200 MHz to 6 GHz
35 dB TruPwr™ Detector
Data Sheet
ADL5903
FEATURES
FUNCTIONAL BLOCK DIAGRAM
VPOS
5
CREG
4
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
ADL5903
INTERNAL
FILTERING
6
1
ENBL
RFIN
630pF
1kΩ
3
7
CRMS
VRMS
4pF
100Ω
RMS CORE
BUFFER
Linear in decibels output, scaled 35.5 mV/dB at 900 MHz
Excellent temperature stability
2
8
GND
NIC
EP
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
Figure 1.
APPLICATIONS
Power amplifier linearization/control loops
Transmitter power controls
Transmitter signal strength indication (TSSI)
RF instrumentation
Wireless repeaters
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 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 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 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.
Rev. B
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