Infineon Technologies CY28412OXC

Overview

CY28412OXC from Cypress Semiconductor is a preliminary clock generator IC designed specifically for Intel® Grantsdale chipset platforms, delivering differential CPU clocks up to 400 MHz, 100-MHz differential SRC clocks, 96-MHz dot clock, 48-MHz USB, and 33-MHz PCI outputs - all from a single 14.318-MHz crystal reference under 3.3V supply.

For engineers reviewing the CY28412OXC datasheet, CY28412OXC pinout, CY28412OXC application, or CY28412OXC equivalent, key selection criteria include I²C-configurable output enables, Lexmark-optimized spread-spectrum EMI reduction, selectable CPU frequency modes via FS_A/B/C latching on VTT_PWRGD#, and differential output drive capability across 56-pin SSOP.

Technical Context

The CY28412OXC integrates two PLLs: PLL1 generates CPU and SRC clocks with selectable multiplication (x2–x8), while PLL2 derives PCI, USB, and dot clocks from the same 14.318-MHz reference. Frequency selection is latched synchronously on VTT_PWRGD# assertion, freezing FS_A/B/C inputs for deterministic boot-time configuration.

It supports SMBus-compatible I²C interface (slave address D2h) for runtime control of individual output enables, spread-spectrum enable/disable, and drive strength settings. All differential outputs (CPUT/CPUC, SRCT/SRCC, DOT96T/C, SATAT/C) comply with LVDS-level swing and termination requirements per Intel Grantsdale timing specifications.

Key Specifications

Pinout & Package

56-pin SSOP package with segregated power/ground domains per functional block (CPU, SRC, PCI, USB, REF, APLL) and dedicated differential pair routing paths. Pin numbering follows standard SSOP convention with pin 1 at top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT 87012AGLFT and ICS9LPRS495AKLFT, the CY28412OXC uniquely combines Intel Grantsdale-specific CPU/SRC/PCI/USB/dot clock ratios, VTT_PWRGD#-latched frequency selection, and Lexmark-validated spread spectrum - making it irreplaceable for legacy P4/Prescott motherboard designs requiring full specification compliance.

Availability

CY28412OXC is available at Aetrix Electronics and suitable for desktop motherboard design, Intel P4/Prescott platform integration, and embedded industrial PC development requiring stable component supply and long-term lifecycle support.

Supply support for CY28412OXC 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 is a U.S.-based semiconductor company specializing in timing, memory, and programmable solutions, acquired by Infineon in 2020 but maintaining legacy product support and documentation integrity.

The CY28412 belongs to Cypress's high-precision clock generator product line, engineered specifically for Intel desktop chipsets from the Grantsdale era to ensure full electrical and timing compliance with P4/Prescott platform requirements.

FAQ

What crystal specifications are mandatory for CY28412OXC operation?

The CY28412OXC requires a 14.31818 MHz parallel-resonant AT-cut crystal with 20 pF load capacitance, maximum 0.1 mW drive level, and ≤50 ppm initial tolerance. Using a series-resonant crystal causes ≥300 ppm frequency error and violates Intel Grantsdale timing specifications.

How does VTT_PWRGD# control frequency selection and output enablement?

VTT_PWRGD# is a level-sensitive strobe that latches FS_A/B/C, USB48/FS_B, REF0/FS_C, REF1/FS_A, TEST_SEL/PCIF0, and ITP_EN inputs on its falling edge. Once latched, these values remain fixed until reset; subsequent transitions have no effect except in test mode.

Can spread spectrum be disabled for specific clock domains only?

Yes - Control Register 1 (Byte 1) provides independent Spread Spectrum Enable bits for CPU/T/C, SRCT/C, PCIF, and PCI groups, and Control Register 0 (Byte 0) allows per-output enable/disable, permitting selective EMI reduction without affecting critical timing domains like CPU or SATA.

Is the CY28412OXC pin-compatible with later Cypress clock generators like CY285xx series?

No - CY28412OXC uses a unique 56-pin SSOP layout optimized for Grantsdale signal routing; later CY285xx devices use 64-pin TSSOP packages with different pin assignments, register maps, and PLL architectures, requiring PCB redesign and firmware updates.