The 5042 series are high-stability clock oscillator ICs with built-in frequency adjustment functions. The frequency adjustment functions can be optimized, by the addition of a minimal adjustment process, to improve the frequency stability. The function is implemented using frequency adjustment data written to a built-in EEPROM over a 1-wire serial interface. The ICs are ideal for compact crystal oscillators for use in applications such as WiMAX (Worldwide Interoperability for Microwave Access) and PLC (Power Line Communication) that require high frequency stability in the order of 30 to 10ppm. They use a pad layout suitable for wire bonding mounting.