100 MHz to 2.7 GHz, 45 dB
RF Detector/Controller
AD8314
FEATURES
Complete RF detector/controller function
Typical range:−58 dBV to −13 dBV
−45 dBm to 0 dBm, re 50 Ω
Frequency response from 100 MHz to 2.7 GHz
Temperature-stable linear-in-dB response
Accurate to 2.7 GHz
Rapid response: 70 ns to a 10 dB step
Low power: 12 mW at 2.7 V
Power down to 20 μA
For convenience, the signal is internally ac-coupled, using a
5 pF capacitor to a load of 3 kΩ in shunt with 2 pF. This high-
pass coupling, with a corner at approximately 16 MHz,
determines the lowest operating frequency. Therefore, the
source can be dc grounded.
The AD8314 provides two voltage outputs. The first, V_UP,
increases from close to ground to about 1.2 V as the input signal
level increases from 1.25 mV to 224 mV. This output is intended
for use in measurement mode. Consult the Applications section
for information on this mode. A capacitor can be connected
between the V_UP and FLTR pins when it is desirable to
increase the time interval over which averaging of the input
waveform occurs.
The second output, V_DN, is an inversion of V_UP but with
twice the slope and offset by a fixed amount. This output starts
at about 2.25 V (provided the supply voltage is ≥3.3 V) for the
minimum input and falls to a value close to ground at the
maximum input. This output is intended for analog control
loop applications. A setpoint voltage is applied to VSET, and
V_DN is then used to control a VGA or power amplifier. Here
again, an external filter capacitor can be added to extend the
averaging time. Consult the Applications section for
information on this mode.
The AD8314 is available in 8-lead MSOP and 8-lead LFCSP
packages and consumes 4.5 mA from a 2.7 V to 5.5 V supply.
When powered down, the typical sleep current is 20 μA.
APPLICATIONS
Cellular handsets (TDMA, CDMA , GSM)
RSSI and TSSI for wireless terminal devices
Transmitter power measurement and control
GENERAL DESCRIPTION
The AD8314 is a complete low cost subsystem for the
measurement and control of RF signals in the frequency range
of 100 MHz to 2.7 GHz, with a typical dynamic range of 45 dB,
intended for use in a wide variety of cellular handsets and other
wireless devices. It provides a wider dynamic range and better
accuracy than possible using discrete diode detectors. In
particular, its temperature stability is excellent over the full
operating range of −40°C to +85°C.
Its high sensitivity allows control at low power levels, thus
reducing the amount of power that needs to be coupled to the
detector. It is essentially a voltage-responding device, with a
typical signal range of 1.25 mV to 224 mV rms or –58 dBV to
−13 dBV. This is equivalent to −45 dBm to 0 dBm, re 50 Ω.
FUNCTIONAL BLOCK DIAGRAM
FLTR
–
+
DET
DET
DET
DET
DET
–
RFIN
10dB
10dB
10dB
10dB
+
X2
V_DN
I-V
V_UP
V-I
VSET
OFFSET
COMPENSATION
COMM
(PADDLE)
AD8314
BAND GAP
REFERENCE
VPOS
ENBL
01086-001
Figure 1.
Rev. B
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: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2006 Analog Devices, Inc. All rights reserved.
AD8314
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution.................................................................................. 4
Pin Configurations and Function Descriptions............................ 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 10
Inverted Output .......................................................................... 11
Applications..................................................................................... 12
Basic Connections ...................................................................... 12
Transfer Function in Terms of Slope and Intercept ............... 12
dBV vs. dBm ............................................................................... 13
Filter Capacitor ........................................................................... 13
Operating in Controller Mode ................................................. 13
Power-On and Enable Glitch .................................................... 14
Input Coupling Options ............................................................ 14
Increasing the Logarithmic Slope in Measurement Mode ... 15
Effect of Waveform Type on Intercept .................................... 15
Mobile Handset Power Control Examples.............................. 16
Operation at 2.7 GHz................................................................. 18
Using the LFCSP Package.......................................................... 18
Evaluation Board ........................................................................ 18
Outline Dimensions ....................................................................... 20
Ordering Guide .......................................................................... 20
REVISION HISTORY
5/06—Rev. A to Rev. B
Updated Format..................................................................Universal
Changes to General Description .................................................... 1
Changes to Table 1............................................................................ 3
Changes to Table 2............................................................................ 4
Inserted Figure 3; Renumbered Sequentially................................ 5
Changes to Figure 4, Figure 5, Figure 6, Figure 7,
and Figure 8 ...................................................................................... 6
Changes to Figure 9, Figure 10, and Figure 12 ............................. 7
Changes to Figure 37...................................................................... 14
Changes to Table 5.......................................................................... 15
Changes to Figure 39...................................................................... 16
Changes to Table 7.......................................................................... 19
Updated Outline Dimensions ....................................................... 20
Changes to Ordering Guide .......................................................... 20
3/02—Rev. 0 to Rev. A
Edit to Product Description.............................................................1
Edit to Specifications.........................................................................2
Edit to Ordering Guide ....................................................................3
Edit to TPC 1......................................................................................4
New Section (Operation at 2.7 GHz) Added.............................. 14
Addition of New Figures 14 and 15 ............................................. 14
Changes to Evaluation Board Section.......................................... 14
Addition of Chip Scale Package.................................................... 16
Rev. B | Page 2 of 20
AD8314
SPECIFICATIONS
V
S
= 3 V, T
A
= 25°C, unless otherwise noted.
Table 1.
