SBOS980A May   2019  – June 2020 TLV9002-Q1 , TLV9004-Q1

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Single-Pole, Low-Pass Filter
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions: TLV9002-Q1
    2.     Pin Functions: TLV9004-Q1
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information for Dual Channel
    5. 7.5 Thermal Information for Quad Channel
    6. 7.6 Electrical Characteristics
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Operating Voltage
      2. 8.3.2 Rail-to-Rail Input
      3. 8.3.3 Rail-to-Rail Output
      4. 8.3.4 Overload Recovery
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 TLV900x-Q1 Low-Side, Current Sensing Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Single-Supply Photodiode Amplifier
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Input and ESD Protection
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Detailed Design Procedure

The transfer function of the circuit in Figure 37 is given in Equation 1:

Equation 1. TLV9002-Q1 TLV9004-Q1 EQ_2_SBOS701.gif

The load current (ILOAD) produces a voltage drop across the shunt resistor (RSHUNT). The load current is set from 0 A to 1 A. To keep the shunt voltage below 100 mV at maximum load current, the largest shunt resistor is shown using Equation 2:

Equation 2. TLV9002-Q1 TLV9004-Q1 EQ_3_SBOS701.gif

Using Equation 2, RSHUNT is calculated to be 100 mΩ. The voltage drop produced by ILOAD and RSHUNT is amplified by the TLV900x-Q1 to produce an output voltage of approximately 0 V to 4.9 V. The gain needed by the TLV900x-Q1 to produce the necessary output voltage is calculated using Equation 3:

Equation 3. TLV9002-Q1 TLV9004-Q1 EQ_4_SBOS701.gif

Using Equation 3, the required gain is calculated to be 49 V/V, which is set with resistors RF and RG. Equation 4 sizes the resistors RF and RG, to set the gain of the TLV900x-Q1 to 49 V/V.

Equation 4. TLV9002-Q1 TLV9004-Q1 EQ_5_SBOS701.gif

Selecting RF as 57.6 kΩ and RG as 1.2 kΩ provides a combination that equals 49 V/V. Figure 38 shows the measured transfer function of the circuit shown in Figure 37. Notice that the gain is only a function of the feedback and gain resistors. This gain is adjusted by varying the ratio of the resistors and the actual resistors values are determined by the impedance levels that the designer wants to establish. The impedance level determines the current drain, the effect that stray capacitance has, and a few other behaviors. There is no optimal impedance selection that works for every system, you must choose an impedance that is ideal for your system parameters.