BAW Resonator Technology

BAW is a micro-resonator technology that enables the integration of high-precision and ultra-low jitter clocks directly into packages that contain other circuits. In the LMK6C and CDC6CLVCMOS oscillators, BAW is integrated with a co-located precision temperature sensor, a ultra-low jitter, low power output divider, and a small power-reset-clock management system consisting of several low noise LDOs.

Figure 1 shows the structure of the BAW resonator technology. The structure includes a thin layer of piezoelectric film sandwiched between metal films and other layers that confine the mechanical energy. The BAW utilizes this piezoelectric transduction to generate a vibration.

BAW Oscillator in Motor Drive Systems

Motor drive systems are used in many industrial and manufacturing applications. These systems require precise control of position, torque, and speed for robust and reliable performance. Many applications such as AC inverter and VF drives, single and multi-axis servo drives, and stepper drives rely on EtherCAT® to transmit data to the host processor, which requires a reliable clocking architecture to achieve the best performance. Figure 2 shows a common clocking architecture for standard EtherCAT applications.

Benefits of the BAW Oscillator

TI's BAW oscillators have many benefits including the following:

• BAW oscillators are available in standard 4-pin package sizes, including the industry's smallest 1.6mm x 1.2mm. Figure 3 showcases BAW Oscillator layouts on the left in comparison to typical crystal layouts for several package sizes. Crystals require up to four external components to tune the resonant frequency and maintain active oscillation. Active oscillators such as the CDC6C or LMK6C only require a single capacitor for power supply filtering, which simplifies the BOM and significantly reduces the layout area required. Additionally, parasitic capacitance from PCB traces will not affect the frequency accuracy of an active oscillator which allows it to be placed much farther away from the receiver compared to crystal.

• BAW technology enables high resiliency to harsh environmental conditions, such as mechanical shock and vibration and achieves 100× better MTBF compared to quartz based designs. As shown in Figure 4, BAW oscillators experience only 1 ppb/g vibration sensitivity, which is 10× better than quartz-based designs.

• BAW oscillators maintain a temperature stability of ±10 ppm over temperature from -40 to +105°C.

• LMK6C oscillators support a typical RMS jitter of 200fs, resulting in optimized bit-error-rate (BER) performance of the Ethernet PHY.

• BAW oscillators include an integrated LDO which provides high-power supply noise immunity.