ISL6505 Datasheet, PDF (15/17 Pages) Intersil Corporation – Multiple Linear Power Controller with ACPI Control Interface

ISL6505
Resistors R20, R21
These two act as a resistor divider off the V_OUT1 output; the
common connection is brought into the FB1 pin. Use the
following equation to determine them:
V_OUT1 = 0.8V * (R20 + R21)/R21.
V_OUT1 is expected to be between 1.2V and 1.5V. Note that
the undervoltage detection for this output will be typically
80% of whatever the output voltage is set at.
The sum of (R20 + R21) should equal approximately 1.2 to
1.5kΩ, in order to draw about 1mA of current. If the current is
too low (resistors are too high in value), there might be a
small offset error due to the input current of the FB1 pin. On
the other extreme, the current can go as high as 10mA, in
order to meet the minimum load current requirement.
C_OUT1 should be chosen as explained in the Linear
Regulator (V_OUT1) Compensation section.
Application Circuit
Figure 13 shows a typical application circuit for the ISL6505.
The circuit provides the 3.3V_DUAL/3.3V_SB voltage, the
Ethernet/LAN V_OUT1 voltage, the 1.2V_VID voltage
identification output, and the 5V_DUAL keyboard/mouse
voltage from +3.3V, +5V_SB, +5V, and +12VDC ATX supply
outputs. Q4 can also be a PNP transistor, such as an
MMBT2907AL. For additional, more detailed information on
the circuit, including a Bill-of-Materials and circuit board
description, see Application Note AN1053. Also see Intersil
Corporation’s web page (www.intersil.com).
+5V_IN
+12V_IN
+5V_SB
+3.3V_IN
V_OUT1
1.2V - 1.5V
C_OUT1
Q2
R_DLA
Q6
DR1
R20
FB1
R21
3V3DLSB
V_OUT3
3.3V_DUAL/3.3V_SB
FAULT
SLP_S3
SLP_S5
SHUTDOWN
Q3
C_OUT3
EN5
LAN
3V3DL
EN5
LAN
FAULT
S3
S5
SS
C_SS
3V3 5V 5VSB
C5
1V2VID
VID_CT
C_{CT_VID}
C_OUT2
V_OUT2
1.2V_VID
R2
ISL6505
VID_PG
5VDLSB
DLA
5VDL
Q5
C_OUT4
VID PGOOD
Q4
V_OUT4
5V_DUAL
GND
V_OUT1 = 1.2V to1.5V: Q6 = FDD6530A, C_OUT1 = 1000µF
V_OUT2 = 1.2V: internal FET, C_OUT2 = 10µF
V_OUT3 = 3.3V: Q2 = 2SD1802, Q3 = FDT459N, C_OUT3 = 330µF
V_OUT4 = 5.0V: Q4 = FDV340P, Q5 = FDT459N, C_OUT4 = 220µF
NOTE: Outputs may also require small (1µF) high frequency
capacitors.
C_{CT_VID} = 0.1µF
C_SS = 0.1µF
C5 = 1.0µF
R_DLA = 1K
R2 = 10K
FIGURE 13. TYPICAL ISL6505 APPLICATION DIAGRAM
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