JAJSJ29D May 2020 – October 2021 TPS61378-Q1
PRODUCTION DATA
There are two ways to set the output voltage of the TPS61378-Q1: adjustable or fixed. If the resistance between FB and GND is higher than 14.4 kΩ and less than 100kΩ during start-up, the TPS61378-Q1 works as an adjustable output version. The FB pin is connected to the negative input of the internal error amplifier directly. The output voltage can be programmed by adjusting the external resistor divider RUpper and RLower according to Equation 3. When the output voltage is in well regulation, the typical voltage at the FB pin is VREF of 0.8 V.
For some applications where the resistor needs to be as low as possible, the low-side divider can be 20 kΩ. The reference voltage is 0.8 V and the high-side divider is 205 kΩ for 9-V output voltage.
For other applications without specific requirements on divider resistance, you can choose RLower to be approximately 80.6 kΩ. Slightly increasing or decreasing RLower can result in closer output voltage matching when using standard values resistors.
For the best accuracy, RLower is recommended to be smaller than 100 kΩ to ensure that the current flowing through RLower is at least 100 times larger than FB pin leakage current. Changing RLower towards the lower value increases the robustness against noise injection. Changing RLower to higher values reduces the quiescent current to achieve higher efficiency at light load.
If the resistance between FB and GND is less than 9.6kΩ during start-up, the TPS61378-Q1 works as a fixed output voltage version. The TPS61378-Q1 uses the internal resistor divider.
For 5-V fixed output voltage, RLower is between 0Ω and 2.4kΩ and RUpper should be removed.
For 5.25-V fixed output voltage, RLower is between 3.6kΩ and 4.8 kΩ and RUpper should be removed.
For 5.5-V fixed output voltage, RLower is between 7.2kΩ and 9.6kΩ and RUpper should be removed.