Renesas 70V631S15PRF8

Overview

70V631S15PRF8 from Integrated Device Technology (IDT) is a high-speed, fully asynchronous 256K × 18-bit dual-port static RAM with independent left/right ports, 15 ns max access time (commercial grade), 3.3 V core supply, and selectable 3.3 V/2.5 V I/O voltage per port via OPT pins - used in real-time inter-processor communication, FPGA co-processing buffers, and legacy bus bridging where simultaneous read/write to shared memory is required.

For engineers reviewing the 70V631S15PRF8 datasheet, 70V631S15PRF8 pinout, 70V631S15PRF8 application, or 70V631S15PRF8 equivalent, key selection criteria include true dual-port arbitration logic, on-chip semaphore support, BUSY flag timing (tBAA ≤ 15 ns), JTAG omission in TQFP packages, and 128-pin TQFP package compatibility with industrial temperature range (–40°C to +85°C) variants.

Technical Context

This device implements fully independent asynchronous access paths for left and right ports, each with dedicated address, data, control (CE0/CE1, R/W, OE, UB/LB), and arbitration signals (BUSY, INT, SEM). Port-to-port contention is resolved by hardware arbitration using either address-match detection or chip-enable priority, with BUSY assertion disabling writes on the contending port.

The 70V631S15PRF8 supports MASTER/SLAVE cascading for 36-bit+ word systems via M/S pin configuration, enabling automatic BUSY flag generation (Master) or acceptance (Slave), and includes full on-chip semaphore signaling across eight flags addressed by A0–A2 - all without external logic.

Key Specifications

Pinout & Package

70V631S15PRF8 is housed in a 128-pin Thin Quad Flatpack (TQFP) package, measuring approximately 14 mm × 20 mm × 1.4 mm. All VDD pins require 3.3 V; VDDQ pins must match OPT pin state (3.3 V if OPT = VIH, 2.5 V if OPT = VIL); all VSS pins connect to ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-15ZXI and AS7C3256B-15TIN, the 70V631S15PRF8 uniquely delivers 256K × 18 density with per-port I/O voltage selection, integrated BUSY arbitration, and Master/Slave cascading - making it irreplaceable in high-reliability, mixed-voltage, or 36-bit+ memory expansion designs.

Availability

70V631S15PRF8 is available at Aetrix Electronics and suitable for industrial PLC communication buffers, FPGA-CPU shared memory interfaces, and legacy bus bridge applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70V631S15PRF8 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 power management ICs for communications, computing, and industrial markets.

The 70V631S15PRF8 belongs to IDT's high-speed asynchronous dual-port SRAM product line, designed specifically for deterministic inter-processor communication and real-time embedded systems requiring zero-software-overhead memory sharing.

FAQ

What is the maximum operating temperature range for the 70V631S15PRF8?

The 70V631S15PRF8 is qualified for industrial temperature operation from –40°C to +85°C. This rating is explicitly confirmed in the "Recommended Operating Temperature and Supply Voltage" table (page 7) and applies to the 70V631S12 and 70V631S15 speed grades. The "S" suffix denotes industrial-grade qualification.

Does the 70V631S15PRF8 support JTAG boundary scan?

No, the 70V631S15PRF8 does not support JTAG boundary scan. The datasheet explicitly states on page 1: "Due to limited pin count, JTAG is not supported on the 128-pin TQFP package." While JTAG pins (TCK, TMS, TDI, TDO, TRST) exist on BGA variants, they are omitted or non-functional in the PK-128 (128-pin TQFP) package used by 70V631S15PRF8.

How does the BUSY arbitration mechanism work on the 70V631S15PRF8?

The 70V631S15PRF8 implements hardware arbitration using the BUSY signal: when M/S = VIH (Master), BUSY is an output that asserts when address contention occurs; when M/S = VIL (Slave), BUSY is an input that blocks writes until deasserted. Timing parameters tBAA (≤15 ns), tBDA, and tBDD ensure deterministic resolution - detailed in Table 14 and Figures 12–15.

Can both ports of the 70V631S15PRF8 operate at different I/O voltages simultaneously?

Yes. The 70V631S15PRF8 supports independent I/O voltage selection per port: OPTL sets left-port VDDQL (3.3 V or 2.5 V), and OPTR sets right-port VDDQR (3.3 V or 2.5 V). The datasheet confirms this on page 5 ("Pin Names") and page 7 ("Recommended DC Operating Conditions"), allowing mixed-voltage interfacing - e.g., left port at 2.5 V to FPGA, right port at 3.3 V to microcontroller.

What is the function of the M/S pin on the 70V631S15PRF8?

The M/S pin configures the 70V631S15PRF8 as either Master (M/S = VIH) or Slave (M/S = VIL). In Master mode, BUSY is an output flag indicating port contention; in Slave mode, BUSY is an input that gates writes. This enables seamless cascading of multiple devices for >18-bit word widths - described in the "Features" section (page 1) and Truth Table I (page 6).