Datasheet

42
LDC1612
,
LDC1614
SNOSCY9A DECEMBER 2014REVISED MARCH 2018
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(1) Channels 2 and 3 are available for LDC1614 only.
Table 41. Current Drive Control Registers
CHANNEL
(1)
REGISTER FIELD [ BIT(S) ] VALUE
All
CONFIG, addr 0x1A SENSOR_ACTIVATE_SEL [11] Sets current drive for sensor activation.
Recommended value is b0 (Full Current
mode).
RP_OVERRIDE_EN [12] Set to b1 for normal operation (RP
Override enabled)
AUTO_AMP_DIS [10] Disables Automatic amplitude correction.
Set to b1 for normal operation (disabled)
0
CONFIG, addr 0x1A HIGH_CURRENT_DRV [6] b0 = normal current drive (1.5 mA)
b1 = Increased current drive (> 1.5 mA)
for Ch 0 in single channel mode only.
Cannot be used in multi-channel mode.
0
DRIVE_CURRENT0, addr 0x1E IDRIVE0 [15:11] Drive current used during the settling and
conversion time for Ch. 0 (auto-amplitude
correction must be disabled and RP over
ride=1 )
INIT_IDRIVE0 [10:6] Initial drive current stored during auto-
calibration. Not used for normal operation.
1
DRIVE_CURRENT1, addr 0x1F IDRIVE1 [15:11] Drive current used during the settling and
conversion time for Ch. 1 (auto-amplitude
correction must be disabled and RP over
ride=1 )
INIT_IDRIVE1 [10:6] Initial drive current stored during auto-
calibration. Not used for normal operation.
2
DRIVE_CURRENT2, addr 0x20 IDRIVE2 [15:11] Drive current used during the settling and
conversion time for Ch. 2 (auto-amplitude
correction must be disabled and RP over
ride=1 )
INIT_IDRIVE2 [10:6] Initial drive current stored during auto-
calibration. Not used for normal operation.
3
DRIVE_CURRENT3, addr 0x21 IDRIVE3 [15:11] Drive current used during the settling and
conversion time for Ch. 3 (auto-amplitude
correction must be disabled and RP over
ride=1 )
INIT_IDRIVE3 [10:6] Initial drive current stored during auto-
calibration. Not used for normal operation.
If the R
P
value of the sensor attached to Channel x is known, Table 42 can be used to select the 5-bit value to be
programmed into the IDRIVEx field for the channel. If the measured R
P
(at maximum spacing between the
sensor and the target) falls between two of the table values, use the current drive value associated with the lower
R
P
from the table. All channels that use an identical sensor/target configuration can use the same IDRIVEx
value. The appropriate sensor drive current can be calculated with:
I
DRIVE
= πV
P
÷ 4R
P
(12)
Table 42. Optimum Sensor R
P
Ranges for Sensor IDRIVEx Setting.
IDRIVEx Register Field Value Nominal Sensor
Current (µA)
Minimum Sensor R
P
(kΩ)
Maximum Sensor R
P
(kΩ)
0 b00000 16 60.0 90.0
1 b00001 18 51.8 77.6
2 b00010 20 44.6 66.9
3 b00011 23 38.4 57.6
4 b00100 28 33.7 49.7
5 b00101 32 29.5 42.8
6 b00110 40 23.6 36.9
7 b00111 46 20.5 31.8
8 b01000 52 18.1 27.4