IC LOGARTIHMIC AMP 70DB 8-MSOP

AD8313ARM

Manufacturer Part NumberAD8313ARM
DescriptionIC LOGARTIHMIC AMP 70DB 8-MSOP
ManufacturerAnalog Devices Inc
TypeLogarithmic Amp
AD8313ARM datasheet
 


Specifications of AD8313ARM

Rohs StatusRoHS non-compliantFrequency100MHz ~ 2.5GHz
Rf TypeRADAR, 802.11/Wi-Fi, 8.2.16/WiMax, Wireless LANInput Range-65dBm ~ 0dBm
Accuracy±1dBVoltage - Supply2.7 V ~ 5.5 V
Current - Supply13.7mAPackage / Case8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Number Of Channels1Number Of Elements8
Power Supply RequirementSingleVoltage Gain Db84dB
Input Resistance0.0009@5VMohmInput Bias Current10@5VnA
Single Supply Voltage (typ)3/5VDual Supply Voltage (typ)Not RequiredV
Power Dissipation200mWRail/rail I/o TypeRail to Rail Output
Single Supply Voltage (min)2.7VSingle Supply Voltage (max)5.5V
Dual Supply Voltage (min)Not RequiredVDual Supply Voltage (max)Not RequiredV
Operating Temp Range-40C to 85COperating Temperature ClassificationIndustrial
MountingSurface MountPin Count8
Package TypeMSOP  
1
Page 1
2
Page 2
3
Page 3
4
Page 4
5
Page 5
6
Page 6
7
Page 7
8
Page 8
9
Page 9
10
Page 10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Page 1/24

Download datasheet (716Kb)Embed
Next
FEATURES
Wide bandwidth: 0.1 GHz to 2.5 GHz min
High dynamic range: 70 dB to ±3.0 dB
High accuracy: ±1.0 dB over 65 dB range (@ 1.9 GHz)
Fast response: 40 ns full-scale typical
Controller mode with error output
Scaling stable over supply and temperature
Wide supply range: 2.7 V to 5.5 V
Low power: 40 mW at 3 V
Power-down feature: 60 mW at 3 V
Complete and easy to use
APPLICATIONS
RF transmitter power amplifier setpoint control and
level monitoring
Logarithmic amplifier for RSSI measurement cellular
base stations, radio link, radar
GENERAL DESCRIPTION
The AD8313 is a complete multistage demodulating logarithmic
amplifier that can accurately convert an RF signal at its differ-
ential input to an equivalent decibel-scaled value at its dc output.
The AD8313 maintains a high degree of log conformance for
signal frequencies from 0.1 GHz to 2.5 GHz and is useful over
the range of 10 MHz to 3.5 GHz. The nominal input dynamic
range is –65 dBm to 0 dBm (re: 50 Ω), and the sensitivity can be
increased by 6 dB or more with a narrow-band input impedance
matching network or a balun. Application is straightforward,
requiring only a single supply of 2.7 V to 5.5 V and the addition
of a suitable input and supply decoupling. Operating on a 3 V
supply, its 13.7 mA consumption (for T
A power-down feature is provided; the input is taken high to
initiate a low current (20 µA) sleep mode, with a threshold at
half the supply voltage.
The AD8313 uses a cascade of eight amplifier/limiter cells, each
having a nominal gain of 8 dB and a −3 dB bandwidth of
3.5 GHz. This produces a total midband gain of 64 dB. At each
amplifier output, a detector (rectifier) cell is used to convert the
RF signal to baseband form; a ninth detector cell is placed
directly at the input of the AD8313. The current-mode outputs
of these cells are summed to generate a piecewise linear approxi-
mation to the logarithmic function. They are converted to a low
impedance voltage-mode output by a transresistance stage, which
also acts as a low-pass filter.
Rev. D
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.
Logarithmic Detector/Controller
VPOS
INHI
INLO
VPOS
When used as a log amplifier, scaling is determined by a separate
feedback interface (a transconductance stage) that sets the slope
to approximately 18 mV/dB; used as a controller, this stage
accepts the setpoint input. The logarithmic intercept is positioned
to nearly −100 dBm, and the output runs from about 0.45 V dc
at −73 dBm input to 1.75 V dc at 0 dBm input. The scale and
intercept are supply- and temperature-stable.
The AD8313 is fabricated on Analog Devices’ advanced 25 GHz
silicon bipolar IC process and is available in an 8-lead MSOP
package. The operating temperature range is −40°C to +85°C.
An evaluation board is available.
= 25°C) is only 41 mW.
2.0
A
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
Figure 2. Typical Logarithmic Response and Error vs. Input Amplitude
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
0.1 GHz to 2.5 GHz 70 dB
FUNCTIONAL BLOCK DIAGRAM
NINE DETECTOR CELLS
+
+
+
+
+
1
2
LP
8dB
8dB
8dB
8dB
3
EIGHT 8dB 3.5GHz AMPLIFIER STAGES
INTERCEPT
AD8313
CONTROL
4
BAND GAP
SLOPE
GAIN
CONTROL
REFERENCE
BIAS
Figure 1.
FREQUENCY = 1.9GHz
0
–80
–70
–60
–50
–40
–30
–20
INPUT AMPLITUDE (dBm)
© 2004 Analog Devices, Inc. All rights reserved.
AD8313
I→V
VOUT
8
C
INT
V→I
7
VSET
6
COMM
5
PWDN
5
4
3
2
1
0
–1
–2
–3
– 4
–5
0
–10
www.analog.com

