SNOA951 June 2016 LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1
The full sample speed of the LDC is not required for HMI application which allows for duty cycling and power consumption savings. The LDC can be sampled at periodic intervals to conserve power consumption, while still providing real-time button detection.
The Inductive Sensing Design Calculator Tool spreadsheet (SLYC137) can calculate the average current consumption in duty-cycled applications. A typical application with two buttons and a sample rate of 10 samples per second may have an average current consumption of 225 µA (113 µA per button), as shown Table 3. In battery powered applications, the tradeoff between sample rate and resolution can be adjusted for further power savings.
| Parameter | Value | Unit |
|---|---|---|
| fREFERENCE input to CLKIN | 20 | MHz |
| RCOUNT Setting (range:0x0003 to 0xFFFF) | 1000 | hex |
| Desired Sample Rate | 10 | sps |
| Number of channels of measurement | 2 | |
| Sensor Frequency (open air) | 8 | MHz |
| Sensor Frequency (in presence of Aluminum at 0.55mm distance) | 9.1 | MHz |
| Sensor Q (max) | 20 | |
| I2C Data rate | 400 | kbit/s |
| Sensor RP | 10 | kΩ |
| LDC Device | LDC1612 | |
| Programmed settle count | 64 | |
| Minimum Settle Count Register Setting | 0x4 | (registers 0x10:0x13) |
| single conversion time | 3.28 | ms |
| LDC Current consumption using Shutdown Mode | 225.29 | µA |
| LDC Current consumption using Sleep Mode | 256.24 | µA |