AD8307 Analog Devices, AD8307 Datasheet
AD8307
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AD8307 Summary of contents
Page 1
... COMPENSATION LOOP Figure 1. only slightly at 500 MHz. There is no minimum frequency limit. The AD8307 can be used at audio frequencies lower. The output is a voltage scaled 25 mV/dB, generated by a current of nominally 2 μA/dB through an internal 12.5 kΩ r esistor. This voltage varies from 0. input of −74 dBm (that is, the ac intercept is at − ...
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... AD8307 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 4 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 Enable Interface ...
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... L AC-coupled input −3 dB AC-coupled input Either input (small signal) R ≤ 50 Ω SOURCE Drift Differential Either pin to ground Either input V ≥ ENB V ≤ ENB Rev Page AD8307 Min Typ Max Unit ±0.3 ±1 dB ±0 mV/ ...
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... Parameter Supply Input Voltage (Pin 1 and Pin 8) Storage Temperature Range Ambient Temperature Range, Rated Performance Industrial, AD8307AN, AD8307AR Lead Temperature Range (Soldering 10 sec) Stresses above those listed under Absolute Maximum Ratings can cause permanent damage to the device. This is a stress Ratings rating only ...
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... DC resistance from INP to INM = 1.1 kΩ. INM INP 1 8 VPS COM 2 AD8307 7 OFS ENB 3 TOP VIEW 6 (Not to Scale) OUT INT 4 5 Figure 2. Pin Configuration /2. POS = 12.5 kΩ. OUT /2. Due to the symmetrical nature of the response, there is no special POS Rev Page AD8307 ...
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... AD8307 TYPICAL PERFORMANCE CHARACTERISTICS 1.0 1.1 1.2 1.3 1.4 1.5 1.6 V (V) ENB Figure 3. Supply Current vs. V ENB 1.0 1.1 1.2 1.3 1.4 1.5 1.6 V (V) ENB Figure 4. Supply Current vs. V ENB 3 2 FREQUENCY INPUT = 300MHz 1 0 –1 FREQUENCY INPUT = 100MHz –2 –3 –80 –60 –40 –20 INPUT LEVEL (dBm) Figure 5 ...
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... INPUT LEVEL (dBm) Input Driven Differentially Using Transformer 3 2 500MHz 1 0 100MHz –1 10MHz –2 –3 –70 –60 –50 –40 –30 –20 –10 INPUT LEVEL (dBm) Figure 14. Log Conformance vs. Input Level Supply Using AD820 as Buffer, Gain = +2 AD8307 100MHz ...
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... SIGNAL PULSE MODE IN OUT PULSE GENERATOR PULSE VPS = 5.0V MODE 0.1µF 1nF INP VPS ENB INT 52.3Ω AD8307 INM COM OFS OUT TEK744A SCOPE TEK P6204 1nF FET PROBE CONNECT Figure 20. Test Setup for V Pulse Response OUT V ...
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... AD8307. While Equation 1 is fundamentally correct, a simpler formula is appropriate for specifying the calibration attributes of a log amp like the AD8307, which demodulates a sine wave input: where: LOG V IN ...
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... X Figure 22. Cascade of Nonlinear Gain Cells To develop the theory, first consider a scheme slightly different from that employed in the AD8307, but simpler to explain and mathematically more straightforward to analyze. This approach is based on a nonlinear amplifier unit, called an A/1 cell, with the transfer characteristic shown in Figure 23. ...
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... V Preference for the A/0 style of log amp, over one using A/1 cells, (5) stems from several considerations. The first is that an A/0 cell can be very simple. In the AD8307 it is based on a bipolar transistor differential pair, having resistive loads, R emitter current source, I voltage of E The large signal transfer function is the hyperbolic tangent (see dotted line in Figure 25) ...
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... The intercept can likewise be specified in dBm. For the AD8307 positioned at −84 dBm, corresponding to a sine amplitude of 20 μ important to bear in mind that log amps do not respond to power, but to the voltage applied to their input ...
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... With care in design, the extension to the dynamic range can be seamless over the full frequency range. For the AD8307, it amounts to a further 27 dB. Therefore, the total dynamic range is theoretically 113 dB. The specified range (−74 dBm to +16 dBm) is for high ...
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... Pin 6 is taken under worst- case conditions. Left unconnected voltage below 1 V, the AD8307 is disabled and consume a sleep current of under 50 μA; tied to the supply voltage above fully enabled. The internal bias circuitry is very fast, typically <100 ns for either off or on ...
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... Pin 1 or Pin 8, with the other pin ac-coupled to ground. Under these conditions, the largest input signal that can be handled by the AD8307 is 10 dBm (sine amplitude of ±1 V) when operating from supply; 16 dBm can be handled using supply. The full 16 dBm can be achieved for supplies down to 2 ...
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... Note that while the AD8307 can operate down to supply voltages of 2.7 V, the output voltage limit is reduced when the supply drops below 4 V. This characteristic is the result of necessary headroom requirements, approximately two V drops, in the design of the output stage ...
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... THEORY OF OPERATION The AD8307 has very high gain and a bandwidth from dc to over 1 GHz, at which frequency the gain of the main path is still over 60 dB. Consequently susceptible to all signals within this very broad frequency range that find their way to the input terminals ...
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... The unequal capacitor values were chosen to provide a well balanced differential drive, and to allow better centering of the frequency response peak when using standard value components; this generally results full AD8307 HF input impedance and the inductor losses are included in the modeling. C1 (pF) C2 (pF) ...
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... The log intercept is adjustable over a ±3 dB range, which is sufficient to absorb the worst-case intercept error in the AD8307, plus some system level errors. For greater range, set R to zero. VR2 is adjusted while applying an accurately known CW signal near the lower end of the dynamic range in order to minimize the effect of any residual uncertainty in the slope. For example, to position the intercept to − ...
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... The residual ripple (±0.02 dB) when the input to the AD8307 Hz. This filter can easily be adapted to other frequencies by proportional scaling (for example, for 100 kHz use 100 pF) ...
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... Now, if the gain control voltage for the X-AMP is derived from the output of the AD8307, the effect is to raise the gain of this front- end stage when the signal is small and lower it when it is large, but without altering the fundamental logarithmic nature of the response ...
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... HF short circuit at the input. This significantly lowers the wideband noise; the noise reduction is about 2 dB compared to when the AD8307 is driven from a 50 Ω source. Ensure that the output is free of post- demodulation ripple by lowering the low-pass filter time constant. ...
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... Figure 47 shows a plot of the logarithmic output of the AD8307 for an input frequency of 900 MHz. The device shows good logarithmic conformance from −50 dBm to −10 dBm. There is a bump in the transfer function at −5 dBm, but if this is acceptable, the device is usable over dynamic range (− ...
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... AD8307ANZ 1 −40°C to +85°C AD8307AR −40°C to +85°C AD8307AR-REEL −40°C to +85°C AD8307AR-REEL7 −40°C to +85°C 1 AD8307ARZ −40°C to +85°C 1 AD8307ARZ-REEL −40°C to +85°C 1 AD8307ARZ-RL7 −40°C to +85° Pb-free part. ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners ...