HIP6501A

FN4749 Rev 6.00

Page 12 of 14

December 30, 2004

Q4

If a P-Channel MOSFET is used to switch the 5VSB output

S4/S5 states (as dictated by EN5VDL status), then, similar to

the situation where Q1 is a MOSFET, the selection criteria of

this device is also proper voltage budgeting. The maximum

so a logic level MOSFET needs to be selected. If a PNP

device is chosen to perform this function, it has to have a low

saturation voltage while providing the maximum sleep-state

current and have a current gain sufficiently high to be

saturated using the minimum drive current (typically 20mA;

4mA during soft-start).

Q3, Q5

The two N-Channel MOSFETs are used to switch the 3.3V

and 5V inputs provided by the ATX supply into the

3.3VDUAL and 5VDUAL outputs, respectively, while in

cases as well, unlike the PMOS, however, these NMOS

(approximately 8V and 7V, respectively).

Q2

The NPN transistor used as sleep-state pass element on the

operating temperature range.