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Infineon Technologies CY26121KZC-21
- Part No.:
- CY26121KZC-21
- Manufacturer:
- Infineon Technologies
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
CY26121KZC-21.pdf
- Description:
- IC FANOUT DIST 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,674
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Product details
Overview
CY26121KZC-21 from Cypress Semiconductor is a Spread Spectrum Clock Generator with integrated PLL, operating at 3.3 V and accepting a 25-MHz crystal or driven reference input. It delivers selectable 33.33-MHz or 25-MHz outputs with –2.8% downspread modulation at 30 kHz, targeting EMI reduction in commercial-grade (0°C to 70°C) digital systems including PC motherboards and graphics controllers.
For engineers reviewing the CY26121KZC-21 datasheet, CY26121KZC-21 pinout, CY26121KZC-21 application, or CY26121KZC-21 equivalent, key selection criteria include output frequency selectability via CLKSEL, 15-pF crystal load compatibility, RMS cycle-to-cycle jitter ≤40 ps, and TSSOP-16 packaging for high-density PCB layouts.
Technical Context
The CY26121KZC-21 implements a dedicated analog PLL with spread-spectrum modulation control logic, generating two independent clock outputs (CLKA–CLKD) referenced to a single 25-MHz input. Its flash-configurable logic block supports CLKSEL-driven output selection between 33.33 MHz and 25 MHz, with fixed –2.8% downspread and 30-kHz nominal modulation frequency.
It features separate analog (AVDD/AVSS) and digital (VDD/VDDL/VSS/VSSL) supply domains, 6–15 pF crystal load support depending on variant, and SSON-controlled spread-spectrum enable/disable functionality. Output edge rates are specified at 0.8–1.4 V/ns with 15-pF load, and duty cycle is maintained within 45–55% across temperature and voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Frequency | 25 MHz crystal or external reference - matches standard low-cost fundamental-mode crystals. |
| Selectable Output Frequencies | 33.33 MHz or 25 MHz - configured by CLKSEL pin logic level; no reprogramming required. |
| Spread Spectrum | –2.8% downspread at 30 kHz - reduces EMI peak amplitude without altering system timing margins. |
| RMS Cycle-to-Cycle Jitter | 15–40 ps - ensures stable setup/hold timing for synchronous interfaces like PCIe Gen1 or DDR1 memory controllers. |
| Supply Voltage | 3.135–3.465 V (VDD/AVDD/VDDL) - compatible with standard 3.3-V LDOs and avoids level-shifting circuitry. |
| Crystal Load Capacitance | 15 pF - supports common high-stability AT-cut crystals used in industrial computing applications. |
| Operating Temperature | 0°C to +70°C - certified for commercial-grade motherboard and peripheral controller environments. |
Pinout & Package
Package: 16-pin Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, lead pitch 0.65 mm, RoHS-compliant (K-suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| XIN (Pin 1) | Reference Input | Accepts 25-MHz crystal or CMOS-level clock; internal oscillator circuit drives crystal directly. |
| VDD (Pin 2) | Digital Supply | Primary 3.3-V supply for logic core and configuration registers. |
| AVDD (Pin 3) | Analog Supply | Isolated 3.3-V rail for PLL analog circuitry to minimize noise coupling into clock generation. |
| CLKSEL (Pin 4) | Output Frequency Select | CMOS input with weak pull-up; logic 0 selects 33.33 MHz, logic 1 selects 25 MHz (for -21 variant). |
| AVSS (Pin 5) | Analog Ground | Dedicated ground return for AVDD to preserve PLL phase noise performance. |
| VSSL (Pin 6) | CLK Ground | Separate ground for clock output drivers (CLKA–CLKD) to reduce switching noise on sensitive outputs. |
| CLKA–CLKD (Pins 7,8,9,12) | Output Terminals | Four identical 3.3-V CMOS clock outputs, each capable of driving 15-pF load at ≤40 ps jitter. |
| SSON (Pin 10) | Spread Spectrum Enable | Active-high control; logic 1 enables –2.8% downspread modulation, logic 0 disables spread for legacy timing compliance. |
| VDDL (Pin 11) | Output Driver Supply | 3.3-V supply dedicated to clock output buffers, decoupled from core logic supply for clean edge integrity. |