AD8313ARM Summary of contents

  • Page 1

    FEATURES Wide bandwidth: 0.1 GHz to 2.5 GHz min High dynamic range ±3.0 dB High accuracy: ±1.0 dB over 65 dB range (@ 1.9 GHz) Fast response full-scale typical Controller mode with error output Scaling ...

  • Page 2

    AD8313 TABLE OF CONTENTS Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 6 ESD Caution.................................................................................. 6 Pin Configurations and Function Description............................. 7 Typical Performance Characteristics ............................................. 8 Circuit Description......................................................................... 11 Interfaces.......................................................................................... 13 Power-Down Interface, PWDN................................................ 13 Signal Inputs, INHI, INLO ........................................................ 13 Logarithmic/Error ...

  • Page 3

    SPECIFICATIONS  kΩ, unless otherwise noted 25° Table 1. Parameter Conditions SIGNAL INPUT INTERFACE Specified Frequency Range DC Common-Mode Voltage Input Bias Currents Input Impedance f ...

  • Page 4

    AD8313 Parameter Conditions 7 2.5 GHz Nominal conditions ±3 dB Dynamic Range Range Center ±1 dB Dynamic Range Slope Intercept 2.7 V ≤ V ±3 dB Dynamic Range Range Center ±1 dB Dynamic Range Slope Intercept Temperature Sensitivity P IN ...

  • Page 5

    Except where otherwise noted; performance Minimum and maximum specified limits on parameters that are guaranteed but not tested are 6 sigma values. 3 Input impedance shown over frequency range in Figure 26. 4 Double vertical bars ...

  • Page 6

    AD8313 ABSOLUTE MAXIMUM RATINGS Table 2. Supply Voltage V S VOUT, VSET, PWDN Input Power Differential (re: 50 Ω, 5.5 V) Input Power Single-Ended (re: 50 Ω, 5.5 V) Internal Power Dissipation θ JA Maximum Junction Temperature Operating Temperature Range ...

  • Page 7

    PIN CONFIGURATIONS AND FUNCTION DESCRIPTION Table 3. Pin Function Descriptions Pin No. Mnemonic Description 1, 4 VPOS Positive Supply Voltage (VPOS INHI Noninverting Input. This input should be ac-coupled. 3 INLO Inverting Input. This ...

  • Page 8

    AD8313 TYPICAL PERFORMANCE CHARACTERISTICS T = 25° input match shown in Figure 29, unless otherwise noted 2.0 1.8 1.6 1.4 1.2 1.9GHz 1.0 2.5GHz 0.8 0.6 0.4 900MHz 0.2 0 –70 –60 ...

