Renesas 71V2556SA100BGI8

Overview

71V2556SA100BGI8 from IDT (now Renesas) is a 128K × 36-bit (4.5 Mbit), 3.3V synchronous ZBT™ SRAM with 2.5V I/O, pipelined outputs, and zero-bus-turnaround architecture. It delivers 166 MHz operation (3.5 ns clock-to-data access), supports 4-word linear/interleaved burst modes via internal counter, and features individual byte write control (BW1–BW4), three chip enables, and optional IEEE 1149.1 JTAG boundary scan. It is used in high-speed packet buffering and cache applications in networking line cards.

For engineers reviewing the 71V2556SA100BGI8 datasheet, 71V2556SA100BGI8 pinout, 71V2556SA100BGI8 application, or 71V2556SA100BGI8 equivalent, key selection considerations include ZBT timing compliance, TQFP-100 package compatibility, industrial temperature range (–40°C to +85°C), 2.5V I/O voltage domain separation, and burst mode configuration via LBO pin.

Technical Context

This device implements a fully synchronous, pipelined read/write interface with positive-edge-triggered registers for address, data, and control signals. Its ZBT architecture eliminates dead cycles between consecutive reads and writes by overlapping bus turnaround with internal memory access.

The on-chip 4-word burst counter advances on ADV/LD = HIGH and supports both linear and interleaved sequences selected by the LBO pin. Output enable (OE) is internally synchronized, removing external timing constraints, while Clock Enable (CEN) halts all synchronous operations without affecting register state.

Key Specifications

Pinout & Package

Packaged in a JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body, lead-free and RoHS-compliant (suffix 'G'). Pin 64 supports ZZ (sleep mode) on latest die revision; pins 14, 16, and 66 require ≥VIH but not direct VDD connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV33-133AXC and AS7C3256A-15JCIN, the 71V2556SA100BGI8 uniquely delivers ZBT timing, 166 MHz operation, and integrated burst control - critical for modern packet-processing pipelines where bus efficiency directly impacts system throughput.

Availability

71V2556SA100BGI8 is available at Aetrix Electronics and suitable for network infrastructure, industrial automation, and telecom equipment requiring stable component supply, long-lifecycle support, and industrial-temperature performance.

Supply support for 71V2556SA100BGI8 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 71V2556SA100BGI8 belongs to IDT's ZBT SRAM product line, designed specifically for zero-bus-turnaround applications in high-speed networking, baseband processing, and real-time embedded systems demanding deterministic latency and burst efficiency.

FAQ

What is the operating temperature range for the 71V2556SA100BGI8?

The 71V2556SA100BGI8 is rated for industrial temperature operation from –40°C to +85°C. This specification is verified per the manufacturer's datasheet and applies to all electrical parameters under recommended DC operating conditions (VDD = 3.3 V ±5%, VDDQ = 2.5 V). The device uses thermal characterization to ensure reliability across this full range.

Does the 71V2556SA100BGI8 support true pipelined read/write operations?

Yes, the 71V2556SA100BGI8 implements fully pipelined synchronous operation: address, control, and data inputs are registered on the rising CLK edge, and output data is valid after a fixed 3.5 ns clock-to-data delay. The ZBT architecture allows immediate transition from write to read (or vice versa) without dead cycles, enabling continuous 166 MHz throughput.

How is burst mode configured on the 71V2556SA100BGI8?

Burst mode on the 71V2556SA100BGI8 is controlled by the LBO (Linear/Interleaved Burst Order) pin. When LBO = VSS, the device executes linear burst (0,1,2,3); when LBO = VDD, it executes interleaved burst (0,2,1,3). The burst counter advances on ADV/LD = HIGH and wraps automatically after four words.

What is the function of the CEN pin on the 71V2556SA100BGI8?

The CEN (Clock Enable) pin on the 71V2556SA100BGI8 is an asynchronous active-high input that gates the internal clock distribution. When CEN = HIGH, CLK edges are blocked, halting all synchronous operations while preserving register contents. This enables low-power suspend modes without losing state, and resumes instantly when CEN returns LOW.

Is JTAG boundary scan mandatory on the 71V2556SA100BGI8?

No, JTAG boundary scan is optional on the 71V2556SA100BGI8. Pins TMS, TDI, TCK, TDO, and TRST are NC on the base "S" version but assigned to JTAG functions on the "SA" version (as in 71V2556SA100BGI8). TRST is pull-up internally and may be left floating if unused. IEEE 1149.1 compliance is implemented only when these pins are actively driven.