MMDF2C03HD ON Semiconductor, MMDF2C03HD Datasheet - Page 5

• Manufacturer Part Number: MMDF2C03HD
• Description: Power MOSFET
• Manufacturer: ON Semiconductor

by recognizing that the power MOSFET is charge
controlled. The lengths of various switching intervals (Dt)
are determined by how fast the FET input capacitance can
be charged by current from the generator.
calculating rise and fall because drain−gate capacitance
varies greatly with applied voltage. Accordingly, gate
charge data is used. In most cases, a satisfactory estimate of
average input current (I
rudimentary analysis of the drive circuit so that
t = Q/I
resistive load, V
known as the plateau voltage, V
times may be approximated by the following:
t
t
V
R
and Q
is not constant. The simplest calculation uses appropriate
values from the capacitance curves in a standard equation for
voltage change in an RC network. The equations are:
t
t
r
f
d(on)
d(off)
G
GG
= Q
= Q
Switching behavior is most easily modeled and predicted
The published capacitance data is difficult to use for
During the rise and fall time interval when switching a
where
During the turn−on and turn−off delay times, gate current
100
= the gate drive resistance
10
= the gate drive voltage, which varies from zero to V
1
= R
2
2
= R
2
G(AV)
0
x R
x R
and V
G
G
V
G
G
GS
C
C
/(V
/V
iss
iss
= 0 V
GSP
Figure 6. Drain−To−Source Leakage
GSP
5
V
GG
In [V
In (V
DS
GS
are read from the gate charge curve.
, DRAIN−TO−SOURCE VOLTAGE (VOLTS)
− V
Current versus Voltage
remains virtually constant at a level
GG
GG
GSP
N−Channel
10
/(V
/V
)
G(AV)
GSP
GG
)
T
− V
SGP
J
100°C
15
) can be made from a
= 125°C
GSP
. Therefore, rise and fall
TYPICAL ELECTRICAL CHARACTERISTICS
)]
20
POWER MOSFET SWITCHING
25
http://onsemi.com
MMDF2C03HD
GG
30
5
at a voltage corresponding to the off−state condition when
calculating t
on−state when calculating t
complicate the analysis. The inductance of the MOSFET
source lead, inside the package and in the circuit wiring
which is common to both the drain and gate current paths,
produces a voltage at the source which reduces the gate drive
current. The voltage is determined by Ldi/dt, but since di/dt
is a function of drain current, the mathematical solution is
complex.
complicates the mathematics. And finally, MOSFETs have
finite internal gate resistance which effectively adds to the
resistance of the driving source, but the internal resistance
is difficult to measure and, consequently, is not specified.
resistance (Figure 9) shows how typical switching
performance is affected by the parasitic circuit elements. If
the parasitics were not present, the slope of the curves would
maintain a value of unity regardless of the switching speed.
The circuit used to obtain the data is constructed to minimize
common inductance in the drain and gate circuit loops and
is believed readily achievable with board mounted
components. Most power electronic loads are inductive; the
data in the figure is taken with a resistive load, which
approximates an optimally snubbed inductive load. Power
MOSFETs may be safely operated into an inductive load;
however, snubbing reduces switching losses.
1000
100
The capacitance (C
At high switching speeds, parasitic circuit elements
The resistive switching time variation versus gate
10
0
V
GS
Figure 6. Drain−To−Source Leakage
The
d(on)
= 0 V
V
5
DS
, DRAIN−TO−SOURCE VOLTAGE (VOLTS)
and is read at a voltage corresponding to the
Current versus Voltage
MOSFET
10
iss
) is read from the capacitance curve
P−Channel
T
d(off)
J
100°C
= 125°C
15
output
.
20
capacitance
25
also
30