Analog Devices AD8361 c Datasheet

LF to 2.5 GHz

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.

3.0

2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

V rms (Volts)

1.0

0.8

0.6

0.4

0.2

0.0
0

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

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

SUPPLY

REFERENCE MODE

INTERNAL

REFERENCE MODE

REFERENCE MODE

RFIN (V rms)

GROUND

0.50.1 0.2 0.3 0.4

01088-C-001

TruPwr™ Detector

AD8361

FUNCTIONAL BLOCK DIAGRAMS

ADD

VPOS

FLTR

VRMS

SREF

COMM

VPOS

FLTR

VRMS

COMM

/7.5.

S

RFIN

PWDN

χ

TRANS­CONDUCTANCE
CELLS

χ

i

2

i

2

BAND-GAP

REFERENCE

ERROR
AMP

INTERNAL FILTER

AD8361

× 7.5
BUFFER

OFFSET

IREF

Figure 2. 8-Lead MSOP

RFIN

PWDN

χ

TRANS­CONDUCTANCE
CELLS

χ

i

2

i

2

BAND-GAP

REFERENCE

ERROR
AMP

INTERNAL FILTER

AD8361

× 7.5
BUFFER

IREF

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.

3. Supply reference mode, which offsets the output to V

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
is fabricated on a proprietary high f

silicon bipolar process.

T

01088-C-002

01088-C-003

Rev. C

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 property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8361

TABLE OF CONTENTS

Specifications..................................................................................... 3

Applications..................................................................................... 12

Absolute Maximum Ratings............................................................ 4

ESD Caution.................................................................................. 4

Pin Configuration and Function Descriptions............................. 5

Typical Performance Characteristics............................................. 6

Circuit Description......................................................................... 11

REVISION HISTORY

8/04—Data Sheet Changed from Rev. B to Rev. C.

Changed Trimpots to Trimmable Potentiometers .........Universal

Changes to Specifications................................................................ 3

Changed Using the AD8361 Section Title to Applications....... 12

Changes to Figure 43...................................................................... 14

Changes to Ordering Guide.......................................................... 24

Updated Outline Dimensions....................................................... 24

2/01—Data Sheet Changed from Rev. A to Rev. B.

Output Reference Temperature Drift Compensation ........... 16

Evaluation Board ............................................................................ 21

Characterization Setups............................................................. 23

Outline Dimensions....................................................................... 24

Ordering Guide .......................................................................... 24

Rev. C | Page 2 of 24

AD8361

SPECIFICATIONS

TA = 25°C, VS = 3 V, fRF = 900 MHz, ground reference output mode, unless otherwise noted.

Table 1.

Parameter Condition Min Typ Max Unit

SIGNAL INPUT INTERFACE (Input RFIN)

Frequency Range
Linear Response Upper Limit VS = 3 V 390 mV rms
Equivalent dBm, re 50 Ω 4.9 dBm
V
Equivalent dBm, re 50 Ω 9.4 dBm
Input Impedance

RMS CONVERSION (Input RFIN to Output V rms)

Conversion Gain 7.5 V/V rms
f
Dynamic Range Error Referred to Best Fit Line

±0.25 dB Error
±1 dB Error CW Input, −40°C < TA < +85°C 23 dB
±2 dB Error CW Input, −40°C < TA < +85°C 26 dB

CW Input, VS = 5 V, −40°C < TA < +85°C 30 dB

Intercept-Induced Dynamic Internal Reference Mode 1 dB

Range Reduction

Supply Reference Mode, VS = 5.0 V 1.5 dB

Deviation from CW Response 5.5 dB Peak-to-Average Ratio (IS95 Reverse Link) 0.2 dB
12 dB Peak-to-Average Ratio (W-CDMA 4 Channels) 1.0 dB
18 dB Peak-to-Average Ratio (W-CDMA 15 Channels) 1.2 dB
OUTPUT INTERCEPT5 Inferred from Best Fit Line3

