National Semiconductor LM and. LM, Respectively description. These devices consist of four independent, high- gain frequency-compensated Norton. LM description These devices consist of four independent, high gain frequency-compensated Norton operational amplifiers that were designed. LM MC Unit. Supply Voltage. VCC. + + V. Input Current. Iin. mA on the individual data sheets and the Selector Guide. All of the.
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LM Datasheet(PDF) – Motorola, Inc
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Thread starter Neil Groves Start date Nov 7, Neil Groves New Member Nov 7, Is an LM a good replacement for an LM? I couldn’t locate one of the latter so relayed my circuit to use an LM instead, well it doesn’t work, i checked my output from the first stage and it sits at 10V although the input is a 4V p-p sine wave from my generator, i am building the circuit here: Hi, The LM was a very different kind of op amp.
It operates on the difference in input current rather than the difference in input voltages. It can not be replaced with a LM op amp. From what i read, the NTE is a replacement. The LM is a high speed version. It would be possible however to change the design a little to use a more typical op amp.
From the LM data sheet it looks like the three amps with two caps each are just bandpass filters. Redesigning them for other op amps probably wouldnt be much of a problem really.
The Q of each bandpass would be a little higher though so you’d have to try it and modify the values slightly if it doesnt seem to work the way you want it to. We can call the input resistor R1 and the resistor to ground R2 and the feedback resistor R3.
The feedback resistor R3 is then: This may not be the ideal setup, but it might still work.
The circuit uses a single polarity supply so grounding the non-inverting input of the opamps would cause their outputs to be grounded and they would work like rectifiers. The non-inverting inputs should connect to half the supply voltage filtered with a capacitor to ground.
Neil Groves New Member Nov 8, The LM is not a normal OP amp. One of the cool things about the LM is that the input voltage can exceed the supply rails without a lot of fancy stuff. Thus you could look for the presence of line to speaker levels very easily and even filter the hiss. That’s what a specific timer of mine does. Hi, I’d be careful about using an AD for a replacement. It’s very different than the LM For one thing, the input bias would be different. I probably have few AD’s around, but i dont think i have any LM’s around anymore.
Back in the 80’s i did. Hi again, Yeah i remember these from back in the ‘s.
LM3900 Datasheet PDF
I am surprised to see them in circuits today. Maybe this was a very old design. Jameco has the LM’s: Roff Well-Known Member Nov 8, lm9300 I seem to have blown out on at least two things here, i’m gonna scrap that project, build something else i need then come back to it using a different circuit.