200 MHz to 6 GHz

35 dB TruPwr™ Detector

Data Sheet

ADL5903

Rev. B

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FEATURES

Accurate rms-to-dc conversion from 200 MHz to 6 GHz

Measurement dynamic range of 35 dB

Ripple-free transfer function

Single-ended input, 50 Ω source compatible

No external matching required

Waveform and modulation independent, such as

GSM/CDMA/W-CDMA/TD-SCDMA/LTE

Linear in decibels output, scaled 35.5 mV/dB at 900 MHz

Excellent temperature stability

Operates from 3.0 V to 5.0 V from −55°C to +125°C

Low power consumption: 3 mA at 3.0 V to 5.0 V supply

8-lead, 2 mm × 2 mm LFCSP package

APPLICATIONS

Power amplifier linearization/control loops

Transmitter power controls

Transmitter signal strength indication (TSSI)

RF instrumentation

Wireless repeaters

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADL5903 is a true rms responding power detector that has

a 35 dB measurement range. It features low power consumption

and an intrinsically ripple-free error transfer function.

The ADL5903 provides a solution in a variety of high frequency

systems requiring an accurate measurement of signal power.

Requiring only a single supply of 3.0 V to 5.0 V and a few

capacitors, it is easy to use and capable of being driven single-

ended or with a balun for differential input drive. An on-chip

matching network provides good return loss over the specified

frequency range of the device. The ADL5903 can operate from

200 MHz to 6 GHz and can accept inputs from −30 dBm to

+20 dBm.

The ADL5903 can be used to determine the true power of a

high frequency signal with a complex modulation envelope

including large crest factor signals such as GSM, CDMA,

W-CDMA, TD-SCDMA, and LTE modulated signals. The

output is then proportional to the logarithm of the rms value

of the input. In other words, the reading is presented directly

in decibels and is scaled about 35.5 mV/dB at 900 MHz.

The ADL5903 has low power consumption when operational

and a disable mode that further reduces the power consumption.

Power consumption is less than 100 µA when the ADL5903

enters power-down mode through a logic low at Pin ENBL.

The ADL5903 is supplied in a 2 mm × 2 mm, 8-lead LFCSP for

operation over the wide temperature range of −55°C to +125°C.

5

1

6

ADL5903

RFIN

ENBL

RMS CORE

INTERNAL

FILTERING

BUFFER

630pF

1kΩ

100Ω

4pF

VPOS

2

GND

8

NIC

EP

4

CREG

3

CRMS

7

VRMS