Ground Reference Mode (GRM) 0 V at SREF, VS at IREF 0 V

f

Internal Reference Mode (IRM) 0 V at SREF, IREF Open 350 mV

f

Supply Reference Mode (SRM) 3 V at IREF, 3 V at SREF 400 mV

V

f
POWER-DOWN INTERFACE

PWDN HI Threshold 2.7 ≤ VS ≤ 5.5 V, −40°C < TA < +85°C VS − 0.5 V

PWDN LO Threshold 2.7 ≤ VS ≤ 5.5 V, −40°C < TA < +85°C 0.1 V

Power-Up Response Time 2 pF at FLTR Pin, 224 mV rms at RFIN 5 µs

100 nF at FLTR Pin, 224 mV rms at RFIN 320 µs

PWDN Bias Current <1 µA
POWER SUPPLIES

Operating Range −40°C < TA < +85°C 2.7 5.5 V

Quiescent Current 0 mV rms at RFIN, PWDN Input LO

Power-Down Current GRM or IRM, 0 mV rms at RFIN, PWDN Input HI <1 µA
SRM, 0 mV rms at RFIN, PWDN Input HI 10 × VS µA

1

Operation at arbitrarily low frequencies is possible; see Ap section. plications

2

Figure 17 and Figure 47 show impedance versus frequency for the MSOP and SOT-23, respectively.

3

Calculated using linear regression.

4

Compensated for output reference temperature drift; see section.

5

SOT-23-6L operates in ground reference mode only.

6

The available output swing, and hence the dynamic range, is altered by both supply voltage and reference mode; see Figure 39 and Figure 40.

7

Supply current is input level dependant; see Figure 16.

1

2

4

5, 6

2.5 GHz

= 5 V 660 mV rms

S

225||1 Ω||pF

= 100 MHz, VS = 5 V 6.5 8.5 V/V rms

RF

3

CW Input, −40°C < TA < +85°C 14 dB

Supply Reference Mode, VS = 3.0 V 1 dB

= 100 MHz, VS = 5 V −50 +150 mV

RF

= 100 MHz, VS = 5 V 300 500 mV

RF

at IREF, VS at SREF VS/7.5 V

S

= 100 MHz, VS = 5 V 590 750 mV

RF

7

Applications

1.1 mA

Rev. C | Page 3 of 24

AD8361

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage V

S

SREF, PWDN 0 V, V
IREF VS − 0.3 V, V
RFIN 1 V rms

Equivalent Power, re 50 Ω 13 dBm

Internal Power Dissipation

1

6-Lead SOT-23 170 mW

8-Lead MSOP 200 mW
Maximum Junction Temperature 125°C
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Lead Temperature Range

(Soldering 60 sec)

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

5.5 V

S

S

200 mW

300°C

1

Specification is for the device in free air.

6-Lead SOT-23: θ
8-Lead MSOP: θ

= 230°C/W; θJC = 92°C/W.

JA

= 200°C/W; θJC = 44°C/W.

JA

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. C | Page 4 of 24

AD8361

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

VPOS

1

IREF
RFIN

PWDN

AD8361

2

TOP VIEW

3

(Not to Scale)

4

Figure 4. 8-Lead MSOP

Table 3. Pin Function Descriptions

Pin No.
MSOP

Pin No.
SOT-23 Mnemonic Description

1 6 VPOS Supply Voltage Pin. Operational range 2.7 V to 5.5 V.
2 N/A IREF

3 5 RFIN

4 4 PWDN

5 2 COMM Device Ground Pin.
6 3 FLTR

7 1 VRMS

8 N/A SREF

SREF

8

VRMS

7
6

FLTR
COMM

5

01088-C-004

VRMS

1

AD8361

2

COMM

FLTR

TOP VIEW

(Not to Scale)

3

Figure 5. 6-Lead SOT-23

6

5

4

VPOS

RFIN

PWDN

01088-C-005

Output Reference Control Pin. Internal reference mode enabled when pin is left open; otherwise, this
pin should be tied to VPOS. Do not ground this pin.

Signal Input Pin. Must be driven from an ac-coupled source. The low frequency real input impedance
is 225 Ω.

Power-Down Pin. For the device to operate as a detector, it needs a logical low input (less than
100 mV). When a logic high (greater than V
current goes to nearly zero (ground and internal reference mode less than 1 µA, supply reference
mode V

divided by 100 kΩ).

S

By placing a capacitor between this pin and VPOS, the corner frequency of the modulation filter is
lowered. The on-chip filter is formed with 27 pF||2 kΩ for small input signals.

