Application Note OptiMOS™ Datasheet Explanation

Application Note AN 2012-03
V1.1 March 2012
Infineon OptiMOSTMPower MOSFET Datasheet
Explanation
Infineon Technologies Austria AG
Power Management and Multimarket
Application Engineer
Alan Huang
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
Application Note AN 2012-03
V1.1 March 2012
Edition 2012-03-16
Published by
Infineon Technologies Austria AG
9500 Villach, Austria
© Infineon Technologies Austria AG 2011.
All Rights Reserved.
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AN 2012-03
Revision History: date (12-03-16) , V1.1
Previous Version: V1.0
Authors: Alan Huang, Power Management & Multimarket
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
Application Note AN 2012-03
V1.1 March 2012
Table of contents
1 Introduction .................................................................................................................................................... 4
2 Datasheet Parameters ................................................................................................................................... 5
2.1
Power dissipation ............................................................................................................................... 5
2.2
Drain current ...................................................................................................................................... 7
2.3
Safe operating area ........................................................................................................................... 9
2.4
Maximum transient thermal impedance ZthJC ................................................................................... 11
2.5
Typical output characteristics........................................................................................................... 12
2.6
Drain-source on-state resistance as a function of Drain current .....................................................13
2.7
Transfer characteristics .................................................................................................................... 14
2.8
Forward transconductance .............................................................................................................. 15
2.9
Drain-source on-state resistance ..................................................................................................... 17
2.10 Gate threshold voltage ..................................................................................................................... 18
2.11 Capacitances ................................................................................................................................... 19
2.12 Reverse diode characteristics .......................................................................................................... 21
2.13 Avalanche characteristics ................................................................................................................ 23
2.14 Drain-source breakdown voltage ..................................................................................................... 24
2.15 Typical gate charge .......................................................................................................................... 25
2.16 Leakage Currents ............................................................................................................................ 28
2.17 Other important parameters ............................................................................................................. 29
2.17.1 Switching Times ....................................................................................................................... 29
2.17.2 Gate resistance .........................................................................................................................30
2.17.3 Additional maximum ratings ......................................................................................................30
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
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Application Note AN 2012-03
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Introduction
A datasheet is the most important tool for the electronics engineer to understand a Power MOSFET device
and to fully appreciate its intended functionalities. Due to a great amount of information a datasheet offers, it
is sometimes deemed to be complicated and a difficult document to comprehend. Furthermore important
parameters can be often missed. This could lead to numerous problems, for example, device failure, PCB redesign, project delay, etc. The document provides a general guideline about how to read and understand a
datasheet with all its parameters and diagrams.
TM
TM
This application note describes Infineon’s OptiMOS Power MOSFET datasheets in detail. OptiMOS is
the trademark for Infineon’s low voltage (up to 300V) Power MOSFET product line. This document provides
background information on each specification parameter and explanation on each of the specification
diagrams. It aims to help the designer to acquire a better understanding of the data sheet.
The parameters and diagrams mentioned in the datasheet provide a complete picture of a MOSFET. With
such information, the designer should be able to understand the device’s intended operation, to determine
the operational limits of the device, and to compare quantitatively against different devices.
This document explains the interaction between the parameters and the influence of temperature or gate
voltage on these parameters.
This document is merely aimed to provide clear explanations of the datasheet figures. For design
recommendation, please go to www.infineon.com or contact Infineon team.
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
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Application Note AN 2012-03
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Datasheet Parameters
Datasheets might be deemed hard to analyze due to its large amount of information in a rather compact
format. Instead of reading the datasheet line by line, it is suggested for the reader to look at each topic
separately. Thus, this section clearly divides datasheets into smaller segments in order to avoid causing
confusion for the reader. Each sub-section presents a single datasheet diagram and its relevant parameters.
Note: This document uses diagrams and parameters from IPP029N06N datasheet rev2.0 as examples. For
TM
TM
the latest version of Infineon OptiMOS datasheets please refer to our OptiMOS (20V – 300V) webpage.
2.1
Power dissipation
The first diagram included in the datasheet is the power dissipation versus case temperature chart (Figure1).
At a certain case temperature, the maximum allowable power dissipation is governed as illustrated.
