Stabilized-capacitance-buffer


Posted on Mar 28, 2013

Ql and Q2 constitute a simple, high-speed FET input buffer. Ql functions as a source follower, with the Q2 current source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is required. Normally, this open-loop configuration would be quite drifty because there is no de feedback. The LTC1052 contributes this function to stabilize the circuit. It does this by comparing the filtered circuit output to a similarly filtered version of the input signal.


Stabilized-capacitance-buffer
Click here to download the full size of the above Circuit.

The amplified difference between these signals is used to set Q2"s bias, and hence Ql "s channel current. Ql "s source line ensures that the gate never forward biases, and the 2000 pF capacitor at Al provides stable loop compensation. The rc network in Al"s output prevents it from seeing high-speed edges coupled through Q2"s collector-base junction. A2"s output is also fed back to the shield around Ql"s gate lead, bootstrapping the circuit"s effective in_put capacitance down to less than 1 pF.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

RC transmitter with MC68HC711
Monostable photocell circuit
neon emergency light battery schematic
app note high voltage led applications
Schematic of a Breadboard Arduino
TWO QUADRANT
35W resistive and capacitive half-wave phase-shift trigger doer control circuit
Sensitive frequency demodulator LM565 LM111
Electronic circuit steady speed motor application



Top