Renesas 70261L55PF

Overview

70261L55PF from IDT (Integrated Device Technology) is a high-speed 16K × 16 dual-port static RAM with interrupt and semaphore support, designed for real-time inter-processor communication in embedded systems. It features 55 ns maximum access time, 1 mW typical standby power, TTL-compatible 5 V ±10% operation, and full asynchronous dual-port architecture enabling simultaneous independent read/write access to the same memory location.

For engineers reviewing the 70261L55PF datasheet, 70261L55PF pinout, 70261L55PF application, or 70261L55PF equivalent, key selection criteria include bus arbitration timing (tBDD ≤ 40 ns), interrupt flag latency (tINS ≤ 40 ns), dual-port contention resolution via BUSY logic, and compatibility with 100-pin TQFP layouts in industrial temperature environments (–40°C to +85°C).

Technical Context

The 70261L55PF implements fully independent left/right ports with separate address decoders, I/O controls, and arbitration logic - enabling true concurrent access without internal serialization. Its on-chip semaphore logic uses A0–A2 to select among eight flags, all written via I/O0 and readable across I/O0–I/O15, with dedicated SEM enable and push-pull INT/BUSY outputs.

Port arbitration operates via hardware-controlled BUSY signaling: when M/S = VIH (Master), BUSY is an output asserting during address/contention conflict; when M/S = VIL (Slave), BUSY is an input that inhibits writes. Interrupts are triggered by writes to fixed mailbox addresses (3FFE_H and 3FFF_H), with flag set/reset timing fully specified (tINS/tINR ≤ 40 ns).

Key Specifications

Pinout & Package

70261L55PF 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 layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-100AXC and IDT70V261S15PF, the 70261L55PF uniquely delivers industrial temperature operation, integrated semaphore/INT logic, and ultra-low 1 mW standby power in a 5 V system - making it optimal for legacy-reliant, power- and reliability-critical embedded platforms.

Availability

70261L55PF is available at Aetrix Electronics and suitable for industrial PLC communication, avionics data exchange, medical imaging subsystems, and automated test equipment requiring stable component supply across extended lifecycle deployments.

Supply support for 70261L55PF 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) was a fabless semiconductor company specializing in timing, memory interface, RF, and sensor solutions before its acquisition by Renesas Electronics in 2019.

The IDT70261 family was engineered for deterministic, low-latency inter-processor communication in real-time embedded systems - emphasizing hardware arbitration, interrupt signaling, and industrial reliability over raw speed or density.

FAQ

What is the maximum operating temperature range supported by the 70261L55PF?

The 70261L55PF is rated for industrial temperature operation from –40°C to +85°C. This specification is validated across all electrical parameters including access time (55 ns max), standby current (1 mW typ), and interrupt timing (tINS ≤ 40 ns). The device uses standard CMOS process technology qualified to meet this extended range without derating.

How does the BUSY arbitration logic function in Master vs. Slave configuration on the 70261L55PF?

When M/S = VIH, the 70261L55PF operates as Master: BUSYL and BUSYR become push-pull outputs that assert low during address/contention conflicts to stall the opposing port. When M/S = VIL, it operates as Slave: BUSYL and BUSYR become inputs that internally inhibit writes when driven low by a Master device - enabling hierarchical multi-device memory sharing.

Can the 70261L55PF be used without enabling the interrupt or semaphore features?

Yes. The 70261L55PF functions as a standard dual-port SRAM without using interrupts or semaphores. Mailbox addresses 3FFE_H and 3FFF_H behave as regular memory locations, and semaphore access requires explicit SEM = VIL - leaving those resources unused unless actively configured. All core read/write operations remain fully functional.

What is the significance of the 'L' suffix in the 70261L55PF part number?

The 'L' in 70261L55PF denotes the low-power variant of the IDT70261 family. It specifies 1 mW typical standby current (ISB3) versus 5 mW for the 'S' variant, achieved through optimized CMOS design. This suffix also correlates with the 55 ns speed grade and industrial temperature qualification - distinguishing it from faster commercial-grade variants like 70261S15PF.

Does the 70261L55PF require external pull-up resistors on INTL/INTR or BUSYL/BUSYR pins?

No. The 70261L55PF features push-pull output drivers on INTL, INTR, BUSYL, and BUSYR - eliminating the need for external pull-ups. These outputs drive actively high or low depending on internal state (e.g., INTR goes low when right-port mailbox 3FFF_H is written). External termination is only required if interfacing with open-drain receivers, which is not the default use case.