- #1
iqjump123
- 61
- 0
Hello all,
I have been building a simple amplifier circuit(diagram attached) that will take in a source voltage and use a resistor divider to divide the voltage down on three different ratios, determined by a manual switch- 1/1, 1/4, and 1/40. It goes through a unity gain configuration through the AD622 (used ad623 on the spice diagram due to lack of availability)
instrumentation amplifier (1.2V/us slew rate and 1MHz bandwidth). I used this component because when I used the INA126 instrumentation amplifier, the low slew rate of the chip started to corrupt the output wave at high frequencies (~100kHz), displaying sharp sawtooth waves when input with an AC wave. I need signals that will give response up to 100khz or so.
However, the frequency response of the circuit reveals that the gain sharply drops from around 10000Hz to about half in 100000Hz range. The chip product itself advertises a 1MHz bandwidth at Gain of 1, but it is obviously not doing that- and the phase response is non linear. As shown in the attached circuit diagram, the chip is being powered on two batteries, which was opened new at the same time. Also, the gain setting is done by a manual switch.
All I need is a 1 gain amplifier, just as long as it can supply for me a noise-free high slew rate high bandwidth. This chip was exactly advertised to do so, yet it is not giving me the result (Tried it with different chip of the same kind).
The output of the circuit is being fed to a data acquisition card. Although advertised to be high impedance, is there a chance that the stray capacitance coming from the acquisition card be the issue? Not sure.
Any help on this matter will be appreciated.
thanks very much!
I have been building a simple amplifier circuit(diagram attached) that will take in a source voltage and use a resistor divider to divide the voltage down on three different ratios, determined by a manual switch- 1/1, 1/4, and 1/40. It goes through a unity gain configuration through the AD622 (used ad623 on the spice diagram due to lack of availability)
instrumentation amplifier (1.2V/us slew rate and 1MHz bandwidth). I used this component because when I used the INA126 instrumentation amplifier, the low slew rate of the chip started to corrupt the output wave at high frequencies (~100kHz), displaying sharp sawtooth waves when input with an AC wave. I need signals that will give response up to 100khz or so.
However, the frequency response of the circuit reveals that the gain sharply drops from around 10000Hz to about half in 100000Hz range. The chip product itself advertises a 1MHz bandwidth at Gain of 1, but it is obviously not doing that- and the phase response is non linear. As shown in the attached circuit diagram, the chip is being powered on two batteries, which was opened new at the same time. Also, the gain setting is done by a manual switch.
All I need is a 1 gain amplifier, just as long as it can supply for me a noise-free high slew rate high bandwidth. This chip was exactly advertised to do so, yet it is not giving me the result (Tried it with different chip of the same kind).
The output of the circuit is being fed to a data acquisition card. Although advertised to be high impedance, is there a chance that the stray capacitance coming from the acquisition card be the issue? Not sure.
Any help on this matter will be appreciated.
thanks very much!