Renesas 70T651S10BC8

Overview

70T651S10BC8 from IDT (now Renesas) is a high-speed 256K × 36-bit asynchronous dual-port static RAM with independent left/right ports, 10 ns max access time (commercial grade), 2.5 V core supply, and selectable 2.5 V/3.3 V I/O interface per port. It enables simultaneous read/write access to the same memory location in telecom switching fabric, network packet buffering, and real-time DSP co-processing systems.

For engineers reviewing the 70T651S10BC8 datasheet, 70T651S10BC8 pinout, 70T651S10BC8 application, or 70T651S10BC8 equivalent, key selection criteria include true dual-port arbitration logic, RapidWrite mode for back-to-back writes, JTAG IEEE 1149.1 compliance, industrial-grade temperature support (–40°C to +85°C), and 256-ball BGA package compatibility with depth/width expansion capability.

Technical Context

The 70T651S10BC8 implements fully asynchronous operation on both ports with on-chip arbitration logic that resolves simultaneous access conflicts via BUSY flag signaling and hardware semaphore support across eight shared flags. Its M/S (Master/Slave) select input configures BUSY as output (Master) or input (Slave), enabling cascaded 72-bit+ memory systems without external logic.

Each port features independent CE0/CE1 chip enables, R/W control, byte-enable lines (BE0–BE3), OPT-selectable I/O voltage (2.5 V or 3.3 V), and sleep mode (ZZL/ZZR) reducing current to ≤10 mA. The device supports RapidWrite mode where address transitions-not R/W pulses-define write cycle boundaries, simplifying high-frequency write sequencing at 100 MHz effective throughput.

Key Specifications

Pinout & Package

70T651S10BC8 is packaged in a 256-ball fine-pitch BGA (BC256) with 17 mm × 17 mm footprint and 1.0 mm ball pitch. Power and ground balls are distributed across the array for low-impedance supply delivery; VDD (2.5 V core) and VDDQ (I/O supply) pins are segregated per port to support independent voltage selection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33 and 70V25L25PF8, the 70T651S10BC8 uniquely delivers 2.5 V core with per-port I/O voltage flexibility, hardware semaphore arbitration, and RapidWrite mode-enabling higher throughput, lower power, and simpler system-level timing in modern heterogeneous compute architectures.

Availability

70T651S10BC8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and aerospace data acquisition requiring stable component supply, long lifecycle support, and RoHS-compliant packaging.

Supply support for 70T651S10BC8 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, computing, and industrial markets.

The 70T651S10BC8 belongs to IDT's high-speed dual-port SRAM product line, engineered for deterministic low-latency memory sharing between heterogeneous processors, FPGAs, and ASICs in real-time embedded systems.

FAQ

What is the maximum operating frequency supported by the 70T651S10BC8?

The 70T651S10BC8 does not operate on a clock signal-it is an asynchronous SRAM. Its 10 ns access time (tAA) supports effective random-access throughput up to 100 MHz in systems where address and control setup/hold times are met. Cycle time (tRC) is also 10 ns, enabling sustained back-to-back operations in RapidWrite mode without intermediate R/W toggling.

Can the left and right ports of the 70T651S10BC8 operate at different I/O voltages?

Yes. The 70T651S10BC8 supports independent I/O voltage selection per port via OPTL and OPTR pins. Setting OPTL = VDD (2.5 V) configures the left port for 3.3 V I/O levels with VDDQL = 3.3 V, while OPTR = VSS (0 V) configures the right port for 2.5 V I/O with VDDQR = 2.5 V-enabling mixed-voltage system integration without level shifters.

How does the RapidWrite mode function in the 70T651S10BC8?

In RapidWrite mode, the 70T651S10BC8 defines write cycle boundaries using address transitions instead of R/W or CE deassertion. R/WL and R/WR can remain low across consecutive writes, eliminating narrow pulse generation. Address stability (tWC = 10 ns), data setup (tDW = 6 ns), and hold (tDH = 0 ns) still apply-but referenced to the ending address edge, simplifying high-speed write sequencing in FPGA or ASIC controllers.

What is the role of the M/S pin in the 70T651S10BC8?

The M/S (Master/Slave) pin configures BUSY flag behavior: when M/S = VIH, BUSYL and BUSYR become outputs indicating local port contention; when M/S = VIL, they become inputs accepting BUSY signals from other devices. This enables daisy-chained arbitration in multi-SRAM systems-e.g., one 70T651S10BC8 as Master coordinates access across three Slave devices in a 108-bit memory bank.

Does the 70T651S10BC8 support JTAG boundary scan, and what pins are required?

Yes, the 70T651S10BC8 fully complies with IEEE 1149.1 JTAG boundary scan. Required pins are TCK (Test Clock), TMS (Test Mode Select), TDI (Test Data In), TDO (Test Data Out), and TRST (Test Reset). These pins remain functional even during ZZ sleep mode, enabling in-system test and debug without disrupting low-power operation.