LTC4217 I mon output

Hi John,

The spec called Ioff(IMON) is the IMON's offset current, and does not mean the output is 'off'.  The IMON current nominally has an offset of zero but can have an error of +/- 7.5uA.  This needs to be applied for all load conditions.  The IMON error is worse under light load conditions, which is the 132mA test condition for this spec.

For your 150mA load example, IMON typically will source 7.5uA but the offset spec tells us that IMON worst case min/max is 0uA/15uA.  At 1.5A load, IMON will source 75uA +/- 7.5uA.

When the output is off, IMON current should be zero.

Regards

Mike

Hi John,

The spec called Ioff(IMON) is the IMON's offset current, and does not mean the output is 'off'.  The IMON current nominally has an offset of zero but can have an error of +/- 7.5uA.  This needs to be applied for all load conditions.  The IMON error is worse under light load conditions, which is the 132mA test condition for this spec.

For your 150mA load example, IMON typically will source 7.5uA but the offset spec tells us that IMON worst case min/max is 0uA/15uA.  At 1.5A load, IMON will source 75uA +/- 7.5uA.

When the output is off, IMON current should be zero.

Regards

Mike

Hello Mike,

Thanks for the explanation. So it is output pin offset current not device off current.

I have measured 36mV at the Imon pin when the output is off. This is developed across 20K which equates to 1.8uA which I suppose is less than the ±7.5uA error.

Is the input supply current IDD 'output off current' documented for this device? All I see is the 'Mosfet On' condition of 1.6 to 3mA.

Thanks again, John M.

John,

Sorry for the delay, I'm still checking and will get back with an answer.

Mike

Hi John,

The Idd current does not change much whether the switch is on or off. Nominally the supply current is 1.6mA and this is reduced by 100uA when the switch is off.

Regards

Mike