Renesas 70V26S35J

Overview

IDT70V26S35J from Integrated Device Technology is a high-speed 3.3V 16K × 16 true dual-port static RAM with independent left/right ports, 35 ns max access time, TTL-compatible I/O, and on-chip semaphore logic for inter-processor resource arbitration in real-time embedded systems.

For engineers reviewing the 70V26S35J datasheet, 70V26S35J pinout, 70V26S35J application, or 70V26S35J equivalent, this page delivers verified functional architecture, bus arbitration timing, byte-select control semantics, and master/slave configuration behavior - all confirmed for the exact 70V26S35J variant with commercial temperature range and PLCC-84 packaging.

Technical Context

The 70V26S35J implements fully asynchronous dual-port operation with separate address, data, and control buses per port (A0L–A13L/I/O0L–I/O15L vs A0R–A13R/I/O0R–I/O15R), enabling simultaneous read/write to identical memory locations without contention-induced corruption. Its hardware semaphore block uses eight dedicated latches addressed by A0–A2 and controlled via SEM/CE polarity inversion (CE=VIH & SEM=VIL).

Port arbitration is implemented through push-pull BUSY outputs (BUSYL/BUSYR) that assert when address matches occur between ports, with priority determined by tAPS (5 ns setup) and M/S pin state: MASTER (M/S=VIH) asserts BUSY as output; SLAVE (M/S=VIL) accepts BUSY as write-inhibit input. Byte enable logic (UBL/LBL, UBR/LBR) supports multiplexed 16-bit bus expansion to 32-bit+ systems using cascaded MASTER/SLAVE topology.

Key Specifications

Pinout & Package

70V26S35J is supplied in an 84-pin Plastic Leaded Chip Carrier (PLCC) package with 0.050-inch lead pitch and 1.15 in × 1.15 in body size. All VDD pins require connection to 3.3 V supply; all VSS pins must be grounded.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C136-35JC and AS7C3256B-35JC, the 70V26S35J uniquely integrates hardware semaphore latches and push-pull BUSY arbitration into a single 3.3V device - eliminating external logic, reducing PCB area by ≥35%, and guaranteeing sub-5 ns arbitration priority setup (tAPS) for deterministic real-time systems.

Availability

70V26S35J is available at Aetrix Electronics and suitable for industrial PLC controllers, telecom line cards, avionics FMS units, and medical imaging pipelines requiring stable component supply with guaranteed long-term sourcing.

Supply support for 70V26S35J 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

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance computing solutions.

The IDT70V26 family was engineered for real-time multi-processor systems requiring deterministic memory access, hardware-enforced resource locking, and seamless bus-width scalability - targeting industrial automation, telecom infrastructure, and safety-critical embedded platforms.

FAQ

What is the maximum operating frequency supported by the 70V26S35J?

The 70V26S35J has a 35 ns maximum access time, supporting up to 28.6 MHz random access on either port. This is derived from tRC = 35 ns (read cycle time), and applies under commercial conditions (0°C to +70°C) with VDD = 3.3 V ± 0.3 V. The 70V26S35J does not specify a clock frequency since it operates asynchronously - timing is governed by address and control signal setup/hold relationships, not a system clock.

How does the M/S pin affect BUSY pin functionality in the 70V26S35J?

In the 70V26S35J, the M/S pin determines BUSY pin directionality: when M/S = VIH, the device operates as MASTER and BUSYL/BUSYR are push-pull outputs signaling address contention; when M/S = VIL, it operates as SLAVE and BUSYL/BUSYR become write-inhibit inputs. This enables scalable memory arrays where one MASTER arbitrates and multiple SLAVES obey its BUSY assertion - no pull-up resistors are needed in MASTER mode due to internal push-pull drivers.

Can the 70V26S35J perform simultaneous reads from both ports to the same memory address?

Yes, the 70V26S35J supports true simultaneous reads from both ports to the same memory address without conflict or data corruption. Its memory cells are designed for concurrent access, and the BUSY logic remains inactive during read/read contention. This behavior is explicitly guaranteed in the datasheet's "True Dual-Ported memory cells which allow simultaneous reads of the same memory location" feature statement and confirmed in Truth Table I for non-contention modes.

What is the purpose of the SEM pin in the 70V26S35J, and how is it used?

The SEM pin in the 70V26S35J enables access to the eight hardware semaphore latches. When CE = VIH and SEM = VIL, the device enters semaphore mode - A0–A2 select one of eight latches, and I/O0 writes the token (0 = request, 1 = release) while all I/O lines (I/O0–I/O15) read the current latch state. This provides atomic set/test capability without software intervention, essential for lock-free inter-processor communication in real-time systems using the 70V26S35J.

Does the 70V26S35J support partial-word writes using byte-enable signals?

Yes, the 70V26S35J supports independent upper- and lower-byte writes via UBL/LBL (left port) and UBR/LBR (right port). When UBL = L and LBL = H, only I/O0–I/O7 are written; when UBL = H and LBL = L, only I/O8–I/O15 are written; both low enables full 16-bit write. This is confirmed in Truth Table I and enables compatibility with multiplexed 8-bit buses and efficient 32-bit word expansion using cascaded MASTER/SLAVE configurations.