ISL6529 Intersil Corporation, ISL6529 Datasheet - Page 12

• Manufacturer Part Number: ISL6529
• Description: Dual Regulator.Synchronous Rectified Buck PWM and Linear Power Controller
• Manufacturer: Intersil Corporation

temperature rise according to package thermal-resistance
specifications. A separate heatsink may be necessary
depending upon MOSFET power, package type, ambient
temperature, air flow, and load current requirements.
The gate drive to the switching transistors ranges from
slightly below 12V to ground. Because of the large voltage
swing, logic-level transistors are not necessary in this
application.
However, if logic-level transistors or transistors with low
V
be exercised, as the low gate threshold could lead to some
shoot-through despite counteracting circuitry present aboard
the ISL6529.
ISL6529 Converter Application Circuit
GS(on)
VOUT2
(1A)
2.5V
are used, close attention to layout guidelines should
+3.3V
Q1, Q2
Q3
L1
L2
C14
Q3
1µF
FIGURE 9. POWER SUPPLY APPLICATION CIRCUIT FOR A GRAPHICS CONTROLLER
IRF7313
919AS-4R7M
MTD3055V
919AS-1R0N
1000µF
C7
C12
1500µF
1.0kΩ
12
4.64kΩ
R13
R5
2.15kΩ
R6
6.8kΩ
470pF
R12
C4
IR
Fairchild
TOKO
TOKO
1µF
+5V
C5
FB2
DRIVE2
GND
5VCC
1µH
ISL6529
ISL6529
L2
12VCC
N-Channel MOSFET Transistor Selection
The main criteria for selection of the linear regulator pass
transistor is package selection for efficient removal of heat.
Select a package and heatsink that maintains the junction
temperature below the rating with a maximum expected
ambient temperature.
The power dissipated in the linear regulator is:
where I
nominal output voltage of the linear regulator.
Linear Regulator Output Capacitors
The output capacitors for the linear regulator provide
dynamic load current. Output capacitors should be selected
for transient load regulation.
P
PGND
UGATE
LGATE
LINEAR
COMP
+12V
C15
1µF
FB
O
≅
is the maximum output current and V
I
O
×
(
470µF
V
1.0kΩ
R4
C6
IN
–
10.7kΩ
R2
V
C1
47nF
OUT
)
Q1
Q2
1.2nF
C2
10Ω
R3
4.7µH
C8
4.7µF
1.0kΩ
L1
470µF
R1
C9
47nF
C3
OUT
C10
1µF
(EQ. 18)
is the
VOUT1
(6A)
1.6V