SBOSAN5A December   2025  – September 2026 INA1H94-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: INA1H94-SEP
    5. 5.5 Electrical Characteristics: VS = ±9V
    6. 5.6 Electrical Characteristics: V+ = 5V and V– = 0V
    7. 5.7 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 Common-Mode Range
      2. 6.3.2 Error Sources
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 SAR ADC 12B, 8-Channel Battery Cell Voltage Monitor
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curves
    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 Device Support
      1. 8.1.1 Documentation Support
        1. 8.1.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.1 Common-Mode Range

Figure 6-1 shows the basic connections required for dual-supply operation. Applications with noisy or high-impedance power-supply lines can require decoupling capacitors placed close to the device pins. The output voltage is equal to the differential input voltage between +IN and −IN. The common-mode input voltage is rejected. Figure 6-2 shows the basic connections required for single-supply operation.

INA1H94-SEP Power and Signal Connections for Dual-Supply Operation Figure 6-1 Power and Signal Connections for Dual-Supply Operation
INA1H94-SEP Power and Signal Connections for Single-Supply Operation Figure 6-2 Power and Signal Connections for Single-Supply Operation

Most applications use the INA1H94-SEP as a simple unity-gain difference amplifier. Equation 1 shows the transfer function:

Equation 1. V OUT = ( +IN ) − ( −IN )

Some applications, however, apply voltages to the reference terminals (REFA and REFB). Equation 2 shows the complete transfer function:

Equation 2. V OUT = ( + IN ) − ( − IN ) + 20 × REF A − 19 × REF B

The INA1H94-SEP is a unity-gain difference amplifier capable of measuring small differential voltages in the presence of high common-mode voltages, with a maximum input range of ±150V. The high common-mode range of the INA1H94-SEP is achieved by attenuating the input signal with a high-precision resistor divider. This resistor divider brings both the positive and negative inputs within the input range of the internal operational amplifier. This input range is bounded by the supply voltages and is also a function of the REFA and REFB reference inputs of the difference amplifier.

The maximum allowable common-mode input range varies as a function of the supply voltages, as well as the reference input voltages, depending on the application circuit. Calculate the INA1H94-SEP input range by verifying that the voltages at both the positive and negative inputs of the internal amplifier at least 1.5V of headroom from the supply rails. Similarly, the output requires at least 1.5V of headroom from the supply rails. The circuit in Figure 6-3 shows a simplified schematic of the difference amplifier circuit inside the INA1H94-SEP and is used to evaluate the critical internal node voltages to confirm that the common-mode and output voltage swings remain within the linear range. Since the linear common-mode and differential input voltage range of the difference amplifier is a function of the supply voltages, reference input voltages, and amplifier output swing, use the INA1H94-SEP Linear Operation Checker to verify the linear range of the device for a specific application circuit.

INA1H94-SEP Internal Amplifier Input Voltage Range and Output Swing
Internal amplifier inputs require 1.5V headroom away from supplies
Figure 6-3 Internal Amplifier Input Voltage Range and Output Swing

Use Figure 5-1 to determine the maximum and minimum common-mode range for a specific supply voltage when REFA and REFB are biased at 0V. Use Figure 5-2 to determine the maximum and minimum common-mode range for a specific unipolar supply voltage when REFA and REFB are biased at mid-supply, or VS/2. Figure 6-4 shows one possible circuit configuration with a unipolar supply and REFA and REFB biased at 2.5V. Figure 6-5 can be used to determine the maximum and minimum common-mode voltage range for a specific unipolar supply voltage when REFA and REFB are biased at 2.5V.

INA1H94-SEP Unipolar Supply Circuit with REFA = REFB = 2.5V Figure 6-4 Unipolar Supply Circuit with REFA = REFB = 2.5V
INA1H94-SEP Common-Mode Range with Unipolar Power Supply and REFA = REFB = 2.5V
REFA = REFB = 2.5V
Figure 6-5 Common-Mode Range with Unipolar Power Supply and REFA = REFB = 2.5V

In case the voltage at the inputs of the internal amplifier exceeds the supply voltage, the internal ESD diodes start conducting current. Limit this current to 10mA to make sure not to exceed the absolute maximum ratings for the device.