MCP14628-E/MF Microchip Technology, MCP14628-E/MF Datasheet - Page 11

• Manufacturer Part Number: MCP14628-E/MF
• Description: IC,Dual MOSFET Driver,LLCC,8PIN,PLASTIC
• Manufacturer: Microchip Technology
• Type: High Side/Low Sider

Specifications of MCP14628-E/MF

• Configuration: High and Low Side, Synchronous
• Input Type: PWM
• Delay Time: 18ns
• Current - Peak: 2A
• Number Of Configurations: 1
• Number Of Outputs: 2
• High Side Voltage - Max (bootstrap): 36V
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Rise Time: 10 ns
• Fall Time: 10 ns
• Supply Voltage (min): 4.5 V
• Supply Current: 0.08 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Number Of Drivers: 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.0
5.1
The selection of the bootstrap capacitor is based upon
the total gate charge of the high-side power MOSFET
and the allowable droop in gate drive voltage while the
high-side power MOSFET is conducting.
EQUATION 5-1:
For example:
A low ESR ceramic capacitor is recommend with a
maximum voltage rating that exceeds the maximum
input voltage, V
V
of C
5.2
Proper decoupling of the MCP14628 is highly recom-
mended to help ensure reliable operation. This decou-
pling capacitor should be placed as close to the
MCP14628 as possible. The large currents required to
quickly charge the capacitive loads are provided by this
capacitor.
recommended.
5.3
The power dissipated in the MCP14628 consists of the
power loss associated with the quiescent power and
the gate charge power.
The quiescent power loss can be calculated by the
following equation and is typically negligible compared
to the gate drive power loss.
© 2008 Microchip Technology Inc.
Where:
SUPPLY
ΔV
BOOT
C
Q
DROOP
BOOT
GATE
. It is also recommended that the capacitance
APPLICATION INFORMATION
Bootstrap Capacitor Select
Decoupling Capacitor
Power Dissipation
not exceed 1.2 uF.
A
C
CC
low
BOOT
=
=
=
ΔV
, plus the maximum supply voltage,
C
Q
DROOP
BOOT
GATE
ESR
bootstrap capacitor value
total gate charge of the high-
side MOSFET
allowable gate drive voltage
droop
≥
-----------------------
Δ
≥ 0.15 uF
= 30 nC
= 200 mV
Q
V
ceramic
DROOP
GATE
capacitor
is
EQUATION 5-2:
The main power loss occurs from the gate charge
power loss. This power loss can be defined in terms of
both the high-side and low-side power MOSFETs.
EQUATION 5-3:
5.4
Proper PCB layout is important in a high current, fast
switching circuit to provide proper device operation.
Improper component placement may cause errant
switching, excessive voltage ringing, or circuit latch-up.
There are two important states of the MCP14628
outputs, high and low.
flow paths when the outputs of the MCP14628 are high
and the power MOSFETs are turned on. Charge
needed to turn on the low-side power MOSFET comes
from the decoupling capacitor C
this capacitor through the internal LOWDR circuitry,
into the gate of the low-side power MOSFET, out the
source, into the ground plane, and back to C
reduce any excess voltage ringing or spiking, the
inductance and area of this current loop must be
minimized.
Where:
Where:
P
P
HIGHDR
LOWDR
P
Q
Q
I
V
VCC
GATE
HIGH
F
P
V
LOW
P
CC
P
SW
Q
CC
P
HIGHDR
PCB Layout
LOWDR
GATE
=
=
=
P
=
=
=
=
=
=
=
Q
=
=
=
=
Quiescent Power Loss
No Load Bias Current
Bias Voltage
P
Total Gate Charge Power Loss
High-Side Gate Charge Power
Loss
Low-Side Gate Charge Power
Loss
Bias Supply Voltage
High-Side MOSFET Total Gate
Charge
Low-Side MOSFET Total GAte
Charge
Switching Frequency
I
V
V
HIGHDR
VCC
Figure 5-1
CC
CC
MCP14628
×
×
×
Q
Q
VCC
V
+
HIGH
LOW
CC
depicts the current
. Current flows from
P
DS22083A-page 11
LOWDR
×
×
F
F
SW
SW
VCC
. To