What is the Essence of Quiescent Current? (Download)

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For an electronic circuit, a quiet state is one in which the circuit isn’t driving any load and its inputs aren’t cycling. Most commonly used for the specification in a datasheet, quiescent current is the current consumed by a circuit when it’s in a quiescent state.

Quiescent current (I_Q) also can be defined as the current consumed by an IC in the no-load and non-switching but enabled state. Generally, quiescent current is the input current consumed by the IC in any ultra-low-power consumption state.

Furthermore, I_Q is the current needed to power a low-dropout (LDO) IC’s internal circuitry when the external load current is zero. Many designers may mistake quiescent current as shutdown current, which is the current drawn when a device is turned off with the battery still connected to the system. The amount of I_Q is determined by the topology of the device, input voltage, and temperature. So, essentially, I_Q = I_IN at no load.