Renesas 71V2556SA100BGG8

Overview

71V2556SA100BGG8 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 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 applications in networking switches and baseband processors.

For engineers reviewing the 71V2556SA100BGG8 datasheet, 71V2556SA100BGG8 pinout, 71V2556SA100BGG8 application, or 71V2556SA100BGG8 equivalent, key selection criteria include ZBT timing compliance, TQFP-100 package compatibility, 3.3V core / 2.5V I/O voltage separation, industrial temperature support (–40°C to +85°C), and burst counter behavior under ADV/LD and LBO control.

Technical Context

The 71V2556SA100BGG8 implements a fully synchronous, clock-edge-triggered architecture with address, data, and control registers aligned to the rising CLK edge. Its internal burst counter advances on ADV/LD = HIGH and loads external addresses on ADV/LD = LOW, enabling deterministic 4-word burst sequences-linear or interleaved per LBO state.

ZBT operation eliminates dead cycles between read/write transitions by overlapping bus turnaround with the next valid cycle; OE is internally synchronized, removing external timing constraints on output enable. The device supports depth expansion via CE1/CE2/CE2 logic and includes CEN for full clock gating without register corruption.

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.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV33-166AXC and AS7C3256B-15JIN, the 71V2556SA100BGG8 uniquely delivers ZBT timing, 36-bit width, and integrated burst counter-enabling direct replacement in legacy IDT-based designs without controller redesign or performance penalty.

Availability

71V2556SA100BGG8 is available at Aetrix Electronics and suitable for network packet buffering, baseband processor cache, industrial PLC memory expansion, and test equipment pattern memory requiring stable component supply and long-term industrial temperature support.

Supply support for 71V2556SA100BGG8 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 semiconductor company specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 71V2556SA100BGG8 belongs to IDT's ZBT SRAM product line, designed specifically for zero-turnaround, high-frequency buffering in packet-switched infrastructure and real-time signal processing systems.

FAQ

What is the function of the LBO pin on the 71V2556SA100BGG8?

The LBO (Linear/Interleaved Burst Order) pin selects the burst addressing sequence: tied to VSS for linear order (A0, A1, A2, A3) or to VDD for interleaved order (A0, A2, A1, A3). This setting determines how the internal burst counter increments during consecutive read/write cycles and is sampled at the start of each burst sequence. The 71V2556SA100BGG8 requires stable LBO voltage before the first clock edge of the burst.

Does the 71V2556SA100BGG8 support true dual-port operation?

No, the 71V2556SA100BGG8 is a single-port synchronous SRAM with shared I/O pins for read and write operations. It does not support simultaneous independent read and write access like QDR or DDR SRAMs. Its ZBT architecture minimizes turnaround delay between successive reads and writes but maintains a single bidirectional data path. The 71V2556SA100BGG8 relies on sequential burst timing-not concurrent ports-to achieve high throughput.

How does the 71V2556SA100BGG8 handle power-up initialization?

Upon power-up, the 71V2556SA100BGG8 ensures all outputs enter high-impedance (Hi-Z) state after the first rising edge of CLK, regardless of input states. Internal registers retain undefined values until first valid clock cycle with proper CE and R/W setup. No external reset is required, but system firmware must observe tINIT (minimum 100 µs) before issuing commands. The 71V2556SA100BGG8 does not perform automatic memory clearing at power-on.

Can the 71V2556SA100BGG8 operate with only two chip enables asserted?

No-the 71V2556SA100BGG8 requires all three chip enables to be in the correct logic state for selection: CE1 = LOW, CE2 = LOW, and CE2 = HIGH. If any one deviates (e.g., CE2 = LOW instead of HIGH), the device remains deselected and ignores address/control inputs. Deselection triggers Hi-Z output after two clocks. The 71V2556SA100BGG8 uses this 3-signal encoding to support flexible depth expansion without external logic.

Is JTAG functionality enabled by default on the 71V2556SA100BGG8?

No-JTAG is optional and disabled by default on the 71V2556SA100BGG8. Pins TMS, TDI, TCK, TDO, and TRST are NC (no-connect) unless the SA version is explicitly ordered with JTAG enabled. When activated, these pins require proper termination and boundary scan controller connection; unused JTAG pins must be pulled to VDD per datasheet guidance. The 71V2556SA100BGG8 does not auto-detect or configure JTAG mode-it is fixed at manufacture.