LF to 2.5 GHz
™
a
TruPwr Detector
AD8361
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
Calibrated RMS Response
Excellent Temperature Stability
Up to 30 dB Input Range at 2.5 GHz
700 mV rms, 10 dBm re 50 ⍀ Maximum Input
؎0.25 dB Linear Response Up to 2.5 GHz
Single Supply Operation: 2.7 V to 5.5 V
Low Power: 3.3 mW at 3 V Supply
Rapid Power-Down to Less than 1 A
micro_SOIC
VPOS
FLTR
INTERNAL FILTER
i
i
2
RFIN
TRANS-
AD8361
CONDUCTANCE
CELLS
ERROR
AMP
2
BUFFER
VRMS
APPLICATIONS
Measurement of CDMA, W-CDMA, QAM, Other
Complex Modulation Waveforms
RF Transmitter or Receiver Power Measurement
ADD
OFFSET
BAND-GAP
REFERENCE
SREF
PWDN
COMM
IREF
PRODUCT DESCRIPTION
SOT-23-6L
The AD8361 is a mean-responding power detector for use in high-
frequency receiver and transmitter signal chains, up to 2.5 GHz.
It is very easy to apply. It requires only a single supply between
2.7 V and 5.5 V, power supply decoupling capacitor and an
input coupling capacitor in most applications. The output is a
linear-responding dc voltage with a conversion gain of 7.5 V/V rms.
An external filter capacitor can be added to increase the averag-
ing time constant.
VPOS
FLTR
INTERNAL FILTER
i
i
2
RFIN
AD8361
TRANS-
CONDUCTANCE
CELLS
ERROR
AMP
2
BUFFER
VRMS
3.0
BAND-GAP
REFERENCE
PWDN
2.8
SUPPLY
REFERENCE MODE
2.6
COMM
2.4
2.2
INTERNAL
REFERENCE MODE
2.0
The AD8361 is intended for true power measurement of simple
and complex waveforms. The device is particularly useful for
measuring high crest-factor (high peak-to-rms ratio) signals, such
as CDMA and W-CDMA.
1.8
1.6
1.4
GROUND
REFERENCE MODE
1.2
1.0
0.8
0.6
The AD8361 has three operating modes to accommodate a
variety of analog-to-digital converter requirements:
0.4
0.2
0.0
1. Ground referenced mode, in which the origin is zero;
2. Internal reference mode, which offsets the output 350 mV
above ground;
0
0.1
0.2
0.3
0.4
0.5
RFIN – V rms
3. Supply reference mode, which offsets the output to VS/7.5.
Figure 1. Output in the Three Reference Modes, Supply 3 V,
Frequency 1.9 GHz (SOT-23-6L Package Ground Reference
Mode Only)
The AD8361 is specified for operation from –40°C to +85°C and
is available in 8-lead micro_SOIC and 6-lead SOT packages.
It is fabricated on a proprietary high fT silicon bipolar process.
TruPwr is a trademark of Analog Devices, Inc.
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2000