FDMF8704V Datasheet, PDF (8/11 Pages) Fairchild Semiconductor – High Efficiency / High Frequency FET plus Driver Multi-chip Module with Internal Voltage Regulator

Application Information
Supply Capacitor Selection
bootstrap capacitance of 100nF, X7R or X5R capacitor is
adequate.
For the supply input (V_CIN) of the FDMF8704V, a local ceramic
bypass capacitor is recommended to reduce the noise and to
supply the peak current. Use at least a 1µF, X7R or X5R capac-
itor. Keep this capacitor close to the FDMF8704V V_CIN and
CGND pins.
The peak surge current rating of the boot diode should be
checked in-circuit, since this is dependent on the equivalent
impedance of the entire bootstrap circuit, including the PCB
traces. Boot diode must be sized big enough to carry the
forward charge current. Refer to Figure 14 for boot diode
average forward current.
Bootstrap Circuit
The bootstrap circuit uses a charge storage capacitor (C_BOOT)
and the external schottky diode, as shown in Figure 18. A
The bootstrap diode must have low V_F and low reverse current
leakage. Breakdown voltage of the bootstrap diode must be
greater than the BOOT to VSWH voltage.
Typical Application
V_IN 12V
NPN-TR
VAUX REG REGFB
VIN
VCIN
PWM
BOOT
HSEN
DISB
VSWH
CGND PGND _FDMF8704V
NPN-TR
VCC EN
PWM1
PWM
PWM2
Controller _PWM3
PWM4
GND
Signal Power
GND GND
VAUX REG REGFB
VIN
VCIN
PWM
BOOT
HSEN
DISB
VSWH
CGND PGND _FDMF8704V
NPN-TR
VAUX REG REGFB
VIN
VCIN
PWM
BOOT
HSEN
DISB
VSWH
CGND PGND _FDMF8704V
VOUT
NPN-TR
FDMF8704V Rev. G
VAUX REG REGFB
VIN
VCIN
PWM
BOOT
HSEN
DISB
VSWH
CGND PGND _FDMF8704V
Figure 17. Typical Application
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