Renesas 70261S25PF/C

Overview

70261S25PF/C from IDT is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 25 ns max access time (industrial/commercial), supporting simultaneous independent read/write access to the same memory location, and featuring separate upper/lower byte enables for multiplexed bus compatibility - used in real-time inter-processor communication systems requiring deterministic arbitration.

For engineers reviewing the 70261S25PF/C datasheet, 70261S25PF/C pinout, 70261S25PF/C application, or 70261S25PF/C equivalent, key selection criteria include BUSY/INT flag timing (tINS/tINR ≤ 20 ns), dual-port arbitration latency (tBDD ≤ 30 ns), 100-pin TQFP package compatibility, and 5 V ±10% single-supply operation with industrial temperature support (-40°C to +85°C).

Technical Context

The device implements fully asynchronous dual-port architecture with independent left/right address, control, and I/O buses - enabling concurrent access without external arbitration logic. On-chip hardware supports semaphore signaling via eight dedicated flags addressed by A0–A2 and controlled by SEM/CE polarity inversion (CE = VIH & SEM = VIL for semaphore access).

Port arbitration uses push-pull BUSY outputs (not open-drain) with priority resolution governed by tAPS (5 ns setup) and address-match detection; M/S pin configures master (BUSY output) or slave (BUSY input) mode for cascaded 32-bit+ memory expansion, while interrupt flags (INTL/INTR) are triggered by writes to fixed mailbox addresses 3FFE_H and 3FFF_H.

Key Specifications

Pinout & Package

70261S25PF/C is housed in a 100-pin TQFP (PNG100) package with 0.5 mm lead pitch and 14 mm × 14 mm body size. All VCC and GND pins must be connected per layout guidelines; no internal power plane coupling is assumed.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-25AXC and AS7C316000B-25JCIN, the 70261S25PF/C uniquely integrates interrupt mailboxes, push-pull BUSY signaling, and atomic semaphores - reducing BOM count and eliminating timing-critical software arbitration in safety-critical embedded systems.

Availability

70261S25PF/C is available at Aetrix Electronics and suitable for real-time inter-processor communication, digital signal processing subsystems, and industrial motion controllers requiring stable component supply with guaranteed long-term availability.

Supply support for 70261S25PF/C 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) is a fabless semiconductor company specializing in high-performance timing, memory interface, and RF solutions, now part of Renesas Electronics.

The IDT70261 product line was designed specifically for deterministic, low-latency inter-processor communication in embedded control and signal processing systems - emphasizing hardware-accelerated arbitration and interrupt delivery.

FAQ

What is the maximum operating temperature range supported by the 70261S25PF/C?

The 70261S25PF/C is rated for industrial temperature operation from -40°C to +85°C, verified across all AC and DC specifications including access time (25 ns max), power consumption, and BUSY/INT timing. This range is explicitly confirmed in the "Maximum Operating Temperature and Supply Voltage" table and applies to both commercial and industrial speed grades of the 70261S25PF/C device.

Does the 70261S25PF/C support true simultaneous access to the same memory address by both ports?

Yes, the 70261S25PF/C implements true dual-ported memory cells that allow simultaneous access to the same memory location. When contention occurs, on-chip arbitration asserts BUSY on the lower-priority port, and the winning port completes its access. The tBDD parameter (≤30 ns for 70261S25PF/C) defines the delay from BUSY deassertion to valid read data - a key timing guarantee confirmed in the AC Electrical Characteristics tables.

How does the interrupt functionality work in the 70261S25PF/C?

The 70261S25PF/C uses fixed mailbox addresses to generate interrupts: writing to 3FFF_H sets INTR (right port flag), and writing to 3FFE_H sets INTL (left port flag). Clearing is performed by reading those same addresses. This behavior is defined in Truth Table III and validated in the Functional Description section - the 70261S25PF/C requires no external logic to implement hardware-acknowledged messaging between processors.

What is the role of the M/S pin on the 70261S25PF/C?

The M/S pin on the 70261S25PF/C configures BUSY pin behavior: when high, the device operates as a master with BUSYL/BUSYR as push-pull outputs; when low, it operates as a slave with BUSYL/BUSYR as inputs that inhibit writes upon assertion. This enables cascaded configurations for 32-bit+ word systems, as documented in the Functional Block Diagram and Pin Configuration notes for the 70261S25PF/C.

Can the 70261S25PF/C be used in a single-port configuration?

Yes, the 70261S25PF/C supports single-port operation: one port can be disabled by holding its CE pin high (VIH), placing it in ultra-low-power standby (ISB3 <1 mA), while the other port remains fully functional. This is confirmed in the DC Electrical Characteristics table (ISB3 test condition) and enables flexible use cases such as boot-time configuration storage or backup memory - without requiring redesign or additional components for the 70261S25PF/C.