📌 Product Overview
The CDCE913 and CDCEL913 belong to Texas Instruments' family of flexible, low-power clock synthesizers. These devices utilize a single PLL to generate up to three independent output clocks from one input frequency, specifically engineered to replace multiple crystals and oscillators in space-constrained designs.
Technical Core & Positioning:
- Function: Modular PLL-based clock generator with programmable Spread Spectrum Clocking (SSC) for EMI reduction.
- Key Difference: The CDCE913 supports 3.3V or 2.5V outputs, while the CDCEL913 is restricted to 1.8V outputs.
- Application Fit: Ideal for systems requiring precise frequency generation and synchronization (e.g., IEEE1394, WLAN, USB, Ethernet) where board space and signal integrity are critical.
🎯 Typical Applications & Design Context
💡 This component excels in mixed-signal environments requiring multiple, synchronized clock domains without the noise penalty of discrete oscillators.
- Consumer Electronics: Digital TVs (D-TV), Set-Top Boxes (STBs), DVD players/recorders.
- Connectivity: WLAN, Bluetooth®, Ethernet PHY, USB Controller.
- Industrial/Computing: FPGA clocking, DSP systems (TI DaVinci™, OMAP™), RFID, and IEEE1394 interfaces.
- Why this component: The integrated SSC (Spread Spectrum Clocking) significantly reduces EMI peaks, often eliminating the need for costly shielding or filtering in mass production.
📊 Key Technical Specifications
🚀 Performance parameters defining the synthesis capability and signal integrity window.
| Parameter | Specification | Notes |
|---|---|---|
| Outputs | 3 (LVCMOS) | Programmable frequency up to 230 MHz. |
| Input | Crystal (8-32 MHz) or LVCMOS (<160 MHz) | On-chip VCXO function with ±150ppm pull range. |
| Supply (Core) | 1.8V | Device core power (VDD). |
| Supply (Output) | CDCE913: 3.3V or 2.5V CDCEL913: 1.8V | Separate VDDOUT pins allow level shifting. |
| Jitter (Period) | Typical 50 ps | Low-noise PLL core; integrated loop filter. |
| Interface | I2C (SDA/SCL) | In-system programmability; nonvolatile EEPROM storage. |
| Temp Range | –40°C to 85°C | Standard industrial operating range. |
⚠️ Absolute Maximum Ratings & Process Limits
⚠️ Reliability Risk: Improper handling of the separate power rails can lead to signal latch-up or permanent IO damage during power-up sequencing.
| Parameter | Rating | Critical Failure Mode (E-E-A-T Analysis) |
|---|---|---|
| Supply Voltage (VDD) | –0.3V to 2.7V | Exceeding this permanently damages the 1.8V core logic. |
| Supply Voltage (VDDOUT) | –0.3V to 4.6V | Overvoltage here degrades the output driver transistors (hot electron effect). |
| Input Voltage (All Pins) | –0.3V to 3.9V | Applying 3.3V logic to a 1.8V specific pin (if not tolerant) causes gate oxide breakdown. |
| ESD Rating | HBM: 2000V; CDM: 500V | High-risk during manual handling; proper grounding is mandatory. |
| Tj (Junction Temp) | 125°C (Max) | Exceeding this triggers thermal shutdown, clocking halt, and long-term lifespan reduction. |
🔒 Engineering Insight:
Since VDD (Core) and VDDOUT (Driver) are separate pins, Power Sequencing is the most common failure point in validation. The datasheet implies flexibility, but in practice, ramping VDDOUT before VDD can cause unpredictable current flow through the ESD protection diodes. Ensure VDD ramps up first or simultaneously.
🧩 Package, Dimensions & Assembly Notes
📏 Physical Implementation: The component is housed in a TSSOP-14 (PW package).
- Dimensions: Nominal 5.0 mm × 6.4 mm. The relatively large footprint for a clock gen simplifies hand rework but requires sufficient clearance for the thermal pad (if present) or standard pin spacing.
- SMT Process:
- Profile: Standard JEDEC Pb-free profile applies (Peak ~260°C).
- Pad Layout: Ensure the PCB footprint accounts for the 0.65mm pitch.
- Grounding: Pins 5 and 10 are GND. Both must be soldered effectively to minimize ground bounce and jitter.
🔍 Procurement & Sourcing Insights
🔎 Supply Chain Reality:
- Lifecycle Status: This is a mature TI component (Active). However, as a programmable part, the risk often lies in the programming.
- Sourcing Trap: Distributors often sell blank devices. If your BOM does not specify "Factory Programmed" (TI uses a specific suffix code), you will receive blank silicon that requires I2C initialization, which the production line may miss.
- Counterfeit Risk: Watch for remarked TSSOP packages. Verify the laser etching date code and lot traceability (Traceability code) against TI's direct database.
- Alternative Strategy: Pin-to-pin replacements are rare due to proprietary PLL register maps. Design-in is sticky; ensure second-source availability or buffer stock early.
❓ FAQ
Q: What is the difference between CDCE913 and CDCEL913?
A: The core PLL architecture is identical. The CDCEL913 features 1.8V outputs only, while the CDCE913 supports 2.5V or 3.3V outputs. If your downstream load (e.g., FPGA or PHY) requires 3.3V LVCMOS levels, you must select the CDCE913.
Q: Do I need an external crystal, or can I use a clock input?
A: The device is flexible. You can use a fundamental mode crystal (8–32 MHz) connected between Xin/Xout, OR feed a single-ended LVCMOS clock into Xin (leaving Xout floating or pulled up). The LVCMOS input supports frequencies up to 160 MHz.
Q: How do I handle the unused outputs (Y1, Y2, Y3)?
A: Unused outputs should generally be disabled via the I2C register map (Power Down bit) to save power. Physically, they can be left unconnected (NC) on the PCB, but ensure the pin does not float electrically if the driver is active.
Q: What is the lead time for programmed samples?
A: Blank parts are often "off-the-shelf" (short lead time). Pre-programmed parts (custom frequency/SSC settings) typically require a 4-6 week lead time for TI factory setup. Validate your register maps long before mass production.
