SBOSA39A April   2025  – October 2025 THS3470

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 ±VS = ±30V
    6. 5.6 Electrical Characteristics ±VS = ±20V
    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 Output Current Limit
      2. 6.3.2 Output Current Enable
      3. 6.3.3 Over Temperature Flag
      4. 6.3.4 Output Current Flags
      5. 6.3.5 Output Current Monitoring
      6. 6.3.6 Die Temperature Monitoring
      7. 6.3.7 External Compensation
    4. 6.4 Device Functional Modes
      1. 6.4.1 Power Modes
      2. 6.4.2 Choosing a Feedback Resistor
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 High-Voltage, High-Precision, Composite Amplifier
        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 120V Bootstrap Amplifier
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Performance Plots
    3. 7.3 Short Circuit Protection
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Thermal Considerations
        1. 7.5.1.1 Top-Side Cooling Benefits
        2. 7.5.1.2 THS3470 Safe Operating Area
      2. 7.5.2 Layout Guidelines
      3. 7.5.3 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
    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
    1. 10.1 TAPE AND REEL INFORMATION

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • REB|42
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3 Short Circuit Protection

Many applications that the THS3470 is used with are often concerned with transient short conditions to either ground or the supplies. In systems with multiple THS3470s, "pin to pin" short scenarios can also develop when cables or PCB fixtures fail which inevitably short the output of one THS3470 to another THS3470. For this reason, all of the THS3470 parameters in the data-sheet are measured with a 5Ω isolation resistor. While this 5Ω resistor can limit the performance of the device in certain scenarios, specifically output headroom under load current and total system bandwidth, the protection benefits are highlighted below.

Note: The output isolation resistor on the THS3470 can be reduced from 5 ohms in applications where short to ground is not a concern. Even in applications where short-to-ground scenarios are unlikely, leave at least 1 ohm of isolation resistance as a safe guard against unforeseen output conditions.
CAUTION: The THS3470 can survive short to VCC, VEE, and "pin to pin" short conditions, but only within the boundaries of the safe operating area. Failure to observe the limitations outlined in Section 7.5.1.2 can result in destructive failures for the THS3470.

To test the performance of the THS3470 during short to ground scenarios, the test setup in Figure 7-11 was used. Using this setup, a function generator is set up for 10,000 cycles at 1%, 5%, and 10% duty cycles with 1 to 100ms on pulse-widths. These test are conducted on the bench, with a limited sample size, and designers need to confirm this performance in the actual application to verify device health.

Note: Make sure to monitor the DIE_TEMP pin and keep the junction temperature below 150C. Additionally, pulsing the output at lower pulse widths, or different duty cycles, can change the safe operating area of the device. See Section 7.5.1.2 for more details about transient safe operating area performance.
THS3470 THS3470 Short To Ground Test Setup Figure 7-11 THS3470 Short To Ground Test Setup

As shown in Figure 7-11, a high current mechanical relay is selected to simulate quick transient fault conditions. Mechanical relays are well suited for simulating rapid fault conditions since the relay contact is a mechanical latch that can cause a near instantaneous inrush current to the device. Solid state relays, in contrast, provide a slow increase in the resistance as the channel closes, thus providing a gradual increase in current that does not emulate a real world fault scenario. In addition, Figure 7-12 shows that the THS3470 is shorted for much more than just 10,000 cycles, since mechanical relays exhibit "bouncing" when "hot switched". These bounces can vary from 2 to 6 cycles when closing the relay, resulting in somewhere between 20,000 to 60,000 cycles for the conducted test.

Figure 7-13 shows the output current and voltage during one of the transient short conditions. If designers are looking to replicate these results, make sure the oscilloscope time scale is minimized to properly quantize the current and voltage spikes of the waveform. Designers need to choose high frequency (>5GHz) oscilloscope probes and oscilloscopes to make sure the output spikes are not filtered by the signal chain.

THS3470 THS3470 practical shorting (with mechanical relay bounce)Figure 7-12 THS3470 practical shorting (with mechanical relay bounce)
THS3470 THS3470 Output Current and Voltage during mechanical shortingFigure 7-13 THS3470 Output Current and Voltage during mechanical shorting