AN3433

Management of CR95HF or STRFNFCA activity

Doc ID 019046 Rev 2

7/34

2.2

Idle command

The Idle command switches the device into WFE mode (low consumption) and defines the

way it returns to Ready state.

In WFE mode, the device has two low consumption states: Hibernate and Sleep/Tag-

Detector.

In Hibernate state, the device power consumption is extremely low (a few microamps)

because most of its resources are switched off. When it receives an external event (pin

IRQ_IN), it will return to Ready mode in only a few milliseconds.

In Sleep/Tag-Detector state, the device power consumption is low (tens of microamps)

depending on the selected wakeup source. The wakeup source can be an internal timer, an

external interrupt or the presence of a tag detected by the device.

In Tag-Detector state, after executing an initial Tag Detection Calibration procedure to set-up

the device, the application engineer must adjust command parameters to select the best

trade-off between the wakeup delay and the power budget.

Figure 1.

CR95HF or STRFNFCA initialization and operating state change