SLVSDO0F September 2018 – March 2024 TPS7H2201-SEP , TPS7H2201-SP
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
When VIN is powered but the TPS7H2201 is disabled (EN is low), the internal FETs are disabled, creating a high impedance path from VIN to VOUT. However, there are parasitic leakage paths that can cause VOUT to slowly charge. The forward leakage current, IF, indicates how much current flows from VIN to VOUT during this situation. The maximum forward of the TPS7H2201-SP current is specified at 250 μA across voltage, temperature and radiation.
Some applications need to pay particular attention to this behavior. Is particularly relevant when VOUT is a high impedance node (and therefore the leakage current goes entirely to charging VOUT instead of being dissipated). By using the basic capacitor equation shown in Equation 11, the time for the voltage to rise to a given value can be theoretically calculated.
where
For example, with a 7-V input voltage and a 220-µF output capacitance, VOUT typically charge to 7 V in approximately 6.2 seconds (using IF = 150 μA, ΔVOUT = 7 V, COUT = 220 µF).
If the output voltage must remain below a certain value, a pull-down resistor can be utilized with a value as calculated by using Equation 12.
where
For example, placing a 2.6-kΩ resistor between VOUT and ground makes sure VOUT does not rise above 0.65-V worse case due to the IF current. The resistor need to be able to handle the worst case power dissipation when the switch is enabled and VOUT ≈ VIN.