Infineon Technologies CY2309SXI-1T

Overview

CY2309SXI-1T from Infineon Technologies (formerly Cypress) is a 3.3 V zero-delay clock buffer IC with nine low-skew outputs, integrated PLL, and dual-bank output control. It operates from 10 MHz to 133 MHz, delivers ≤85 ps typical output-to-output skew, supports 5-V-tolerant REF input, and features test-mode bypass and power-down mode drawing <25.0 μA. Used in Pentium-based CPU clock distribution and PCI bus timing systems.

For engineers reviewing the CY2309SXI-1T datasheet, CY2309SXI-1T pinout, CY2309SXI-1T application, or CY2309SXI-1T equivalent, key selection considerations include its 16-pin SOIC/TSSOP package, dual-bank (4+4+1) output architecture, S1/S2-selectable bank enable/test mode, zero-input-output propagation delay under matched loading, and industrial temperature range (–40°C to +85°C).

Technical Context

The CY2309SXI-1T implements an on-chip PLL with internal feedback from the CLKOUT pin to achieve zero input-output propagation delay when all outputs-including CLKOUT-are uniformly loaded. Its dual-bank output structure (Bank A: CLKA1–CLKA4; Bank B: CLKB1–CLKB4) is controlled by S1/S2 select inputs, enabling independent bank enable, three-state, or reference-pass-through modes.

It supports two operating configurations: normal PLL-locked mode and test mode (S1=1, S2=0), where the input clock is directly routed to outputs without PLL processing. Power-down occurs automatically when REF has no rising edges or when S1=0/S2=0, tri-stating all outputs and reducing IDD to <25.0 μA.

Key Specifications

Pinout & Package

Package: 16-pin SOIC (150-mil) or 4.4-mm TSSOP - surface-mount compatible with standard reflow profiles and IPC-compliant board layouts.

Key Features

Applications

Equivalent & Alternatives

Two verified alternatives exist for CY2309SXI-1T in industrial-temperature, 9-output zero-delay buffer applications:

Compared with IDT 8T49N241 and ON Semi NB3N3020B, CY2309SXI-1T uniquely provides dual-bank output enable/disable and test-mode bypass via S1/S2 pins-critical for modular system bring-up and power-gated subsystems-while maintaining pin compatibility with legacy Cypress designs and industrial temperature rating.

Availability

CY2309SXI-1T is available at Aetrix Electronics and suitable for desktop motherboard clock distribution, PCI bus timing modules, and industrial PLC backplane synchronization requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.

Supply support for CY2309SXI-1T 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

Infineon Technologies is a global semiconductor leader headquartered in Munich, Germany, specializing in power management, automotive MCUs, and timing solutions with broad industrial and automotive qualification.

CY2309SXI-1T belongs to Infineon's legacy Cypress timing portfolio, designed specifically for high-fidelity, low-skew clock fanout in cost-sensitive computing and industrial control systems where zero-delay PLL behavior and flexible output control are essential.

FAQ

What is the function of the CLKOUT pin on CY2309SXI-1T?

The CLKOUT pin serves as the internal PLL feedback node and must be loaded identically to all other outputs to achieve zero input-output propagation delay. Even if unused, it requires a capacitive load matching the output load (10 pF ≥100 MHz or 30 pF <100 MHz) to maintain PLL lock and skew control. Its voltage swing and drive strength match other outputs, and it is always active when PLL is enabled.

How does the S1/S2 select logic affect output behavior?

S1 and S2 are weak-pull-up control inputs that determine bank enable state and PLL operation. When S1=0/S2=0, both banks are three-stated and PLL shuts down. When S1=1/S2=0, REF passes directly to enabled banks (test mode). When S1=0/S2=1, only Bank A drives; when S1=1/S2=1, both banks drive with PLL active. This enables dynamic power gating and system-level validation.

Can CY2309SXI-1T operate with a 5 V input clock?

Yes-the REF input is explicitly 5-V-tolerant per datasheet Absolute Maximum Conditions and Electrical Characteristics. It accepts 0–7 V DC input voltage and uses a VDD/2 threshold, allowing direct connection to 5 V oscillators or clock generators without external level-shifting circuitry. All other inputs and outputs are strictly 3.3 V compatible.

What is the minimum load capacitance required for stable operation at 133 MHz?

At 133 MHz, the maximum allowable load capacitance per output is 10 pF, as specified in the Operating Conditions table for CY2309SI-XX devices. Exceeding this value increases edge distortion and cycle-to-cycle jitter beyond the rated 60 ps typical. Layout best practices include minimizing trace length, avoiding stubs, and using controlled-impedance routing to meet this requirement.