SBOS988A August   2019  – April 2020 DRV425-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Fluxgate Sensor Front-End
        1. 7.3.1.1 Fluxgate Sensor
        2. 7.3.1.2 Bandwidth
        3. 7.3.1.3 Differential Driver for the Internal Compensation Coil
        4. 7.3.1.4 Magnetic Field Range, Overrange Indicator, and Error Flag
      2. 7.3.2 Shunt-Sense Amplifier
      3. 7.3.3 Voltage Reference
      4. 7.3.4 Low-Power Operation
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Linear Position Sensing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Current Sensing in Busbars
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power Supply Decoupling
    2. 9.2 Power-On Start-Up and Brownout
    3. 9.3 Power Dissipation
      1. 9.3.1 Thermal Pad
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1.2 Bandwidth

The small-signal bandwidth of the DRV425-Q1 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 22 Ω and BSEL = 0, the bandwidth is 32 kHz; for BSEL = 1, the bandwidth is 47 kHz.

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. DRV425-Q1 ai_eq_bw_sbos729.gif

where

  • RCOIL = internal compensation coil resistance (100 Ω).
  • RSHUNT = external shunt resistance.
  • BW22Ω = sensor bandwidth with RSHUNT = 22 Ω (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 > 500 μT), the effective bandwidth of the sensor is limited by fluxgate saturation effects. For a magnetic signal with a 2-mT amplitude, the large-signal bandwidth is 10 kHz with BSEL = 0, or 15 kHz with BSEL = 1.

Although the analog output responds slowly to large fields, a magnetic field with a magnitude ≥ 1.6 mT beyond the measurement range of the DRV425-Q1 triggers the ERROR pin within 4 µs to 6 µs. See the Magnetic Field Range, Overrange Indicator, and Error Flag section for more details.