Renesas 71V3556SA100BG8

Overview

71V3556SA100BG8 from IDT (now Renesas) is a 3.3V synchronous ZBT SRAM with 128K × 36-bit organization (4.5 Mbit), 100 MHz clock speed, 3.5 ns clock-to-data access, zero bus turnaround architecture, and JEDEC-standard 100-pin TQFP package. It serves as a high-bandwidth, low-latency memory buffer in network packet processors and telecom line cards requiring burst pipelined reads/writes without dead cycles.

For engineers reviewing the 71V3556SA100BG8 datasheet, 71V3556SA100BG8 pinout, 71V3556SA100BG8 application, or 71V3556SA100BG8 equivalent, key selection criteria include ZBT™ timing compliance, 4-word burst mode (linear/interleaved), individual byte write control (BW1–BW4), JTAG boundary scan support, and industrial temperature operation (–40°C to +85°C).

Technical Context

The 71V3556SA100BG8 implements a fully pipelined synchronous interface with positive-edge-triggered address, data, and control registers. Its ZBT™ architecture eliminates bus turnaround latency by enabling immediate read-after-write or write-after-read transitions without idle cycles.

It integrates an on-chip burst counter, selectable linear/interleaved burst order via LBO, and three chip enables (CE1, CE2, CE2) for depth expansion. The optional IEEE 1149.1 JTAG interface supports boundary scan testing in BGA variants - though this specific TQFP variant (100BG8) excludes TRST and dedicated JTAG pins per pinout documentation.

Key Specifications

Pinout & Package

71V3556SA100BG8 is packaged in a 100-pin thin quad flatpack (TQFP), JEDEC MO-140AC, 14 mm × 20 mm body, 0.5 mm lead pitch. Pin 1 is located at bottom-left corner when notch faces up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1356BV18-100BZI and AS7C33128PFSI-100, the 71V3556SA100BG8 delivers deterministic zero-turnaround performance, integrated burst sequencing, and granular byte write control - making it uniquely suited for latency-critical telecom and networking datapaths where bus efficiency directly impacts system throughput.

Availability

71V3556SA100BG8 is available at Aetrix Electronics and suitable for telecom infrastructure, network test equipment, and industrial embedded controllers requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature compliance.

Supply support for 71V3556SA100BG8 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, and interface solutions for communications and computing markets.

The 71V3556SA100BG8 belongs to IDT's ZBT™ SRAM product line, engineered specifically for zero-latency, high-throughput memory subsystems in packet-switched networks, wireless base stations, and real-time digital signal processing platforms.

FAQ

What is the memory organization and total capacity of the 71V3556SA100BG8?

The 71V3556SA100BG8 is configured as 128K × 36-bit, delivering 4,718,592 bits (4.5 Mbit) of synchronous SRAM. This organization supports 36-bit-wide data buses common in network processors and DSPs, and is distinct from the 256K × 18-bit variant (71V3558SA). The 71V3556SA100BG8 uses address lines A0–A16 (17 bits) for full addressing; A17 is not used in this configuration.

Does the 71V3556SA100BG8 support JTAG boundary scan, and which pins implement it?

No, the 71V3556SA100BG8 in its 100-pin TQFP package does not support JTAG boundary scan. While the "SA" suffix denotes JTAG capability in BGA variants (e.g., BG119/BQ165), the PKG100 pinout omits TMS, TDI, TCK, TDO, and TRST pins - confirmed by the absence of these signals in the 100-pin TQFP pin configuration diagrams and their explicit listing as "NC" or absent in Tables 02 and 03 of the datasheet.

How does the ZBT™ feature eliminate bus turnaround cycles in the 71V3556SA100BG8?

The ZBT™ architecture in the 71V3556SA100BG8 allows immediate transition from a write cycle to a read cycle (or vice versa) without inserting idle bus cycles. This is achieved through separate, independently controlled write and read data paths and internal pipelining that decouples address/control registration from data transfer timing - ensuring the bus remains 100% utilized in back-to-back operations, unlike conventional synchronous SRAMs requiring turnaround wait states.

What is the function of the ADV/LD and LBO pins in burst operation of the 71V3556SA100BG8?

In the 71V3556SA100BG8, ADV/LD determines whether the internal burst counter loads a new external address (ADV/LD = LOW) or increments (ADV/LD = HIGH). LBO selects burst order: LOW enables linear sequence (0,1,2,3), HIGH enables interleaved (0,2,3,1). Both signals must remain static during burst execution - changing LBO mid-burst causes undefined behavior, and toggling ADV/LD incorrectly disrupts burst continuity.

Can the 71V3556SA100BG8 operate with different supply voltages for core and I/O, and what are the tolerances?

Yes, the 71V3556SA100BG8 uses split supplies: VDD (core) and VDDQ (I/O), both rated at 3.3 V ±5% (3.135 V to 3.465 V). This separation allows independent noise management and supports mixed-voltage system designs. The datasheet explicitly prohibits exceeding VDDQ +0.3 V on I/O pins and mandates that no pin voltage exceed VDDQ +0.5 V during operation - critical for interoperability with 3.3V logic families.