ISL6520B Intersil Corporation, ISL6520B Datasheet - Page 8

• Manufacturer Part Number: ISL6520B
• Description: Single Synchronous Buck Pulse-Width Modulation (PWM) Controller
• Manufacturer: Intersil Corporation

circumvented by these MOSFETs if they have large parasitic
impedences and/or capacitances that would inhibit the gate
of the MOSFET from being discharged below it’s threshold
level before the complementary MOSFET is turned on.
Component Selection Notes:
C
C
D1 - 30mA Schottky Diode, MA732 or Equivalent
+
-
ISL6520B
IN
OUT
+5V
- Each 330mF 6.3WVDC, Sanyo 6TPB330M or Equivalent.
VCC
FIGURE 6. UPPER GATE DRIVE BOOTSTRAP
- Each 330mF 6.3WVDC, Sanyo 6TPB330M or Equivalent.
+5V
8200pF
1.00kΩ
10.0kΩ
50kΩ
+ V
GND
D
BOOT
BOOT
UGATE
PHASE
LGATE
D
-
C
BOOT
COMP/SD
8
470pF
Q1
Q2
FB
+5V
0.1µF
U
7
6
ISL6520B
1
REF
FIGURE 7. 5V to 3.3V 15A DC-DC CONVERTER
NOTE:
V
OSC
NOTE:
V
G-S
+
-
SOFT START
G-S
≈
POR
AND
≈
V
V
CC
5
CC
VCC
3
+
-
GND
-V
D
60.4Ω
ISL6520B
3.16kΩ
2 x 330µF
C
18000pF
IN
1
2
4
8
Figure 6 shows the upper gate drive (BOOT pin) supplied by a
bootstrap circuit from V
develops a floating supply voltage referenced to the PHASE
pin. The supply is refreshed to a voltage of V
diode drop (V
ISL6520B DC-DC Converter Application
Circuit
Figure 7 shows an application circuit of a DC-DC Converter.
Detailed information on the circuit, including a complete Bill-
of-Materials and circuit board description, can be found in
Application Note AN9932.
+
BOOT
UGATE
PHASE
L
Q
LGATE
1
1
- 3.1µH Inductor, Panasonic P/N ETQ-P6F2ROLFA or Equivalent.
, Q
2
- Fairchild MOSFET; HUF76143.
D
) each time the lower MOSFET, Q
Q
Q
1
2
CC
0.1µF
D
1
L
. The boot capacitor, C
1
2 x 1µF
3 x 330µF
C
OUT
+
CC
0.1µF
V
less the boot
OUT
BOOT
2
, turns on.
,