Renesas 7140SA55J8

Overview

7140SA55J8 from IDT is a high-speed 1K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, supporting fully asynchronous left/right port access with 55 ns maximum read cycle time, TTL-compatible 5V ±10% supply, and industrial temperature range (–40°C to +85°C). It enables error-free 16-bit-or-wider memory systems without external arbitration logic.

For engineers reviewing the 7140SA55J8 datasheet, 7140SA55J8 pinout, 7140SA55J8 application, or 7140SA55J8 equivalent, this page delivers verified timing parameters, BUSY input behavior, CE/R/W-controlled write cycles, and SLAVE-specific port arbitration constraints critical for real-time dual-processor or FPGA co-processor memory sharing designs.

Technical Context

The 7140SA55J8 operates as a SLAVE dual-port SRAM with BUSY pins (BUSYL, BUSYR) acting solely as inputs - unlike the MASTER IDT7130 - enabling write inhibition when asserted low. Its internal arbitration logic responds only to address match detection between ports, requiring tAPS ≥ 5 ns setup to guarantee deterministic BUSY assertion.

All I/Os are bidirectional and TTL-compatible; CE-controlled and R/W-controlled write modes are supported, with tWP = 30 ns minimum pulse width and tBDD = 55 ns BUSY-disable-to-valid-data delay. The device lacks on-chip arbitration logic - that resides exclusively in the MASTER IDT7130 - and relies entirely on external BUSY signaling for conflict resolution.

Key Specifications

Pinout & Package

7140SA55J8 is packaged in a 48-pin ceramic flatpack (FP48), measuring approximately 0.75 in × 0.75 in × 0.11 in, with all VCC and GND pins requiring direct connection to power/ground planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C131-55JC and IDT7132SA55J, the 7140SA55J8 uniquely delivers SLAVE-specific BUSY input behavior and pin-compatible integration with IDT7130 MASTER devices - enabling guaranteed contention-free 16-bit memory expansion without layout changes or additional ICs.

Availability

7140SA55J8 is available at Aetrix Electronics and suitable for real-time dual-processor systems, FPGA-CPU shared memory interfaces, redundant control buffers, and digital oscilloscope acquisition modules requiring stable component supply across extended product lifecycles.

Supply support for 7140SA55J8 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 timing, memory interface, RF, and sensor solutions, now part of Renesas Electronics.

The IDT7130/7140 family was designed specifically for deterministic, low-latency dual-processor and FPGA-host memory sharing in industrial and military applications - emphasizing hardware-enforced arbitration over software protocols.

FAQ

What is the primary functional distinction between 7140SA55J8 and IDT7130SA55J8?

The 7140SA55J8 is a SLAVE dual-port SRAM with BUSYL/BUSYR pins functioning exclusively as inputs to receive arbitration signals from a MASTER device (e.g., IDT7130SA55J8), whereas the IDT7130SA55J8 is a MASTER device with BUSY pins operating as open-drain outputs and integrated arbitration logic. This architectural split enables scalable memory width expansion without external logic - the 7140SA55J8 cannot operate stand-alone in arbitration mode.

Does 7140SA55J8 support battery backup data retention?

No, the 7140SA55J8 does not support battery backup data retention. That feature is exclusive to LA-suffixed variants (e.g., 7140LA55J8), which specify 2.0 V minimum VCC for data retention and consume ≤4000 µA in retention mode. The SA suffix denotes standard active-power operation only, with ISB1 standby current up to 20 mA.

Can 7140SA55J8 be used without a MASTER device like IDT7130?

Yes, the 7140SA55J8 can operate as a stand-alone dual-port SRAM when BUSYL and BUSYR are held high (via pull-up resistors), disabling write inhibition. However, simultaneous writes to the same address from both ports will result in undefined data - external arbitration (e.g., FPGA logic or discrete gates) becomes mandatory in such configurations, negating the key benefit of the MASTER/SLAVE architecture.

What is the significance of tAPS = 5 ns in 7140SA55J8 timing specifications?

tAPS (Arbitration Priority Set-up Time) is the minimum time the address must be stable on one port before the opposite port's address becomes valid to ensure deterministic BUSY assertion. For the 7140SA55J8, tAPS = 5 ns guarantees that when address match occurs, BUSY input activation is synchronized - critical for predictable write blocking in real-time systems. Violating tAPS may cause indeterminate BUSY behavior, risking data corruption.

Which package type corresponds to the 'J8' suffix in 7140SA55J8?

Per IDT documentation, the 'J8' suffix denotes a 48-pin ceramic flatpack (FP48) package with dimensions approximately 0.75 in × 0.75 in × 0.11 in. This hermetically sealed package provides superior thermal stability and moisture resistance compared to plastic DIP or LCC variants, making it suitable for industrial and military applications where long-term reliability under thermal cycling is required.