Renesas 70T631S12BF

Overview

IDT70T631S12BF from Integrated Device Technology is a high-speed 256K × 18-bit asynchronous dual-port static RAM with independent left/right ports, 12 ns maximum access time, 2.5 V core supply, and selectable 2.5 V/3.3 V I/O interface per port. It supports simultaneous read/write to the same memory location and is used in real-time inter-processor communication systems requiring deterministic latency and hardware semaphore arbitration.

For engineers reviewing the IDT70T631S12BF datasheet, IDT70T631S12BF pinout, IDT70T631S12BF application, or IDT70T631S12BF equivalent, key selection considerations include dual-port timing independence, RapidWrite Mode back-to-back write capability, BUSY flag arbitration for master/slave configurations, and BGA-208 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

This device implements true dual-port SRAM architecture with on-chip arbitration logic enabling concurrent access without external control logic. Each port has independent CE0/CE1, R/W, OE, UB/LB, and address/data buses - supporting fully asynchronous operation with no clock required.

It features hardware semaphore signaling across ports using dedicated SEM pins and eight shared semaphore flags addressed via A0–A2. The BUSY flag operates bidirectionally: output when M/S = VIH (Master), input when M/S = VIL (Slave), enabling lock-step synchronization between processors.

Key Specifications

Pinout & Package

Package: 208-ball fine-pitch BGA (BF208), body size 15 mm × 15 mm × 1.4 mm, 0.8 mm ball pitch. All VDD pins require 2.5 V; VDDQ pins must match OPT pin setting (2.5 V if OPT = VSS, 3.3 V if OPT = VDD).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-12ZXC and R1EX24016AS0C-12, the IDT70T631S12BF uniquely delivers per-port I/O voltage flexibility, hardware semaphore, and BUSY-flag arbitration in a single BGA-208 package - reducing board area and eliminating external glue logic in safety-critical dual-processor designs.

Availability

IDT70T631S12BF is available at Aetrix Electronics and suitable for telecom line card control, industrial PLC dual-core coordination, avionics sensor fusion hubs, and medical imaging real-time buffers requiring stable component supply across extended product lifecycles.

Supply support for IDT70T631S12BF 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 sensor signal conditioning ICs for communications and industrial markets.

IDT70T631S12BF belongs to the 70T63x family of high-speed asynchronous dual-port SRAMs designed specifically for deterministic inter-processor communication in real-time embedded systems where latency predictability and hardware arbitration are critical.

FAQ

What is the memory organization of the IDT70T631S12BF?

The IDT70T631S12BF is organized as 256K × 18 bits (4.608 Mbit), with separate 18-bit data buses for left and right ports. Address line A18 is a no-connect (NC) per datasheet note 1, confirming the 256K depth. This configuration supports 18-bit parallel interfaces without external data-width expansion logic.

Does the IDT70T631S12BF support both 2.5 V and 3.3 V I/O interfaces simultaneously?

Yes - the IDT70T631S12BF 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 (requiring VDDQL = 2.5 V), while OPTR = VDD configures the right port for 3.3 V I/O (requiring VDDQR = 3.3 V). This enables seamless interfacing between mixed-voltage processor subsystems.

How does the BUSY flag function in master/slave configurations with the IDT70T631S12BF?

In the IDT70T631S12BF, the BUSY flag behavior depends on the M/S pin state: when M/S = VIH, BUSYL is an output and BUSYR is an input (Master mode); when M/S = VIL, BUSYL is an input and BUSYR is an output (Slave mode). This bidirectional assignment enables hardware-enforced arbitration without external logic, ensuring only one port writes to contested addresses.

What is RapidWrite Mode and how does it improve performance in the IDT70T631S12BF?

RapidWrite Mode in the IDT70T631S12BF allows consecutive write operations without toggling R/W, CE, or byte-enable signals between cycles. The write cycle ends on the next address transition instead of R/W deassertion, reducing control overhead. This cuts effective write cycle time by up to 40% at 12 ns timing, easing timing closure in high-throughput inter-processor data transfer.

Is JTAG boundary scan supported on the IDT70T631S12BF, and which packages include it?

Yes - the IDT70T631S12BF supports IEEE 1149.1 JTAG boundary scan in both BGA-208 (BF208) and BGA-256 packages. Pins TDI, TDO, TCK, TMS, and TRST are dedicated and functional across all speed grades and temperature ranges. JTAG remains active even during ZZ-driven sleep mode, enabling in-system test and debug without waking the core.