Renesas 70V658S15DR

Overview

70V658S15DR from IDT is a high-speed 64K × 36-bit asynchronous dual-port static RAM with independent left/right ports, 15 ns max access time (commercial/industrial), LVTTL-compatible 3.3 V core supply, and selectable 3.3 V/2.5 V I/O voltage per port via OPT pins - used in real-time inter-processor communication buffers for telecom line cards and industrial motion controllers.

For engineers reviewing the 70V658S15DR datasheet, 70V658S15DR pinout, 70V658S15DR application, or 70V658S15DR equivalent, this page delivers verified electrical specs, dual-port arbitration timing, JTAG-compliant test interface details, and master/slave semaphore signaling implementation guidance - all confirmed for the exact 70V658S15DR variant with 208-pin PQFP packaging and –40°C to +85°C industrial temperature rating.

Technical Context

The 70V658S15DR implements true dual-port SRAM cells enabling simultaneous read/write access to the same memory location without contention. Its on-chip arbitration logic resolves port conflicts using BUSY flag signaling, with M/S pin configuring master (BUSY output) or slave (BUSY input) behavior.

It supports IEEE 1149.1 JTAG boundary-scan via dedicated TDI/TDO/TCK/TMS/TRST pins and provides full hardware semaphore support across ports using SEML/SEMR inputs and eight shared semaphore flags addressed by A0–A2. Each port has independent byte enables (BE0–BE3) for 9-bit granularity control.

Key Specifications

Pinout & Package

70V658S15DR 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 3.3 V; VDDQ pins must match OPT pin selection (3.3 V if OPT = VDD, 2.5 V if OPT = VSS); 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 CY7C1362BV33-15ZXI, the 70V658S15DR offers per-port I/O voltage selection and JTAG testability - critical for mixed-signal systems and production test coverage; versus IDT70V659S15DR, it trades density for cost and power efficiency in 64K-constrained designs.

Availability

70V658S15DR is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, medical imaging, and avionics applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70V658S15DR 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 semiconductor company specializing in timing, memory interface, RF, and sensor signal conditioning ICs, now part of Renesas Electronics.

The IDT70V658S15DR belongs to the 70V659/58/57 family of high-speed asynchronous dual-port SRAMs designed for deterministic, low-latency inter-processor communication in real-time embedded systems.

FAQ

What is the maximum operating frequency supported by the 70V658S15DR?

The 70V658S15DR does not operate at a fixed clock frequency - it is an asynchronous device. Its performance is defined by timing parameters: tRC = 15 ns read cycle time and tWC = 15 ns write cycle time. This corresponds to a maximum effective throughput of ~66.7 MHz for consecutive accesses, assuming no address or control setup/hold violations. The 70V658S15DR achieves this without internal clocking, relying instead on external address/control strobes.

Does the 70V658S15DR support both 3.3 V and 2.5 V I/O on the same device?

Yes - the 70V658S15DR supports independent I/O voltage selection per port. OPTL sets the left port's I/O voltage (3.3 V if OPTL = VDD, 2.5 V if OPTL = VSS); OPTR sets the right port's I/O voltage identically. VDDQL and VDDQR must be supplied at the corresponding voltage. This allows the 70V658S15DR to interface with 3.3 V and 2.5 V subsystems simultaneously, such as an FPGA and a legacy DSP.

How does the BUSY flag function in master vs. slave configuration for the 70V658S15DR?

When M/S = VIH, the 70V658S15DR operates as a master: BUSYL/BUSYR are totem-pole outputs that assert low when the opposite port initiates a write to the same address. When M/S = VIL, it operates as a slave: BUSYL/BUSYR become inputs, and the external master drives them low to block writes during contention. This dual-mode design enables flexible system-level arbitration without external logic.

Can the 70V658S15DR be used in a master/slave cascade for wider data buses?

Yes - the 70V658S15DR supports master/slave cascading via the M/S pin and BUSY signaling. Multiple devices can be stacked to expand beyond 36 bits (e.g., two 70V658S15DRs yield 72-bit width). The IDT70V659/58/57 family documentation confirms that 70V659/58/57 devices "easily expands data bus width to 72 bits or more using the Master/Slave select when cascading more than one device," and the 70V658S15DR shares identical cascade architecture.

Is JTAG boundary-scan supported on the 70V658S15DR, and what pins are required?

Yes - the 70V658S15DR fully supports IEEE 1149.1 JTAG boundary-scan. Required pins are TDI (pin 199), TDO (pin 200), TCK (pin 203), TMS (pin 204), and TRST (pin 202), all located on the 208-pin PQFP package. These pins enable full boundary-scan testing of the 70V658S15DR's I/Os and internal logic, supporting production test and debug without physical probe access.