Renesas 70T631S12BCI

Overview

70T631S12BCI from IDT (now Renesas) is a high-speed 256K × 18-bit asynchronous dual-port static RAM with independent left/right ports, 12 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-processor buffering, and legacy bus arbitration systems.

For engineers reviewing the 70T631S12BCI datasheet, 70T631S12BCI pinout, 70T631S12BCI application, or 70T631S12BCI equivalent, this page delivers verified timing specs, BGA-208 pin mapping, RapidWrite Mode behavior, semaphore arbitration logic, and industrial-grade (-40°C to +85°C) operation - all confirmed for the exact 70T631S12BCI variant.

Technical Context

This device implements true dual-port SRAM architecture with on-chip port arbitration, allowing simultaneous read/write access to the same memory location without external logic. It supports hardware semaphore signaling via SEM pins and provides BUSY flag handshaking for master/slave coordination between ports.

RapidWrite Mode enables back-to-back write cycles without toggling R/W or CE between addresses, reducing system timing overhead. JTAG IEEE 1149.1 test support is integrated and active in BGA-208 packaging, with dedicated TCK/TMS/TDI/TDO pins and TRST reset.

Key Specifications

Pinout & Package

70T631S12BCI is housed in a 208-ball fine-pitch BGA (package code BF208/BFG208), with 15 mm × 15 mm footprint and 0.8 mm ball pitch. Pin functions are asymmetrically distributed across left (L) and right (R) ports, supporting independent control and data paths.

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 70T631S12BCI uniquely delivers per-port voltage flexibility, RapidWrite Mode, and deterministic hardware arbitration - making it irreplaceable in real-time dual-CPU or FPGA-host buffer architectures requiring sub-12 ns latency and mixed-voltage interoperability.

Availability

70T631S12BCI is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and embedded computing applications requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70T631S12BCI 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, specializes in high-performance timing, memory, and interface solutions for communications and industrial markets.

The 70T631S12BCI belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic inter-processor communication, real-time data buffering, and legacy bus bridging in harsh-environment systems.

FAQ

What is the memory organization of the 70T631S12BCI?

The 70T631S12BCI implements a 256K × 18-bit asynchronous dual-port SRAM array. Address pin A18 is marked NC (no connect), confirming the 256K depth. Each port has fully independent 18-bit bidirectional data lines (I/O0L–I/O17L and I/O0R–I/O17R), separate address buses (A0L–A17L and A0R–A17R), and dedicated control signals - enabling true concurrent access without contention.

Does the 70T631S12BCI support both 2.5 V and 3.3 V I/O interfaces simultaneously?

Yes. The 70T631S12BCI supports 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 levels (with VDDQL = 2.5 V), while setting OPTR = VDD configures the right port for 3.3 V I/O levels (with VDDQR = 3.3 V). This allows direct interfacing with mixed-voltage systems without external level shifters.

How does RapidWrite Mode function in the 70T631S12BCI?

RapidWrite Mode in the 70T631S12BCI allows consecutive write operations without toggling R/W, CE, or byte-enable signals between addresses. The write cycle is terminated by the ending address transition, not signal deactivation. This simplifies timing-critical FPGA or ASIC controller design and improves sustained write throughput - provided tAAS (≤1 ns) and tARF (≥1.5 V/ns) specifications are met.

What is the role of the M/S pin in the 70T631S12BCI?

The M/S (Master/Slave Select) pin determines BUSY signal direction: when M/S = VIH, the 70T631S12BCI operates as Master and asserts BUSY as an output; when M/S = VIL, it operates as Slave and accepts BUSY as an input. This enables daisy-chained MASTER/SLAVE configurations for expanding data width beyond 18 bits - e.g., cascading two devices to form a 36-bit word system.

Is JTAG boundary scan supported on the 70T631S12BCI in its BGA-208 package?

Yes. The 70T631S12BCI supports full IEEE 1149.1 JTAG boundary scan in the BF208/BFG208 package. Pins TCK, TMS, TDI, TDO, and TRST are dedicated and functional regardless of sleep mode (ZZL/ZZR assertion). JTAG remains operational during normal operation and is unaffected by port arbitration or RapidWrite Mode activity.