Output Pin. Near rail-to-rail voltage output with limited current drive capabilities. Expected load
>10 kΩ to ground.

Supply Reference Control Pin. To enable supply reference mode, this pin must be connected to VPOS;
otherwise, it should be connected to COMM (ground).

− 0.5 V) is applied, the device is turned off and the supply

S

Rev. C | Page 5 of 24

AD8361

TYPICAL PERFORMANCE CHARACTERISTICS

2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

OUTPUT (V)

1.0

0.8

0.6

0.4

0.2

0.0
0

Figure 6. Output vs. Input Level, Frequencies 100 MHz, 900 MHz,

1900 MHz, and 2500 MHz, Supply 2.7 V, Ground Reference Mode, MSOP

900MHz

100MHz

INPUT (V rms)

2.5GHz

1900MHz

0.50.1 0.2 0.3 0.4

01088-C-006

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

0.01

0.02

(–21dBm)

MEAN ±3 SIGMA

0.1

(–7dBm)

INPUT (V rms)

0.4

(+5dBm)

01088-C-009

Figure 9. Error from Linear Reference vs. Input Level, 3 Sigma to Either Side of

Mean, Sine Wave, Supply 3.0 V, Frequency 900 MHz

5.5

5.0

4.5

4.0

3.5

3.0

2.5

OUTPUT (V)

2.0

1.5

1.0

0.5

0.0
0

INPUT (V rms)

5.5V

2.7V

0.50.1 0.2 0.3 0.4

0.6 0.7 0.8

3.0V

Figure 7. Output vs. Input Level,

Supply 2.7 V, 3.0 V, 5.0 V, and 5.5 V, Frequency 900 MHz

5.0

4.5

4.0

3.5

3.0

2.5

2.0

OUTPUT (V)

1.5

1.0

0.5

0.0

0

IS95

REVERSE LINK

INPUT (V rms)

CW

WCDMA

4- AND 15-CHANNEL

0.50.1 0.2 0.3 0.4

0.6 0.7 0.8

Figure 8. Output vs. Input Level with

Different Waveforms Sine Wave (CW), IS95 Reverse Link,

W-CDMA 4-Channel and W-CDMA 15-Channel, Supply 5.0 V

5.0V

01088-C-007

01088-C-008

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

0.01

MEAN ±3 SIGMA

0.10.02

(–7dBm)(–21dBm)

INPUT (V rms)

0.6

(+8.6dBm)

01088-C-010

Figure 10. Error from Linear Reference vs. Input Level, 3 Sigma to Either Side

of Mean, Sine Wave, Supply 5.0 V, Frequency 900 MHz

3.0

2.5

2.0

1.5

1.0

0.5

0.0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

CW

4-CHANNEL

15-CHANNEL

0.02 0.6
INPUT (V rms)

0.2

IS95

REVERSE LINK

1.00.01 0.1

01088-C-011

Figure 11. Error from CW Linear Reference vs. Input with Different Waveforms

Sine Wave (CW), IS95 Reverse Link, W-CDMA 4-Channel and

W-CDMA 15-Channel, Supply 3.0 V, Frequency 900 MHz

Rev. C | Page 6 of 24

AD8361

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0

2.5

–3.0

0.01

MEAN ±3 SIGMA

0.10.02

(–7dBm)(–21dBm)

INPUT (V rms)

0.4

(+5dBm)

01088-C-012

Figure 12. Error from CW Linear Reference vs. Input, 3 Sigma to Either Side of

Mean, IS95 Reverse Link Signal, Supply 3.0 V, Frequency 900 MHz

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

0.01

INPUT (V rms)

+85°C

–40°C

0.10.02

(–7dBm)(–21dBm)

0.4

(+5dBm)

Figure 15. Output Delta from +25°C vs. Input Level, 3 Sigma to Either

Side of Mean Sine Wave, Supply 3.0 V, Frequency 1900 MHz,

Temperature −40°C to +85°C

01088-C-015

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

0.01

MEAN ±3 SIGMA

0.10.02

(–7dBm)(–21dBm)

INPUT (V rms)

0.6

(+8.6dBm)

