A project log for "High" Bandwidth - Current Sense Amplifier

Configurable gain and bandwidth current sense amplifier. DC to 1MHz/100kHz bandwidth, at 25x/50x gain.

jesse-farrellJesse Farrell 06/04/2023 at 20:280 Comments

Compulsory LTspice simulation. Note that I’m not too concerned which op-amps are used in the sim… this is just to validate the overall design. 

As expected, our simulated bandwidth is a lower than the -3dB point calculated using 1/(2*pi*R*C). This is mainly caused by the cascading of amplifiers. To adjust this, we would need to tweak the feedback capacitors… but since we are using relatively high gain-set resistors, this isn’t too easy. Ideally, I’d be using lower resistances, but these aren’t in stock. (Wanted to use low drift, high spec ACAS network resistors… can use 0402 parts in place though).