Datasheet
Measurement
Core
f
SENSOR0
f
SENSOR
2
(
1
)
Int. Osc.
f
REF
Data
Output
REF_CLK_SRC
(0x1A)
f
REF0
f
REF1
f
REF2
(1)
f
REF3
(1)
f
IN
f
IN0
f
IN1
f
IN2
(1)
f
IN3
(1)
CONFIG (0x1A)
MUX_CONFIG (0x1B)
IN2A
(1)
IN2B
(1)
IN0A
IN0B
Sensor 1
Sensor 2
(1)
Sensor 0
Sensor 3
(1)
f
CLKIN
CLKIN
f
SENSOR1
IN1A
IN1B
f
SENSOR
3
(
1
)
IN3A
(1)
IN3B
(1)
÷ FREF_DIVIDER0
(0x14)
÷ FREF_DIVIDER1
(0x15)
÷
FREF_DIVIDER2
(1)
(0x16)
÷
FREF_DIVIDER3
(1)
(0x17)
f
INT
÷ FIN_DIVIDER3
(1)
(0x17)
CH3
Driver
÷ FIN_DIVIDER2
(1)
(0x16)
CH2
Driver
÷ FIN_DIVIDER1
(0x15)
CH1
Driver
÷ FIN_DIVIDER0
(0x14)
CH0
Driver
45
LDC1612
,
LDC1614
www.ti.com
SNOSCY9A –DECEMBER 2014–REVISED MARCH 2018
Product Folder Links: LDC1612 LDC1614
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8.1.5.5 Channel 0 High Current Drive
Channel 0 provides a high sensor current drive mode to drive sensor coils with a typical drive current >3.5 mA.
This feature can be used to drive sensors with an R
P
lower than 350 Ω. Set the HIGH_CURRENT_DRV field to
b1 to enable this mode. This drive mode is only available on Channel 0, and can only be enabled in single
channel mode (AUTOSCAN_EN = 0).
8.1.6 Clocking Architecture
Optimum LDC1612/LDC1614 performance requires a clean reference clock with a limited frequency range. The
device provides digital dividers for the ƒ
CLK
and the sensor inputs to adjust the effective frequency. For most
systems, the maximum permitted reference frequency provides the best performance. The dividers provide
flexibility in system design so that the full range of sensor frequencies can be supported with available f
CLK
. Each
channel has a dedicated divider configuration.
Figure 57 shows the clock dividers and multiplexers of the LDC.
Figure 57. Clocking Diagram
(1) LDC1614 only
In Figure 57, the key clocks are ƒ
INx
, ƒ
REFx
, and ƒ
CLK
. ƒ
CLK
is selected from either the internal clock source or
external clock source (CLKIN). The frequency measurement reference clock, ƒ
REF
, is derived from the ƒ
CLK
source.
The internal oscillator (ƒ
INT
) is highly stable across temperature and is suitable for applications when the
maximum performance of the LDC1612/4 is not needed or when an external oscillator is not available. For
precision applications, it is recommended to use an external oscillator for the reference clock; the external
oscillator should offer the stability and accuracy requirements suitable for the application. Note that some internal
functions, such as watchdog timers, always use ƒ
INT
for timing.
The ƒ
INx
clock is derived from sensor frequency for channel x, ƒ
SENSORx
. ƒ
REFx
and ƒ
INx
must meet the
requirements listed in Table 43, depending on whether ƒ
CLK
(reference clock) is the internal or external clock.