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Emitter follower

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quintessential

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Could the right emitter follower scheme,say for instance the one in the diagram be used to produce a 200mv ripple with a 3volt DC offset at the output assuming the load at the output sinks large(600mA-1A) amounts of current? In accordance with the unity gain votage of an emitter follower would i just set bias points and input a 200mv sin wave at the input?....with the caps in place would i have any DC at all? this is related to this thread:https://www.electro-tech-online.com/threads/what-op-amp-to-use.31477/?highlight=psrr
 

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What is the DC output voltage range you need? Are you planning to sweep the input frequency? If so, over what range?
 
Roff said:
What is the DC output voltage range you need? Are you planning to sweep the input frequency? If so, over what range?

oh...ideally im planning to sweep from DC to 20 Mhz but ill take whatever range i get a flat response from....the voltage supply is 3.6V DC but with a 200mv ripple(the ripple amplitude is flexible)
 
quintessential said:
oh...ideally im planning to sweep from DC to 20 Mhz but ill take whatever range i get a flat response from....the voltage supply is 3.6V DC but with a 200mv ripple(the ripple amplitude is flexible)
Do you have any restrictions on the voltage that powers the circuit that you're proposing?
 
Roff said:
Do you have any restrictions on the voltage that powers the circuit that you're proposing?

No, no restrictions on the voltage supply. I made a mistake in my last post.....,its my output voltage that i need at around 3.6V with about 200mv ripple.there is no restriction on the supply
 
quintessential said:
No, no restrictions on the voltage supply. I made a mistake in my last post.....,its my output voltage that i need at around 3.6V with about 200mv ripple.there is no restriction on the supply
To clarify: 3.6VDC with 200mV p-p ripple is the input to the regulators you are testing, and you want a circuit that can deliver this at up to one amp?
 
Do you need a capacitor on the input of your regulator for stability? Most do. If so, it will be pretty much impossible to drive to 200mV p-p at 20MHz.
What kind of regulator are you testing?
 
the regulators are designed to work with a 3.6V DC input,its this input i wanted to replace with something else just to see how the regulators would perform on PSRR
 
quintessential said:
the regulators are designed to work with a 3.6V DC input,its this input i wanted to replace with something else just to see how the regulators would perform on PSRR
OK, but you didn't answer my questions.
 
quintessential said:
the regulators dont have caps on the input,they're buck regulators
The input current to a buck regulator is discontinuous. The transient currents mean that your ripple generator will need to have very low impedance, even at high frequencies. I don't think that is going to work with an emitter follower.
 
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