ZHCSET4B December 2015 – April 2024 LDC0851
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Pin Configuration and Functions
- 5 Specifications
- 6 Detailed Description
- 7 Application and Implementation
- 8 Device and Documentation Support
- 9 Revision History
- 10Mechanical, Packaging, and Orderable Information
6.4.2 Active Mode
When the LDC0851 EN pin is pulled high, the LDC0851 is put into active mode. The active supply current (IDD) is broken up into three pieces: Static current (Istatic), Dynamic current (Idyn), and Sensor current (Isensor).
Static current is the DC device current given in the electrical characteristics and does not vary over frequency.
Dynamic current is the AC device current which varies with both sensor frequency (?SENSOR) and board parasitic capacitance (CBOARD). Dynamic current can be computed with the following equation:
where:
- Idyn is the dynamic current drawn by the device and board parasitics
- ?SENSOR is the sensor frequency calculated from Equation 6
- CBOARD is the parasitic capacitance of the board, see Figure 7-1
Sensor current is the AC current required to drive an external LC sensor. Sensor current varies with both the frequency and inductance of the sensor and is given by the following equation:
where:
- ISENSOR is current required to drive the sensor
- LSENSOR is the measured inductance of the sensor
- ?SENSOR is the sensor frequency calculated from Equation 6
The total active supply current is given by the following equation:
where:
- IDD is the total active supply current
- Idyn is the dynamic current drawn by the device as given by Equation 3
- Istatic is the static current as given in the electrical table
- ISENSOR is current required to drive the sensor as given by Equation 4