ISL6527 Intersil Corporation, ISL6527 Datasheet - Page 12

• Manufacturer Part Number: ISL6527
• Description: Single Synchronous Buck Pulse-Width Modulation (PWM) Controller
• Manufacturer: Intersil Corporation

minimize the voltage drop across the bootstrap capacitor
during the on-time of the upper MOSFET. Initial calculations
with V
bootstrap capacitor range.
For example, consider an upper MOSFET is chosen with a
maximum gate charge, Q
drop across the bootstrap capacitor to 1V results in a value
of no less than 0.1µF. The tolerance of the ceramic capacitor
should also be considered when selecting the final bootstrap
capacitance value.
A fast recovery diode is recommended when selecting a
bootstrap diode to reduce the impact of reverse recovery
Component Selection Notes:
C3,8,9 - Each 150mF, Panasonic EEF-UE0J151R or Equivalent.
D1 - 30mA Schottky Diode, MA732 or Equivalent
L1 - 1µH Inductor, Panasonic P/N ETQ-P6F1ROSFA or Equivalent.
Q1- Fairchild MOSFET; ITF86110DK8.
0.8V External Reference
BOOT2
no less than 4V will quickly help narrow the
GND
3.3V
0.22µF
g
, of 100nC. Limiting the voltage
C4
12
TP1
10
4
5
1
9
CT1
CT2
CPGND
GND
REF_IN
FIGURE 8. 3.3V to 2.5V 5A DC-DC CONVERTER
COMP
8
6.49kΩ
0.1µF
C1
R2
ISL6527
C10
33pF
VCC
5600pF
11
C11
OCSET/SD
ISL6527
CPVOUT
FB
UGATE
PHASE
LGATE
7
BOOT
R5
U1
13
14
12
charge loss. Otherwise, the recovery charge, Q
have to be added to the gate charge of the MOSFET and
taken into consideration when calculating the minimum
bootstrap capacitance.
ISL6527 DC-DC Converter Application
Circuit
Figure 8 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 AN9994.
6
3
2
TP3
D1
C7
124Ω
R4
2.26kΩ
R3
1000pF
0.1µF
9.76kΩ
8200pF
C2
R1
C12
Ceramic
C5
10µF
Q1
C6
C3
1µF
L1
C8,9
2.5V @ 5A
RR
, would
GND