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 BAW oscillator, the BAW is integrated with a co-located precision temperature
sensor, a ultra-low jitter, low power fractional output divider (FOD), a single-ended LVCMOS
and differential LVPECL, LVDS, and HCSL output driver, 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. The 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, Figure 3, and Figure 4 show common clocking architectures for standard EtherCAT applications.
Benefits of the BAW Oscillator
TI's BAW oscillators have many benefits including the following:
- BAW oscillators are available in small package
sizes (3.2 mm × 2.5 mm and 2.5 mm × 2.0 mm) and do not require the additional capacitors
that crystals require, which allows for reduced PCB space that is allocated to the
oscillator. Figure 5 shows how using a BAW oscillator can help save PCB space.
- 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 6, 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 RMS jitter of
250 fs (typical), resulting in optimized BER performance and improved synchronization
between the processor and Ethernet PHY.
- BAW oscillators include an integrated LDO
which provides high-power supply noise immunity.