Datasheet
43
LDC1612
,
LDC1614
www.ti.com
SNOSCY9A –DECEMBER 2014–REVISED MARCH 2018
Product Folder Links: LDC1612 LDC1614
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Table 42. Optimum Sensor R
P
Ranges for Sensor IDRIVEx Setting. (continued)
IDRIVEx Register Field Value Nominal Sensor
Current (µA)
Minimum Sensor R
P
(kΩ)
Maximum Sensor R
P
(kΩ)
9 b01001 59 16.1 23.6
10 b01010 72 13.1 20.4
11 b01011 82 11.5 17.6
12 b01100 95 9.92 15.1
13 b01101 110 8.57 13.0
14 b01110 127 7.42 11.2
15 b01111 146 6.46 9.69
16 b10000 169 5.58 8.35
17 b10001 195 4.83 7.20
18 b10010 212 4.45 6.21
19 b10011 244 3.86 5.35
20 b10100 297 3.17 4.61
21 b10101 342 2.76 3.97
22 b10110 424 2.22 3.42
23 b10111 489 1.93 2.95
24 b11000 551 1.71 2.54
25 b11001 635 1.48 2.19
26 b11010 763 1.24 1.89
27 b11011 880 1.07 1.63
28 b11100 1017 0.93 1.40
29 b11101 1173 0.80 1.21
30 b11110 1355 0.70 1.05
31 b11111 1563 0.60 0.90
Sensors with R
P
greater than 90 kΩ can be driven by placing a 100 kΩ resistor in parallel with the sensor
inductor to reduce the effective R
P
.
Sensors which have a wide range of R
P
may require more than one current drive setting across the range of
operation - the current would need to be dynamically set based on the target position. Note that some high-
resolution applications will experience an output code offset when the current drive is changed. Another
approach for systems which have a wide range of R
P
is to place a discrete resistor in parallel with the inductor to
limit the range of R
P
variation in the system. This will also reduce the sensor Q, and so may not be feasible for
some implementations.
8.1.5.1 Inactive Channel Sensor Connections
The LDC1612/LDC1614 ties the INAx and INBx pins for all channels to ground by ~10 Ω except for the active
channel; in Sleep and Shutdown modes there are no active channels and so all channels are tied to ground. By
grounding the channels, potential interactions between sensors are minimized. For multi-channel sequencing,
only the active channel is driven with the IDRIVE current during the conversion time; once the conversion for the
specific channel completes, the sensor is tied to ground to shut off the sensor, and the next sensor is activated.
For systems which do not use all sensor channels, it is acceptable to leave the unused INAx and INBx pins No-
Connect.