asynchronous access with 35 ns maximum address access time (tAA). This corresponds to a theoretical maximum sustained throughput of approximately 28.6 million words per second per port under ideal timing conditions, assuming no bus turnaround or wait states.

Does the 70261L35PFI8 require external pull-up resistors on INTL/INTR pins?

No. The 70261L35PFI8 features push-pull output drivers on INTL and INTR pins, eliminating the need for external pull-up resistors. These outputs drive actively high or low and are compatible with TTL and CMOS logic families without additional biasing components.

How is semaphore arbitration implemented in the 70261L35PFI8?

Semaphore arbitration in the 70261L35PFI8 uses eight dedicated flags addressed by A0–A2. Writing "0" to I/O0 while SEM = VIL and CE = VIH sets the flag; reading returns the value across all 16 I/O lines. The hardware ensures atomic read-modify-write behavior without software intervention or external locking logic.

Can the 70261L35PFI8 be used in a single-port configuration?

Yes. Either port (left or right) can be used independently by tying its CE pin high (disabling that port) and using only the active port's address, control, and I/O signals. The unused port draws only ISB1 = 30 mA (typical) in standby, preserving power efficiency.

What is the function of the M/S pin on the 70261L35PFI8?

The M/S pin configures the 70261L35PFI8 as MASTER (M/S = HIGH) or SLAVE (M/S = LOW). In MASTER mode, BUSYL/BUSYR are outputs asserting during address contention; in SLAVE mode, they become inputs that stall writes when driven low - enabling hardware-synchronized cascading of multiple devices.