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AD8318:  1 MHz TO 8 GHz, 70 dB Logarithmic Detector / Controller

Product Details

Product Status:Recommended for New Designs

The AD8318 is a demodulating logarithmic amplifier, capable of accurately converting an RF input signal to a corresponding decibel-scaled output voltage. It employs the progressive compression technique over a cascaded amplifier chain, each stage of which is equipped with a detector cell. The device is used in measurement or controller mode. The AD8318 maintains accurate log conformance for signals of 1 MHz to 6 GHz and provides useful operation to 8 GHz. The input range is typically 60 dB (re: 50 Ω) with error less than ±1 dB. The AD8318 has a 10 ns response time that enables RF burst detection to beyond 45 MHz. The device provides unprecedented logarithmic intercept stability vs. ambient temperature conditions. A 2 mV/°C slope temperature sensor output is also provided for additional system monitoring. A single supply of 5 V is required. Current consumption is typically 68 mA. Power consumption decreases to <1.5 mW when the device is disabled.

The AD8318 can be configured to provide a control voltage to a VGA, such as a power amplifier or a measurement output, from Pin VOUT. Because the output can be used for controller applications, wideband noise is minimal. In this mode, the setpoint control voltage is applied to VSET. The feedback loop through an RF amplifier is closed via VOUT, the output of which regulates the amplifier output to a magnitude corresponding to VSET. The AD8318 provides 0 V to 4.9 V output capability at the VOUT pin, suitable for controller applications. As a measurement device, Pin VOUT is externally connected to VSET to produce an output voltage, VOUT, which is a decreasing linear-in-dB function of the RF input signal amplitude.

The logarithmic slope is nominally −25 mV/dB but can be adjusted by scaling the feedback voltage from VOUT to the VSET interface. The intercept is 20 dBm (re: 50 Ω, CW input) using the INHI input. These parameters are very stable against supply and temperature variations.

The AD8318 is fabricated on a SiGe bipolar IC process and is available in a 4 mm × 4 mm, 16-lead LFCSP for the operating temperature range of –40°C to +85°C.

Applications

  • RF transmitter PA setpoint control and level monitoring
  • RSSI measurement in base stations, WLAN, WiMAX, and radars

FEATURES and BENEFITS

  • Wide bandwidth:
    1 MHz to 8 GHz
  • High accuracy: ±1.0 dB over 55 dB range (f < 5.8 GHz)
  • Stability over temperature: ±0.5 dB
  • Low noise measurement/controller
    output (VOUT)
  • Pulse response time:
    10 ns/12 ns (fall/rise)
  • Integrated temperature sensor
  • Small footprint LFCSP
  • Power-down feature:
    <1.5 mW at 5 V
  • Single-supply operation:
    5 V @ 68 mA
  • Fabricated using high speed SiGe process
  • Supports defense and aerospace applications (AQEC standard)
    Download AD8318-EP Data Sheet (pdf)
  • V62/12665 DSCC Drawing Number

Functional Block Diagram for AD8318

Additional Qualifications

AD8318SCPZ-EP is qualified for EP (Enhanced Product).

Documentation

Title Content Type File Type
AD8318: 1 MHz to 8 GHz, 70 dB Logarithmic Detector/Controller Data Sheet  (Rev B, 04/2007) (pdf, 2000 kB) Data Sheets PDF
AN-1040: RF Power Calibration Improves Performance of Wireless Transmitters  (pdf, 152 kB) Application Notes PDF
CN-0150: Software Calibrated, 1 MHz to 8 GHz, 70 dB RF Power Measurement System Using the AD8318 Logarithmic Detector  (pdf, 250 kB) Circuit Note PDF
CN-0050: Stable, Closed-Loop Automatic Power Control for RF Applications  (pdf, 232 kB) Circuit Note PDF
Measurement and Control of RF Power
by Eamon Nash, Analog Devices, Inc.
Technical Articles HTML
Detecting Fast RF Bursts using Log Amps  (pdf, 174 kB)
by Yuping Toh, Analog Devices, Inc.
Technical Articles PDF
Make Precise Base-Station Power Measurements  (pdf, 1764 kB)
(Microwaves and RF, November 2002)
Technical Articles PDF
Log Amps and Directional Couplers Enable VSWR Detection  (pdf, 2223 kB)
by Anil Rachakonda and Larry Hawkins, Analog Devices, Inc. (RF Design, 1/1/2007)
Technical Articles PDF
Measuring VSWR and Gain in Wireless Systems  (pdf)
By Eamon Nash, Analog Devices Inc., (Microwave Journal, Nov 2005)
Technical Articles PDF
Measuring the RF Power in CDMA2000 and W-CDMA High Power Amplifiers (HPAs)  (pdf, 609 kB)
By Larry Hawkins, Analog Devices, Inc. (MPD Digest, Nov. 2005)
Technical Articles PDF
Design a Logamp RF Pulse Detector  (pdf, 338 kB)
by Eamon Nash
(Microwaves & RF, January 1, 2000)
Technical Articles PDF
AD8318: Breakthrough IN RF Power Detection Up To 8 GHz  (htm)
(analogZONE, May 31,2004)
Product Reviews HTM
RF Source Booklet  (PDF, 4353 kB)
RF IC Product Overview - Version P (02/2014)
Overview PDF
Industrial Applications Overview HTML
We measure portable performance in µA and MHz. In handheld designs, analog is everywhere. Overview HTML
ICs for Enhanced Handset User Experience Overview HTML
RAQs index Rarely Asked Questions HTML
What is an RF Detector, and how is it used? FAQs/RAQs HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADIsimRF
ADI’s ADIsimRF design tool provides calculations for the most important parameters within the RF signal chain, including cascaded gain, noise figure, IP3, P1dB, and total power consumption.
ADIsim Design/Simulation Tools HTML
ADIsimPLL™- Version 3.43
ADIsimPLL enables the rapid and reliable evaluation of new high performance PLL products from ADI. It is the most comprehensive PLL Synthesizer design and simulation tool available today. Simulations performed include all key non-linear effects that are significant in affecting PLL performance. ADIsimPLL removes at least one iteration from the design process, thereby speeding the design- to-market.
ADIsim Design/Simulation Tools HTML
CN0150 FMC-SDP Interposer & Evaluation Board / Xilinx KC705 Reference Design FPGA HDL HTML
BeMicro FPGA Project for CN0150 with Nios driver FPGA HDL HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

Product Recommendations & Reference Designs

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Price, packaging, availability

AD8318 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD8318ACPZ-R2 Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Reel, 250 $6.06 $6.06 Y  Material Info PCN Purchase
AD8318ACPZ-REEL7 Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Reel, 1500 - $5.05 Y  Material Info PCN Purchase Sample
AD8318ACPZ-WP Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Tray, 64 $6.06 $6.06 Y  Material Info PCN Purchase
AD8318SCPZ-EP-R2 Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Reel, 250 - - Y  Material Info PCN Purchase
AD8318SCPZ-EP-RL7 Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Reel, 1500 - - Y  Material Info PCN Purchase
AD8318SCPZ-EP-WP Status: Production 16 ld LFCSP (4x4x.85mm, 2.10mm exposed pad) 16 Ind Tray, 64 - - Y  Material Info Notify Me Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

AD8318 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD8318-EVALZ Status: Production Evaluation Board $140.00 Yes -
AD8318-EP-EVALZ Status: Production Evaluation Board - Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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