What is the relationship between frequency range and GBW in amplifiers?

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Discussion Overview

The discussion revolves around the relationship between frequency range and gain-bandwidth product (GBW) in amplifiers, specifically focusing on operational amplifiers. Participants explore concepts related to bandwidth, amplification, and the implications of frequency specifications.

Discussion Character

  • Technical explanation, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant questions whether frequency range is equivalent to bandwidth, suggesting that in this context, it is.
  • Another participant proposes a calculation for GBW based on a given amplification and frequency range, asserting that GBW = A_v * BW = 100 * 20k = 2 MHz.
  • A subsequent reply challenges the calculation, stating that GBW is defined under the assumption of a single-pole roll-off and that an upper frequency limit does not imply a first-order system.
  • There is a request for clarification regarding the type of amplifier being discussed and the reason for the specified lower cutoff frequency.

Areas of Agreement / Disagreement

Participants express differing views on the equivalence of frequency range and bandwidth, as well as the validity of the GBW calculation. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Limitations include assumptions about the amplifier type and the implications of frequency specifications on GBW calculations, which are not fully addressed.

Omsin
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I have an op-amp with frequency range 20Hz - 20kHz. Is frequency range the same as bandwidth?
 
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Let's say I have 40 dB amplification and frequency range of 20 Hz - 20 kHz

Is my GBW = A_v * BW = 100 * 20k = 2 MHz?
 
Omsin said:
Is frequency range the same as bandwidth?

in this context ... yes

what is the op-amp ? ... that's a really narrow freq range

Omsin said:
Let's say I have 40 dB amplification and frequency range of 20 Hz - 20 kHz

Is my GBW = A_v * BW = 100 * 20k = 2 MHz?

will let some one else answer that
 
Omsin said:
Let's say I have 40 dB amplification and frequency range of 20 Hz - 20 kHz
Is my GBW = A_v * BW = 100 * 20k = 2 MHz?
No, not in general - the definition of the GBW is based on the assumption of a single-pole roll-off.
A specification of an upper frequency limit does not automatically imply a 1st-oder system.
What kind of amplifier are you speaking of? What is the reason for the lower cut.off frequency?
 

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