Infineon Technologies CY22381FXCT

Overview

CY22381FXCT from Cypress Semiconductor is a three-PLL, flash-programmable clock generator in an 8-pin SOIC package, operating at 3.3 V. It supports crystal inputs from 8–30 MHz or external reference clocks up to 166 MHz, delivers three independent programmable outputs (CLKA/CLKB/CLKC), and features ultra-wide dividers (11-bit P, 8-bit Q, 7-bit post-divide) for precise frequency synthesis in networking and datacom systems.

For engineers reviewing the CY22381FXCT datasheet, CY22381FXCT pinout, CY22381FXCT application, or CY22381FXCT equivalent, key selection considerations include its field-programmable PLL architecture, glitch-free frequency select via FS pin, on-die linear crystal load capacitors (6–30 pF), low-jitter performance (200 ps peak-to-peak), and configurable power-saving modes (Shutdown, OE, Suspend).

Technical Context

The CY22381FXCT integrates three fully independent PLLs-each with 11-bit feedback (P) and 8-bit reference (Q) dividers-feeding a 4×3 crosspoint switch that routes any source (REF, PLL1, PLL2, PLL3) to CLKA, CLKB, or CLKC. Each output passes through a 7-bit post-divider with dual-register support for FS-controlled frequency switching.

Its crystal oscillator includes programmable drive strength and on-die linear parallel-plate load capacitors (6–30 pF in 0.375-pF steps), eliminating external caps and reducing frequency drift across temperature, supply, and bias variations. The FS/SUSPEND/OE/SHUTDOWN pin (Pin 8) serves four configurable roles with guaranteed glitch-free transitions during frequency reconfiguration.

Key Specifications

Pinout & Package

Package: 8-pin small outline integrated circuit (SOIC), RoHS-compliant, NiPdAu lead finish (CY223811 variant). Pin pitch: 1.27 mm; body width: 3.9 mm; total length: 4.9 mm.

Key Features

Applications

Equivalent & Alternatives

Cypress CY22381FXCT is superseded by newer-generation programmable clock generators with enhanced features and broader frequency coverage.

Compared with CY22381FXCT, CY22394FXCT offers higher frequency headroom and spread-spectrum capability but demands PCB redesign, while Si5338A-B-GM delivers order-of-magnitude jitter improvement at the cost of increased complexity and cost-making CY22381FXCT optimal for cost-sensitive, mid-jitter applications like enterprise switching and industrial controllers.

Availability

CY22381FXCT is available at Aetrix Electronics and suitable for 10G Ethernet line cards, OTN framer modules, FPGA protocol converters, and industrial PLC backplane controllers requiring stable component supply, long-term lifecycle support, and field-programmable clock flexibility.

Supply support for CY22381FXCT 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 mixed-signal ICs for connectivity, memory, and programmable systems, with global R&D centers and manufacturing partnerships ensuring reliability and scalability.

The CY22381FXCT belongs to Cypress's Flash Programmable Clock Generator product line, engineered specifically for networking, telecommunications, and datacom equipment requiring flexible, low-jitter, single-chip clock synthesis with field-upgradable configurations.

FAQ

What is the maximum crystal frequency supported by CY22381FXCT?

The CY22381FXCT supports crystal frequencies from 8 MHz to 30 MHz, operating in fundamental parallel-resonant mode. This range is fixed by the internal oscillator design and cannot be extended via configuration. External clock inputs up to 166 MHz are supported separately, but those bypass the crystal oscillator entirely and require XTALOUT to be left floating.

Can CY22381FXCT generate three completely independent output frequencies simultaneously?

Yes. Its three independent PLLs-each with dedicated 11-bit P and 8-bit Q dividers-allow CLKA, CLKB, and CLKC to operate at unrelated frequencies derived from the same reference. For example, it can simultaneously output 125 MHz (PLL1), 156.25 MHz (PLL2), and 250 MHz (PLL3), all locked to an 8–30 MHz crystal without shared divider constraints.

How does the FS pin enable glitch-free frequency switching?

The FS pin selects between two pre-programmed frequency configurations stored in separate registers for CLKA, CLKB, and PLL1. Internal logic ensures that divider updates occur synchronously with output clock edges, preventing runt pulses or metastability. This guarantees zero-cycle interruption-verified in Cypress test circuits-and is essential for hitless clock switching in telecom infrastructure.

Is CY22381FXCT pin-compatible with CY2081?

No. Although CY22381FXCT is described as an upgrade to CY2081, it uses an 8-pin SOIC package with different pin assignments: CY2081 has CLKA on Pin 1 and GND on Pin 8, whereas CY22381FXCT places CLKC on Pin 1 and FS/SUSPEND/OE/SHUTDOWN on Pin 8. Board-level replacement requires schematic and layout revision.