Renesas 70V631S12BFI8

Overview

70V631S12BFI8 from IDT (Integrated Device Technology) is a high-speed, asynchronous dual-port static RAM with 256K × 18-bit organization (4,608 Kbit), supporting simultaneous independent read/write access on left and right ports. It operates at 3.3V core supply and offers selectable 3.3V/2.5V I/O voltage per port via OPTL/OPTR pins, with 12 ns max access time across commercial and industrial temperature ranges (–40°C to +85°C). It is used in real-time inter-processor communication, FPGA co-processing buffers, and legacy telecom line card memory subsystems.

For engineers reviewing the 70V631S12BFI8 datasheet, 70V631S12BFI8 pinout, 70V631S12BFI8 application, or 70V631S12BFI8 equivalent, key selection criteria include dual-port arbitration timing (tAPS = 5 ns), BUSY flag behavior under M/S = VIH/VIL configuration, semaphore support for resource locking, and compatibility with 128-pin TQFP, 208-ball BGA, and 256-ball BGA packages - all confirmed for this specific speed grade and industrial-grade variant.

Technical Context

The 70V631S12BFI8 implements true dual-port SRAM cells with fully asynchronous operation on both ports, enabling concurrent access to the same memory location without external arbitration logic. Its on-chip port arbitration logic supports automatic BUSY flag generation during address contention and includes full hardware semaphore signaling using A0–A2 addressing and SEM/INT pins.

It features separate byte controls (UBL/LBR, UBL/LBL), dual chip enables per port (CE0L/CE1L, CE0R/CE1R), and Master/Slave cascading capability via M/S pin for 36-bit+ word expansion. JTAG (IEEE 1149.1) is omitted in the 128-pin TQFP package due to pin count constraints - a confirmed limitation for this exact package variant.

Key Specifications

Pinout & Package

70V631S12BFI8 is packaged in a 128-pin Thin Quad Flatpack (TQFP), body size ≈14 mm × 20 mm × 1.4 mm. All VDD pins require 3.3V; VDDQL/VDDQR must match OPTL/OPTR logic level (3.3V if VIH, 2.5V 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 CY7C1362BV33-12BGXI and AS7C3256B-12JIN, the 70V631S12BFI8 uniquely delivers per-port I/O voltage selection, integrated semaphore, and configurable BUSY arbitration - critical for deterministic real-time inter-processor communication without added components.

Availability

70V631S12BFI8 is available at Aetrix Electronics and suitable for telecom infrastructure, avionics data acquisition, and industrial PLC I/O subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 70V631S12BFI8 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, specializes in high-performance timing, memory interface, and RF solutions for communications, computing, and industrial markets.

The 70V631S12BFI8 belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic, low-latency inter-processor communication in mission-critical embedded systems.

FAQ

What is the operating temperature range for the 70V631S12BFI8?

The 70V631S12BFI8 is rated for industrial temperature operation from –40°C to +85°C, as confirmed in the "Recommended Operating Temperature" table (page 7) and validated across all AC/DC specifications for the 'S12' speed grade. This range applies to both ports simultaneously and is guaranteed without derating.

Does the 70V631S12BFI8 support JTAG boundary-scan testing?

No - JTAG (IEEE 1149.1) is explicitly excluded from the 128-pin TQFP package of the 70V631S12BFI8 due to insufficient pin count, as stated in the Features section ("Due to limited pin count, JTAG is not supported on the 128-pin TQFP package"). JTAG is only available on BGA variants (208/256-ball), not this specific TQFP part.

How does the BUSY signal behave when the 70V631S12BFI8 is configured as a Slave?

When M/S = VIL, BUSY functions as an input (BUSYL or BUSYR) that must be driven high by the Master device to enable writes. The 70V631S12BFI8 will not initiate writes unless the corresponding BUSY input is asserted - this prevents simultaneous writes during address contention and is defined in Note 1 of the Functional Block Diagram.

Can both ports of the 70V631S12BFI8 operate at different I/O voltages?

Yes - OPTL and OPTR are independent; one port can be set to 3.3V I/O (OPT = VIH, VDDQX = 3.3V) while the other operates at 2.5V (OPT = VIL, VDDQX = 2.5V), as specified in Pin Names table (page 5) and DC Operating Conditions (pages 7–8). This enables direct interfacing with mixed-voltage SoCs or FPGAs.

What is the minimum pulse width required for reliable semaphore flag writes on the 70V631S12BFI8?

The minimum semaphore write pulse width (tSOP) is 4 ns for the 70V631S12BFI8, as specified in Table 12 (AC Electrical Characteristics). This timing ensures reliable latching of semaphore flags across the full industrial temperature range and is measured under standard AC test conditions with appropriate load.