I am trying to select a current sense amplifier for my design. My design parameters are :-

Vrail:- 9V to 21V ILoad :- 20A(max)

When I look on digikey,


I am confused with 2 parameters:-

  1. Gain bandwidth product
  2. -3db Bandwidth

Can someone explain these parameters? What is their significance in selecting right sense amplifier?

  • \$\begingroup\$ How high frequency do you need to measure to? How much output voltage do you need to produce at maximum current? The product of these two answers are your gain-bandwidth product. -3dB bandwidth of the OPamp should be higher than the maximum frequency you need to measure. \$\endgroup\$ – winny Jul 5 '16 at 7:09
  • \$\begingroup\$ Here is one of the many Internet resources that provide the answers to your questions regarding op amp bandwidth: Operational Amplifier Basics. \$\endgroup\$ – Jim Fischer Jul 5 '16 at 7:19
  • \$\begingroup\$ There are also dedicated current sense amplifiers. You might consider using one of those, depending on details of your application. \$\endgroup\$ – mkeith Jul 5 '16 at 7:46
  • 1
    \$\begingroup\$ What is the current that you are trying to measure? An op-amp may not be the best solution. Try googling "current-sense amplifier". (oops, mkeith beat me by a minute - I need to type faster). \$\endgroup\$ – Mark Jul 5 '16 at 7:48

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