Renesas 71V2556SA100BGGI8

Overview

71V2556SA100BGGI8 from IDT (now Renesas) is a 3.3V synchronous ZBT™ SRAM with 128K × 36-bit (4.5 Mbit) organization, 166 MHz operation (3.5 ns clock-to-data access), pipelined outputs, and zero-bus-turnaround architecture. It features individual byte write control (BW1–BW4), three chip enables for depth expansion, and supports industrial temperature range (–40°C to +85°C). It is used in high-speed packet buffering and network switch fabric memory subsystems.

For engineers reviewing the 71V2556SA100BGGI8 datasheet, 71V2556SA100BGGI8 pinout, 71V2556SA100BGGI8 application, or 71V2556SA100BGGI8 equivalent, key selection considerations include burst mode timing (linear/interleaved), 2.5V I/O supply compatibility, JTAG test interface availability, and TQFP-100 package mechanical fit in space-constrained telecom line cards.

Technical Context

This device implements a fully synchronous, clock-edge-triggered architecture with input registers for address, data, and control signals. Its on-chip burst counter enables 4-word bursts (linear or interleaved per LBO pin state), and internally synchronized output enable eliminates external OE timing constraints.

The ZBT™ architecture ensures no dead cycles between read and write operations by overlapping bus turnaround with internal pipeline stages. It supports pipelined reads/writes with two-cycle latency from address/control registration to data valid, and uses separate VDD (3.3V) and VDDQ (2.5V) supplies for core logic and I/O domains.

Key Specifications

Pinout & Package

Packaged in JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body, 0.5 mm pitch. Pin 1 marked via corner notch; top-side marking includes "71V2556SA" and date code.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-166AXC and AS7C3256B-15JIN, the 71V2556SA100BGGI8 uniquely delivers ZBT™-enabled back-to-back access, integrated burst counter with LBO-selectable sequencing, and optional JTAG-making it optimal for telecom and networking systems demanding deterministic high-throughput memory behavior.

Availability

71V2556SA100BGGI8 is available at Aetrix Electronics and suitable for network switch buffering, telecom line card memory, baseband processing cache, and industrial PLC data logging requiring stable component supply across long production lifecycles.

Supply support for 71V2556SA100BGGI8 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 71V2556SA100BGGI8 belongs to IDT's ZBT™ SRAM product line, designed specifically for high-speed packet-processing systems requiring zero-bus-turnaround, burst capability, and industrial-grade reliability in telecom and datacom equipment.

FAQ

What is the maximum operating frequency of the 71V2556SA100BGGI8?

The 71V2556SA100BGGI8 is rated for 166 MHz operation, corresponding to a 6.0 ns clock period. This frequency is guaranteed across the full industrial temperature range (–40°C to +85°C) and specified supply conditions (VDD = 3.3 V ±5%, VDDQ = 2.5 V ±5%). At this speed, the device achieves 3.5 ns clock-to-data access time for reads, enabling high-throughput pipelined memory access in switch fabric and packet buffer applications.

Does the 71V2556SA100BGGI8 support both linear and interleaved burst modes?

Yes, the 71V2556SA100BGGI8 supports both linear and interleaved 4-word burst sequences, selected by the LBO (Linear/Interleaved Burst Order) pin. When LBO = VSS, the burst order is linear (A, A+1, A+2, A+3); when LBO = VDD, it is interleaved (A, A+2, A+1, A+3). This flexibility allows optimization for different data access patterns-linear for sequential streaming, interleaved for cache-line-aligned fetches common in DSP and baseband processing.

What is the purpose of the three chip enable pins (CE1, CE2, CE2) on the 71V2556SA100BGGI8?

The 71V2556SA100BGGI8 uses three chip enable pins (CE1, CE2, CE2) to implement hierarchical depth expansion. Selection requires CE1 = Low, CE2 = Low, and CE2 = High simultaneously. This 3-pin scheme allows flexible decoding-e.g., using one CE pair for bank selection and the third for global enable-enabling scalable memory subsystems without external logic. Deselection of any one CE terminates new operations but completes pending transfers.

Is JTAG boundary scan functionality standard or optional on the 71V2556SA100BGGI8?

JTAG boundary scan (IEEE 1149.1) is an optional feature on the 71V2556SA100BGGI8, implemented only on the "SA" version (as indicated by the "SA" suffix in the part number). Pins TMS, TDI, TCK, TDO, and TRST are dedicated to JTAG and are NC on non-SA variants. When enabled, it supports PCB interconnect testing and in-system diagnostics, but requires proper termination and clocking per IEEE 1149.1 requirements.

How does the ZBT™ architecture eliminate dead cycles in the 71V2556SA100BGGI8?

The ZBT™ (Zero Bus Turnaround) architecture in the 71V2556SA100BGGI8 eliminates dead cycles by overlapping bus direction control with internal pipeline stages. Unlike conventional SRAMs that require idle cycles to change bus direction (read→write or write→read), the 71V2556SA100BGGI8 uses internal registers and dual-phase control to initiate the next operation immediately after the previous data transfer, achieving true back-to-back access at full clock rate-critical for high-efficiency packet buffering.