01088-C-013

Figure 13. Error from CW Linear Reference vs. Input Level, 3 Sigma to Either

Side of Mean, IS95 Reverse Link Signal, Supply 5.0 V, Frequency 900 MHz

3.0

2.5

2.0

1.5

1.0

0.5
0

–0.5

ERROR (dB)

–1.0
–1.5
–2.0
–2.5

–3.0

0.01

INPUT (V rms)

+85°C

–40°C

0.10.02

(–7dBm)(–21dBm)

0.4

(+5dBm)

01088-C-014

Figure 14. Output Delta from +25°C vs. Input Level, 3 Sigma to

Either Side of Mean Sine Wave, Supply 3.0 V,

Frequency 900 MHz, Temperature −40°C to +85°C

11
10

9
8
7
6
5
4

3

SUPPLY CURRENT (mA)

2
1

0

0

+85°C

+25°C

VS = 3V

INPUT OUT
OF RANGE

–40°C

VS = 5V

INPUT OUT
OF RANGE

–40°C

INPUT (V rms)

+25°C

0.50.1 0.2 0.3 0.4

+85°C

0.6 0.7 0.8

Figure 16. Supply Current vs. Input Level, Supplies 3.0 V, and 5.0 V,

Temperatures −40°C, +25°C, and +85°C

250

+25°C

200

–40°C

150

100

+25°C

SHUNT RESISTANCE (Ω)

50

0

0 500 1000

+85°C

+85°C

–40°C

FREQUENCY (MHz)

1500

2000 2500

Figure 17. Input Impedance vs. Frequency, Supply 3 V,

Temperatures −40°C, +25°C, and +85°C, MSOP

(See Applications for SOT-23 Data)

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

01088-C-016

SHUNT CAPACITANCE (pF)

01088-C-017

Rev. C | Page 7 of 24

AD8361

0.03

0.02

0.01

0.00

–0.01

–0.02

INTERCEPT CHANGE (V)

–0.03

–0.04

–0.05

Figure 18. Output Reference Change vs. Temperature,

MEAN ±3 SIGMA

60 80 100

TEMPERATURE (°C)

40–40 –20 0 20

Supply 3 V, Ground Reference Mode

01088-C-018

0.18

0.16

0.14

0.12

0.10

0.08

0.02

GAIN CHANGE (V/V rms)

0.00

–0.02
–0.04

–0.06

0.06

0.04

MEAN±3 SIGMA

40–40 –20 0 20

TEMPERATURE (°C)

60 80 100

Figure 21. Conversion Gain Change vs. Temperature, Supply 3 V,

Ground Reference Mode, Frequency 900 MHz

01088-C-021

0.02

0.01

0.00

–0.01

INTERCEPT CHANGE (V)

–0.02

–0.03

MEAN ±3 SIGMA

TEMPERATURE (°C)

40–40 –20 0 20

60 80 100

Figure 19. Output Reference Change vs. Temperature, Supply 3 V,

Internal Reference Mode (MSOP Only)

0.03

0.02

0.01

0.00

–0.01

–0.02

INTERCEPT CHANGE (V)

–0.03

–0.04

–0.05

MEAN ±3 SIGMA

TEMPERATURE (°C)

40–40 –20 0 20

60 80 100

Figure 20. Output Reference Change vs. Temperature, Supply 3 V,

Supply Reference Mode (MSOP Only)

01088-C-019

01088-C-020

0.18

0.16

0.14

0.12

0.10

0.08

0.02

GAIN CHANGE (V/V rms)

0.00

–0.02
–0.04

–0.06

0.06

0.04

MEAN±3 SIGMA

40–40 –20 0 20

TEMPERATURE (°C)

60 80 100

Figure 22. Conversion Gain Change vs. Temperature, Supply 3 V,

Internal Reference Mode, Frequency 900 MHz (MSOP Only)

0.18

0.16

0.14

0.12

0.10

0.08

0.02

GAIN CHANGE (V/V rms)

0.00

–0.02
–0.04

–0.06

0.06

0.04

MEAN±3 SIGMA

40–40 –20 0 20

TEMPERATURE (°C)

60 80 100

Figure 23. Conversion Gain Change vs. Temperature, Supply 3 V,

Supply Reference Mode, Frequency 900 MHz (MSOP Only)

01088-C-022

01088-C-023

Rev. C | Page 8 of 24