LF to 2.5 GHz

TruPwr™ Detector

Data Sheet

AD8361

Rev. F

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FEATURES

Calibrated rms response

Excellent temperature stability

Up to 30 dB input range at 2.5 GHz

700 mV rms, 10 dBm, re 50 Ω 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 µA

APPLICATIONS

Measurement of CDMA, W-CDMA, QAM, other complex

modulation waveforms

RF transmitter or receiver power measurement

GENERAL DESCRIPTION

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 a single supply only

between 2.7 V and 5.5 V, a 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 averaging time constant.

Figure 1. Output in the Three Reference Modes, Supply 3 V, Frequency 1.9 GHz

(6-Lead SOT-23 Package Ground Reference Mode Only)

FUNCTIONAL BLOCK DIAGRAMS

Figure 2. 8-Lead MSOP

Figure 3. 6-Lead SOT-23

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.

The AD8361 has three operating modes to accommodate a

variety of analog-to-digital converter requirements:

1. Ground reference mode, in which the origin is zero.

2. Internal reference mode, which offsets the output 350 mV

above ground.

The AD8361 is specified for operation from −40°C to +85°C

and is available in 8-lead MSOP and 6-lead SOT-23 packages. It

RFIN (V rms)

3.0

1.6

0

0.5

0.1

0.2

0.3

0.4

2.6

2.2

2.0

1.8

2.8

2.4

1.4

1.2

1.0

0.6

0.8

0.4

0.2

0.0

SUPPLY

REFERENCE MODE

INTERNAL

REFERENCE MODE

GROUND

REFERENCE MODE

RFIN

IREF

PWDN

VPOS

FLTR

SREF

VRMS

COMM

BAND-GAP

REFERENCE

ERROR

AMP

AD8361

INTERNAL FILTER

ADD

OFFSET

TRANS-

CONDUCTANCE

CELLS

i

i

× 7.5

BUFFER

RFIN

IREF

PWDN

VPOS

FLTR

VRMS

COMM

BAND-GAP

REFERENCE

ERROR

AMP

AD8361

INTERNAL FILTER

TRANS-

CONDUCTANCE

CELLS

i

i

× 7.5

BUFFER