Renesas 71342SA70J

Overview

IDT71342SA70J from Integrated Device Technology is a high-speed 4K × 8 dual-port static RAM with on-chip semaphore logic, operating at 70 ns max read cycle time, supporting independent asynchronous access from left and right ports, and featuring TTL-compatible 5V ±10% supply - used in real-time interprocessor communication systems requiring concurrent memory access without arbitration wait states.

For engineers reviewing the IDT71342SA70J datasheet, IDT71342SA70J pinout, IDT71342SA70J application, or IDT71342SA70J equivalent, key selection criteria include dual-port timing (tRC = 70 ns), semaphore flag latency (tSOP = 20 ns), industrial-grade temperature range (–40°C to +85°C), and PLCC-52 package compatibility for legacy board designs.

Technical Context

The IDT71342SA70J implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling simultaneous read/write operations across ports without bus contention. Its dedicated 3-bit address space (A0–A2) selects one of eight hardware semaphore latches, each accessible only when SEM = VIL and CE = VIH.

Semaphore operation uses active-low token passing: writing '0' to a flag grants exclusive write access to that side; reading returns replicated bit values across all 8 I/O lines. Power management includes four standby modes (ISB1–ISB4), with full CMOS-level standby drawing just 1.0 mA typical at 5V.

Key Specifications

Pinout & Package

Package: 52-pin Plastic Leaded Chip Carrier (PLCC), body size ≈ 20.0 mm × 20.0 mm × 4.3 mm, lead pitch 0.635 mm, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1352BV-70AC, IDT71342SA70J delivers hardware semaphore coherency without external logic, reducing BOM count and timing uncertainty; versus IDT71342LA70J, it trades battery backup capability for lower active-mode power and identical industrial temperature support.

Availability

IDT71342SA70J is available at Aetrix Electronics and suitable for real-time motion control, dual-CPU industrial PLCs, avionics display processors, and baseband signal processing applications requiring stable component supply across extended product lifecycles.

Supply support for IDT71342SA70J 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 signal conditioning ICs for high-performance computing and communications infrastructure.

IDT71342SA70J belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in hard real-time systems where software arbitration introduces unacceptable latency jitter.

FAQ

What is the maximum operating frequency supported by IDT71342SA70J?

IDT71342SA70J does not operate at a fixed clock frequency; instead, its 70 ns read cycle time (tRC) sets the upper bound for sustained asynchronous access rate. This corresponds to a theoretical maximum throughput of approximately 14.3 million 8-bit words per second per port. Actual system bandwidth depends on address/data setup/hold timing margins and bus protocol overhead, not a synchronous clock input.

Does IDT71342SA70J support battery backup operation?

No, IDT71342SA70J does not support battery backup. Only the LA variant (e.g., IDT71342LA70J) provides 2V data retention capability with typical ICCDR of 100 µA. The SA suffix explicitly denotes the standard-power version without retention circuitry - it requires continuous 4.5–5.5 V supply to maintain data integrity.

How are the semaphore flags addressed and controlled in IDT71342SA70J?

Semaphore flags in IDT71342SA70J occupy a separate 8-location address space selected by A0–A2 only. To access them, SEM must be driven LOW while CE is HIGH; R/W and OE control read/write direction and output enable. Writing '0' to D0 asserts the token for that port; writing '1' releases it. All 8 I/O lines reflect the same flag value during reads.

Can both ports of IDT71342SA70J perform simultaneous writes to the same memory location?

No - simultaneous writes to the same non-semaphore memory location cause undefined data states and are prohibited per the functional description. The device provides no hardware resolution for such conflicts. System software must use the semaphore logic to serialize access to shared memory regions, ensuring only one port writes at a time.

What is the purpose of the N/C pins on the PLCC-52 package of IDT71342SA70J?

IDT71342SA70J's PLCC-52 package includes multiple No-Connect (N/C) pins - specifically pins 1, 46, 47, 49, 50, 51, 52, and others marked "N/C" in the pin diagram. These pins are physically present but internally unconnected; they must remain unconnected on the PCB and should never be tied to VCC, GND, or signals, as doing so may compromise signal integrity or thermal performance.