SLVSJ50A February   2026  – July 2026 INA951-SEP

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 Amplifier Input Common-Mode Signal
        1. 6.3.1.1 Input-Signal Bandwidth
        2. 6.3.1.2 Low Input Bias Current
        3. 6.3.1.3 Low VSENSE Operation
        4. 6.3.1.4 Wide Fixed Gain Output
        5. 6.3.1.5 Wide Supply Range
    4. 6.4 Device Functional Modes
      1. 6.4.1 Unidirectional Operation
      2. 6.4.2 High Signal Throughput
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 RSENSE and Device Gain Selection
      2. 7.1.2 Input Filtering
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Overload Recovery With Negative VSENSE
      3. 7.2.3 Application Curve
    3. 7.3 Power Supply Recommendations
    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 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.1 RSENSE and Device Gain Selection

The accuracy of any current-sense amplifier is maximized by choosing the current-sense resistor to be as large as possible. A large sense resistor maximizes the differential input signal for a given amount of current flow and reduces the error contribution of the offset voltage. However, there are practical limits as to how large the current-sense resistor can be in a given application because of the resistor size and maximum allowable power dissipation. Equation 1 gives the maximum value for the current-sense resistor for a given power dissipation budget:

Equation 1. R S E N S E < P D M A X I M A X 2

where:

  • PDMAX is the maximum allowable power dissipation in RSENSE.
  • IMAX is the maximum current that flows through RSENSE.

An additional limitation on the size of the current-sense resistor and device gain is due to the power-supply voltage, VS, and device swing-to-rail limitations. To make sure that the current-sense signal is properly passed to the output, both positive and negative output swing limitations must be examined. Equation 2 provides the maximum values of RSENSE and GAIN to keep the device from exceeding the positive swing limitation.

Equation 2. I M A X × R S E N S E × G A I N < V S P

where:

  • IMAX is the maximum current that flows through RSENSE.
  • GAIN is the gain of the current-sense amplifier.
  • VSP is the positive output swing as specified in the datasheet.

To avoid positive output swing limitations when selecting the value of RSENSE, there is always a trade-off between the value of the sense resistor and the gain of the device under consideration. If the sense resistor selected for the maximum power dissipation is too large, then selecting a lower-gain device to avoid positive swing limitations is also possible.

The negative swing limitation places a limit on how small the sense resistor value can be for a given application. Equation 3 provides the limit on the minimum value of the sense resistor.

Equation 3. I M I N × R S E N S E × G A I N > V S N

where:

  • IMIN is the minimum current that flows through RSENSE.
  • GAIN is the gain of the current-sense amplifier.
  • VSN is the negative output swing of the device.

Table 7-1 shows an example of the different results obtained from using five different gain versions of the INA951-SEP. From the table data, the highest gain device allows a smaller current-shunt resistor and decreased power dissipation in the element.

Table 7-1 RSENSE Selection and Power Dissipation
PARAMETER(1) EQUATION RESULTS AT VS = 5V
A1 DEVICES
G Gain 20V/V
VDIFF Ideal differential input voltage VDIFF = VOUT / G 250mV
RSENSE Current sense resistor value RSENSE = VDIFF / IMAX 25mΩ
PSENSE Current-sense resistor power dissipation RSENSE × IMAX2 2.5W
(1) Design example with 10A full-scale current with maximum output voltage set to 5V.