Renesas 70T631S10BF

Overview

70T631S10BF from Integrated Device Technology is a high-speed 256K × 18 asynchronous dual-port static RAM with true simultaneous access to the same memory location, 10 ns max read cycle 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 systems requiring deterministic latency and hardware semaphore arbitration.

For engineers reviewing the 70T631S10BF datasheet, 70T631S10BF pinout, 70T631S10BF application, or 70T631S10BF equivalent, key selection criteria include port arbitration timing (tSPS = 5 ns), RapidWrite Mode support for back-to-back writes without R/W toggling, BUSY flag behavior in Master/Slave cascading, and BGA-208 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The 70T631S10BF implements fully asynchronous dual-port architecture with independent left/right address, control, and data buses, enabling concurrent read/write operations across ports without clock synchronization. It integrates on-chip port arbitration logic, semaphore signaling (SEML/SEMR), and BUSY/INT flags for inter-port coordination.

RapidWrite Mode redefines write termination by address transition instead of R/W edge, requiring strict tAAS ≤ 1 ns address skew and tARF ≥ 1.5 V/ns slew rate. The device supports JTAG IEEE 1149.1 test access in BGA-208 packages and uses separate OPTL/OPTR pins to configure each port's I/O voltage (2.5 V or 3.3 V) independently.

Key Specifications

Pinout & Package

70T631S10BF is housed in a 208-ball fine-pitch BGA (package code BF208/BFG208), with 15 mm × 15 mm footprint, 0.8 mm ball pitch, and standard power/ground ball distribution per IDT documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV18 and AS7C33256P, the 70T631S10BF uniquely delivers 10 ns dual-port access with integrated semaphore logic, RapidWrite Mode, and flexible 2.5 V/3.3 V per-port I/O-making it irreplaceable for deterministic inter-processor communication in industrial and avionics systems.

Availability

70T631S10BF is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, avionics data hubs, and medical imaging systems requiring stable component supply across extended product lifecycles.

Supply support for 70T631S10BF 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, designs high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 70T631S10BF belongs to IDT's high-speed asynchronous dual-port SRAM family, engineered specifically for deterministic inter-processor communication in real-time embedded systems requiring hardware arbitration and mixed-voltage interoperability.

FAQ

What is the maximum operating frequency supported by the 70T631S10BF?

The 70T631S10BF does not operate on a clock; it is an asynchronous dual-port SRAM. Its performance is specified by access time: 10 ns maximum for tAA, tACE, and tAOE. This corresponds to a theoretical maximum random-access throughput of 100 MHz, but actual system bandwidth depends on bus protocol, address stability, and control signal timing margins-not a fixed clock frequency. The 70T631S10BF datasheet confirms no clock input is required.

Does the 70T631S10BF support both 2.5 V and 3.3 V I/O on the same device?

Yes-the 70T631S10BF 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 (with VDDQL = 2.5 V), while OPTR = VDD configures the right port for 3.3 V I/O (with VDDQR = 3.3 V). This allows seamless interfacing between mixed-voltage subsystems without external level shifters, as confirmed in IDT datasheet section "Pin Names" and "Recommended DC Operating Conditions".

How does the BUSY flag function in Master/Slave configuration for the 70T631S10BF?

In Master mode (M/S = VIH), BUSYL/BUSYR are outputs indicating port contention during simultaneous writes to the same address. In Slave mode (M/S = VIL), BUSYL/BUSYR become inputs used to detect Master-initiated busy states. This bidirectional behavior is explicitly defined in the 70T631S10BF datasheet Note 2 on page 5 and Truth Table I, enabling scalable depth expansion using multiple devices without external glue logic.

Is RapidWrite Mode available on the 70T631S10BF, and what design constraints does it impose?

Yes-RapidWrite Mode is fully supported on the 70T631S10BF and eliminates the need to toggle R/W between consecutive writes. However, it imposes two critical layout constraints: allowable address skew (tAAS ≤ 1 ns) and minimum address slew rate (tARF ≥ 1.5 V/ns), as specified in Table 14 and Figure 8 of the datasheet. Failure to meet these causes potential miswrites during address transitions, making controlled PCB routing and termination essential.

What JTAG capabilities does the 70T631S10BF provide, and which packages support them?

The 70T631S10BF implements full IEEE 1149.1 JTAG boundary scan with TCK, TMS, TDI, TDO, and TRST pins. These functions are explicitly supported only in the BGA-208 (BF208/BFG208) package, as stated in the "Features" section and Pin Configuration diagrams. JTAG remains operational during sleep mode (ZZ = VIH), though the datasheet recommends avoiding boundary scan during sleep for reliability.