The preferred choice for clock oscillation circuit design in crystal oscillator audio devices with phase jitter as low as 65fs

Compared with ordinary audio devices, high-end audio devices have better sound quality and better human-computer interaction experience. The high-end audio equipment system diagram shown in Figure 1 mainly includes modules such as microphone, AMP (electronic amplifier), ADC (analog-to-digital converter), DAC (digital to analog converter), SRC (sampling rate converter), USB interface, Ethernet, and digital audio processor. Among them, clock signals are required to be connected to modules such as digital audio processors, Ethernet, USB interfaces, and DACs to ensure the stable and orderly operation of various electronic components in the system. In order to generate clock signals, the system needs to have a clock oscillation circuit, and a crystal oscillator is an essential part of this circuit.

When designing clock oscillation circuits for high-end audio equipment systems, this article recommends using the SG7050EBN crystal oscillator solution launched by EPSON, which has low phase jitter (as shown in Figure 2, can be as low as 65fs), can effectively avoid interference, and has high output accuracy. In addition, SG7050EBN supports a frequency range of 100MHz~175MHz, with a frequency stability of ± 50 × 10-6 (maximum value, including initial frequency tolerance, temperature changes, power supply voltage changes, reflow soldering drift, and 10-year aging factors). It supports power supply voltage inputs of 3.3V ± 0.165V or 2.5V ± 0.125V, and can operate normally in the temperature range of -40 ° C~+85 ° C (storage temperature support -55 ° C~+125 ° C). It has strong environmental adaptability and can meet the design requirements of different users.

It is worth mentioning that the packaging size of SG7050EBN is only 7.0mm × 5.0mm × 1.5mm, so it occupies a small space and provides greater flexibility for system design. In addition, it supports LV-PECL (Low Voltage Positive emitter Coupled Logic) output, and the current consumption during normal operation can be as low as 75mA (3.3V ± 0.165V, 50 Ω) or 55mA (2.5V ± 0.125V, 50 Ω), which is conducive to reducing system power consumption and is an ideal choice for high-end audio devices.