AD8307

FEATURES
Complete multistage logarithmic amplifier 92 dB dynamic range: -75 dBm to +17 dBm to -90 dBm

using matching network Single supply 2.7 V minimum 7.5 mA typical to 500 MHz operation, ±1 dB linearity Slope of 25 mV/dB, intercept of -84 dBm Highly stable scaling over temperature Fully differential dc-coupled signal path 100 ns power-up time, 150 A sleep current

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 (to 120 dB) Signal level determination down 20 Hz True decibel ac mode for multimeters

The AD8307 is the first logarithmic amplifier made available an 8-lead SOIC_N package. is a complete 500 MHz monolithic demodulating logarithmic amplifier based on the progressive compression (successive detection) technique, providing a dynamic range ±3 dB law conformance and to a tight ±1 dB error bound at all frequencies to 100 MHz. The AD8307 is extremely stable and easy to use, requiring no significant external components. A single-supply voltage mA is needed. A fast acting CMOScompatible control pin can disable the to a standby current 150 A.

The AD8307 operates over the industrial temperature range to +85°C and is available an 8-lead SOIC package and an 8-lead PDIP.

NINE DETECTOR CELLS SPACED 14.3dB INPUT-OFFSET COMPENSATION LOOP
Lower Input Range (80 dB), Operation to 4 GHz, Higher Power Consumption
AD8309 Higher Input Range (100 dB), Limiter Output
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.
Tel: 781.329.4700 ©1997­2019 Analog Devices, Inc. All rights reserved.

ESD Caution : 4 Pin Configuration and Function Descriptions : 5 Typical Performance Characteristics : 6 Log Amp Theory : 9

Progressive Compression : 10 Demodulating Log Amps : 11 Intercept Calibration : 12 Offset Control : 12 Extension of Range : 13 Interfaces : 14

D to Rev. E Changes to General Description Section : 1 Added Table 1; Renumbered Sequentially : 1

C to Rev. D Deleted DC-Coupled Applications Section : 22 Deleted Operation Above 500 MHz Section : 23 Updated Outline Dimensions : 23

B to Rev. C Updated Format : Universal Changes to Table : 3 Changes to Table : 5 Changes to Offset Interface : 15 Changes to Output Interface : 15 Updated captions to Outline Dimensions : 24 Changes to Ordering Guide : 24

Enable Interface : 14 Input Interface : 14 Offset Interface : 15 Output Interface : 15 Theory of Operation : 17 Basic Connections : 17 Input Matching : 18 Narrow-Band Matching : 18 Slope and Intercept Adjustments : 19 Applications Information : 20 Buffered Output : 20 Four-Pole Filter kW 50 Power Meter : 21 Measurement System with 120 dB Dynamic Range : 21 Operation at Low Frequencies : 22 Outline Dimensions : 23 Ordering Guide : 24

A to Rev. B Renumbered TPCs and Figures : Universal Changes to Ordering Guide : 3 Changes to Figure : 17 Deleted Evaluation Board Information : 18 Updated Outline Dimensions : 19

SPECIFICATIONS
Input Range (±3 dB Error) Input Range (±1 dB Error) Logarithmic Conformance

vs. Temperature Input Noise Spectral Density Operating Noise Floor Output Resistance Internal Load Capacitance Response Time

Upper Usable Frequency Lower Usable Frequency AMPLIFIER CELL CHARACTERISTICS Cell Bandwidth Cell Gain INPUT CHARACTERISTICS DC Common-Mode Voltage Common-Mode Range DC Input Offset Voltage3

Incremental Input Resistance Input Capacitance Bias Current POWER INTERFACES Supply Voltage Supply Current Disabled

From noise floor to maximum input From noise floor to maximum input f 100 MHz, central = 500 MHz, central dB Unadjusted1

AC-coupled input Either input (small signal) RSOURCE 50 Drift Differential Either pin to ground Either input

1 This can be adjusted downward by adding a shunt resistor from the output to ground. 50 k resistor reduces the nominal slope to 20 mV/dB. 2 This can be adjusted in either direction by a voltage applied to Pin 5, with a scale factor of 8 dB/V. 3 Normally nulled automatically by internal offset correction loop and can be manually nulled by a voltage applied between Pin 3 and ground; see the Applications