  • Page 9

    FREQUENCY (MHz) Figure 10. V Slope vs. Frequency for Multiple Temperatures OUT 24 23 SPECIFIED OPERATING RANGE 22 21 2.5GHz 20 100MHz 19 900MHz 18 1.9GHz ...

  • Page 10

    AD8313 100.00 13.7mA 10.00 1. +3V V POS POS 0.10 0. PWDN VOLTAGE (V) Figure 16. Typical Supply Current vs. PWDN Voltage CH. 1 AND CH. 2: 1V/DIV CH. 1 GND CH. 2 GND ...

  • Page 11

    CIRCUIT DESCRIPTION The AD8313 is an 8-stage logarithmic amplifier, specifically designed for use in RF measurement and power amplifier control applications at frequencies up to 2.5 GHz. A block diagram is shown in Figure 22. For a detailed description of ...

  • Page 12

    AD8313 With Pins 7 and 8 connected (log amp mode), the output can be stated 100 dBm ) OUT SLOPE IN where P is the input power stated in dBm when the source ...

  • Page 13

    INTERFACES This section describes the signal and control interfaces and their behavior. On-chip resistances and capacitances exhibit variations ±20%. These resistances are sometimes temperature-dependent, and the capacitances may be voltage- dependent. POWER-DOWN INTERFACE, PWDN The power-down threshold ...

  • Page 14

    AD8313 SETPOINT INTERFACE, VSET The setpoint interface is shown in Figure 28. The voltage, V divided by a factor resistive attenuator of 18 kΩ total resistance. The signal is converted to a current by the action ...

  • Page 15

    APPLICATIONS BASIC CONNECTIONS FOR LOG (RSSI) MODE Figure 29 shows the AD8313 connected in its basic measurement mode. A power supply between 2.7 V and 5 required. The power supply to each of the VPOS pins should be ...

  • Page 16

    AD8313 INPUT COUPLING The signal can be coupled to the AD8313 in a variety of ways. In all cases, there must not path from the input pins to ground. Some of the possibilities include dual-input coupling capacitors, ...

  • Page 17

    SOURCE C1 50Ω L MATCH C2 Figure 35. Narrow-Band Reactive Match Typically, the AD8313 needs to be matched to 50 Ω. The input impedance of the AD8313 at 100 MHz can be read from the Smith chart (Figure 26) ...

  • Page 18

    AD8313 As previously discussed, a modification of the board layout produces networks that may not perform as specified. At 2.5 GHz, a shunt inductor is sufficient to achieve proper matching. Con- sequently, C1 and C2 are set sufficiently high that ...

  • Page 19

    INCREASING OUTPUT CURRENT To drive a more substantial load, either a pull-up resistor or an emitter-follower can be used. In Figure 40 kΩ pull-up resistor is added at the output, which provides the load current necessary to drive ...

  • Page 20

    AD8313 EVALUATION BOARD SCHEMATIC AND LAYOUT Figure 44 shows the schematic of the AD8313 evaluation board. Note that uninstalled components are indicated as open. This board contains the AD8313 as well as the AD8009 current- feedback operational amplifier. This is ...

  • Page 21

    Figure 42. Layout of Signal Layer Figure 43. Signal Layer Silkscreen Rev Page AD8313 ...

  • Page 22

    AD8313 R1 10Ω V PS1 C1 680pF INHI C2 680pF INLO R9 0Ω R2 10Ω R2 10Ω V PS1 Table 7. Evaluation Board Configuration Options Component Function VPS1, VPS2, Supply Pins. VPS1 is the positive supply pin for the AD8313. ...

  • Page 23

    TRACE WIDTH 15 UNIT = MILS 27 Figure 45. Detail of PCB Footprint for Package and Pads for Matching Network 54.4 90 91.3 126 ...

  • Page 24

    ... AD8313ARM-REEL7 −40°C to +85°C 1 AD8313ARMZ −40°C to +85°C 1 AD8313ARMZ-REEL7 −40°C to +85°C AD8313-EVAL Pb-free part. © 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 3.00 ...