The output stages of the UCC53x0 family feature a pullup structure that delivers the highest peak-source current when it is most needed which is during the Miller plateau region of the power-switch turnon transition (when the power-switch drain or collector voltage experiences dV/dt). The output stage pullup structure features a P-channel MOSFET and an additional pullup N-channel MOSFET in parallel. The function of the N-channel MOSFET is to provide a brief boost in the peak-sourcing current, which enables fast turn-on. Fast turn-on is accomplished by briefly turning on the N-channel MOSFET during a narrow instant when the output is changing states from low to high. Table 1 lists the typical internal resistance values of the pullup and pulldown structure.
|UCC5320SC and UCC5320EC||4.5||12||0.65||Not applicable||Ω|
|UCC5390SC and UCC5390EC||0.76||12||0.13||Not applicable||Ω|
The ROH parameter is a DC measurement and is representative of the on-resistance of the P-channel device only. This parameter is only for the P-channel device, because the pullup N-channel device is held in the OFF state in DC condition and is turned on only for a brief instant when the output is changing states from low to high. Therefore, the effective resistance of the UCC53x0 pullup stage during this brief turnon phase is much lower than what is represented by the ROH parameter, which yields a faster turnon. The turnon-phase output resistance is the parallel combination ROH || RNMOS.
The pulldown structure in the UCC53x0 S and E versions is simply composed of an N-channel MOSFET. For the M version, an additional FET is connected in parallel with the pulldown structure when the CLAMP and OUT pins are connected to the gate of the IGBT or MOSFET. The output voltage swing between VCC2 and VEE2 provides rail-to-rail operation.