Renesas 7142LA35CB

Overview

7142LA35CB from IDT is a 2K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, featuring 35 ns maximum read cycle time (tRC), 1 mA typical full-standby current (ISB3), battery-backed data retention at 2 V, and TTL-compatible 5 V ±10% operation. It enables error-free 16-bit-or-wider memory systems when paired with IDT7132 MASTER RAMs in industrial temperature applications.

For engineers reviewing the 7142LA35CB datasheet, 7142LA35CB pinout, 7142LA35CB application, or 7142LA35CB equivalent, this page delivers verified timing parameters, BUSY-input arbitration behavior, package-specific pin validation (48-pin Flatpack), and real-world design implications for concurrent port access and power-down sequencing.

Technical Context

The 7142LA35CB operates as a SLAVE dual-port SRAM with independent left/right address, control, and I/O buses-no on-chip arbitration logic. Its BUSY pin functions exclusively as an input to inhibit writes during contention, unlike the MASTER IDT7132 which drives BUSY as an open-drain output requiring a 270 Ω pull-up.

It supports two asynchronous access modes: CE-controlled and R/W-controlled write cycles, with guaranteed tWC = 35 ns, tWP = 25 ns, and tBDD = 35 ns (BUSY-disable-to-valid-data). Battery backup mode retains data at VCC = 2.0 V with ICCDR ≤ 4 µA (commercial) or ≤ 4000 µA (military/industrial).

Key Specifications

Pinout & Package

7142LA35CB is packaged in a 48-pin Flatpack (FP48), with 24 pins per side, body dimensions ≈ 0.75 in × 0.75 in × 0.11 in. All VCC and GND pins must be connected per datasheet Note 1–2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C133-35JC and IDT7132LA35CB, the 7142LA35CB uniquely provides SLAVE-specific BUSY input behavior and guaranteed 2 V data retention-critical for industrial safety systems where write-inhibit reliability and power-fail resilience outweigh pin compatibility.

Availability

7142LA35CB is available at Aetrix Electronics and suitable for industrial motion control, avionics data acquisition, and medical imaging systems requiring stable component supply, long-term lifecycle support, and MIL-PRF-38535-compliant manufacturing traceability.

Supply support for 7142LA35CB 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 memory, timing, and interface solutions, now part of Renesas Electronics.

The IDT7132/7142 family was designed specifically for deterministic, contention-free memory sharing between heterogeneous processors in real-time embedded systems-emphasizing hardware arbitration, low-power standby, and industrial-grade reliability.

FAQ

What is the function of BUSYL and BUSYR on the 7142LA35CB?

On the 7142LA35CB, BUSYL and BUSYR serve exclusively as inputs-not outputs-to receive BUSY signals from a MASTER IDT7132 device. When either pin is driven low, the corresponding port's write operations are internally inhibited, preventing data corruption during address contention. This SLAVE-specific behavior is fundamental to the device's role in width-expanded memory systems and differs from the MASTER's open-drain BUSY output requiring a 270 Ω pull-up resistor.

Does the 7142LA35CB support battery backup, and what voltage is required?

Yes, the 7142LA35CB supports battery backup data retention at VCC = 2.0 V minimum, as confirmed in Table 6 of the datasheet. At this voltage, it draws ≤4 µA (commercial grade) or ≤4000 µA (industrial/military) in data retention mode. This capability allows direct connection to a backup coin cell to preserve memory contents during main power failure-making the 7142LA35CB suitable for safety-critical industrial and avionics applications where zero data loss is mandatory.

Can the 7142LA35CB operate independently without a MASTER IDT7132?

Yes, the 7142LA35CB can operate as a standalone dual-port SRAM with fully independent left and right ports. However, its BUSY pins remain functional only as inputs-so hardware arbitration requires an external MASTER (e.g., IDT7132) or alternative logic. In standalone use, BUSY lines must be held high (via pull-up) to enable writes. The 7142LA35CB retains all timing, power, and interface specifications regardless of MASTER presence, but loses automatic contention resolution without BUSY-driven write inhibition.

What is the maximum operating temperature range for the 7142LA35CB?

The 7142LA35CB is rated for industrial temperature operation from –40°C to +85°C, as specified in the "Recommended Operating Temperature and Supply Voltage" table. This range applies to all speed grades (including the 35 ns version) and package types (Flatpack, LCC, DIP, PLCC). It is not qualified for military-grade –55°C to +125°C operation-those requirements are met only by the MIL-PRF-38535 QML-certified variants designated with appropriate suffixes beyond the 7142LA35CB ordering code.

How does the 7142LA35CB handle simultaneous access to the same memory location from both ports?

The 7142LA35CB itself does not resolve simultaneous access conflicts-it relies on an external MASTER IDT7132 to assert BUSY on the contending port. When both ports attempt access to identical addresses, the MASTER detects contention via address/CE match and drives BUSY low on the affected SLAVE port. The 7142LA35CB responds by gating its internal write path, blocking the write regardless of R/W or CE state. Read operations remain unaffected, but write attempts during BUSY assertion yield no memory update-ensuring deterministic, hardware-enforced arbitration without software overhead.