Renesas 71V547S100PFG8

Overview

71V547S100PFG8 from IDT (now Renesas) is a 3.3V, 128K × 36-bit synchronous SRAM with Zero Bus Turnaround (ZBT™) architecture, flow-through outputs, and 4-word burst capability (linear or interleaved). It delivers 95 MHz operation with 8 ns clock-to-data access and supports individual byte write control via BW1–BW4. Used in high-speed packet buffering and network switch fabric interfaces where zero-cycle bus turnaround between read/write transitions is critical.

For engineers reviewing the 71V547S100PFG8 datasheet, 71V547S100PFG8 pinout, 71V547S100PFG8 application, or 71V547S100PFG8 equivalent, key selection criteria include ZBT timing compliance, 100-pin TQFP mechanical fit, 3.3V ±5% supply tolerance, industrial temperature support (–40°C to +85°C), and synchronous burst counter behavior under ADV/LD and LBO control.

Technical Context

The 71V547S100PFG8 implements a fully synchronous interface with all inputs (except OE) sampled on the rising CLK edge. Its ZBT architecture eliminates dead cycles by enabling immediate read-after-write or write-after-read transitions without bus idle periods - achieved through internal address/control registration and burst counter advancement on ADV/LD = HIGH.

It features three chip enables (CE1, CE2 low-active; CE2 high-active) for depth expansion, a static LBO pin selecting linear/interleaved burst order, and flow-through output path (no output register), resulting in deterministic tCD delay but requiring external OE management for tri-state control during shared-bus operation.

Key Specifications

Pinout & Package

Packaged in a JEDEC-standard 100-pin TQFP (14 mm × 20 mm, 0.5 mm pitch), RoHS-compliant, with exposed thermal pad (PFG suffix).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous SRAM applications.

Compared with CY7C1362BV18 and AS7C31026B, the 71V547S100PFG8 uniquely balances ZBT timing, 36-bit width, and industrial TQFP packaging - making it optimal for legacy telecom and industrial systems requiring zero-turnaround burst efficiency without QDR complexity or async latency penalties.

Availability

71V547S100PFG8 is available at Aetrix Electronics and suitable for packet buffering, network switch fabric, telecom line cards, and industrial real-time controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 71V547S100PFG8 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, is a fabless semiconductor company specializing in high-performance timing, memory interface, and RF solutions for communications and computing infrastructure.

The 71V547S100PFG8 belongs to IDT's ZBT SRAM product line, designed specifically for zero-turnaround, burst-capable memory subsystems in high-speed networking and telecom equipment where deterministic latency and bus efficiency are critical.

FAQ

What does the 'S100' in 71V547S100PFG8 indicate?

The 'S100' denotes the speed grade: 100 MHz maximum clock frequency (tCYC = 15 ns). This is confirmed in the AC Electrical Characteristics table where 71V547S100 specifies tCYC ≤ 15 ns and tCD ≤ 10 ns. The 71V547S100PFG8 is rated for guaranteed operation up to 100 MHz across its full industrial temperature range (–40°C to +85°C), distinguishing it from slower variants like S80 (12.5 ns) or S90 (11.1 ns).

Does the 71V547S100PFG8 support true ZBT operation with no dead cycles?

Yes, the 71V547S100PFG8 implements true Zero Bus Turnaround (ZBT™) functionality. As documented in the Functional Description and Truth Tables, a read cycle can immediately follow a write cycle (and vice versa) without inserting idle bus cycles - provided ADV/LD transitions correctly and chip enables remain asserted. This is enabled by internal address/control registration and burst counter logic, and is verified in timing waveforms showing uninterrupted data flow across access boundaries.

How is burst order controlled on the 71V547S100PFG8?

Burst order is controlled exclusively by the LBO (Linear Burst Order) pin: when LBO = LOW, the device executes linear bursts (A0, A1, A2, A3); when LBO = HIGH, it executes interleaved bursts (A0, A2, A3, A1). This static DC input is sampled synchronously and defines the 4-word sequence for all burst operations initiated after ADV/LD = HIGH. The LBO pin is internally pulled to VDD if left unconnected.

Can the 71V547S100PFG8 operate with OE tied permanently low?

Yes - OE can be tied low in point-to-point configurations where the 71V547S100PFG8 is the sole driver on the data bus. The datasheet explicitly states "OE does not need to be actively controlled for read and write cycles" and "in normal operation, OE can be tied low." However, OE must be actively driven high to tri-state outputs during bus sharing or power-up initialization to prevent contention.

What is the function of the three chip enables (CE1, CE2, CE2) on the 71V547S100PFG8?

The three chip enables provide flexible depth expansion: CE1 and CE2 are active-low, while CE2 is active-high. The device is selected only when CE1 = LOW, CE2 = LOW, and CE2 = HIGH simultaneously. This asymmetric polarity allows cascading multiple 71V547S100PFG8 devices using simple logic - for example, using a 2-bit decoder to drive CE2/CE2 pairs while keeping CE1 common - enabling 2× or 3× memory depth without external address decoding.