Peer-to-peer, engineer-to-engineer questions and answers from the EDABoard.com engineering community around analog ICs and analog design. Click the “Read more” link and follow the entire conversation and maybe add your two cents by logging in to EDAboard.com.

Capacitor as a MOSFET in RC circuit – I have a resistor-capacitor circuit that I fitted with a MOSFET and want the MOSFET capacitor to phase shift. Unfortunately, as much as I could increase the amount of this capacitor by increasing the transistor w and l and parallelizing several transistors, I saw no phase difference. Read more

Average vs RMS load-current for LDO design – I am designing an LDO that will be used to power a small digital circuit. I have access to the said digital circuit and have been simulating my LDO with it. When designing my pass device to support maximum load current, which numbers should I use, average or RMS current? And why? Read more

Newbie question on dynamic mic circuit problems – I made a prototype for a dynamic mic amplifier on a transistor and LM386 which contains a transformer and 4 electrolytic capacitors (and some others for bypassing and filter – 1n, 100n). Electrolytic ones are 100 uF and 220 uF 16V. The source voltage is 9V. The prototype works, so I made a PCB for SMD components. It came out very good. But when I soldered everything I had smoke somewhere in the capacitor’s area. Read more 

PWM applied to load while current limiting on load simultaneously – I have an electrolysis cell to produce brown’s gas from water. In the process, the gas barrier decreases the efficiency of cell while it may consume huge amounts of current, too. So, I need to apply PWM pulses to increase electrode efficiencies and control current consumption in one circuit. But I have no clue how to couple them in one circuit for load full control. Read more

 

 

 

 

 

 

 

 

Need help with ADS momentum co-simulation – I am doing power amplifier design, and have to do momentum co-simulation. I created an EM model from the layout, then I opened it from the schematic window as shown in the attached file. However, when I run the simulation it doesn’t show any performance. It looks like there is something wrong. Read more

 

Analog realization of trigonometric function – After a frantic search to realize sine/cosine functions in analog, I came across the patent reference https://patentimages.storage.googlea…/US4164729.pdf. Can anybody explain, how the linear approximation arrived? Read more

What’s the problem with this MIC circuits? – I found a MIC circuit, which converts the single-ended MIC signal to diff-MIC signals. I simulated it in ADS and found the results are weird. The following pictures are the TD response & FD response, who can comment on the problem of this circuit? Read more

 

 

 

 

 

Switching voltage amplifier into transconductance amplifier – I have designed a voltage amplifier and I have a high impedance on the input and low impedance on the output. The amplifier plot and its gain response is shown below. In the schematics below there is a transimpedance amplifier design. Read more

 

 

 

 

 

 

 

 

Generate spice netlist from Cadence Spectre schematic – I would like to generate a spice netlist from Cadence Schematic. I have found comments saying using HSPICE simulator which is not working for me. Is there another way to generate a spice netlist from Schematic? Read more

Ferrite beads for EMC testing – I’m looking at the effect of ferrite bead on a PCB to improve susepability when EMC testing. Looking at the curves on the datasheets, the peak resistance seems to be around the 2 MHz range. Does this mean the ferrite bead will filter out frequencies around this range, i.e. the higher the resistance (and reactance) the better the filtering? Read more