SBAA783 January   2026 ISOM8600 , ISOM8610

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Digital Output in PLC/DCS, Motor Drives and Robotics
    1. 1.1 Sink and Source Outputs: Supports Bidirectional Operation
    2. 1.2 PLC/DCS
    3. 1.3 Motor Drives
    4. 1.4 Robotics
  5. 2Design Procedures for Driving a Relay (Inductive Load)
    1. 2.1 Introduction to a Mechanical Relay
    2. 2.2 ISOM8600 Design Example
    3. 2.3 Test Results based on ISOM8600 and relay
      1. 2.3.1 Test 1: No Protection
      2. 2.3.2 Test 2: Capacitive Filter
      3. 2.3.3 Test 3: Zener Active Clamping Diode
  6. 3ISOM86x0 Advantages
    1. 3.1 Isolation Technology
    2. 3.2 Opto-Emulator Signal Chain
  7. 4Summary
  8. 5References

2.3.1 Test 1: No Protection

Test Circuit 1 – No Protection Figure 2-1 Test Circuit 1 – No Protection

Figure 2-1 was constructed, and the scope was set trigger on the first falling edge. The input of ISOM8600 is driven using a 5mA supply current. When the input is switched off the transient was captured.

Back EMF for Circuit 1 Figure 2-2 Back EMF for Circuit 1

The scope probe protections circuits cause clamping at 100V however the transient exceeds the recommended VOFF of the ISOM8600 above 40V. To maintain the lifetime reliability of the ISOM8600 we need consider a protection circuit to limit the back EMF.