Renesas 70261S15PF/T

Overview

70261S15PF/T from IDT (Integrated Device Technology) 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. It supports simultaneous asynchronous access to the same memory location from left and right ports, features 15 ns max read cycle time (commercial grade), 5 V ±10% single-supply operation, and integrated BUSY/INT flag signaling. It is used in telecom line cards, industrial PLCs, and military avionics data buffers.

For engineers reviewing the 70261S15PF/T datasheet, 70261S15PF/T pinout, 70261S15PF/T application, or 70261S15PF/T equivalent, key selection criteria include dual-port arbitration latency, interrupt mailbox address mapping (0x3FFE/0x3FFF), semaphore flag timing (tSPS = 5 ns), and TQFP-100 thermal/power behavior under concurrent port activity.

Technical Context

The 70261S15PF/T implements fully asynchronous dual-port architecture with independent 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 identical addresses - with priority determined by tAPS (5 ns setup) and M/S pin configuration (master/slave cascading).

It integrates dedicated interrupt generation (INTL/INTR) triggered by writes to fixed mailbox addresses (0x3FFE and 0x3FFF), and eight hardware semaphores accessed via A0–A2 with CE=VIH/SEM=VIL mode. All timing parameters-including tBDD (BUSY disable to valid data), tSWRD (semaphore write-to-read), and tWDD (write pulse to data delay)-are specified over commercial temperature range (0°C to +70°C) at VCC = 5.0 V ±10%.

Key Specifications

Pinout & Package

70261S15PF/T is packaged 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 connected per datasheet note; package supports standard surface-mount reflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-15AXC and IDT70V261S15PF, the 70261S15PF/T uniquely delivers 5 V native operation, commercial-grade speed with proven field reliability in telecom infrastructure, and seamless integration into legacy 5 V controller buses without voltage translation overhead.

Availability

70261S15PF/T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and defense electronics requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for 70261S15PF/T 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 high-performance timing, memory, and interface solutions, acquired by Renesas Electronics in 2019. Known for precision clock ICs and dual-port SRAMs.

The IDT70261 product line was engineered for deterministic inter-processor communication in real-time embedded systems, emphasizing hardware arbitration, mailbox interrupts, and seamless 5 V system integration.

FAQ

What is the maximum operating frequency supported by the 70261S15PF/T?

The 70261S15PF/T does not operate on a clock; it is fully asynchronous. Its maximum sustained read throughput is defined by tRC = 15 ns, yielding an effective cycle rate of 66.7 MHz. Write cycles also follow tWC = 15 ns. Timing is governed by address, CE, OE, and R/W setup/hold relationships-not a system clock.

Does the 70261S15PF/T support industrial temperature range operation?

No. The 70261S15PF/T is rated for commercial temperature range only: 0°C to +70°C. Industrial-grade variants (e.g., 70261S20PF/T) exist with -40°C to +85°C rating and 20 ns speed, but the "15" suffix explicitly denotes commercial-only qualification per IDT datasheet Table 2 and ordering information.

How are the interrupt mailbox addresses configured for the 70261S15PF/T?

The 70261S15PF/T uses fixed interrupt mailbox addresses: INTL (left port interrupt) is asserted when the right port writes to address 0x3FFE; INTR (right port interrupt) is asserted when the left port writes to 0x3FFF. These locations are hardwired per Truth Table III - no configuration register or strap pin modifies them.

Can the 70261S15PF/T be used in a master/slave configuration for 32-bit data width expansion?

Yes. When multiple 70261S15PF/T devices are cascaded, the M/S pin configures one as master (M/S = HIGH, BUSY output) and others as slaves (M/S = LOW, BUSY input). This enables synchronous 32-bit or wider memory expansion without external arbitration logic, as described in the Functional Description section and Figure 1.

What is the role of the SEM pins in the 70261S15PF/T, and how are semaphores accessed?

SEML and SEMR enable hardware semaphore register access. To use semaphores, set CE = VIH and SEM = VIL (per Truth Table IV), then address A0–A2 select one of eight flags. I/O0 writes the flag value; all I/O0–I/O15 reflect the current value. This mode is electrically isolated from RAM access mode (CE = VIL, SEM = VIH).