TPS22810 Load Switch: 7 Checks for UVLO and Discharge Limits
TPS22810 Load Switch: 7 Checks for UVLO and Discharge Limits
Plan TPS22810 rails with seven checks for package current, UVLO, adjustable rise time, QOD energy limits, thermal restart and reverse paths. This is a documentation-based planning guide, not a report of independent hands-on testing.
1. Select the package before assigning a current rating
TPS22810 is a load switch for a 2.7-V to 18-V input range, not an 18-V regulator. Its SOT-23 package and WSON package have different maximum continuous-current figures, 2 A and 3 A respectively, subject to the documented thermal and operating conditions. Check the six-pin drawing and the complete order code instead of relying on a generic module title. Begin with a limited source and benign load; connector, trace and package heating can establish a lower practical current limit. Manufacturer documentation.
2. Define the EN/UVLO threshold and shutdown behavior
The active-high EN/UVLO pin can be driven by suitable logic or a divider from the source. A divider implements an application-level undervoltage threshold, distinct from the device internal VIN lockout. Do not leave EN/UVLO floating. Calculate threshold tolerance and hysteresis from the appropriate electrical limits, then verify them with a slow source ramp and representative loading. A weak battery can recover after disconnection and repeatedly restart the load, so consider system behavior rather than only the nominal turn-on voltage. Manufacturer documentation.
3. Use CT to budget inrush rather than promise current limiting
An external capacitor sets rise behavior using the documented slew relationship. The published rise-time examples apply when VIN is already stable before enable is asserted, so they are not automatically valid during a rising-input startup. Estimate capacitive current from load capacitance and voltage slope, then add the load operating demand. Measure the actual ramp and input droop. Controlled rise time is not a general programmable current limiter and does not eliminate the need for an appropriately protected upstream source. Manufacturer documentation.
4. Configure quick discharge as a real energy path
QOD can be connected directly to VOUT, connected through an external resistor, or left unused for no quick discharge. With an external resistor, total discharge resistance includes both that resistor and the internal pulldown. The stored energy is one-half capacitance multiplied by voltage squared, so a large charged rail can dissipate appreciable energy when disabled. The datasheet limits direct use of the internal discharge path to no more than 200 microfarads; larger loads require the reviewed external resistance and thermal analysis. Manufacturer documentation.
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5. Do not assume QOD survives every fault or power loss
Quick discharge is unavailable during thermal shutdown. It also stops as VIN falls below the relevant undervoltage condition, so removing system power may leave residual charge after the internal pulldown disengages. Input capacitance and the selected UVLO level affect that sequence. Check output voltage over the full off interval, not merely the first part of its decay. A rail that remains above a peripheral reset threshold may fail to perform a clean restart even though enable was briefly low. Manufacturer documentation.
6. Analyze reverse paths and automatic thermal recovery
The intrinsic body diode can conduct from output toward input if a charged or externally powered output rises above the falling input. QOD is not reverse-current blocking, and pulling an externally powered rail down through it can create another fault. Review alternate supplies and signal-pin backfeed. Thermal shutdown disables the switch and operation resumes after cooling, so a connected mechanism can restart unless the system prevents it. Keep that automatic recovery distinct from a deliberately latched-off protection design. Manufacturer documentation.
7. Test startup and shutdown as separate operating cases
Capture VIN, VOUT, EN/UVLO and current during stable-input enable, source ramp-up, ordinary disable and source removal. Use noncritical loads and do not deliberately exceed device ratings to demonstrate thermal protection. Record package, capacitances, CT, discharge resistance and load behavior with each waveform. Compare residual voltage against downstream reset requirements and repeat the intended duty cycle. The useful outcome is a validated rail sequence with bounded energy and recovery behavior, not a blanket statement that an enabled switch guarantees a healthy power domain. Manufacturer documentation.
Related reading: TPS22924C Load Switch: 7 Checks for Slow Rise and Residual Voltage.
Catalog note: The exact-part search did not return a matching Epro listing during preparation. Check the current catalog; this guide makes no price, availability or included-accessory claim.