Texas Instruments DRV425, User Manual

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Magnetic Field Interface
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3 Magnetic Field Interface
The DRV425 device contains and integrated fluxgate sensor which is located between pins 2 and 14. The
magnetic field sensitivity is parallel to the surface of the chip.
Figure 1. Magnetic Field Axis of Sensitivity
3.1 Power Supply
The DRV425EVM Board can be powered by a user provided 3.0 V to 5.5 V DC supply. The supply voltage
is applied to J1 pin 4 (VDD) referenced to pin 3 (GND).
3.2 Reference Voltages
The DRV425EVM has an internal reference source, which is enabled automatically when the appropriate
power source is applied to the device. There are three options for the reference voltage which depend on
the state of two reference selection pins RSEL1 and RSEL0 as shown in
Table 1 .
Table 1. Internal Reference Options
RSEL1 RSEL0 REFERENCE VOLTAGE
0 0 Fixed Reference of 2.5 V
0 1 Fixed Reference of 1.65 V
1 0
Ratio-metric reference equal to VDD/2 (default)
1 1
The reference options provided are based on the typical operating voltages of the device. For applications
using a 3.3-V power supply, the reference can be fixed at 1.65 V. For 5-V operation, the reference is
normally set for 2.5 V. In applications where the supply voltage may vary, the ratiometric option is
provided.
The DRV425EVM is not directly configured for an external reference. If an external reference is desired,
the trace between pins 4 and 5 of the DRV425 device can be cut as noted in
Figure 2 .
2 DRV425 Evaluation Module SLOU410A – September 2015 – Revised October 2015
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