Infineon Technologies CY24292LFXIT

Overview

CY24292LFXIT from Cypress Semiconductor is a four-output PCI-Express clock generator with integrated PLL, delivering four 100 MHz differential HCSL-compatible outputs and one 25 MHz single-ended LVCMOS output. It accepts a 25 MHz crystal or clock input, supports spread spectrum modulation on all 100 MHz outputs using a Lexmark profile for EMI reduction, and operates at 3.3 V in commercial and industrial temperature ranges. Used in PCIe Gen1/Gen2 root complexes and add-in cards.

For engineers reviewing the CY24292LFXIT datasheet, CY24292LFXIT pinout, CY24292LFXIT application, or CY24292LFXIT equivalent, key selection criteria include differential output compliance (HCSL), SMBus programmability for individual output enable/disable and spread spectrum control, 32-pin QFN package thermal performance, and IREF current-source configuration via external 475 Ω resistor.

Technical Context

The CY24292LFXIT integrates a PLL-based clock synthesizer with programmable dividers and independent output buffers. Its core timing architecture uses a 25 MHz reference to generate four synchronized 100 MHz differential clocks with phase-matched outputs and one buffered 25 MHz single-ended clock.

SMBus interface (slave address D2h/D3h) enables real-time register access to control spread spectrum (–0.5% down-spread), global/output-specific enable bits, and reset state management. All 100 MHz outputs support HCSL-compatible drive strength and require external series + ground termination per PCIe layout guidelines.

Key Specifications

Pinout & Package

Package: 32-pin QFN (5 mm × 5 mm, 0.5 mm pitch), thermally enhanced with exposed pad tied to GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PCI-Express clock generator applications.

Compared with IDT 8T49N241 and ON Semi NB3N3020B, CY24292LFXIT provides balanced PCIe Gen2 timing compliance, Lexmark spread spectrum, and granular output control in a compact 32-pin QFN-making it optimal for space-constrained, EMI-sensitive PCIe implementations requiring industrial temperature support.

Availability

CY24292LFXIT is available at Aetrix Electronics and suitable for PCIe root complexes, add-in cards, and industrial backplane systems requiring stable component supply, long-term lifecycle assurance, and verified industrial temperature performance.

Supply support for CY24292LFXIT 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 timing, memory, and programmable logic solutions for embedded and industrial applications.

The CY24292 belongs to Cypress's PCI-Express clock generator product line, engineered specifically to meet Gen1/Gen2 timing, jitter, and EMI requirements in space-constrained computing platforms.

FAQ

What is the function of the IREF pin (Pin 4) and how must it be configured?

The IREF pin provides a precision current reference for all four differential HCSL outputs. It must be connected to ground via a 475 Ω ±1% resistor to set the nominal output current to 2.32 mA. This directly determines the output voltage swing and impedance matching for PCIe-compliant signaling; deviation beyond tolerance risks violating HCSL voltage thresholds or jitter specs.

Can the CY24292LFXIT operate with an external 25 MHz clock instead of a crystal?

Yes - the XIN/EXCLKIN pin (Pin 22) accepts either a 25 MHz fundamental-mode crystal (with XOUT, Pin 23, connected) or a single-ended 25 MHz CMOS clock signal. When using an external clock, XOUT must be left floating. Crystal mode requires parallel-resonant type; series-resonant crystals cause frequency error and ppm specification violation.

How does the PD_RESET# pin interact with SMBus-controlled output enables?

PD_RESET# is an asynchronous hardware reset that forces all outputs into high-impedance state and reloads SMBus registers to power-on defaults. It overrides all software-configured output enables. After reset release, outputs remain disabled until SMBus writes re-enable them or global OE bit (Byte 0, bit 5) is set - ensuring deterministic startup behavior in fault-recovery scenarios.

What termination is required for the 100 MHz differential outputs to meet PCIe specifications?

Each differential pair (e.g., PCIE0P/PCIE0N) requires a 50 Ω series resistor in each leg plus a 50 Ω pull-down to ground at the receiver end - forming a Thevenin-equivalent 50 Ω termination. This matches the PCIe HCSL standard and ensures proper common-mode voltage (≈0.8 V) and differential swing (≈800 mV). Layout must maintain tight length matching (<5 mil) between P/N traces.