Hi All,
I built a full wave rectifier using a AD8036, based on the diagram from the spec sheet of AD8036/AD8037. I made a nice PCB, I used for decoupling the 100nF capacitors and 10uF/25V tantalum caps. I used a sinewave signal generator and tested with various frequencies from 1kHz to approx 100kHz. Checking with the oscilloscope on the input/output, I noticed the input gets a DC offset, while the output is strongly assimetrical for the two halfs of the rectified sinewave. Eventually I got some decent output by placing a 100ohm resistor between input to ground and changing RG (resistor between Input and pin2 of IC) from 274ohm to 200ohm. You can check image AD8036_FWR1.jpg.
When I used the original circuit, as described in the spec sheet, the rectified output looked like in AD8036_FWR2.jpg.
I tried connecting my sinewave generator through a 100nF capacitor, just to make sure the offset is not from my generator and the waveform still remained bad. The IC is new (I tried two) and the resistors are 100ohm, 271ohm and 272ohm (instead of 274ohm).
So how should my setup be in order to get the expected results from the schematic published? I expect the diagram to work with AD8036 as well, not only with AD8037.
Regards,
Nicolae
I built a full wave rectifier using a AD8036, based on the diagram from the spec sheet of AD8036/AD8037. I made a nice PCB, I used for decoupling the 100nF capacitors and 10uF/25V tantalum caps. I used a sinewave signal generator and tested with various frequencies from 1kHz to approx 100kHz. Checking with the oscilloscope on the input/output, I noticed the input gets a DC offset, while the output is strongly assimetrical for the two halfs of the rectified sinewave. Eventually I got some decent output by placing a 100ohm resistor between input to ground and changing RG (resistor between Input and pin2 of IC) from 274ohm to 200ohm. You can check image AD8036_FWR1.jpg.
When I used the original circuit, as described in the spec sheet, the rectified output looked like in AD8036_FWR2.jpg.
I tried connecting my sinewave generator through a 100nF capacitor, just to make sure the offset is not from my generator and the waveform still remained bad. The IC is new (I tried two) and the resistors are 100ohm, 271ohm and 272ohm (instead of 274ohm).
So how should my setup be in order to get the expected results from the schematic published? I expect the diagram to work with AD8036 as well, not only with AD8037.
Regards,
Nicolae
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