Renesas 70V658S12DRI

Overview

70V658S12DRI from IDT is a high-speed 64K × 36 asynchronous dual-port static RAM with independent left/right ports, 12 ns maximum access time (industrial grade), 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 conflict-free shared memory access.

For engineers reviewing the 70V658S12DRI datasheet, 70V658S12DRI pinout, 70V658S12DRI application, or 70V658S12DRI equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 12 ns), byte-selectable 9-bit I/O groups (BE0–BE3), JTAG IEEE 1149.1 compliance, and selectable 3.3V/2.5V I/O voltage per port via OPTL/OPTR pins.

Technical Context

The 70V658S12DRI implements true dual-port SRAM cells with fully asynchronous operation on both ports, enabling concurrent access without external synchronization. Its on-chip arbitration logic handles port contention using BUSY flag signaling and semaphore registers addressed via A0–A2 on either port.

It features separate VDDQ supplies per port (3.3V ±150 mV or 2.5V ±100 mV) controlled by OPTL/OPTR inputs, while core VDD remains fixed at 3.3V. The device supports MASTER/SLAVE cascading for 72-bit+ data width expansion using M/S pin configuration and BUSY input/output mode switching.

Key Specifications

Pinout & Package

70V658S12DRI 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 be set to 3.3V or 2.5V based on OPTL/OPTR configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-12BGXI and AS7C361024B-12TIN, the 70V658S12DRI uniquely integrates per-port I/O voltage selection, JTAG testability, and hardware semaphore/BUSY arbitration - reducing BOM count and eliminating timing-critical software arbitration in real-time embedded systems.

Availability

70V658S12DRI is available at Aetrix Electronics and suitable for real-time inter-processor communication, industrial PLC backplane memory, and avionics data concentrator interface applications requiring stable component supply, long-term lifecycle support, and industrial-grade thermal performance.

Supply support for 70V658S12DRI 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), now part of Renesas Electronics, is a semiconductor company specializing in timing, memory interface, RF, and high-performance interconnect solutions.

The 70V658S12DRI belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic, low-latency shared memory in multi-processor embedded systems where hardware arbitration and mixed-voltage interoperability are critical.

FAQ

What is the memory organization and address mapping of the 70V658S12DRI?

The 70V658S12DRI provides 64K × 36 bits of true dual-port SRAM, meaning it has 65,536 words of 36-bit width. Address lines A0–A15 are functional; A16 is a no-connect (NC) for this variant. Each port (left/right) has independent 16-bit addressing, supporting full 64K-word access without decoding overhead. The memory array is physically shared, enabling simultaneous access to identical addresses.

How does the BUSY flag operate in MASTER vs. SLAVE configuration on the 70V658S12DRI?

When M/S = VIH, the 70V658S12DRI operates as MASTER: BUSYL/BUSYR are totem-pole outputs that assert when the opposite port initiates a conflicting write to the same address. When M/S = VIL, it operates as SLAVE: BUSYL/BUSYR become inputs that must be driven externally (e.g., by another 70V658S12DRI's BUSY output) to stall writes during contention. This enables daisy-chained arbitration across multiple devices.

Can the left and right ports of the 70V658S12DRI operate at different I/O voltages simultaneously?

Yes. The 70V658S12DRI supports independent I/O voltage selection per port: OPTL sets left-port I/O levels (VIH/VIL thresholds and VDDQL), and OPTR sets right-port levels. If OPTL = VIH and OPTR = VIL, the left port operates at 3.3V while the right port operates at 2.5V - requiring VDDQL = 3.3V and VDDQR = 2.5V. This eliminates external level shifters in mixed-voltage system architectures.

What is the role of the semaphore function in the 70V658S12DRI, and how is it accessed?

The 70V658S12DRI includes eight hardware semaphore flags accessible via I/O0–I/O35 using address lines A0–A2. To access semaphores, CE must be VIH and SEM must be VIL (opposite of RAM access). A write to I/O0 updates the selected flag; a read returns the flag state across all 36 I/O bits. This enables atomic lock/unlock operations between ports without software intervention or memory corruption risk.

Does the 70V658S12DRI support JTAG boundary-scan, and which pins are dedicated to it?

Yes, the 70V658S12DRI fully complies with IEEE 1149.1 JTAG boundary-scan. Dedicated pins include TDI (pin 199), TDO (pin 198), TCK (pin 195), TMS (pin 194), and TRST (pin 193). These pins enable in-system testability, fault isolation, and programming verification without requiring external test fixtures - critical for high-reliability industrial and aerospace deployments.