AD8310 Fast, Voltage-Out, DC to 440 MHz, 95 dB Logarithmic Amplifier

Each of the six cascaded amplifier/limiter cells has a small-signal gain of 14.3 dB, with a −3 dB bandwidth of 900 MHz. A total of nine detector cells are used to provide a dynamic range that extends from −91 dBV (where 0 dBV is defined as the amplitude of a 1 V rms sine wave), an amplitude of about ±40 μV, up to +4 dBV (or ±2.2 V). The demodulated output is accurately scaled, with a log slope of 24 mV/dB and an intercept of −108 dBV. The scaling parameters are supply- and temperature-independent. The fully differential input offers a moderately high impedance (1 kΩ in parallel with about 1 pF). A simple network can match the input to 50 Ω and provide a power sensitivity of −78 dBm to +17 dBm. The logarithmic linearity is typically within ±0.4 dB up to 100 MHz over the central portion of the range, but it is somewhat greater at 440 MHz. There is no minimum frequency limit; the AD8310 can be used down to low audio frequencies. Special filtering features are provided to support this wide range. The output voltage runs from a noise-limited lower boundary of 400 mV to an upper limit within 200 mV of the supply voltage for light loads. The slope and intercept can be readily altered using external resistors. The output is tolerant of a wide variety of load conditions and is stable with capacitive loads of 100 pF. The AD8310 provides a unique combination of low cost, small size, low power consumption, high accuracy and stability, high dynamic range, a frequency range encompassing audio to UHF, fast response time, and good load-driving capabilities, making this product useful in numerous applications that require the reduction of a signal to its decibel equivalent. The AD8310 is available in the industrial temperature range of −40°C to +85°C in an 8-lead MSOP package. Applications Conversion of signal level to decibel form Transmitter antenna power measurement Receiver signal strength indication (RSSI) Low cost radar and sonar signal processing Network and spectrum analyzers Signal-level determination down to 20 Hz True-decibel ac mode for multimeters

The AD8310 is a complete, dc to 440 MHz demodulating logarithmic amplifier (log amp) with a very fast voltage mode output, capable of driving up to 25 mA into a grounded load in under 15 ns. It uses the progressive compression (successive detection) technique to provide a dynamic range of up to 95 dB to ±3 dB law conformance or 90 dB to a ±1 dB error bound up to 100 MHz. It is extremely stable and easy to use, requiring no significant external components. A single-supply voltage of 2.7 V to 5.5 V at 8 mA is needed, corresponding to a power consumption of only 24 mW at 3 V. A fast-acting CMOS-compatible enable pin is provided.

Each of the six cascaded amplifier/limiter cells has a small-signal gain of 14.3 dB, with a −3 dB bandwidth of 900 MHz. A total of nine detector cells are used to provide a dynamic range that extends from −91 dBV (where 0 dBV is defined as the amplitude of a 1 V rms sine wave), an amplitude of about ±40 μV, up to +4 dBV (or ±2.2 V). The demodulated output is accurately scaled, with a log slope of 24 mV/dB and an intercept of −108 dBV. The scaling parameters are supply- and temperature-independent.

The fully differential input offers a moderately high impedance (1 kΩ in parallel with about 1 pF). A simple network can match the input to 50 Ω and provide a power sensitivity of −78 dBm to +17 dBm. The logarithmic linearity is typically within ±0.4 dB up to 100 MHz over the central portion of the range, but it is somewhat greater at 440 MHz. There is no minimum frequency limit; the AD8310 can be used down to low audio frequencies. Special filtering features are provided to support this wide range.

The output voltage runs from a noise-limited lower boundary of 400 mV to an upper limit within 200 mV of the supply voltage for light loads. The slope and intercept can be readily altered using external resistors. The output is tolerant of a wide variety of load conditions and is stable with capacitive loads of 100 pF.

The AD8310 provides a unique combination of low cost, small size, low power consumption, high accuracy and stability, high dynamic range, a frequency range encompassing audio to UHF, fast response time, and good load-driving capabilities, making this product useful in numerous applications that require the reduction of a signal to its decibel equivalent.

The AD8310 is available in the industrial temperature range of −40°C to +85°C in an 8-lead MSOP package.

Applications
  • Conversion of signal level to decibel form
  • Transmitter antenna power measurement
  • Receiver signal strength indication (RSSI)
  • Low cost radar and sonar signal processing
  • Network and spectrum analyzers
  • Signal-level determination down to 20 Hz
  • True-decibel ac mode for multimeters
Features and Benefits
  • Multistage demodulating logarithmic amplifier
  • Voltage output, rise time <15 ns
  • High current capacity: 25 mA into grounded RL
  • 95 dB dynamic range: –91 dBV to +4 dBV
  • Single supply of 2.7 V min at 8 mA typ
  • DC to 440 MHz operation, ±0.4 dB linearity
  • Slope of +24 mV/dB, intercept of –108 dBV
  • Highly stable scaling over temperature
  • Fully differential dc-coupled signal path
  • 100 ns power-up time, 1 mA sleep current
  • RF & Microwave
    SPICE Models
    Data Sheets
    Documentnote
    AD8310: Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier Data Sheet (Rev. F)PDF 524 kB
    Application Notes
    Documentnote
    AN-1040: RF Power Calibration Improves Performance of Wireless Transmitters (Rev. 0)PDF 152 kB
    AN-691: Operation of RF Detector Products at Low Frequency (Rev. 0)PDF 778 kB
    Frequently Asked Questions
    Documentnote
    What is an RF Detector, and how is it used?PDF 344.98 K
    Product Highlight
    Documentnote
    Order Information
    Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
    AD8310ACHIPS ProductionCHIPS OR DIEREEL 45625C75.75Y
    AD8310ARM Production8 ld MSOPOTH 50-40 to 85C5.84.62N
    AD8310ARM-REEL7 Production8 ld MSOPREEL 1000-40 to 85C04.62N
    AD8310ARMZ Production8 ld MSOPOTH 50-40 to 85C5.014Y
    AD8310ARMZ-REEL7 Production8 ld MSOPREEL 1000-40 to 85C04Y
    Evaluation Boards
    Part NumberDescriptionPriceRoHS
    AD8310-EVALZEvaluation Board100.19Y
    Reference Materials
    AD8310: Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier Data Sheet (Rev F, 06/2010) AD8310
    AD8310 SPICE Model ad8310
    AD8310 Sub Circuit ad8310
    AD8310: Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier Data Sheet (Rev. F) ad8310
    AN-1040: RF Power Calibration Improves Performance of Wireless Transmitters (Rev. 0) ad8307
    AN-691: RF检波器的低频工作特性 (Rev. 0) ad8307
    AN-1040: RF功率校准提高无线发射机的性能 (Rev. 0) ad8307
    AN-691: Operation of RF Detector Products at Low Frequency (Rev. 0) ad8307
    What is an RF Detector, and how is it used? ad8310
    Design and Operation of Automatic Gain Control Loops for Receivers in Modern... ad8369
    RF Source Booklet adf9010
    Measurement and Control of RF Power, Part I ad640
    Measurement and Control of RF Power, Part II ad640
    Measurement and Control of RF Power, Part III ad640
    Log Amps and Directional Couplers Enable VSWR Detection ad640
    Measuring VSWR and Gain in Wireless Systems ad640
    Measuring the RF Power in CDMA2000 and W-CDMA High Power Amplifiers (HPAs) ad640
    Detecting Fast RF Bursts using Log Amps ad640
    Make Precise Base-Station Power Measurements ad640
    Design a Logamp RF Pulse Detector ad640