SBOS729B October   2015  – October 2025 DRV425

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Fluxgate Sensor Front-End
        1. 6.3.1.1 Fluxgate Sensor
        2. 6.3.1.2 Bandwidth
        3. 6.3.1.3 Differential Driver for the Internal Compensation Coil
        4. 6.3.1.4 Magnetic Field Range, Overrange Indicator, and Error Flag
      2. 6.3.2 Shunt-Sense Amplifier
      3. 6.3.3 Voltage Reference
      4. 6.3.4 Low-Power Operation
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Linear Position Sensing
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Current Sensing in Busbars
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
      1. 7.3.1 Power Supply Decoupling
      2. 7.3.2 Power-On Start-Up and Brownout
      3. 7.3.3 Power Dissipation
        1. 7.3.3.1 Thermal Pad
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Receiving Notification of Documentation Updates
    5. 8.5 Support Resources
    6. 8.6 Trademarks
    7. 8.7 Electrostatic Discharge Caution
    8. 8.8 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.1.2 Bandwidth

The small-signal bandwidth of the DRV425 is determined by the behavior of the compensation loop versus frequency. The implemented integrator limits the bandwidth of the loop to provide a stable response. Use digital input pin BSEL to select the bandwidth. With a shunt resistor of 22Ω and BSEL = 0, the bandwidth is 32kHz; for BSEL = 1, the bandwidth is 47kHz.

The shunt resistor and the compensation coil resistance form a voltage divider; therefore, to reduce the bandwidth, increase the value of the shunt resistor. To calculate the reduced bandwidth (BW), use Equation 2:

Equation 2. B W = R C O I L + 22 Ω R C O I L + R S H U N T × B W 22 Ω = 122 Ω 100 Ω + R S H U N T × B W 22 Ω

where

  • RCOIL = internal compensation coil resistance (100Ω).
  • RSHUNT = external shunt resistance.
  • BW22Ω = sensor bandwidth with RSHUNT = 22Ω (depending on the BSEL setting).

The bandwidth for a given shunt resistor value can also be calculated using the DRV425 System Parameter Calculator. For large magnetic fields (B > 500μT), the effective bandwidth of the sensor is limited by fluxgate saturation effects. For a magnetic signal with a 2mT amplitude, the large-signal bandwidth is 10kHz with BSEL = 0, or 15kHz with BSEL = 1.

Although the analog output responds slowly to large fields, a magnetic field with a magnitude ≥ 1.6mT beyond the measurement range of the DRV425 triggers the ERROR pin within 4µs to 6µs. See the Magnetic Field Range, Overrange Indicator, and Error Flag section for more details.