Parameter
OVERALL FUNCTION
Frequency Range
1
Input Voltage Range
Equivalent Power Range
Logarithmic Slope
Logarithmic Intercept
Equivalent dBm Level
INPUT INTERFACE
DC Resistance to COMM
Inband Input Resistance
Input Capacitance
MAIN OUTPUT
Voltage Range
Minimum Output Voltage
Maximum Output Voltage
3
General Limit
Available Output Current
Response Time
Residual RF (at 2f )
INVERTED OUTPUT
Gain Referred to V_UP
Minimum Output Voltage
Maximum Output Voltage
Available Output Current
Output-Referred Noise
Response Time
Full-Scale Settling Time
SETPOINT INPUT
Voltage Range
Input Resistance
Logarithmic Scale Factor
ENABLE INTERFACE
Logic Level to Enable Power
Input Current when HI
Logic Level to Disable Power
POWER INTERFACE
Supply Voltage
Quiescent Current
Overtemperature
Total Supply Current when Disabled
Overtemperature
1
2
Conditions
To meet all specifications
Internally ac-coupled
52.3 Ω external termination
Main output, V_UP, 100 MHz
2
Main output, V_UP, 100 MHz
52.3 Ω external termination
Pin RFIN
f = 0.1 GHz
f = 0.1 GHz
Pin V_UP
V_UP connected to VSET
No signal at RFIN, R
L
≥ 10 kΩ
R
L
≥ 10 kΩ
2.7 V ≤ V
S
≤ 5.5 V
Sourcing/sinking
10% to 90%, 10 dB step
f = 0.1 GHz (worst condition)
Pin V_DN
V
DN
= 2.25 V − 2 × V
UP
V
S
≥ 3.3 V
V
S
≥ 3.3 V
4
Sourcing/sinking
RF input = 2 GHz, –33 dBV, f
NOISE
= 10 kHz
10% to 90%, 10 dB input step
−40 dBm to 0 dBm input step to 95%
Pin VSET
Corresponding to central 40 dB
f = 0.900 GHz
f = 1.900 GHz
Pin ENBL
HI condition, −40°C ≤ T
A
≤ +85°C
2.7 V at ENBL, −40°C ≤ T
A
≤ +85°C
LO condition, −40°C ≤ T
A
≤ +85°C
Pin VPOS
Min
0.1
1.25
−45
18.85
−68
−55
Typ
Max
2.5
224
0
23.35
−56
−43
Unit
GHz
mV rms
dBm
mV/dB
dBV
dBm
kΩ
kΩ
pF
21.3
−62
−49
100
3
2
0.01
0.01
1.9
V
S
− 1.1
1/0.5
0.02
2
V
S
− 1
2/1
70
100
−2
0.05
2.2
6/200
1.05
70
150
1.2
0.05
V
V
V
V
mA
ns
μV
0.01
2.1
4/100
0.1
2.5
V
V
mA/μA
μV/√Hz
ns
ns
V
kΩ
mV/dB
mV/dB
V
μA
V
V
mA
mA
μA
μA
0.15
7
1.2
10
20.7
19.7
V
POS
300
+0.8
5.5
5.7
6.6
95
1.6
20
−0.5
2.7
3.0
2.7
3.0
4.5
4.4
20
40
−40°C ≤ T
A
≤ +85°C
−40°C ≤ T
A
≤ +85°C
For a discussion on operation at higher frequencies, see Applications section.
Mean and standard deviation specifications are available in Table 4.
3
Increased output possible when using an attenuator between V_UP and VSET to raise the slope.
4
Refer to Figure 22 for details.
Rev. B | Page 3 of 20
AD8314
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltage VPOS
V_UP, V_DN, VSET, ENBL
Input Voltage
Equivalent Power
Internal Power Dissipation
θ
JA
(MSOP)
θ
JA
(LFCSP, Paddle Soldered)
θ
JA
(LFCSP, Paddle Not Soldered)
Maximum Junction Temperature
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering 60 sec)
8-Lead MSOP
8-Lead LFCSP
Value
5.5 V
0 V, VPOS
1.6 V rms
17 dBm
200 mW
200°C/W
80°C/W
200°C/W
125°C
−40°C to +85°C
−65°C to +150°C
300°C
240°C
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.
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. B | Page 4 of 20
AD8314
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
RFIN
1
ENBL
2
VSET
3
FLTR
4
8
AD8314
TOP VIEW
(Not to Scale)
VPOS
V_DN
COMM
01086-002
7
6
5
V_UP
Figure 2. RM-8 Pin Configuration
RFIN 1
ENBL 2
VSET 3
FLTR 4
8 VPOS
AD8314
TOP VIEW
(Not to Scale)
7 V_DN
5 V_UP
5 COMM
01086-003
Figure 3. CP-8-1 Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
Mnemonic
RFIN
ENBL
VSET
FLTR
COMM
V_UP
V_DN
VPOS
Description
RF Input.
Connect Pin to V
S
for Normal Operation. Connect pin to ground for disable mode.
Setpoint Input for Operation in Controller Mode. To operate in detector mode connect VSET to V_UP.
Connection for an External Capacitor to Slow the Response of the Output. Capacitor is connected between
FLTR and V_UP.
Device Common (Ground)
Logarithmic Output. Output voltage increases with increasing input amplitude.
Inversion of V_UP, Governed by: V_DN = 2.25 V − 2 × V
UP
.
Positive Supply Voltage (V
S
), 2.7 V to 5.5 V.
Rev. B | Page 5 of 20
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