Renesas 71V3557S80BG8

Overview

71V3557S80BG8 from Integrated Device Technology is a 128K × 36-bit (4.5 Mbit), 3.3V synchronous ZBT™ SRAM with flow-through outputs, 100 MHz operation (7.5 ns clock-to-data access), and 4-word burst capability. It features zero bus turnaround for seamless read/write transitions and supports linear or interleaved burst ordering via the LBO pin. This device serves as high-speed buffer memory in network packet processors and telecom line cards requiring deterministic latency.

For engineers reviewing the 71V3557S80BG8 datasheet, 71V3557S80BG8 pinout, 71V3557S80BG8 application, or 71V3557S80BG8 equivalent, key selection criteria include ZBT™ timing compliance, TQFP-100 package compatibility, 3.3V core/I/O supply requirements, burst counter synchronization, and JTAG boundary-scan support for production testability.

Technical Context

The 71V3557S80BG8 implements a synchronous dual-register architecture: address/control signals are latched on the rising CLK edge when ADV/LD is low and chip enables are asserted, while data input is registered and output is flow-through (no output register). Its internal burst counter advances on ADV/LD high, enabling four consecutive data cycles per address load.

Three chip enables (CE1, CE2 active-low; CE2 active-high) provide flexible depth expansion control, and Clock Enable (CEN) suspends all synchronous logic without affecting output state. The optional IEEE 1149.1 JTAG interface supports boundary-scan testing with TMS, TDI, TCK, TDO, and TRST pins.

Key Specifications

Pinout & Package

71V3557S80BG8 is packaged in a JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body, 0.5 mm pitch. Pin 1 is located at top-left corner (notch-marked side), with pins numbered counter-clockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV18-100AXC and AS7C31026B-10JC, the 71V3557S80BG8 uniquely delivers 7.5 ns clock-to-data access with zero bus turnaround and configurable 4-word burst - making it irreplaceable in latency-critical, burst-oriented telecom and networking datapaths.

Availability

71V3557S80BG8 is available at Aetrix Electronics and suitable for network packet buffering, telecom line card memory, baseband processor cache, and digital signal processing buffer applications requiring stable component supply, long-term industrial temperature support, and verified ZBT™ timing compliance.

Supply support for 71V3557S80BG8 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 high-performance interconnect solutions.

The 71V3557S80BG8 belongs to IDT's ZBT™ SRAM product line, engineered specifically for high-speed networking and telecommunications infrastructure where deterministic latency, burst efficiency, and bus utilization are critical.

FAQ

What is the maximum operating frequency and corresponding clock-to-data access time for the 71V3557S80BG8?

The 71V3557S80BG8 operates at a maximum frequency of 100 MHz, with a guaranteed clock-to-data access time of 7.5 ns. This specification is measured under industrial temperature conditions (–40°C to +85°C) and 3.3V ±5% supply, ensuring deterministic latency for real-time packet processing applications where the 71V3557S80BG8 is deployed.

Does the 71V3557S80BG8 support both linear and interleaved burst modes, and how is the selection made?

Yes, the 71V3557S80BG8 supports both linear and interleaved 4-word burst sequences. Selection is controlled by the static LBO (Linear/Interleaved Burst Order) pin: LBO = VSS selects linear order, and LBO = VDD selects interleaved order. This configuration must remain stable during device operation, as changing LBO mid-burst is undefined and may corrupt burst sequencing in the 71V3557S80BG8.

How does the ZBTTM (Zero Bus Turnaround) feature function in the 71V3557S80BG8, and what system-level benefit does it provide?

The ZBTTM feature in the 71V3557S80BG8 eliminates idle bus cycles when switching between read and write operations. By allowing immediate back-to-back accesses without turnaround overhead, it increases effective bus bandwidth by up to 30% in mixed-access scenarios. This directly improves throughput in network processors and telecom line cards where the 71V3557S80BG8 serves as a shared buffer.

What are the voltage requirements for VDD and VDDQ on the 71V3557S80BG8, and are they required to be independently regulated?

The 71V3557S80BG8 requires VDD = 3.3 V ±5% for core logic and VDDQ = 3.3 V ±5% for I/O drivers. Although both supplies share the same nominal voltage, IDT specifies separate decoupling and recommends independent regulation to prevent I/O switching noise from coupling into core logic - a critical requirement for signal integrity in high-speed designs using the 71V3557S80BG8.

Is JTAG boundary-scan support mandatory on the 71V3557S80BG8, and which pins implement this interface?

JTAG boundary-scan is optional on the 71V3557S80BG8 and implemented via dedicated pins: TMS, TDI, TCK, TDO, and optional TRST. TRST has an internal pull-up and may be left floating if not used. The interface complies with IEEE 1149.1 and is enabled only when configured in the "SA" variant; the "S" version (including 71V3557S80BG8) supports it but requires proper strap configuration and is not factory-enabled by default.