Renesas 70V658S12DR

Overview

70V658S12DR from IDT is a high-speed 64K × 36 asynchronous dual-port static RAM with true independent left/right ports, 12 ns maximum access time (commercial & industrial), LVTTL-compatible I/Os, and on-chip semaphore arbitration logic. It supports simultaneous read/write to the same memory location and is used in real-time inter-processor communication systems requiring deterministic latency and collision-free data exchange.

For engineers reviewing the 70V658S12DR datasheet, 70V658S12DR pinout, 70V658S12DR application, or 70V658S12DR equivalent, key selection criteria include dual-port arbitration timing (tAPS = 5 ns), BUSY flag behavior under MASTER/SLAVE configuration, byte-enable granularity (four 9-bit bytes), JTAG IEEE 1149.1 compliance, and selectable 3.3V/2.5V I/O voltage per port via OPT pins.

Technical Context

The 70V658S12DR implements fully asynchronous operation on both ports with independent CE0/CE1, R/W, OE, and BE0–BE3 controls per side. Its on-chip arbitration logic resolves port contention using semaphore flags (A0–A2 address space) and BUSY signaling-asserted when M/S = VIH (Master) or sampled when M/S = VIL (Slave).

It features separate VDDQ supplies per port (3.3V ±150 mV or 2.5V ±100 mV) controlled by OPTL/OPTR, enabling mixed-voltage system interfacing. The core VDD remains fixed at 3.3V, and all 36-bit I/Os are LVTTL-compatible with push-pull BUSY/INT outputs and non-tri-state semantics.

Key Specifications

Pinout & Package

70V658S12DR is packaged in a 208-pin Plastic Quad Flatpack (PQFP), body size ≈28 mm × 28 mm × 3.5 mm, with 0.5 mm lead pitch. All VDD pins require connection to 3.3V; VDDQL/VDDQR must match OPTL/OPTR settings (3.3V or 2.5V); all VSS pins connect to ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-12BGXI and AS7C364096B-12JIN, the 70V658S12DR delivers unique value through integrated per-port voltage control, hardware semaphore flags, and JTAG testability-reducing BOM count, PCB area, and firmware complexity in demanding industrial and telecom applications.

Availability

70V658S12DR is available at Aetrix Electronics and suitable for real-time inter-processor communication, digital signal processing buffering, and industrial motion control applications requiring stable component supply across extended product lifecycles.

Supply support for 70V658S12DR 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 interconnect solutions, now part of Renesas Electronics.

The 70V658S12DR belongs to IDT's high-speed asynchronous dual-port SRAM family, designed specifically for deterministic, low-latency data exchange between heterogeneous processors, FPGAs, and ASICs in industrial, telecom, and aerospace systems.

FAQ

What is the memory depth and width configuration of the 70V658S12DR?

The 70V658S12DR is configured as 64K × 36 bits (2.25 Mbit total). Address lines A0–A15 are functional; A16 is a no-connect per datasheet Note 1. This provides 65,536 words of 36-bit data, supporting applications requiring wide data paths such as video frame buffering or high-throughput packet processing. The 70V658S12DR does not support 128K or 32K variants - those correspond to other members of the 70V659/58/57 family.

How does the M/S pin affect BUSY functionality in the 70V658S12DR?

In the 70V658S12DR, the M/S pin configures BUSY as either an output (M/S = VIH, Master mode) or input (M/S = VIL, Slave mode). When acting as Master, the device asserts BUSYR/BUSYL to block the opposing port during conflicting accesses. As Slave, it samples the incoming BUSY signal to defer writes. This dual-role design enables flexible master/slave topologies without external logic, and the 70V658S12DR guarantees tWB = 0 ns BUSY-to-write delay in Slave mode.

Can the left and right ports of the 70V658S12DR operate at different I/O voltages?

Yes. The 70V658S12DR supports independent I/O voltage selection per port: OPTL sets the left port's VDDQL (3.3V or 2.5V), and OPTR sets the right port's VDDQR (3.3V or 2.5V). Both ports may run at the same voltage or different voltages simultaneously. This capability allows the 70V658S12DR to bridge 3.3V FPGAs and 2.5V ASICs in the same system without external level shifters - a key differentiator versus single-supply dual-port SRAMs.

What is the purpose of the semaphore flags in the 70V658S12DR, and how are they accessed?

The 70V658S12DR integrates eight hardware semaphore flags accessible via I/O0–I/O7 using address lines A0–A2. They are read/written using dedicated SEM and CE control (Truth Table II): CE = VIH and SEM = VIL enables semaphore access. These flags provide atomic resource locking between ports, eliminating software polling and race conditions. The 70V658S12DR implements full on-chip semaphore signaling - no external logic or memory-mapped registers are needed to manage shared resources.

Does the 70V658S12DR support JTAG boundary-scan, and what pins are required?

Yes, the 70V658S12DR fully complies with IEEE 1149.1 JTAG boundary-scan. Required pins are TMS, TCK, TDI, TDO, and TRST (active-low reset). These signals are dedicated and do not share with functional I/Os. JTAG enables production test coverage, interconnect verification, and in-system debugging - a capability confirmed in the device's Features section and Functional Block Diagram. The 70V658S12DR requires no special configuration mode to activate JTAG; it is operational whenever power and clock are applied.