ANALOG DEVICES ADL5505 Service Manual

450 MHz to 6000 MHz

RFIN

VPOS

VRMS

COMM

ADL5505

INTERNAL FILTERING

RMS CORE

BUFFER

100Ω

05799-001

0.01

0.1

–25 –20 –15 –10 –5 0 5 10 15

OUTPUT (V)

INPUT (d Bm)

05799-002

FEATURES

True rms response detector Excellent temperature stability ±0.25 dB rms detection accuracy vs. temperature Over 35 dB input power dynamic range, inclusive of crest factor RF bandwidths from 450 MHz to 6000 MHz 500 Ω input impedance Single-supply operation: 2.5 V to 3.3 V Low power: 1.8 mA at 3.0 V supply RoHS-compliant part

APPLICATIONS

Power measurement of W-CDMA, CDMA2000, QPSK-/QAM-

based OFDM (LTE and WiMAX), and other complex modulation waveforms

RF transmitter or receiver power measurement

TruPwr Detector

ADL5505

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADL5505 is a TruP wr™ mean-responding (true rms) power detector for use in high frequency receiver and transmitter signal chains from 450 MHz to 6000 MHz. Requiring only a single supply between 2.5 V and 3.3 V, the detector draws less than

1.8 mA. The input is internally ac-coupled and has a nominal input impedance of 500 Ω. The rms output is a linear-responding dc voltage with a conversion gain of 1.86 V/V rms at 900 MHz.

The ADL5505 is a highly accurate, easy to use means of determining the rms of complex waveforms. It can be used for power measurements of both simple and complex waveforms but is particularly useful for measuring high crest factor (high peak-to-rms ratio) signals, such as W-CDMA, CDMA2000, WiMAX, WLAN, and LTE waveforms.

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the prop erty of their respective owner s.

Figure 2. Output vs. Input Level, Supply = 3.0 V, Frequency = 1900 MHz

The on-chip modulation filter provides adequate averaging for most waveforms. An on-chip, 100 Ω series resistance at the output, combined with an external shunt capacitor, creates a lowpass filter response that reduces the residual ripple in the dc output voltage.

The ADL5505 offers excellent temperature stability across a 30 dB range and near 0 dB measurement error across temperature over the top portion of the dynamic range. In addition to its temperature stability, the ADL5505 offers low process variations that further reduce calibration complexity.

The power detector operates from −40°C to +85°C and is available in an 4-ball, 0.8 mm × 0.8 mm wafer-level chip scale package. It is fabricated on a high f

silicon BiCMOS process.