Infineon Technologies CY28441ZXCT

Overview

CY28441ZXCT from Cypress Semiconductor is a clock generator IC compliant with Intel® CK410M specification, designed for Intel Alviso chipset platforms and Pentium®-M CPU systems. It delivers differential 100-MHz SRC clocks, fixed 96-MHz dot clock, 48-MHz USB clock, 33-MHz PCI clock, and 14.318-MHz reference clock - all from a single 14.318-MHz crystal input in a 56-pin TSSOP package.

For engineers reviewing the CY28441ZXCT datasheet, CY28441ZXCT pinout, CY28441ZXCT application, or CY28441ZXCT equivalent, key selection criteria include Intel CK410M compliance, I²C programmability for clock enable/disable control, selectable CPU frequency modes (100/133 MHz), differential output drive capability, and Lexmark-specified spread-spectrum EMI reduction profile.

Technical Context

The CY28441ZXCT integrates two PLLs: PLL1 generates the 14.318-MHz reference and USB/PCI clocks via integer division, while PLL2 synthesizes CPU and SRC clocks using fractional-N or integer-N multiplication. Frequency selection is latched at VTT_PWRGD# assertion via three 3.3V-tolerant FS pins (FS_A/B/C), enabling static configuration of CPU core clock (100/133 MHz) and associated peripheral clocks.

It supports dynamic clock gating through dedicated control inputs: CPU_STP# stops CPU clock pairs synchronously; PCI_STP# halts PCI outputs; CLKREQA#/CLKREQB# independently disable up to six SRC clock pairs via SMBus-configurable mapping. All differential outputs meet LVDS-compatible voltage swing (±350 mV) and skew <100 ps.

Key Specifications

Pinout & Package

Package: 56-pin TSSOP (7.0 mm × 12.5 mm, 0.5 mm pitch), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICS954202AGLFT and ICS952601AGT, the CY28441ZXCT uniquely combines Intel CK410M compliance, dual-PLL synthesis for CPU/SRC clocks, hardware-based clock gating (CPU_STP#/CLKREQ#), and SATA-optimized differential reference outputs - making it irreplaceable in Alviso-based laptop and embedded designs requiring full feature parity.

Availability

CY28441ZXCT is available at Aetrix Electronics and suitable for laptop motherboard timing, Intel Pentium®-M embedded systems, and desktop chipset reference designs requiring stable component supply and long-term lifecycle support.

Supply support for CY28441ZXCT 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) is a U.S.-based semiconductor company specializing in timing, memory, and programmable solutions for computing and communications markets.

The CY28441 belongs to Cypress's CK410M-compliant clock generator product line, engineered specifically to replace discrete oscillator/buffer combinations in Intel mobile chipset platforms while meeting strict jitter, skew, and EMI requirements.

FAQ

What crystal specifications are required for CY28441ZXCT operation?

The CY28441ZXCT requires a 14.318-MHz parallel-resonant crystal with load capacitance between 12 pF and 20 pF. Series-resonant crystals must not be used - doing so causes frequency error exceeding ±300 ppm and violates Intel CK410M timing specifications. Crystal ESR must be ≤ 80 Ω, and drive level must be ≤ 100 μW.

How does the VTT_PWRGD# pin function during system boot?

VTT_PWRGD# is a level-sensitive strobe that latches the states of FS_A/B/C and PCIF0/ITP_EN inputs upon first assertion (LOW). Once sampled, further transitions on those pins are ignored until reset. After latching, VTT_PWRGD# becomes a real-time power-down input (HIGH = PD mode), disabling internal regulators and placing outputs in high-impedance state.

Can the CY28441ZXCT generate both 100-MHz and 133-MHz CPU clocks simultaneously?

No - the CY28441ZXCT selects either 100-MHz or 133-MHz CPU clock frequency at boot time via FS_A/B/C pin states latched at VTT_PWRGD# assertion. Both frequencies are not generated concurrently. The device supports only one active CPU clock pair (CPUT/C0–2) at a time, determined statically during initialization.

What is the purpose of the IREF pin, and how must it be connected?

IREF is an analog current reference input requiring connection to a precision 10.0 kΩ ±0.1% resistor tied to ground. This sets the internal PLL bias current and directly affects output jitter performance and frequency stability. Using a non-precision or incorrect-value resistor causes deviation from datasheet jitter specs (≤1.5 ps RMS) and may induce frequency drift beyond ±50 ppm.