Renesas 70V631S10BF

Overview

70V631S10BF from Integrated Device Technology (IDT) is a high-speed, fully asynchronous 256K × 18-bit dual-port static RAM with 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 real-time control systems requiring deterministic arbitration.

For engineers reviewing the 70V631S10BF datasheet, 70V631S10BF pinout, 70V631S10BF application, or 70V631S10BF equivalent, key selection considerations include its dual-chip-enable depth expansion capability, on-chip semaphore signaling for inter-processor synchronization, BUSY flag arbitration logic, and support for MASTER/SLAVE cascading to build 36-bit-or-wider memory systems without external logic.

Technical Context

The 70V631S10BF implements true dual-port SRAM cells with full hardware port arbitration, allowing concurrent read/write operations on both ports without collision. Its internal logic supports JTAG boundary-scan (IEEE 1149.1) - though disabled in the 128-pin TQFP package due to pin count constraints.

Each port features independent chip enables (CE0/CE1), byte controls (UB/LB), read/write (R/W), output enable (OE), and dedicated semaphore (SEM) and interrupt (INT) flags. The M/S pin configures master/slave behavior for cascaded configurations, where BUSY acts as output (master) or input (slave) to coordinate access to shared memory locations.

Key Specifications

Pinout & Package

70V631S10BF is housed in a 128-pin Thin Quad Flatpack (TQFP) package. All VDD pins require connection to 3.3 V; VDDQ pins must match OPT pin state (3.3 V if OPT = VIH, 2.5 V if OPT = 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 CY7C1362BV33-10BGXI and IDT70V3609S10PFI, the 70V631S10BF uniquely integrates per-port voltage selection, MASTER/SLAVE cascade capability, and hardware BUSY arbitration-enabling single-device 36-bit+ memory expansion and eliminating external glue logic in tightly coupled multiprocessor systems.

Availability

70V631S10BF is available at Aetrix Electronics and suitable for industrial motion control, telecom line card buffering, avionics display generation, and medical imaging pipeline applications requiring stable component supply and long-term obsolescence management.

Supply support for 70V631S10BF 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 real-time interconnect solutions for communications, computing, and industrial markets.

The 70V631S10BF belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic, low-latency data sharing between independent processors, FPGAs, or ASICs in real-time embedded systems.

FAQ

What is the maximum operating speed of the 70V631S10BF?

The 70V631S10BF has a guaranteed maximum read cycle time (tRC) of 10 ns and address access time (tAA) of 10 ns under commercial temperature conditions (0°C to +70°C). This corresponds to a theoretical maximum throughput of 100 MHz for consecutive read operations, assuming optimal timing margins and proper signal integrity layout.

Does the 70V631S10BF support JTAG boundary-scan testing?

No, the 70V631S10BF does not support JTAG boundary-scan. Although the IDT70V631 family includes IEEE 1149.1 compliance, JTAG functionality is explicitly disabled in the 128-pin TQFP package (PKG128) due to insufficient pin count - a limitation confirmed in the datasheet note on page 1.

How does the M/S pin affect BUSY signal behavior in the 70V631S10BF?

In the 70V631S10BF, the M/S pin configures BUSY as an output when pulled high (VIH), making the device a MASTER that asserts BUSY to block conflicting writes on the other port. When M/S is low (VIL), BUSY becomes an input (SLAVE mode), requiring external assertion from a MASTER device to gate local write operations.

Can both ports of the 70V631S10BF operate at different I/O voltages simultaneously?

Yes. The 70V631S10BF supports independent I/O voltage selection per port: OPTL sets left-port VDDQL (3.3 V or 2.5 V), and OPTR sets right-port VDDQR (3.3 V or 2.5 V). This allows one port to interface with a 3.3 V FPGA while the other connects to a 2.5 V ASIC - verified in DC Operating Conditions tables on pages 7–8 of the datasheet.

What is the purpose of the semaphore feature in the 70V631S10BF?

The semaphore feature in the 70V631S10BF provides eight hardware-managed synchronization flags accessible via A0–A2 address lines. These flags enable lock-free inter-processor communication - for example, one port writes to I/O0 to claim a resource, and the other reads all I/O lines to detect the flag state - eliminating software overhead and race conditions in real-time systems.