SLVUC68 September 2021 TPSM5601R5H
In an IBB configuration, the enable voltage thresholds are referenced to –VOUT instead of GND as in a typical non-inverting buck. This behavior can cause difficulties enabling or disabling the device. Therefore, the TPSM5601R5H-IBB-EVM includes a level-shifting circuitry (Figure 5-1) to alleviate any problems associated with the offset EN threshold voltages. This eliminates the need for negative EN signals. If the enable/disable feature is not needed, then remove resistor R9 located on the bottom side of the EVM and place the jumper on VIN_EN jumper (J7). For a deeper understanding of the EN level-shifting circuitry, see the Inverting Application for the TPSM5601R5H Application Report.
The following are connection steps required to use enable/disable level-shifting circuitry: