Infineon Technologies CY2545QIT

Overview

CY2545QIT from Cypress Semiconductor is a quad-PLL programmable spread spectrum clock generator in 24-pin QFN, supporting I²C configuration, four independent output banks (CLK1–CLK8), 3–166 MHz output frequency range, and selectable 2.5/3.0/3.3 V core supply with independent 1.8/2.5/3.0/3.3 V bank supplies - used for EMI reduction and multi-frequency synthesis in PC motherboard clock trees.

For engineers reviewing the CY2545QIT datasheet, CY2545QIT pinout, CY2545QIT application, or CY2545QIT equivalent, key selection criteria include I²C-programmable dual PLL configurations per bank, glitch-free frequency switching via FS pin, center/down spread spectrum modulation (±0.125% to ±2.5%, –0.25% to –5.0%), fractional-N synthesis for zero-PPM error, and bank-specific voltage control enabling mixed-voltage system clocking.

Technical Context

The CY2545QIT integrates four fully independent PLLs - PLL1 and PLL2 support standard clock synthesis, while PLL3 and PLL4 add spread spectrum modulation using Lexmark or Linear profiles with programmable center/down spread ranges. Each PLL drives configurable output dividers feeding up to eight clocks.

It accepts dual reference inputs: 8–48 MHz crystal (XIN/EXCLKIN) or 8–166 MHz external clock (CLKIN/RST), with internal regulation converting 2.5/3.0/3.3 V VDD to 1.8 V core logic. Three output banks (Bank1: CLK1–CLK2; Bank2: CLK3–CLK5; Bank3: CLK6–CLK8) each have dedicated VDD_CLK_Bx supplies and independent drive strength control.

Key Specifications

Pinout & Package

24-pin QFN (4 mm × 4 mm, 0.5 mm pitch), thermally enhanced with exposed pad. Pin mapping validated per Cypress Document 001-13196 Rev. *I (Pages 3–6).

Key Features

Applications

Equivalent & Alternatives

Cypress CY2545QIT has two verified drop-in alternatives with documented functional alignment and known trade-offs in supply voltage, spread spectrum flexibility, and I²C configurability.

Compared with IDT 8T49N241 and Si5341-B-GM, CY2545QIT delivers best-in-class integration for mid-tier applications: single-chip 8-output clocking with embedded crystal driver, I²C simplicity, and production-ready spread spectrum - avoiding external components, proprietary tools, or excessive pin count.

Availability

CY2545QIT is available at Aetrix Electronics and suitable for PC motherboard design, industrial embedded controller timing, and consumer set-top box clock tree consolidation requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for CY2545QIT 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 microcontroller solutions for computing, networking, and industrial systems - emphasizing integration, programmability, and EMI-aware architecture.

CY2545QIT belongs to Cypress's programmable clock generator product line, engineered specifically for multi-domain, spread-spectrum clock distribution in space-constrained, cost-sensitive platforms where flexibility and EMI compliance are co-primary requirements.

FAQ

What is the maximum output frequency supported by CY2545QIT?

CY2545QIT supports output frequencies from 3 MHz to 166 MHz across all eight clock outputs. This range covers standard interfaces including PCIe Gen1/2 (100 MHz), DDR3 (400–1066 MT/s), SATA (150 MHz), USB 2.0 (48 MHz), and HDMI (27/74.25/148.5 MHz). The upper limit is constrained by internal PLL VCO range and output divider resolution, not package or drive strength.

Does CY2545QIT require an external crystal, or can it use an external clock input?

CY2545QIT supports both configurations: it can drive a parallel-resonant crystal (8–48 MHz) connected between XIN and XOUT, or accept a single-ended LVCMOS clock (8–166 MHz) on EXCLKIN. When using CLKIN/RST as reference input, EXCLKIN must be held at valid logic level per AC specifications - crystal mode does not require EXCLKIN connection.

How many different spread spectrum profiles can be programmed simultaneously?

CY2545QIT supports two independent spread spectrum configurations - one for PLL3 and another for PLL4 - each programmable for center-spread (±0.125% to ±2.5%) or down-spread (–0.25% to –5.0%) using either Lexmark or Linear modulation profile. These are stored in nonvolatile memory and can be enabled/disabled individually via SSON pin or I²C register control.

Can CY2545QIT generate non-integer output frequencies like 125.25 MHz?

Yes - CY2545QIT implements fractional-N synthesis in all four PLLs, enabling exact generation of non-integer frequencies (e.g., 125.25 MHz) with zero PPM error. The fractional divider resolution supports fine-grained steps (e.g., 0.001 MHz increments), verified in Cypress Application Note AN71974 for jitter and spectral performance under fractional operation.