hip6500 Intersil Corporation, hip6500 Datasheet - Page 13

• Manufacturer Part Number: hip6500
• Description: Multiple Linear Power Controller With Acpi Control Interface
• Manufacturer: Intersil Corporation

the supplied outputs. At the transition between active and
sleep states, this phenomena could result in the 5VSB
voltage dropping below the POR level (typically 4.1V) and
temporarily disabling the HIP6500. The solution to a
potential problem such as this is using larger input
capacitors with a lower total combined ESR.
Transistor Selection/Considerations
The HIP6500 usually requires one P-Channel (or bipolar
PNP), two N-Channel MOSFETs and two bipolar NPN
transistors.
One important criteria for selection of transistors for all the
linear regulators/switching elements is package selection for
efficient removal of heat. The power dissipated in a linear
regulator/switching element is
Select a package and heatsink that maintains the junction
temperature below the rating with the maximum expected
ambient temperature.
Q1
The active element on the 2.5V/3.3V
different requirements for each of the two voltage settings. In
2.5V systems utilizing RDRAM (or voltage-compatible)
memory, Q1 has to be a bipolar NPN capable of conducting
up to 7.5A and exhibit a current gain (h
this current and 0.7V V
is actively regulated while in active state. In 3.3V systems
(SDRAM or compatible) Q1 has to be an N-Channel
MOSFET; in such systems the MOSFET is switched on
during active state (S0, S1). The main criteria for the
selection of this transistor is output voltage budgeting. The
maximum r
can be expressed with the following equation:
r
V
V
I
The gate bias available for this MOSFET is of the order of 8V.
DS ON max
OUTmax
P
OUTmin
INmin
LINEAR
- minimum input voltage
- maximum output current
- minimum output voltage allowed
=
DS(ON)
I
=
O
V
-------------------------------------------------- -
INmin
V
IN
allowed at highest junction temperature
I
OUTmax
–
–
V
CE
V
OUT
OUTmin
; in such systems the 2.5V output
13
, where
MEM
fe
) of minimum 40 at
output has
HIP6500
Q5
If a P-Channel MOSFET is used to switch the 5VSB output
of the ATX supply into the 5V
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
r
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
current and have a current gain sufficiently high to be
saturated using the minimum drive current (typically 20mA).
Q3,4
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
(S0, S1) state. Similar r
as well. Unlike the PMOS, however, these NMOS transistors
get the benefit of an increased V
and 7V, respectively).
Q2
The NPN transistor used as sleep state pass element (Q2)
on the 3.3V
of 100 at 1.5V V
operating temperature range.
DS(ON)
, however, has to be achieved with only 4.5V of V
DUAL
CE
output has to have a minimum current gain
and 500mA I
DS(ON)
DUAL
criteria apply in these cases
GS
CE
output during S3 and S5
drive (approximately 8V
throughout the in-circuit
GS
,