JAJSET0B December 2018 – October 2019 TPS7A26
PRODUCTION DATA.
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The power-good (PG) pin is an open-drain output and can be connected to a regulated supply through an external pullup resistor. The maximum pullup voltage is listed as VPG in the Recommended Operating Conditions table. For the PG pin to have a valid output, the voltage on the IN pin must be greater than VUVLO(RISING), as listed in the Electrical Characteristics table. When the VOUT exceeds VIT(PG,RISING), the PG output is high impedance and the PG pin voltage pulls up to the connected regulated supply. When the regulated output falls below VIT(PG,FALLING), the open-drain output turns on and pulls the PG output low after a short deglitch time. If output voltage monitoring is not needed, the PG pin can be left floating or connected to ground.
By connecting a pullup resistor to an external supply, any downstream device can receive power-good (PG) as a logic signal that can be used for sequencing. Make sure that the external pullup supply voltage results in a valid logic signal for the receiving device.
The recommended maximum PG pin sink current (IPG-SINK) and the leakage current into the PG pin (ILKG(PG)) are listed in the Electrical Characteristics table.
The PG pullup voltage (VPG_PULLUP), the desired minimum power-good output voltage (VPG(MIN)), and ILKG(PG) limit the maximum PG pin pullup resistor value (RPG_PULLUP). VPG_PULLUP, the PG pin low-level output voltage (VOL(PG)), and IPG-SINK limit the minimum RPG_PULLUP. Maximum and minimum values for RPG_PULLUP can be calculated from the following equations:
For example, if the PG pin is connected to a pullup resistor with a 3.3-V external supply, from Equation 2, RPG_PULLUP(MAX) is 11 MΩ. From Equation 3, RPG_PULLUP(MIN) is 5.8 kΩ.