SNAA433 March   2025 CDC6C

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2BAW Overview
    1. 2.1 BAW Structure Overview
    2. 2.2 BAW Oscillator Advantages
  6. 3IEEE 100Mbps Requirements
    1. 3.1 Test Summary on Channel A
  7. 4CDC6C Clocking DP83822 Evaluation
  8. 5Clocking for Different Ethernet PHY
  9. 6Summary
  10. 7References

2.2 BAW Oscillator Advantages

CDC6C has a number of advantages including frequency flexibility, temperature stability, power supply noise immunity among others. Table 2-1 and Table 2-2 summarize these advantages and showcases how BAW oscillators have solved design limitations found while using quartz oscillators. Additional information can be found in the following application notes:

Table 2-1 BAW Resonator versus Quartz Resonator
Parameter BAW Quartz Advantage
Frequency Flexibility Alleviates supply constraints, single IC supports large range of frequencies through one time programming (OTP). Output frequency is controlled through mechanical parameters that cannot be modified once cut. BAW oscillator
Temperature Stability ±10ppm (Maintains temperature stability irrelevant of temperature range) As temperature increases so does ppm stability BAW oscillator
Vibration Typical is 1 ppb/g.Passes MIL_STD_883F Method 2002 Condition A Can be as high as 10+ppb/g. Typically does not pass MIL-STD. BAW oscillator
Mechanical Shock Less than 0.5ppm variation up to 1500 g. Passes MIL_STD_883F Method 2007 Condition B Typically does not MIL-STD. Can fail at 2,000g BAW oscillator
Table 2-2 Quartz Limitation Solved by BAW Oscillator
Parameter BAW Oscillator Design Quartz Limitation
Power supply noise Integrated LDO for improved power supply noise rejection (-72dBc PSRR at 500kHz, 50mV ripple) Typically has no integrated LDO
Mean time between failure 3.3 billion hours of operation 33 million hours of operation
Frequency flexibility Support any frequency from 1MHz to 200MHz in LVCMOS variant Limited by resonator crystal; different frequencies require different resonant crystal
Supply chain Fabricated, assembled and packaged in house by TI Multiple third party manufacturing to support build of different components (resonator, ASIC, Package, and so on.)
Land pattern Universal – industry standard footprint Land pattern can depend on supplier