Renesas 70V631S15BF8

Overview

70V631S15BF8 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 access on left and right ports. It operates at 3.3V core supply with selectable 3.3V/2.5V I/O voltage per port via OPT pins, features on-chip arbitration, semaphore signaling, and BUSY/INT flags, and is used in real-time inter-processor communication, FPGA co-processing, and telecom packet buffering.

For engineers reviewing the 70V631S15BF8 datasheet, 70V631S15BF8 pinout, 70V631S15BF8 application, or 70V631S15BF8 equivalent, this page delivers verified specifications, validated package mapping (208-ball BGA, BF208), confirmed pin functions, industrial-grade timing (15 ns max read cycle), and two rigorously cross-checked alternative parts for memory expansion or voltage-flexible designs.

Technical Context

The 70V631S15BF8 implements true dual-port SRAM cells enabling concurrent read/write to identical addresses without external arbitration logic. Its port arbitration logic resolves contention via BUSY flag assertion (M/S = VIH) or BUSY input synchronization (M/S = VIL), with tBDD ≤ 15 ns ensuring deterministic data validity after port-to-port write-read sequences.

It supports JTAG IEEE 1149.1 boundary-scan only in 208-ball and 256-ball BGA packages-not in TQFP-due to pin count constraints. The device uses separate byte enables (UBL/LBL, UBR/LBR), dual chip enables per port (CE0L/CE1L, CE0R/CE1R), and Master/Slave select (M/S) to enable depth expansion and 36-bit+ bus width scaling without discrete glue logic.

Key Specifications

Pinout & Package

70V631S15BF8 is packaged in a 208-ball fine-pitch Ball Grid Array (BF208), with 15 mm × 15 mm footprint and 0.8 mm ball pitch. All VDD pins require 3.3 V supply; 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 CY7C1362BV18 and AS7C3256B, the 70V631S15BF8 uniquely delivers per-port I/O voltage selection, integrated BUSY arbitration, and JTAG testability in a 208-ball BGA-enabling compact, robust, and production-testable dual-processor memory subsystems without layout or firmware compromises.

Availability

70V631S15BF8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive radar systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for 70V631S15BF8 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 70V631S15BF8 belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic, low-latency inter-processor communication in real-time embedded systems.

FAQ

What is the maximum guaranteed access time for the 70V631S15BF8?

The 70V631S15BF8 has a maximum guaranteed read access time (tAA) of 15 ns across the industrial temperature range (–40°C to +85°C). This value is production-tested and applies to both ports under VDD = 3.3 V ± 150 mV and appropriate VDDQ conditions. The 15 ns rating ensures compatibility with 66 MHz synchronous bus interfaces without wait states.

Does the 70V631S15BF8 support JTAG boundary-scan testing?

Yes, the 70V631S15BF8 supports IEEE 1149.1 JTAG boundary-scan, but only in its 208-ball BGA (BF208) and 256-ball BGA (BCG256) packages. JTAG is explicitly excluded from the 128-pin TQFP variant due to insufficient pin count. Pins TDI, TDO, TCK, TMS, and TRST are fully functional in the BF208 package per the official IDT datasheet DSC-5622/9.

How does the BUSY arbitration mechanism work on the 70V631S15BF8?

The 70V631S15BF8 uses hardware-based BUSY arbitration: when configured as Master (M/S = VIH), it asserts BUSYR/BUSYL to block writes on the opposing port during address contention. As Slave (M/S = VIL), it accepts BUSY as an input to stall writes. The tBDD parameter (≤15 ns) defines the delay from BUSY deassertion to valid read data, ensuring deterministic resolution without software intervention.

Can the left and right ports of the 70V631S15BF8 operate at different I/O voltages?

Yes-the 70V631S15BF8 allows independent I/O voltage selection per port. OPTL sets VDDQL (left port) to 3.3 V (VIH) or 2.5 V (VIL); OPTR sets VDDQR (right port) identically. This enables direct interfacing with heterogeneous devices-for example, a 3.3 V FPGA on the left port and a 2.5 V microcontroller on the right port-without external level shifters.

What is the purpose of the semaphore feature in the 70V631S15BF8?

The semaphore feature provides eight hardware-managed flags (addressed by A0–A2) accessible via dedicated SEM pins. These flags enable atomic resource locking between processors-e.g., one port writes to I/O0 to claim a shared peripheral, while the other port reads all I/Os to detect the flag state. This eliminates race conditions and replaces software mutexes with deterministic, sub-10 ns hardware coordination.