Renesas 70V631S15BC

Overview

70V631S15BC from Integrated Device Technology (IDT) 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 3.3 V core supply and offers selectable 3.3 V or 2.5 V I/O voltage per port via OPTL/OPTR pins, with 15 ns maximum read/write cycle time for commercial temperature range (0°C to +70°C). It is used in real-time inter-processor communication, video frame buffering, and FPGA co-processor memory subsystems.

For engineers reviewing the 70V631S15BC datasheet, 70V631S15BC pinout, 70V631S15BC application, or 70V631S15BC equivalent, key selection considerations include dual-port arbitration logic, BUSY/INT flag behavior, semaphore support across both ports, JTAG omission in TQFP packages, and compatibility with 128-pin TQFP (BC package code) mechanical and thermal specifications.

Technical Context

The 70V631S15BC implements true dual-port SRAM cells enabling concurrent read/write operations to the same memory location without external arbitration. Its on-chip port arbitration logic resolves contention using BUSY flag assertion (MASTER mode) or sampling (SLAVE mode), with tBDD ≤15 ns propagation delay ensuring deterministic data validity during port-to-port reads.

It supports full hardware semaphore signaling via dedicated SEM pins and eight shared semaphore flags addressed by A0–A2, enabling inter-port synchronization without software overhead. The device uses separate CE0/CE1 enables per port and byte-select controls (UBL/LBL, UBR/LBR) to enable 9-bit sub-word writes, with independent R/WL/R/WR and OEL/OER signals for precise timing control.

Key Specifications

Pinout & Package

70V631S15BC is housed in a 128-pin Thin Quad Flatpack (TQFP) package, designated PK-128 or BC. Pin assignments follow standard IDT dual-port RAM layout with mirrored left/right port signal groups, dedicated arbitration (BUSY, INT, SEM), and power/ground distribution optimized for low-noise dual-bus operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-15ZXI and AS7C3256B-15TIN, the 70V631S15BC uniquely delivers true dual-port operation with per-port voltage configurability, hardware semaphore support, and MASTER/SLAVE expandability-enabling deterministic real-time data sharing without external logic or software overhead.

Availability

70V631S15BC is available at Aetrix Electronics and suitable for real-time inter-processor communication, video frame buffering, and FPGA co-processor memory applications requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for 70V631S15BC 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, designs high-performance timing, memory interface, and RF products for communications, computing, and industrial markets.

The 70V631S15BC belongs to IDT's high-speed asynchronous dual-port SRAM product line, engineered specifically for deterministic, low-latency inter-processor data exchange in real-time embedded systems.

FAQ

What is the maximum operating frequency supported by the 70V631S15BC?

The 70V631S15BC does not operate at a fixed clock frequency-it is an asynchronous device. Its timing is defined by access and cycle times: maximum read/write cycle time (tRC/tWC) is 15 ns, corresponding to an effective throughput ceiling of approximately 66.7 MHz for consecutive operations. Actual system speed depends on external controller timing margins and bus loading.

Does the 70V631S15BC support JTAG boundary scan?

No, the 70V631S15BC does not support JTAG boundary scan. As explicitly stated in the datasheet, JTAG functionality (TMS, TCK, TDI, TDO, TRST) is omitted in the 128-pin TQFP package due to insufficient pin count-this applies to all variants in the PK-128 footprint, including the 70V631S15BC.

How does the BUSY signal function in MASTER versus SLAVE configuration on the 70V631S15BC?

When M/S = VIH, the 70V631S15BC operates as MASTER: BUSYL/BUSYR are outputs that assert low during port contention to block conflicting writes. When M/S = VIL, it operates as SLAVE: BUSYL/BUSYR become inputs that must be driven low by a MASTER device to inhibit local writes-enabling hierarchical arbitration in multi-device systems.

Can the left and right ports of the 70V631S15BC operate at different I/O voltages simultaneously?

Yes. The 70V631S15BC supports independent I/O voltage selection per port: OPTL sets VDDQL to 2.5 V or 3.3 V for the left port, while OPTR sets VDDQR accordingly for the right port. This allows direct interfacing with mixed-voltage systems-for example, left port to a 2.5 V FPGA bank and right port to a 3.3 V microcontroller bus.

What is the purpose of the semaphore feature in the 70V631S15BC, and how is it accessed?

The 70V631S15BC provides eight hardware semaphore flags for inter-port synchronization. They are accessed by asserting SEM = VIL and CE = VIH while addressing A0–A2 (0–7); I/O0 carries the flag value during reads, and I/O0 carries the write value. This eliminates software-based locking and prevents race conditions during shared resource management.