| VSS (Pin 13) | Digital Ground | Main ground reference for VDD and logic blocks; tied to system digital ground plane. |
| REF (Pin 14) | Reference Output | Buffered copy of XIN signal at VDD level; usable as feedback source or secondary reference. |
| NC (Pin 15) | No Connect | Internally unconnected; must remain floating or grounded per layout best practices. |
| XOUT (Pin 16) | Crystal Output | Drives crystal's parallel-resonant node; must be left floating if XIN is externally driven. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Analog PLL with Modulation Control | Enables deterministic EMI reduction without external modulators or complex firmware control. |
| Separate AVDD/AVSS and VDDL/VSSL Supplies | Reduces power-supply-induced jitter by isolating analog PLL and digital clock driver domains. |
| CLKSEL-Driven Dual-Frequency Selection | Allows board-level frequency configuration without solder jumpers or EEPROM programming. |
| 15-pF Crystal Load Support | Matches widely available, low-cost 25-MHz AT-cut crystals with tight tolerance and aging stability. |
| SSON-Controlled Spread Enable/Disable | Permits runtime EMI mitigation toggling - critical for compliance testing and thermal-aware system modes. |
Applications
| PC Motherboard Clock Distribution | Graphics Controller Reference Timing |
|---|---|
Use Scenario: Provides primary system clock and PCI Express reference for Intel/AMD chipset platforms with EMI-sensitive RF co-location. IC Role / Device Role / Timing Role: Spread spectrum clock generator delivering synchronized 33.33-MHz and 25-MHz outputs to CPU, GPU, and southbridge domains. Use Value: Reduces 33–250 MHz radiated emissions by >10 dB peak, enabling FCC Class B compliance without shielding or ferrites. | Use Scenario: Supplies pixel clock and memory interface timing to discrete GPU modules where thermal throttling affects clock stability. IC Role / Device Role / Timing Role: Low-jitter clock source with configurable output frequency and disable-on-thermal-alert capability via SSON. Use Value: Maintains <40 ps RMS jitter under 70°C ambient, preserving HDMI 1.4 pixel timing integrity and GDDR3 setup margins. |
| Embedded Industrial Controller | Network Interface Card (NIC) Timing |
Use Scenario: Generates timing for ARM-based controller I/O peripherals including USB 2.0 PHY, Ethernet MAC, and SPI flash interface. IC Role / Device Role / Timing Role: Single-chip clock source replacing multiple oscillators and reducing BOM count in space-constrained designs. Use Value: Eliminates need for three discrete 25/33.33/50-MHz oscillators while maintaining ±50 ppm total stability over 0–70°C. | Use Scenario: Supplies 25-MHz reference to Gigabit Ethernet PHY and 33.33-MHz clock to PCI-X bus interface in server NICs. IC Role / Device Role / Timing Role: Dual-output clock generator with independent enable control per output bank for power-gated subsystems. Use Value: Enables selective clock gating during low-power link states without disrupting PHY lock or MAC synchronization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar spread spectrum clock generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT 8T49N241 | Programmable output frequencies (up to 750 MHz), I²C-configurable, higher power (85 mA typical) | Supports multi-protocol timing (PCIe, SATA, USB 3.0); requires firmware initialization | Choose when flexible frequency synthesis and protocol agility outweigh cost and simplicity needs. |
| ON Semi NB3N502 | Fixed 25/33.33-MHz outputs, no spread spectrum, lower jitter (12 ps RMS), 3.3-V only | Lacks EMI reduction; suited for noise-isolated lab or test equipment environments | Choose when absolute jitter minimization is prioritized over EMI compliance in controlled enclosures. |
Compared with IDT 8T49N241 and ON Semi NB3N502, the CY26121KZC-21 offers a balance of fixed-frequency reliability, hardware-selectable outputs, and integrated spread-spectrum EMI suppression - ideal for cost-sensitive, high-volume commercial computing platforms requiring zero-firmware clocking.
