DRV425 Datasheet, PDF (24/37 Pages) Texas Instruments – DRV425 Fluxgate Magnetic-Field Sensor

DRV425
SBOS729 – OCTOBER 2015
8 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DRV425 is a high-sensitivity and high-performance magnetic-field sensor. The analog output of the DRV425
can be processed by a 12- to 16-bit analog to digital converter (ADC). The following sections show examples of
DRV425-based applications.
8.2 Typical Applications
8.2.1 Linear Position Sensing
The high sensitivity of the fluxgate sensor, combined with the high linearity of the compensation loop and low
noise of the DRV425, make the device suitable for high-performance linear-position sense applications. A typical
schematic of such a 5-V application using an internal 2.5-V reference is shown in Figure 67.
5V
RSHUNT
DRV2
DRV1
AINP
AINN
COMP1
COMP2
Device
VOUT
REFIN
REFOUT
OR
ERROR
MCU
GPIO0
GPIO1
ADC
1 µF 1 µF
10 k:
10 k:
5V
Figure 67. Simplified Schematic of a DRV425-Based Linear-Position Sensing Application
8.2.1.1 Design Requirements
For the example shown in Figure 67, use the parameters listed in Table 2 as a starting point of the design.
DESIGN PARAMETER
Magnetic field range
Supply voltage, VDD
Reference voltage, V_REFIN
Shunt resistor, R_SHUNT
Table 2. Design Parameters
EXAMPLE VALUE
VDD = 5 V: ±2 mT (max)
VDD = 3.3 V: ±1.3 mT (max)
3.0 V to 5.5 V
Range: GND to VDD
If an internal reference is used: 2.5 V, 1.65 V, or VDD / 2
Depends on the desired magnetic field range, reference, and supply voltage; see the
DRV425 System Parameter Calculator, SLOC331 for details.
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