Renesas 70V26S55J

Overview

70V26S55J from Integrated Device Technology is a high-speed 3.3V 16K × 16 true dual-port static RAM with independent left/right ports, 55 ns max access time, 300 mW typical active power, and on-chip semaphore logic for inter-processor resource arbitration in real-time embedded systems.

For engineers reviewing the 70V26S55J datasheet, 70V26S55J pinout, 70V26S55J application, or 70V26S55J equivalent, this device supports simultaneous asynchronous reads/writes to shared memory locations, hardware BUSY arbitration, byte-selectable I/O, and master/slave cascading for 32-bit+ data bus expansion without external logic.

Technical Context

The 70V26S55J implements fully asynchronous dual-port operation with separate address, control, and bidirectional I/O buses per port - enabling concurrent access to any memory location without internal synchronization overhead. Its on-chip arbitration logic resolves contention via push-pull BUSY outputs (BUSYL/BUSYR) that gate writes when address matches occur across ports.

Semaphore functionality operates in a dedicated 8-flag register space accessed via SEM = VIL, using A0–A2 for flag selection and I/O0 for write control; all eight semaphores are readable across all 16 I/O lines. The device supports TTL-compatible 3.3V ±0.3V single-supply operation and automatic power-down per port via CE-driven standby modes.

Key Specifications

Pinout & Package

70V26S55J is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC) package with 1.15 in × 1.15 in footprint and 0.17 in height. All VDD pins require connection to 3.3V 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 CY7C136-55JC and IDT70V36S55PF, the 70V26S55J delivers optimal balance of proven 16K×16 capacity, integrated hardware arbitration, PLCC package reliability, and commercial-temperature performance - making it ideal for cost-sensitive, space-constrained dual-processor designs where deterministic inter-core communication is mandatory.

Availability

70V26S55J is available at Aetrix Electronics and suitable for industrial motion controllers, avionics display systems, and medical imaging data pipelines requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for 70V26S55J 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 sensor solutions for communications, computing, and industrial markets.

The 70V26S55J belongs to IDT's high-speed dual-port SRAM product line, designed specifically for real-time embedded systems requiring deterministic, low-latency inter-processor communication without software overhead.

FAQ

What is the maximum operating temperature range for the 70V26S55J?

The 70V26S55J is rated for commercial temperature operation from 0°C to +70°C. This specification is confirmed in the Absolute Maximum Ratings table and Operating Conditions section of the official datasheet, where ambient temperature under bias is defined as 0°C to +70°C for commercial-grade devices. It does not support industrial (-40°C to +85°C) or extended temperature ranges.

Does the 70V26S55J support true simultaneous read operations from both ports to the same memory address?

Yes, the 70V26S55J supports true simultaneous reads from both ports to the same memory location. This capability is explicitly stated in the Features section as "True Dual-Ported memory cells which allow simultaneous reads of the same memory location." No BUSY assertion or arbitration occurs during concurrent reads, ensuring deterministic zero-latency access for mirrored data retrieval.

How does the M/S pin affect BUSY signal behavior in the 70V26S55J?

The M/S pin configures the 70V26S55J as either master (M/S = VIH) or slave (M/S = VIL). In master mode, BUSYL and BUSYR function as push-pull outputs indicating address contention; in slave mode, they become inputs used to inhibit writes on the receiving port. This configuration enables hierarchical BUSY arbitration in cascaded multi-device memory systems.

What is the purpose of the SEM pin on the 70V26S55J, and how is it used?

The SEM pin on the 70V26S55J enables access to the dedicated 8-flag semaphore register space. When SEM = VIL, the device enters semaphore mode - allowing reads/writes to semaphore latches using A0–A2 for address selection and I/O0 for data. This provides hardware-assisted token-passing arbitration between processors without consuming main memory space or requiring software polling.

Can the 70V26S55J be used in a 32-bit data bus configuration, and if so, how?

Yes, the 70V26S55J supports 32-bit bus expansion via master/slave cascading. One device is configured as master (M/S = VIH) and others as slaves (M/S = VIL); the master's BUSY outputs coordinate arbitration across the array, while the slave BUSY inputs gate writes. This method requires no external logic and maintains full-speed operation, as documented in the Functional Description and Master/Slave Arrays sections.