MCP1406 Microchip Technology, MCP1406 Datasheet - Page 11

• Manufacturer Part Number: MCP1406
• Description: 6A High-Speed Power MOSFET Drivers
• Manufacturer: Microchip Technology

The MCP1406/07 devices have two pins each for V
OUTPUT, and GND. Both pins must be used for proper
operation. This also lowers path inductance which will,
along with proper decoupling, help minimize ringing in
the circuit.
Placing a ground plane beneath the MCP1406/07 will
help as a radiated noise shield as well as providing
some heat sinking for power dissipated within the
device.
4.5
The total internal power dissipation in a MOSFET driver
is the summation of three separate power dissipation
elements.
4.5.1
The power dissipation caused by a capacitive load is a
direct function of frequency, total capacitive load, and
supply voltage. The power lost in the MOSFET driver
for a complete charging and discharging cycle of a
MOSFET is:
© 2006 Microchip Technology Inc.
Where:
Where:
f = Switching frequency
C
V
P
P
P
P
T
DD
T
L
Q
CC
Power Dissipation
= Total load capacitance
= Total power dissipation
= Load power dissipation
= Quiescent power dissipation
= MOSFET driver supply voltage
= Operating power dissipation
CAPACITIVE LOAD DISSIPATION
P
P
T
L
=
=
P
f C
L
×
+
P
T
Q
×
+
V
DD
P
CC
2
DD
,
4.5.2
The power dissipation associated with the quiescent
current draw depends upon the state of the input pin.
The MCP1406/07 devices have a quiescent current
draw when the input is high of 0.13 mA (typ) and
0.035 mA (typ) when the input is low. The quiescent
power dissipation is:
4.5.3
The operating power dissipation occurs each time the
MOSFET driver output transitions because for a very
short period of time both MOSFETs in the output stage
are on simultaneously. This cross-conduction current
leads to a power dissipation describes as:
Where:
Where:
P
Q
CC = Cross-conduction constant (A*sec)
f = Switching frequency
V
I
D = Duty cycle
I
V
QH
QL
=
DD
DD
= Quiescent current in the low state
= Quiescent current in the high state
(
= MOSFET driver supply voltage
= MOSFET driver supply voltage
QUIESCENT POWER DISSIPATION
OPERATING POWER DISSIPATION
I
QH
P
CC
×
D
=
MCP1406/07
+
CC f
I
QL
×
×
(
×
1 D
V
–
DS22019A-page 11
DD
)
) V
×
DD