TPS23750
TPS23770
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SLVS590A–JULY 2005–REVISED AUGUST 2005
TMR controls softstart, overload time-out, and automatic restart on overload, which is referred to as a hiccup
function.
VBIAS –This 5-V bias supply powers the bulk of the converter functions. VBIAS can be used to power the feedback
optocoupler in isolated applications. External loading should be minimized to avoid excessive power dissipation.
VBIAS has a UVLO function that inhibits converter operation at outputs of less than 4.6 V. VBIAS should be
bypassed with a capacitor between 0.08 µF and 1.5 µF. Do not apply external bias to this pin.
VDD – This is the positive power pin to the IC.
VSS – Common ground for the internal PoE circuits. This pin is connected to the low side of the rectified PoE
voltage. An internal power MOSFET connects RTN to VSS under control of the PoE section. The PowerPAD on
the bottom of the package is internally connected to VSS. The PowerPAD is used to remove heat from the die
through the PCB.
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