Renesas IDT70825S25PF

Overview

IDT70825S25PF from Integrated Device Technology is a high-speed 8K × 16-bit Sequential Access Random Access Memory (SARAM™) with dual-port architecture: asynchronous random-access port (25 ns tAA) and synchronous sequential-access port (25 ns clock cycle). It supports independent buffer management via two programmable address ranges, TTL-compatible 5V operation, and industrial temperature range (–40°C to +85°C). Used in real-time data buffering for telecom line cards and packet switching engines.

For engineers reviewing the IDT70825S25PF datasheet, IDT70825S25PF pinout, IDT70825S25PF application, or IDT70825S25PF equivalent, key selection criteria include dual-port timing isolation, EOB flag-controlled buffer chaining, byte-selectable random access (LB/UB), sequential pointer load control (SLD/SSTRT1/SSTRT2), and 2V data retention capability.

Technical Context

The IDT70825S25PF implements a Dual-Port RAM cell architecture with physically separate I/O paths: one asynchronous SRAM interface (A0–A12, I/O0–I/O15, CE/OE/R/W/LB/UB) and one synchronous clocked interface (SCLK, SCE, SR/W, SI/O0–SI/O15, CNTEN, SLD, SSTRT1/SSTRT2). Address pointer logic supports two independently configurable buffers with start/end registers and four flow modes (BUFFER CHAINING, STOP, LINEAR, MASK).

Control register access occurs via CMD mode using A0–A2 and I/O0–I/O12 under CE = VIH/CMD = VIL, enabling read/write of buffer addresses, flow control bits (bits 0–3), and EOB flag status/clear. Reset (RST) is asynchronous and initializes pointer to 0, clears EOB flags, and sets default BUFFER CHAINING mode.

Key Specifications

Pinout & Package

Package: 80-pin Thin Quad Flatpack (TQFP), PN80-1, 14 mm × 14 mm × 1.4 mm body, lead-free compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-25AC and IDT70V25S25PF, the IDT70825S25PF uniquely integrates sequential streaming logic with programmable buffer flow control in a 5V-compatible package, eliminating external counter/flag logic while supporting brown-out data retention - critical for telecom and industrial real-time buffering.

Availability

IDT70825S25PF is available at Aetrix Electronics and suitable for telecom infrastructure, industrial motion control, and radar signal processing requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.

Supply support for IDT70825S25PF 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) is a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance interconnect solutions for communications and computing markets.

The IDT70825S25PF belongs to IDT's SARAM™ family, designed specifically to replace discrete FIFO + control logic combinations in real-time data acquisition and streaming applications where deterministic latency and buffer management autonomy are essential.

FAQ

What is the primary functional distinction between the random and sequential ports of the IDT70825S25PF?

The IDT70825S25PF random port operates asynchronously with standard SRAM timing (CE/OE/R/W controlled), enabling CPU or DSP direct access to any 16-bit word. The sequential port is synchronous, clocked by SCLK, and uses internal pointer logic to stream data linearly or in configured buffers - allowing continuous high-throughput transfer without address bus cycling. This separation eliminates arbitration and enables true concurrent access.

How does the IDT70825S25PF implement buffer chaining between two memory regions?

The IDT70825S25PF implements buffer chaining via its flow control register (bit 0–1 = 00). When the sequential address pointer reaches the end address of Buffer #1, EOB1 asserts and the pointer automatically loads the start address of Buffer #2. Similarly, reaching Buffer #2's end triggers a jump to Buffer #1's start. This creates a seamless circular buffer without CPU intervention, enabled solely by register configuration and EOB flag detection.

Can the IDT70825S25PF retain data during power loss, and what conditions must be met?

Yes, the IDT70825S25PF supports data retention at VCC ≥ 2.0 V. To enter retention mode, both ports must be disabled: CE and SCE must be driven HIGH (VIH), and all inputs held static. The device retains full 8K × 16-bit content indefinitely under these conditions, making it suitable for battery-backed applications such as industrial logging or telecom alarm storage.

What is the role of the SLD pin in sequential port operation of the IDT70825S25PF?

The SLD (Sequential Load) pin on the IDT70825S25PF enables dynamic loading of an arbitrary address into the sequential address pointer. When SLD is sampled LOW, SI/O0–SI/O12 data is latched on the next SCLK rising edge; on the subsequent rising edge, that value becomes the new pointer address. This allows runtime repositioning of the sequential stream - for example, skipping corrupted data blocks or restarting from a known good offset.

Does the IDT70825S25PF support partial-word writes on the random access port, and how is it controlled?

Yes, the IDT70825S25PF supports independent 8-bit writes via LB (Lower Byte) and UB (Upper Byte) enables. When LB = LOW and UB = HIGH, only I/O0–I/O7 are written; when UB = LOW and LB = HIGH, only I/O8–I/O15 are written; both LOW enables full 16-bit write. This avoids read-modify-write cycles and reduces bus contention in systems sharing the random port with multiple masters.