Availability
CY26121KZC-21 is available at Aetrix Electronics and suitable for PC motherboard design, graphics controller integration, embedded industrial controller development, and network interface card production requiring stable component supply and commercial-temperature grade assurance.
Supply support for CY26121KZC-21 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 fabless semiconductor company specializing in programmable system-on-chip (PSoC), memory, and timing solutions for embedded and industrial applications.
The CY26121 belongs to Cypress's PacketClock™ family of spread spectrum clock generators, designed specifically to meet EMI reduction requirements in high-speed digital systems without compromising timing accuracy or design simplicity.
FAQ
What is the function of the SSON pin on CY26121KZC-21?
The SSON pin (Pin 10) is an active-high spread spectrum enable control. When driven high (≥2.3 V), it activates the –2.8% downspread modulation at 30 kHz; when pulled low (≤0.8 V), spread spectrum is disabled and the device operates as a fixed-frequency clock generator. Internal weak pull-up ensures default enabled behavior if left unconnected.
Can CY26121KZC-21 drive a 15-pF load at full specification?
Yes. The device is characterized for 15-pF load capacitance per output (CLKA–CLKD), with guaranteed AC parameters including 0.8–1.4 V/ns edge rates and 45–55% duty cycle. This matches the crystal load requirement for the -21 variant and supports direct connection to standard CMOS inputs without series termination.
How does CLKSEL determine output frequency in CY26121KZC-21?
For CY26121KZC-21 (a -21 variant), CLKSEL = 0 selects 33.33 MHz output and CLKSEL = 1 selects 25 MHz output. This mapping is hardwired in silicon and confirmed in Table 1 and Pin Definition table; no configuration register or external resistor is needed - simple logic-level assertion suffices.
Is CY26121KZC-21 compatible with externally driven reference signals?
Yes. When an external 25-MHz CMOS clock is applied to XIN (Pin 1), XOUT (Pin 16) must be left floating per datasheet Note 1. The internal oscillator circuit automatically disables, and the device uses the external signal as its reference - eliminating crystal placement constraints and enabling use in systems with centralized clock trees.
CY26121KZC-21 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- PacketClock™
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Fanout Distribution, Multiplexer, Spread Spectrum Clock Generator
- PLL:
- Yes with Bypass
- Input:
- Clock, Crystal
- Output:
- Clock
- Number of Circuits:
- 1
- Ratio - Input:Output:
- 1:5
- Differential - Input:Output:
- No/No
- Frequency - Max:
- 33.33MHz
- Divider/Multiplier:
- Yes/No
- Voltage - Supply:
- 3.135V ~ 3.465V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-TSSOP
CY26121KZC-21 FAQ
1.How can I place an order for CY26121KZC-21 through Aetrix?
Please submit a Request for Quotation (RFQ) for CY26121KZC-21 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for CY26121KZC-21 reliable?
The price and inventory of CY26121KZC-21 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY26121KZC-21 is usually 5 days.
3.What payment methods are accepted for CY26121KZC-21?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY26121KZC-21 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY26121KZC-21?
CY26121KZC-21 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY26121KZC-21 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for CY26121KZC-21?
For technical support, including CY26121KZC-21 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY26121KZC-21 requirements.
6.How does Aetrix verify that CY26121KZC-21 is sourced from the original manufacturer or authorized distributors?
All CY26121KZC-21 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CY26121KZC-21 meets industry standards.
7.What is the process for return or replacement of CY26121KZC-21?
All CY26121KZC-21 units undergo pre-shipment inspection (PSI). If there is an issue with CY26121KZC-21, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The CY26121KZC-21 part is unused and in its original packaging.
Return procedure for CY26121KZC-21:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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