Renesas 7140SA25J

Overview

7140SA25J from IDT is a 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 25ns max read cycle time, 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 7140SA25J datasheet, 7140SA25J pinout, 7140SA25J application, or 7140SA25J equivalent, key selection criteria include BUSY input behavior, port-to-port write contention timing (tWB = 0 ns), tWDD ≤ 50 ns, and compatibility with IDT7130SA25J as MASTER in high-speed embedded control and real-time data buffering.

Technical Context

The 7140SA25J operates as a SLAVE dual-port SRAM with dedicated BUSY input pins (BUSYL, BUSYR) that inhibit writes when asserted low-unlike the MASTER IDT7130 which drives open-drain BUSY outputs. Its arbitration logic responds only to address match events from the MASTER port.

It supports R/W-controlled and CE-controlled write cycles with tWP = 15 ns min, tWC = 25 ns max, and tBDD = 35 ns max for BUSY-disable-to-valid-data timing. All I/Os are TTL-compatible, and power-down is controlled independently per port via CEL/CER.

Key Specifications

Pinout & Package

7140SA25J is available in 48-pin ceramic flatpack (FP48) and 48-pin sidebraze DIP (SB48) packages. Pin functions are identical across both variants per IDT documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1354V25 and AS7C31026B-25JC, the 7140SA25J uniquely delivers integrated BUSY-input arbitration for MASTER/SLAVE configurations, enabling true lock-free dual-processor communication without external logic-critical for deterministic real-time systems.

Availability

7140SA25J is available at Aetrix Electronics and suitable for motor control systems, industrial PLCs, DSP-CPU co-processing architectures, and legacy bus bridging applications requiring stable component supply across extended product lifecycles.

Supply support for 7140SA25J 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, and interface solutions for communications, computing, and industrial markets.

The IDT7140 family was designed specifically as SLAVE dual-port SRAMs to complement the IDT7130 MASTER in scalable, high-speed memory expansion-targeting real-time embedded systems where deterministic latency and hardware arbitration are mandatory.

FAQ

What is the role of 7140SA25J in a MASTER/SLAVE dual-port SRAM configuration?

The 7140SA25J functions exclusively as the SLAVE device in an IDT MASTER/SLAVE architecture. It receives BUSY signals (BUSYL/BUSYR) from the MASTER IDT7130 to prevent write contention. Unlike the MASTER, it does not generate BUSY outputs and relies entirely on external arbitration signals for safe concurrent access-enabling seamless 16-bit-or-wider memory expansion without discrete logic.

Does 7140SA25J support battery backup data retention?

No, the 7140SA25J does not support battery backup data retention. That feature is exclusive to LA-grade variants (e.g., 7140LA25J), which specify VDR = 2.0V and ICCDR ≤ 4000 µA under data retention conditions. The 'SA' suffix denotes standard active power rating, with typical active power of 550 mW and standby current of 25 mA (ISB2).

What is the significance of tWB = 0 ns in 7140SA25J timing specifications?

tWB = 0 ns means the 7140SA25J responds to a low-going BUSY input with zero propagation delay-immediately inhibiting writes to the affected port. This eliminates race conditions during address contention and ensures deterministic behavior in real-time systems where worst-case latency must be bounded, such as motion control or avionics data buffers.

Can 7140SA25J operate with only one port enabled while the other is powered down?

Yes, the 7140SA25J supports independent port power management. With CEL = VIH and CER = VIL, only the right port is active (ISB2 ≈ 25 mA typ.), while the left port enters TTL-level standby. Full CMOS-level standby (ISB3 ≈ 0.2 mA) is achieved when both CEL and CER exceed VCC – 0.2 V-allowing dynamic power scaling in multi-processor systems.

How does interrupt functionality work on 7140SA25J?

The 7140SA25J uses INTL and INTR as open-drain interrupt flags. Writing to address 3FFH on one port sets the opposite port's interrupt (e.g., left port write to 3FFH asserts INTR), while writing to 3FEH clears it. These signals require external pull-up resistors and are synchronized to the local port's R/W and CE timing-enabling reliable inter-processor signaling without shared clocks.