Simple Driving Capacitive Loads Circuit

This is a simple circuit design for capacitive load driver. This circuit is built by LF155. LF155 is an op amps that is feature low input bias and offset currents/low offset voltage and offset voltage drift, coupled with offset adjust which does not degrade drift or common-mode rejection. This is the figure of the circuit.


This figure in above is the circuit for drive capacitive loads. For make this circuit, we need resistor 5K if we used this op amps. This is due to a unique output stage design, these amplifiers have the ability to drive large capacitive loads and still maintain stability. CL(MAX) 0.01μF. This circuit has overshoot ≤ 20%. [Circuit source: National Semiconductor, Inc]

Simple Video Line Driver Circuit

This is a simple design schematic for video line driver. This circuit is based on IC LT1206 that is suitable for driving multiple video cables since it has 60MHz bandwidth, 250mA output current capability, and low output impedance. Please keep in mind about un-terminated line effect when driving multiple cables. A reflected wave would propagate back to the driver cause a crosstalk to other lines since the driver output is non-zero impedance. This is the figure of the circuit.


The schematic diagram shows the LT1206 connected as a distribution amplifier. To minimize the effect of reflection, each line is separately terminated. Differential gain and phase performance are also important and have been considered in the internal design of the device, especially useful if the signal is video composite. Note that at 5MHz the output impedance of LT1206 is only 0.6W, much smaller than the terminating resistor separators. [Schematic diagram source: Linear Technology Application Notes]