Renesas 7140SA20J

Overview

7140SA20J 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 20 ns max read cycle time, TTL-compatible 5V ±10% operation, and industrial temperature range (–40°C to +85°C). It serves as the slave unit in 16-bit-or-wider memory subsystems for real-time digital signal processors.

For engineers reviewing the 7140SA20J datasheet, 7140SA20J pinout, 7140SA20J application, or 7140SA20J equivalent, key selection criteria include BUSY input behavior, CE-controlled write timing, port-to-port arbitration compatibility with IDT7130SA20J, and 48-pin ceramic flatpack package constraints.

Technical Context

The 7140SA20J implements a true dual-port architecture with independent left (L) and right (R) address/data/control buses, where BUSYL and BUSYR are dedicated inputs - unlike the IDT7130's open-drain outputs - enabling external arbitration logic to block writes during contention. Its internal arbitration relies on address match detection and tAPS setup timing.

It operates in fully asynchronous mode with no clock required; read/write cycles are controlled solely by CE, R/W, and OE transitions. The device supports battery backup data retention only in LA variants - not applicable to the SA grade - and requires pull-up resistors on INTL/INTR and BUSY inputs per datasheet Note 2.

Key Specifications

Pinout & Package

48-pin ceramic flatpack (FP48) package with 0.75″ × 0.75″ footprint and 0.11″ height; pins arranged in dual in-line configuration with index corner marked. All VCC pins require local decoupling; all GND pins must be connected to system ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C130-25JC and AS7C31025B-20JI, the 7140SA20J delivers deterministic hardware arbitration via BUSY inputs and drop-in compatibility with IDT7130 MASTER - eliminating design risk in time-critical embedded systems requiring guaranteed contention resolution.

Availability

7140SA20J is available at Aetrix Electronics and suitable for real-time digital signal processing, redundant control systems, and telecom line card applications requiring stable component supply across extended product lifecycles.

Supply support for 7140SA20J 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 high-performance silicon solutions for communications, computing, and industrial markets.

The IDT7140 product line was designed specifically as the SLAVE companion to the IDT7130 MASTER dual-port SRAM, enabling scalable, high-speed, error-free memory expansion in mission-critical embedded systems.

FAQ

What is the role of 7140SA20J in a MASTER/SLAVE dual-port SRAM configuration?

The 7140SA20J functions exclusively as the SLAVE device in a MASTER/SLAVE pair with the IDT7130. It receives BUSY signals from the MASTER to inhibit writes during address contention and provides identical 1K × 8 memory space accessible from either port. Unlike the MASTER, it has no on-chip arbitration logic - its BUSYL and BUSYR pins are inputs only. This architecture eliminates external logic for 16-bit-or-wider memory expansion. The 7140SA20J is fully specified for 20 ns access in industrial temperature range.

Does 7140SA20J support battery backup data retention?

No, the 7140SA20J does not support battery backup data retention. That feature is exclusive to the LA variant (e.g., 7140LA20J), which specifies 2.0 V minimum VCC for data retention and consumes ≤4000 µA in that mode. The SA suffix denotes standard active power profile - typical active power is 550 mW, with standby current of 30 mA (ISB1). For battery-backed applications, the 7140LA20J must be selected instead of the 7140SA20J.

How are BUSY signals used with 7140SA20J?

On the 7140SA20J, BUSYL and BUSYR are dedicated input pins - not outputs - and must be driven low by an external MASTER device (e.g., IDT7130) during address contention to block writes to the corresponding port. These inputs are open-drain compatible and require external pull-up resistors (typically 4.7 kΩ to VCC). When asserted, they internally disable write operations regardless of R/W or CE state. This hardware-level arbitration ensures deterministic resolution without software intervention - a key requirement in real-time 7140SA20J deployments.

Which packages are available for 7140SA20J, and what is the standard option?

The 7140SA20J is available in multiple packages including 48-pin DIP, LCC, ceramic flatpack (FP48), 52-pin PLCC, and 64-pin STQFP/TQFP. The standard offering for the 7140SA20J is the 48-pin ceramic flatpack (FP48), as indicated by the "J" suffix in the part number. This hermetically sealed package measures 0.75″ × 0.75″ × 0.11″ and is qualified for industrial temperature operation. Other variants (e.g., "P" for plastic DIP or "G" for TQFP) require separate ordering codes and are not interchangeable with the 7140SA20J.

Can 7140SA20J operate with a 3.3V supply?

No, the 7140SA20J is strictly a 5V device with absolute maximum VCC of 5.5V and minimum operating VCC of 4.5V. Its input thresholds (VIH = 2.2V min, VIL = 0.8V max) and output drive strength are specified only for 5V ±10% operation. Applying 3.3V will result in non-compliant VIH margins, unreliable output levels, and undefined timing behavior. For 3.3V dual-port SRAMs, designers must select alternatives such as the AS7C31025B series - but those lack the MASTER/SLAVE arbitration architecture intrinsic to the 7140SA20J.