Issue encountered with MAX44284 (SOT23 Package). The device generally works as expected, other than when I generate a transient load condition (step change current consumption). Same behaviour seen in multiple systems.
Setup details:
- device powered (VDD) from 3V3, with 100nF and 1uF ceramic capacitors.
- Voltage powering load is 12V
- I am using a 50mR sense resistor, with 330R 'in-line' RIN resistors between RS+/RS- and the sense resistor.
- I am using 10nF filtering cap between Rs+ and Rs-. No other filtering caps.
- The output of the amplifier generally behaves as expected, with the output voltage being proportional to the current.
- I have left the output of the amplifier floating (other than oscilloscope probe) to avoid potential issues with stability / capacitive loading.
The issue appears when I simulate a load transient, effectively creating a step change in the current consumption. The device output seems to get 'stuck' at around 0.6V for 8 seconds or so, and then eventually rises to the expected value.
I have tried the following with no results:
- Increasing the filtering cap from 10nF to 100nF with no change.
- Increasing the 'in-line' RIN resistors from 330R to 1k, with no change.
- Adding more decoupling caps on VDD, no change.
- Adding filtering caps between RIN and GND on both sides RS+ and RS-, no change.
Any help would be greatly appreciated.
Hugo
