SLVSIR8 June 2026 TPS61383-Q1
PRODUCTION DATA
The characteristics of the input supply must be capable of delivering the required input current to the loaded regulator. The average input current is calculated with the following equation.
where
If the regulator is connected to the input supply through long wires or PCB traces, special care is required to achieve good performance. The parasitic inductance and resistance of the input cables has adverse effect on the operation of the regulator. The parasitic inductance, in combination with the low-ESR ceramic input capacitors, results in LC resonant circuit. This LC ring results in overvoltage transients at the input to the regulator or tripping UVLO. Consider that the supply voltage dips when a load transient is applied to the output depending on the parasitic resistance and inductance of the harness and characteristics of the supply. If the application is operating close to the minimum input voltage, this dip causes the regulator to momentarily shut down and reset. The best way to solve these kinds of issues is to reduce the distance from the input supply to the regulator. Additionally, use an aluminum input capacitor in parallel with the ceramics. The moderate ESR of this type of capacitor helps damping the input resonant circuit and reduce any overshoots or undershoots. A value in the range of 47µF to 100µF is typically sufficient to provide input damping and help hold the input voltage steady during large load transients.