Renesas 70V631S10BF8

Overview

70V631S10BF8 from IDT (Integrated Device Technology) is a high-speed 256K × 18 asynchronous dual-port static RAM with fully independent left/right ports, 10 ns max read cycle time, LVTTL-compatible 3.3 V core supply, and selectable 3.3 V/2.5 V I/O voltage per port. It enables simultaneous access to the same memory location in telecom switching fabric and real-time DSP co-processing systems.

For engineers reviewing the 70V631S10BF8 datasheet, 70V631S10BF8 pinout, 70V631S10BF8 application, or 70V631S10BF8 equivalent, key selection criteria include true dual-port arbitration logic, on-chip semaphore support, BUSY flag timing (≤10 ns), Master/Slave cascading capability for 36-bit+ word width, and industrial-grade temperature operation (–40°C to +85°C).

Technical Context

The 70V631S10BF8 implements fully asynchronous dual-port architecture with separate address, control, and data buses per port-no clock required. Its on-chip arbitration logic resolves port contention via hardware-controlled BUSY signaling, with priority determined by address match or chip enable assertion timing.

It supports independent I/O voltage selection (3.3 V or 2.5 V) per port via OPTL/OPTR pins, while maintaining a fixed 3.3 V ±150 mV core supply (VDD). Semaphore and interrupt flags (SEML/SEMR, INTL/INTR) are implemented as dedicated hardware registers accessible via specific address ranges (e.g., 3FFFE_H, 3FFFF_H), not software-emulated.

Key Specifications

Pinout & Package

70V631S10BF8 is packaged in a 128-pin Thin Quad Flatpack (TQFP) with 0.5 mm lead pitch and body dimensions ≈14 mm × 20 mm × 1.4 mm. All VDD pins require 3.3 V; VDDQL/VDDQR must match OPTL/OPTR logic level (3.3 V if VIH, 2.5 V if VIL); 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 CY7C028V-10AXC and AS7C3256A-10TCN, the 70V631S10BF8 uniquely integrates hardware semaphore, Master/Slave cascading, and per-port I/O voltage selection-reducing BOM count and PCB complexity in high-reliability dual-processor systems.

Availability

70V631S10BF8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial motion control, avionics data acquisition, and real-time DSP co-processing requiring stable component supply across extended product lifecycles.

Supply support for 70V631S10BF8 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 power management ICs for communications and computing markets.

The 70V631S10BF8 belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic, low-latency memory sharing between independent processors or ASICs in mission-critical embedded systems.

FAQ

What is the maximum operating frequency supported by the 70V631S10BF8?

The 70V631S10BF8 does not operate on a clock; it is an asynchronous device. Its speed is defined by timing parameters-not frequency. The 10 ns maximum read cycle time (tRC) corresponds to a theoretical maximum sustained throughput of 100 MHz for back-to-back reads, but actual system performance depends on address/control setup/hold times and bus turnaround delays.

Does the 70V631S10BF8 support JTAG boundary scan?

No. The 70V631S10BF8 does not support JTAG boundary scan. Although the device includes IEEE 1149.1-compliant JTAG signals (TCK, TMS, TDI, TDO, TRST), the 128-pin TQFP package (BF8) lacks sufficient pins to implement full JTAG functionality. JTAG is explicitly disabled in this package variant per the datasheet note on page 1.

How is the BUSY signal used in Master vs. Slave configuration of the 70V631S10BF8?

In Master configuration (M/S = VIH), BUSY is an output that asserts when port contention occurs-blocking writes on the opposing port until resolved. In Slave configuration (M/S = VIL), BUSY is an input; the device halts its own write operations until the Master's BUSY signal deasserts. This hardware handshake ensures atomic access without software intervention.

Can both ports of the 70V631S10BF8 operate at different I/O voltages simultaneously?

Yes. The 70V631S10BF8 allows independent I/O voltage selection per port: OPTL sets left-port I/O voltage (3.3 V if VIH, 2.5 V if VIL), and OPTR sets right-port I/O voltage. VDDQL must match OPTL level, and VDDQR must match OPTR level. This enables direct interfacing with mixed-voltage processors (e.g., 3.3 V FPGA + 2.5 V DSP) without level shifters.

What is the purpose of the semaphore feature in the 70V631S10BF8?

The semaphore feature provides eight hardware-managed synchronization flags accessible via I/O0–I/O17 and addressed by A0–A2. These flags enable atomic test-and-set operations between ports-critical for coordinating shared resources (e.g., buffers, registers) in multi-processor systems. Unlike software locks, they require no CPU cycles and guarantee mutual exclusion at the silicon level.