ADL5501 Datasheet | Analog Devices

FEATURES True rms response Excellent temperature stability Up to 30 d B input dynamic range at 4 GHz 50 Ω input impedance 1.25 V rms, +15 d Bm, maximum input Single-supply operation: 2.7 V to 5.5 V Low power: 3 m W at 3 V supply Ro HS pliant 50 MHz to 4 GHz Tru Pwr™ Detector ADL5501 FUNCTIONAL BLOCK DIAGRAM RFIN x2 i INTERNAL FILTER CAPACITOR VPOS FLTR TRANSCONDUCTANCE CELLS x2 i ERROR AMP BUFFER 100 Ω VRMS APPLICATIONS Measurement of CDMA, CDMA2000, W-CDMA, and QPSK/QAM-based OFDM, and other plex modulation waveforms RF transmitter or receiver power measurement BAND-GAP REFERENCE ENBL M Figure 1. GENERAL DESCRIPTION The ADL5501 is a mean-responding power detector for use in high frequency receiver and transmitter signal chains from 50 MHz to 4 GHz. It is easy to apply, requiring only a single supply between 2.7 V and 5.5 V and a power supply decoupling capacitor. The input is internally ac-coupled and has a nominal input impedance of 50 Ω. The output is a linear-responding dc voltage with a conversion gain of 6.6 V/V rms at 900 MHz. The ADL5501 is intended for true power measurement of simple and plex waveforms. The device is particularly useful for measuring high crest factor (high peak-to-rms ratio) signals, such as CDMA, CDMA2000, W-CDMA, and QPSK/QAM-based OFDM waveforms. The on-chip modulation filter provides adequate averaging for most waveforms. The on-chip, 100 Ω series resistance at the output bined with an external shunt capacitor creates a low-pass filter response that reduces the residual ripple in the dc output voltage. For more plex waveforms, an external capacitor at the FLTR pin can be used for supplementary signal demodulation. The ADL5501 offers excellent temperature stability across a 30 d B range and near 0 d B measurement error across temperature over the top portion of the dynamic range. In addition to its temperature stability, the ADL5501 offers low process variations which further reduces calibration plexity. The ADL5501...