[sdiy] Killing OTAs [was: Re: SEM LFO square wave mod...]

[Magnus Danielson]

On 05/28/2011 07:28 PM, lanterma at ece.gatech.edu wrote:
>
> On May 27, 2011, at 9:57 PM, Paul Perry wrote:
>
>> Anyone playing around with a CA3080 - or any similar OTA like the LM13600 - needs to know that the maximum curren tthat can go into pin 5 is 2mA.
>> DO NOT connect it directly to a voltage, that will kill it stone dead in a microsecond.
>> I always connect a 10K resistor to pin 5 (or the equivalent pin) because that prevents current overload, no matter what you connect it to. It isn't a control voltage input, it is a CURRENT control input.
>> By running voltage through the resistor, you make it look roughly like a voltage control.
>
> The lab project part of my class is largely defined by students killing OTAs when they're poking around their circuit - it's a veritable 13700 grave yard. ;)
>
> Sometimes when you blow an OTA you can tell by taking a DC reading at the current control pin. It should read about a volt about the negative rail; if it doesn't it's blown.

Most labs blow their fuses or caps... you guys qualify into speciallized 
in blowing your OTAs... :P

Get a life, get more excitement into your life and blow your fuses... :D

Cheers,
Magnus