Renesas 71V2556SA100BG

Overview

71V2556SA100BG from IDT (now Renesas) is a 128K × 36-bit (4.5 Mbit), 3.3V synchronous ZBT™ SRAM with pipelined outputs, 2.5V I/O supply, 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 ADV/LD and LBO control, and features individual byte write (BW1–BW4), three chip enables (CE1/CE2/CE2), and optional IEEE 1149.1 JTAG boundary scan. It is used in high-speed packet buffering and cache coherency applications in telecom switching fabric.

For engineers reviewing the 71V2556SA100BG datasheet, 71V2556SA100BG pinout, 71V2556SA100BG application, or 71V2556SA100BG equivalent, key selection considerations include its ZBT™ zero-bus-turnaround timing for back-to-back read/write cycles, 100-pin TQFP package compatibility, industrial temperature support (–40°C to +85°C), and dual-supply operation (3.3V core / 2.5V I/O).

Technical Context

The 71V2556SA100BG implements a fully synchronous, clock-edge-triggered architecture with address, data, and control registers sampled on the positive clock edge. Its internal burst counter enables single-address-initiated 4-word transfers, with sequence order (linear or interleaved) selected by the LBO pin.

It integrates pipelined output registers and an internally synchronized OE function-eliminating external OE timing constraints-and supports depth expansion via three independent chip enables. The SA variant includes optional JTAG (TMS/TDI/TCK/TDO/TRST) compliant with IEEE 1149.1, and supports sleep mode via ZZ (pin 64, BGA T7) for power reduction during idle periods.

Key Specifications

Pinout & Package

71V2556SA100BG is packaged in a JEDEC-standard 100-pin plastic thin quad flatpack (TQFP), 14 mm × 20 mm body size, with 0.5 mm lead pitch. Pin 1 is located at top-left corner (marked by dot or bevel), and pin numbering proceeds counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1356BV18-167BZI and AS7C3256A-10JIN, the 71V2556SA100BG uniquely combines ZBT™ zero-turnaround timing, industrial temperature range, JTAG testability, and TQFP packaging-making it optimal for telecom infrastructure and deterministic embedded systems requiring both performance and manufacturability.

Availability

71V2556SA100BG is available at Aetrix Electronics and suitable for telecom switching fabric, industrial PLC data logging, and medical imaging frame buffering requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.

Supply support for 71V2556SA100BG 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 markets.

The 71V2556SA100BG belongs to IDT's ZBT™ SRAM product line, engineered specifically for zero-latency bus turnaround in high-speed networking and real-time control systems where deterministic memory access is critical.

FAQ

What is the maximum operating frequency of the 71V2556SA100BG?

The 71V2556SA100BG is rated for a maximum clock frequency of 166 MHz, corresponding to a 3.5 ns clock-to-data access time under specified conditions (VDD = 3.3 V ±5%, VDDQ = 2.5 V ±5%, TA = –40°C to +85°C). This timing is guaranteed across the full industrial temperature range and supports sustained burst-mode operation without derating.

Does the 71V2556SA100BG support both linear and interleaved burst modes?

Yes, the 71V2556SA100BG supports both linear and interleaved 4-word burst sequences. The LBO (Linear/Interleaved Burst Order) pin selects the mode: tied to VSS for linear (0,1,2,3) and to VDD for interleaved (0,2,1,3). This flexibility allows optimization for cache line alignment or memory controller addressing schemes without firmware changes.

What is the purpose of the ZZ pin on the 71V2556SA100BG?

The ZZ pin on the 71V2556SA100BG enables deep sleep mode. When asserted low, it places the device into a low-power standby state drawing less than 10 µA ICC while retaining stored data. This feature is essential for power-constrained applications like remote base stations or portable diagnostic equipment where intermittent operation is required.

Is JTAG boundary scan functionality standard on the 71V2556SA100BG?

Yes, the "SA" suffix in 71V2556SA100BG explicitly denotes inclusion of IEEE 1149.1-compliant JTAG boundary scan. Pins TMS, TDI, TCK, TDO, and optional TRST are functional and documented in the pinout. This enables in-circuit test, system-level debug, and manufacturing verification without requiring additional test fixtures.

How does the 71V2556SA100BG handle read/write transitions without bus dead cycles?

The 71V2556SA100BG implements ZBTTM (Zero Bus Turnaround) architecture, which uses internal pipelining and synchronized control to eliminate idle cycles between consecutive read and write operations. The device internally manages bus direction and timing, allowing back-to-back cycles with no gap-achieving continuous 166 MHz throughput in mixed-access workloads typical of packet buffering.