AN95102

Philips Semiconductors Application note Low power single/dual frequency synthesizers: UMA1017M/1018M/1019M(AM)/1020M(AM) Author: P. Hugues AN95102 UMA1018M and UMA1020M/UMA1020AM low power dual frequency synthesizers UMA1017M and UMA1019M/UMA1019AM low power single frequency synthesizers www.datasheet4u.com SUMMARY This application note describes the UMA1018M and UMA1020M/UMA1020AM from Philips Semiconductors. They permit a low-voltage low-power single-chip solution to designing dual PLL frequency synthesizers. They are intended for use in digital or analogue wireless communications equipment. Typical applications include GSM, DECT and DCS1800. Three low-voltage low-power solutions to single frequency synthesizers are also briefly described. The UMA1017M and UMA1019M/UMA1019AM are derivatives from UMA1018M and UMA1020M, respectively, and are hence closely related. The overall performance of any PLL frequency synthesizer system is critically determined by the low pass filter used. Described in this report is a basic loop filter design method with worked examples and some measurement results. To reduce crosstalk between different parts of the synthesizer, separate power supply and ground pins are provided to the analogue and digital sections. Each synthesizer can be powered down independently to save current via software programming or hardwire pins AON / PON. An on-chip 7 bit DAC allows adjustment of external functions, such as temperature compensation of the VTCXO, power ...