Figure 4-2. Schematic Snippet of DAC43701 Portion of TMAG5328EVM
4.1.2 Adjusting Threshold With Potentiometer
The B
OP
of the TMAG5328 can also be set with the analog potentiometer that is on the EVM. To select the
potentiometer option for setting B
OP
, the potentiometer must be connected to the ADJ pin, which is done by the
following steps:
• Do not populate resistor R7.
• Connect a jumper between the "APOT" (pin 3) and "ADJ" (pin 2) pins of header J3.
Use
to translate the resistance between its ADJ and GND pins into the B
OP
setting:
B
OP
= ADJ
resistance
(2)
where:
• B
OP
is in units of mT
• ADJ
resistance
is in units of kΩ
As an example, if the resistance between ADJ and GND is 8.5 kΩ, the B
OP
will be set to 8.5 mT.
shows the schematic snippet for the potentiometer portion of the EVM. This circuit consists of a 10-kΩ
potentiometer (R13) in series with a 4.3-kΩ fixed resistor (R2). When the potentiometer is used for setting the
B
OP
, the ADJ pin sees a resistance equal to the sum of resistances R2 and R13. As a result, the ADJ pin would
see a resistance somewhere between 4.3 kΩ to 14.3 kΩ, depending on the position of the potentiometer. The
4.3-kΩ to 14.3-kΩ resistance range corresponds to a B
OP
of 4.3 mT to 14.3 mT. A 10-kΩ potentiometer is used,
therefore the potentiometer only simultaneously covers a 10-mT range of B
OP
settings. The resistor R2 can be
modified, however, to select which B
OP
options are supported. As an example, if you want to support a 2-mT to
12-mT range, you can replace R2 with a 2-kΩ resistor. Similarly, if you want to support a 5-mT to 15-mT range,
you can replace R2 with a 5-kΩ resistor.
Hardware
SBAU376 – DECEMBER 2021
TMAG5328 Evaluation Module
7
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