I’m using an ADP7118 LDO in a battery-powered design.

• Load current: 15 mA
• Ground current (datasheet): ~0.19 mA at this load
• Shutdown mode: Currently not used, but may be used later.

I want to calculate the total input current drawn from the battery and clarify a few points:


1. Do I need to add quiescent current separately, or is it already included in the ground current spec?
My assumption:

Iin = Iload + Ignd
(or if quiescent current is separate)
Iin = Iload + Ignd + Iq

2. If I enable shutdown mode, should I add the shutdown current to the total input current calculation? Or does it replace the normal ground current?

Iin = Iload +Ignd +Ishutdown

3. Can I consider the worst case input current as,

Iin = Iload + Ignd + Iq + Ishutdown

Is there any other current component I should consider for accurate battery life estimation?

 

Quiescent current = 80 μA typ, 190 μA max
Shutdown current = 3 μA typ, 10 μA max
Total active current = 15 mA

 

A very simple sketch showing the actual location of the named currents would probably provide the answer to the TS question.