12

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

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 active

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

and 7V, respectively).

Q2

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

operating temperature range.

HIP6501A