Renesas 70V631S12PRF

Overview

70V631S12PRF from IDT (Integrated Device Technology) is a high-speed, asynchronous dual-port static RAM with 256K × 18-bit organization (4,608 Kbit), operating at 3.3 V core supply and supporting independent 3.3 V or 2.5 V I/O on each port. It features true dual-port architecture enabling simultaneous read/write access to the same memory location, 12 ns max access time (industrial grade), on-chip semaphore and interrupt logic, and BUSY flag arbitration - used in real-time inter-processor communication, FPGA co-processing, and legacy bus bridging systems.

For engineers reviewing the 70V631S12PRF datasheet, 70V631S12PRF pinout, 70V631S12PRF application, or 70V631S12PRF equivalent, this page delivers verified technical context, validated pin functions for TQFP-128 package, exact timing parameters across commercial/industrial grades, real-world use cases in embedded control and data acquisition, and two confirmed alternative parts with documented functional and interface differences.

Technical Context

The 70V631S12PRF implements fully asynchronous dual-port operation with separate address, control, and data buses per port - no clock required. Its on-chip arbitration logic resolves contention via BUSY flag assertion (MASTER mode) or input (SLAVE mode), controlled by M/S pin, with tBDD ≤ 12 ns propagation delay from write completion to valid read data on the opposing port.

It supports mixed-voltage I/O via independent OPTL/OPTR pins: each port selects 3.3 V (VIH) or 2.5 V (VIL) signaling levels, requiring corresponding VDDQL/VDDQR supplies. Semaphore flags (8 bits, addressed A2–A0) and interrupt flags (INTL/INTR) are hardware-managed with dedicated SEM/INT pins and fixed address-mapped trigger addresses (e.g., 3FFFE_H for INTL set).

Key Specifications

Pinout & Package

70V631S12PRF is packaged in a 128-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, body size 14 mm × 20 mm × 1.4 mm. All VDD pins require 3.3 V; VDDQL/VDDQR must match OPTL/OPTR logic level (3.3 V for VIH, 2.5 V for 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 CY7C1362BV33-12BGXI and AS7C3256B-12JIN, the 70V631S12PRF uniquely integrates per-port I/O voltage selection, hardware BUSY arbitration, and on-chip semaphore logic - reducing BOM count and firmware complexity in real-time heterogeneous systems.

Availability

70V631S12PRF is available at Aetrix Electronics and suitable for industrial PLC backplanes, FPGA co-processing interfaces, avionics data acquisition, and legacy bus bridge designs requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70V631S12PRF 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, specializes in high-performance timing, memory interface, and RF solutions for communications, computing, and industrial markets.

The 70V631S12PRF 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 system modernization where low-latency, hardware-managed arbitration is critical.

FAQ

What is the maximum supported I/O voltage for each port of the 70V631S12PRF?

The 70V631S12PRF supports either 3.3 V or 2.5 V I/O voltage per port, selected independently via OPTL and OPTR pins. When OPTL = VIH (≥2.0 V), VDDQL must be 3.3 V ±150 mV; when OPTL = VIL (≤0.8 V), VDDQL must be 2.5 V ±100 mV - same applies to OPTR/VDDQR. This enables direct interfacing with both LVTTL and LVCMOS25 devices without level shifters.

How does the BUSY flag function in MASTER versus SLAVE mode on the 70V631S12PRF?

When M/S = VIH, the 70V631S12PRF operates as MASTER: BUSYL/BUSYR are totem-pole outputs asserting low during port contention. When M/S = VIL, it operates as SLAVE: BUSYL/BUSYR become inputs that must be driven low by a MASTER device to block writes. The 70V631S12PRF's tBDD ≤ 12 ns ensures valid read data appears within 12 ns after BUSY deassertion in MASTER mode.

Can the 70V631S12PRF be used to build a 36-bit-wide memory system? If so, how?

Yes - the 70V631S12PRF supports 36-bit expansion using MASTER/SLAVE cascading. One device is configured as MASTER (M/S = VIH), another as SLAVE (M/S = VIL). The MASTER's BUSY output connects to the SLAVE's BUSY input. Data bus width doubles (18 + 18 bits), and address/data routing is handled internally via dedicated I/O0–I/O17 pins on each port - no external logic required for depth or width expansion.

What are the valid address ranges for setting and clearing interrupt flags on the 70V631S12PRF?

Interrupt flags are set/cleared via fixed address-mapped accesses: writing any value to address 3FFFE_H sets INTL (left port), while writing to 3FFFF_H sets INTR (right port). To clear, write to 3FFFE_H with right port active (CE0R=VIL, CE1R=VIH) to reset INTL, or to 3FFFF_H with left port active to reset INTR. Both INTL and INTR must be initialized at power-up per datasheet note.

Does the 70V631S12PRF support JTAG boundary scan, and if not, why?

No, the 70V631S12PRF does not support JTAG boundary scan in the 128-pin TQFP package (PKG128). Although JTAG pins (TCK, TMS, TDI, TDO, TRST) are present in BGA variants (BF208/BC256), the TQFP package lacks sufficient pins to implement IEEE 1149.1 compliance - a deliberate trade-off to maintain compact footprint while retaining core dual-port functionality.