Renesas 70T631S10BCI8

Overview

70T631S10BCI8 from IDT (now Renesas) is a high-speed 256K × 18-bit asynchronous dual-port static RAM with independent left/right ports, 10 ns max access time, 2.5 V core supply, and selectable 2.5 V/3.3 V I/O interface per port-used in real-time inter-processor communication, FPGA co-processing, and telecom packet buffering.

For engineers reviewing the 70T631S10BCI8 datasheet, 70T631S10BCI8 pinout, 70T631S10BCI8 application, or 70T631S10BCI8 equivalent, key selection criteria include dual-port arbitration logic, RapidWrite Mode timing compliance, BUSY/INT flag behavior in Master/Slave cascading, and BGA-208 package thermal/mechanical constraints for high-density PCB layout.

Technical Context

This device implements true dual-port SRAM cells enabling simultaneous read/write to the same memory location without external arbitration. Its on-chip port arbitration logic resolves contention via semaphore signaling and BUSY flag handshaking, supporting both autonomous and JTAG-controlled operation.

The 70T631S10BCI8 operates fully asynchronously per port with separate CE0/CE1, R/W, OE, UB/LB controls and supports RapidWrite Mode-eliminating R/W pulse requirements between back-to-back writes by using address transition as the write boundary, subject to tAAS ≤ 1 ns and tARF ≥ 1.5 V/ns.

Key Specifications

Pinout & Package

208-ball fine-pitch BGA (BF208) package, 0.8 mm ball pitch, 15 mm × 15 mm footprint, 1.4 mm height. Thermal pad not present; all VDD/VSS balls require dedicated power/ground plane stitching.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-10ZXC and AS7C33256PFS-10BIN, the 70T631S10BCI8 uniquely delivers per-port I/O voltage flexibility, RapidWrite Mode for burst throughput, and integrated JTAG - making it the only option supporting certified avionics and telecom infrastructure designs requiring deterministic latency and testability.

Availability

70T631S10BCI8 is available at Aetrix Electronics and suitable for telecom infrastructure, avionics data concentrators, and industrial FPGA co-processing applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.

Supply support for 70T631S10BCI8 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

IDT (Integrated Device Technology), now part of Renesas Electronics, is a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 70T631S10BCI8 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 where software arbitration introduces unacceptable jitter or overhead.

FAQ

What is the maximum operating frequency supported by the 70T631S10BCI8?

The 70T631S10BCI8 does not operate on a clock signal-it is an asynchronous dual-port SRAM. Its performance is defined by access time (tAA ≤ 10 ns) and cycle time (tRC ≤ 10 ns), enabling reliable operation in systems with effective data rates up to 100 MHz for back-to-back reads/writes under proper timing margins and load conditions.

Does the 70T631S10BCI8 support JTAG boundary scan testing?

Yes, the 70T631S10BCI8 supports IEEE 1149.1 JTAG boundary scan in its BGA-208 package (BF208). Pins TCK, TMS, TDI, TDO, and TRST are dedicated for this function, and JTAG operation remains functional even during sleep mode (ZZ asserted), though boundary scan is not recommended during sleep per datasheet Note 4.

How does the BUSY pin function in Master vs. Slave configuration on the 70T631S10BCI8?

When M/S = VIH, BUSYL/BUSYR act as totem-pole outputs indicating local port contention; when M/S = VIL, they become inputs accepting BUSY signals from a Master device. This bidirectional behavior enables daisy-chained arbitration in multi-device 36-bit+ memory systems without external logic, as confirmed in datasheet Note 2 and Truth Table I.

Can both ports of the 70T631S10BCI8 operate at different I/O voltages simultaneously?

Yes-the 70T631S10BCI8 allows independent I/O voltage selection per port via OPTL and OPTR pins. Setting OPTL = VSS configures the left port for 2.5 V I/O, while OPTR = VDD configures the right port for 3.3 V I/O, with corresponding VDDQL/VDDQR supplies. This is explicitly documented in datasheet Note 3 on page 5.

What is the purpose of the RapidWrite Mode in the 70T631S10BCI8?

RapidWrite Mode allows consecutive write operations without pulsing R/W, CE, or byte enables between cycles-the ending address transition defines the write boundary. This reduces control timing complexity and improves sustained write throughput, provided tAAS ≤ 1 ns and tARF ≥ 1.5 V/ns per datasheet Table 14 and Figure 8.