LMV221

www.DataSheet4U.com LMV221 50 MHz to 3.5 GHz 40 dB Logarithmic Power Detector for CDMA and WCDMA December 2006 LMV221 50 MHz to 3.5 GHz 40 dB Logarithmic Power Detector for CDMA and WCDMA General Description The LMV221 is a 40 dB RF power detector intended for use in CDMA and WCDMA applications. The device has an RF frequency range from 50 MHz to 3.5 GHz. It provides an accurate temperature and supply compensated output voltage that relates linearly to the RF input power in dBm. The circuit operates with a single supply from 2.7V to 3.3V. The LMV221 has an RF power detection range from −45 dBm to −5 dBm and is ideally suited for direct use in combination with a 30 dB directional coupler. Additional low-pass filtering of the output signal can be realized by means of an external resistor and capacitor. Figure (a) shows a detector with an additional output low pass filter. The filter frequency is set with RS and CS. Figure (b) shows a detector with an additional feedback low pass filter. Resistor RP is optional and will lower the Trans impedance gain (RTRANS). The filter frequency is set with CP//CTRANS and RP//RTRANS. The device is active for Enable = High, otherwise it is in a low power consumption shutdown mode. To save power and prevent discharge of an external filter capacitance, the output (OUT) is high-impedance during shutdown. The LMV221 power detector is offered in the small 2.2 mm x 2.5 mm x 0.8 mm LLP package. Features ■ ■ ■ ■ ■ ■ ■ 40 dB linear in dB power detec...