Renesas 70T651S10DR

Overview

70T651S10DR from IDT (now Renesas) is a high-speed 256K × 36-bit asynchronous dual-port static RAM with independent left/right ports, 10 ns read cycle time, 2.5 V core supply, and selectable 2.5 V/3.3 V I/O interface per port. It enables simultaneous access to the same memory location in telecom switching fabric, real-time DSP buffer sharing, and FPGA co-processor data exchange.

For engineers reviewing the 70T651S10DR datasheet, 70T651S10DR pinout, 70T651S10DR application, or 70T651S10DR equivalent, key selection criteria include dual-port arbitration logic, RapidWrite mode timing compliance, M/S master/slave cascading for 72+ bit bus expansion, and industrial-grade –40°C to +85°C operation in DR-208 PQFP package.

Technical Context

This device implements true dual-port SRAM cells with full on-chip hardware semaphore signaling and port arbitration logic, supporting fully asynchronous operation from either port without external synchronization. Each port has independent CE0/CE1, R/W, OE, BE0–BE3, and address lines (A0–A17), enabling concurrent reads/writes at up to 100 MHz effective throughput.

The RapidWrite mode eliminates need to toggle R/W between consecutive writes-address transition defines end of write cycle-reducing control logic complexity in high-throughput packet buffering. Sleep mode (ZZL/ZZR) reduces standby current to ≤10 µA while preserving JTAG accessibility.

Key Specifications

Pinout & Package

70T651S10DR is housed in a 208-pin Plastic Quad Flat Pack (PQFP), designated DR-208 per IDT documentation. Package dimensions are approximately 28 mm × 28 mm × 3.5 mm with 0.5 mm lead pitch. All VDD pins require 2.5 V; VDDQL/VDDQR must match OPTL/OPTR configuration (2.5 V if OPT = VSS, 3.3 V if OPT = VDD).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-10BGXI and AS7C3256B-10JIN, the 70T651S10DR uniquely delivers per-port voltage selection, on-chip semaphore, and RapidWrite-enabling lower-latency, lower-BOM, and thermally robust dual-access designs in telecom, industrial, and aerospace systems.

Availability

70T651S10DR is available at Aetrix Electronics and suitable for telecom switching fabric, industrial PLC motion control, and avionics data concentrator applications requiring stable component supply across extended product lifecycles.

Supply support for 70T651S10DR 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 fabless semiconductor company specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 70T651S10DR belongs to IDT's high-speed asynchronous dual-port SRAM product line, engineered specifically for deterministic, low-latency inter-processor data exchange in mission-critical infrastructure equipment.

FAQ

What is the maximum operating frequency supported by the 70T651S10DR?

The 70T651S10DR supports a 10 ns read cycle time (tRC), enabling effective operation at up to 100 MHz in burst-mode applications. Its asynchronous architecture means it does not rely on a clock signal-timing is governed solely by setup/hold and access specifications such as tAA (10 ns max) and tACE (10 ns max), verified across the industrial temperature range (–40°C to +85°C).

How does the RapidWrite mode function in the 70T651S10DR?

In RapidWrite mode, the 70T651S10DR allows back-to-back write operations without toggling R/W, CE, or BE signals-address transition defines the end of each write cycle. This eliminates narrow pulse generation challenges, reduces control logic complexity, and maintains full 10 ns write cycle compliance. Input data setup (tDW) and hold (tDH) times are referenced to the ending address transition, not R/W deassertion.

Can the left and right ports of the 70T651S10DR operate at different I/O voltages?

Yes-the 70T651S10DR supports independent I/O voltage selection per port via OPTL and OPTR pins. Setting OPTL = VSS configures the left port for 2.5 V I/O; setting OPTL = VDD configures it for 3.3 V I/O. The same applies to OPTR for the right port. VDDQL and VDDQR supplies must match the selected levels, enabling seamless interfacing with mixed-voltage SoCs, FPGAs, and DSPs.

What is the role of the M/S pin in 70T651S10DR system design?

The M/S pin configures the 70T651S10DR as either a master (M/S = VIH) or slave (M/S = VIL) in cascaded configurations. As master, BUSYL/BUSYR become outputs indicating port contention; as slave, they become inputs for handshake coordination. This enables 72+ bit word expansion using multiple devices without external logic, maintaining full-speed operation and eliminating timing skew from discrete arbitration circuits.

Does the 70T651S10DR support JTAG boundary scan during sleep mode?

Yes-the 70T651S10DR maintains full IEEE 1149.1 JTAG functionality (TCK, TMS, TDI, TDO, TRST) even when ZZL and/or ZZR are asserted to enter sleep mode. JTAG inputs remain active and unaffected, allowing in-system test, debug, and programming without waking the core or disrupting low-power operation-a critical capability for field-upgradable telecom and avionics systems.