Infineon Technologies CY7C1345G-100AXIT

Overview

CY7C1345G-100AXIT from Cypress Semiconductor is a 4-Mbit (128K × 36) flow-through synchronous SRAM with 3.3 V core supply, 2.5/3.3 V I/O supply, 8.0 ns clock-to-output delay at 100 MHz, and user-selectable Intel Pentium–compatible interleaved or linear burst sequences. It serves as secondary cache memory in high-speed microprocessor systems requiring glueless interface, low-latency burst reads/writes, and synchronous self-timed write control.

For engineers reviewing the CY7C1345G-100AXIT datasheet, CY7C1345G-100AXIT pinout, CY7C1345G-100AXIT application, or CY7C1345G-100AXIT equivalent, key selection criteria include burst mode configuration (MODE pin), dual address strobe support (ADSP/ADSC), synchronous byte-write granularity (BWA–BWD + BWE), ZZ sleep mode implementation, and TQFP-100 package thermal and routing constraints.

Technical Context

The CY7C1345G-100AXIT implements a synchronous, flow-through architecture where all address, control, and data inputs are registered on the rising edge of CLK. Its 2-bit on-chip wrap-around burst counter captures A[1:0] at ADSP/ADSC assertion and auto-increments for subsequent burst cycles - supporting both linear and interleaved sequences per MODE pin state.

Burst initiation is decoupled between processor (ADSP) and controller (ADSC) paths, with priority given to ADSP when both are active. Write operations use synchronous self-timed logic: global writes (GW) override byte-write enables (BWE + BWx), while OE remains asynchronous for output tristate control independent of clock timing.

Key Specifications

Pinout & Package

Package: 100-pin TQFP (14 × 20 × 1.4 mm), lead-free (Pb-free), RoHS-compliant, with exposed thermal pad (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IS61LV51236L-100TQLI and MT55LSD25636DZ-100:J, the CY7C1345G-100AXIT uniquely combines Pentium-compatible interleaved bursting, dual-strobe address capture, and hardware-configurable sleep - making it irreplaceable in legacy x86 cache and safety-critical buffered memory roles.

Availability

CY7C1345G-100AXIT is available at Aetrix Electronics and suitable for secondary cache subsystems, network packet buffers, real-time DSP data exchange, and avionics display frame memory requiring stable component supply across extended product lifecycles.

Supply support for CY7C1345G-100AXIT 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

Cypress Semiconductor (now part of Infineon Technologies) designs high-performance memory and programmable solutions for embedded systems, emphasizing reliability, low power, and interface compatibility.

The CY7C1345G belongs to Cypress's synchronous SRAM product line, engineered specifically for glueless integration with x86 and RISC microprocessors requiring burst-mode cache memory with deterministic timing and minimal external logic.

FAQ

What is the correct connection for the ZZ pin on CY7C1345G-100AXIT?

The ZZ pin (Pin 64) must be externally connected to ground (GND), as specified in the silicon errata on page 22 of the datasheet. Leaving it floating or pulling it HIGH violates the device's sleep mode specification and may cause unpredictable behavior or failure to enter sleep. The internal pull-down is insufficient for reliable operation - a direct PCB trace to GND is mandatory.

Can CY7C1345G-100AXIT operate with VDDQ = 2.5 V while VDD = 3.3 V?

Yes. The device supports independent core (VDD = 3.3 V ± 0.3 V) and I/O (VDDQ = 2.5 V or 3.3 V) supplies. This allows interfacing with 2.5 V logic families (e.g., older PCI-X or AGP buses) while maintaining full 3.3 V core performance. VDDQ must be stable before VDD ramp-up, and both supplies require separate decoupling per the layout guidelines in section "Power Supply Decoupling" (p.12).

How does the MODE pin affect burst addressing in practice?

When MODE is LOW (tied to GND), the device uses linear burst addressing: A0–A1 increment sequentially (e.g., 00→01→10→11). When MODE is HIGH (tied to VDD or floating), it uses interleaved addressing: A0–A1 follow Pentium order (00→10→01→11). This mapping is hardwired in the burst counter logic and affects every burst access - no software configuration is required or possible.

Is CY7C1345G-100AXIT pin-compatible with earlier CY7C1345 variants?

Yes - all CY7C1345G speed grades (e.g., -80, -100) share identical 100-pin TQFP pinout, signal definitions, and power requirements. The -100AXIT variant adds Pb-free packaging and extended temperature range (–40°C to +85°C), but electrical timing and functional behavior are fully backward-compatible with -80AXI and -100AXI versions.