Renesas 70V631S12BC

Overview

70V631S12BC from IDT (Integrated Device Technology) is a high-speed, fully asynchronous 256K × 18-bit dual-port static RAM with independent left/right ports, 12 ns max access time (industrial grade), 3.3 V core supply, and selectable 3.3 V/2.5 V I/O voltage per port via OPT pins - used in real-time inter-processor communication, FPGA co-processor buffering, and legacy bus arbitration systems.

For engineers reviewing the 70V631S12BC datasheet, 70V631S12BC pinout, 70V631S12BC application, or 70V631S12BC equivalent, this page delivers verified package mapping (128-pin TQFP), true dual-port arbitration logic, BUSY/INT/SEM flag behavior, industrial temperature support (–40°C to +85°C), and precise JTAG exclusion status for the BC variant.

Technical Context

The 70V631S12BC implements true dual-port SRAM cells enabling simultaneous read/write access to the same memory location without external arbitration. Its on-chip port arbitration logic resolves contention using BUSY flag assertion based on address match or chip enable timing, with M/S pin configuring master/slave role for cascaded 36-bit+ memory expansion.

Each port supports independent I/O voltage selection (3.3 V or 2.5 V) via dedicated OPTL/OPTR pins and separate VDDQL/VDDQR supplies, while core logic operates at fixed 3.3 V. Semaphore signaling across ports uses A0–A2 addressing and I/O0–I/O17 data lines, with full hardware semaphore enable (SEML/SEMR) and interrupt flag generation (INTL/INTR) tied to specific address writes (e.g., 3FFFE_H, 3FFFF_H).

Key Specifications

Pinout & Package

70V631S12BC is housed in a 128-pin Thin Quad Flatpack (TQFP) package (PKG128), measuring approximately 14 mm × 20 mm × 1.4 mm, with 0.5 mm lead pitch. All VDD pins require 3.3 V; VDDQL/VDDQR must match OPTL/OPTR logic levels (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 CY7C1362BV33-12BGXI and AS7C3256B-12JIN, the 70V631S12BC uniquely delivers per-port I/O voltage selection and integrated BUSY/SEM/INT logic in a 128-pin TQFP - reducing BOM count and PCB area in mixed-voltage, real-time systems.

Availability

70V631S12BC is available at Aetrix Electronics and suitable for real-time inter-processor communication, FPGA co-processing buffers, and avionics data concentrators requiring stable component supply across extended lifecycle programs.

Supply support for 70V631S12BC 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 70V631S12BC belongs to IDT's high-speed asynchronous dual-port SRAM product line, engineered for deterministic low-latency memory sharing in multi-processor and FPGA-based real-time systems.

FAQ

What is the maximum operating temperature range for the 70V631S12BC?

The 70V631S12BC is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the "Recommended Operating Temperature and Supply Voltage" table (page 7) and applies to the 70V631S12BC variant specifically. It ensures reliable performance in demanding environments such as factory automation controllers and transportation electronics where ambient thermal stress is significant.

Does the 70V631S12BC support JTAG boundary scan?

No, the 70V631S12BC does not support JTAG boundary scan. The datasheet explicitly states: "Due to limited pin count, JTAG is not supported on the 128-pin TQFP package" and "JTAG is not supported in the PK-128 package" (pages 1 and 3). The 70V631S12BC uses the 128-pin TQFP (PKG128), so JTAG functionality is omitted - only the 208-ball and 256-ball BGA variants include TDI/TDO/TCK/TMS/TRST pins.

How does the BUSY signal function in master versus slave configuration for the 70V631S12BC?

In master configuration (M/S = VIH), BUSYL/BUSYR is a totem-pole output that asserts low during port contention to block writes on the opposing port. In slave configuration (M/S = VIL), BUSYL/BUSYR becomes an input - the external master drives it low to stall writes. This dual-role behavior is defined in Note 1 on page 2 and timing diagrams on pages 15–16, and is fundamental to the 70V631S12BC's hardware arbitration capability.

Can both ports of the 70V631S12BC operate at different I/O voltages simultaneously?

Yes, the 70V631S12BC supports independent I/O voltage selection: OPTL sets left-port I/O voltage (3.3 V or 2.5 V), and OPTR sets right-port I/O voltage (3.3 V or 2.5 V). The datasheet confirms this on page 5 ("OPT pins are independent of one another - both ports can operate at 3.3V levels, both can operate at 2.5V levels, or either can operate at 3.3V with the other at 2.5V"), enabling direct interfacing with heterogeneous logic families without level shifters.

What is the purpose of the SEM pins on the 70V631S12BC, and how are they used?

The SEML and SEMR pins enable hardware semaphore mode on the left and right ports respectively. When asserted (VIH), they activate the 8-bit semaphore register addressed by A0–A2, allowing atomic flag exchange across ports via I/O0–I/O17. This is detailed in Truth Table II (page 6) and the Functional Description (page 18). The 70V631S12BC uses this feature to coordinate resource access without CPU intervention - a key advantage over single-port or software-managed SRAMs.