Power dissipation
Ptot=f(TC)
Figure 1
Power dissipation Ptot = f(TC)
There are two power dissipation parameters listed in the datasheet – total junction-to-case and total junctionto-ambient power dissipation. These two numbers can be obtained using eq. (1) and (2).The junction-to-case
thermal resistance is material and dimension dependent. With increasing case temperature, the allowable
power dissipation decreases
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Application Note AN 2012-03
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
(1)
Ptot (TC ) =
(2)
Ptot (TA ) =
V1.1 March 2012
T j − TC
RthJC
T j − TA
RthJA
Using these examples, the maximum power dissipation with the highest allowable temperature increase can
be calculated. Eq. (3) demonstrates how the numbers in the example (as in Figure 2) were derived.
Ptot (TC ) max
(3)
(175 − 25) K
=
= 136W
1.1 K
W
Ptot (T A ) max =
(175 − 25) K
= 3.0W
K
50
W
Note: The temperature difference in unit K is the same as in unit °C.
Parameter
Power dissipation
2)
Symbol Conditions
Ptot
Value
TC=25 °C
136
TA=25 °C,
RthJA=50 K/W2)
3.0
Unit
W
Device on 40 mm x 40 mm x 1.5 mm epoxy PCB FR4 with 6 cm2 (one layer, 70 μm thick) copper area for drain connection.
PCB is vertical in still air.
Figure 2
Maximum ratings for Ptot (datasheet)
The junction-to-ambient thermal resistance is layout dependent; therefore, in most cases, a footnote
regarding the junction-to-ambient thermal resistance is included. It specifies the condition where the
specified RthJA rating is estimated.
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
2.2
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Drain current
The datasheet specifies the maximum continuous drain current (ID) under different operating conditions and
the pulsed drain current (ID,pulse) as in Figure 3. The maximum pulsed drain current is specified at 4 times the
maximum continuous drain current. As the pulse width increases, the pulsed drain current rating decreases
due to the thermal characteristics of the device. This can be clearly observed in the safe operating area
diagram in Section 2.3.
ID
Continuous drain current
ID,pulse
Pulsed drain current
2)
VGS=10 V, TC=25 °C
100
VGS=10 V, TC=100 °C
100
VGS=10 V, TC=25 °C,
RthJA =50K/W 2)
24
TC=25 °C
A
400
Device on 40 mm x 40 mm x 1.5 mm epoxy PCB FR4 with 6 cm2 (one layer, 70 µm thick) copper area for drain
connection. PCB is vertical in still air.
Figure 3
Maximum ratings for ID (datasheet)
When the maximum continuous drain current depends solely on the maximum power dissipation (Section
2
2.1), the maximum ID would be defined by the rearranged Power Law (P = I *R). Substituting P in eq. (1)
derives eq. (4), where the junction-to-case temperature difference (Tj - TC), thermal resistance (RthJC), and
on-state resistance at maximum junction temperature (RDS(on),Tj(max)) come into play.
See Section 2.9 for the temperature dependency of the on-state resistance.
T j − TC
(4)
I D (TC ) =
RthJC
I D (25°C ) =
RDS ( on ),Tj (max)
(175 − 25) K
0.8 K
W = 169 A
0.0066Ω
Note: The temperature difference in unit K is the same as in unit °C.
However, in reality, additional boundary conditions, governed by bond wire diameter, chip design and
assembly, limit the maximum continuous drain current as illustrated in Figure 4. At TC = 25°C, ID is capped at
100 A instead of 169 A as calculated in eq. (4). This diagram illustrates that at low TC, maximum ID stays
constant; at high TC, it rolls off with acceleration until reaching zero at TC = Tj(max).
Note: This diagram only presents the limit of the continuous drain current limit. For pulsed current, refer to
the safe operating area diagram in Section 2.3.
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
Drain current
ID=f(TC); VGS≥10 V
Figure 4
Drain current ID = f(TC)
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
2.3
Application Note AN 2012-03
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Safe operating area
Figure 5 shows the drain current (ID) as a function of the drain-source voltage (VDS) with different pulse
lengths. This is one of the most complicated but important figure that should not be ignored in the datasheet.
This section briefly describes each region of operation and its boundary limits. In complementary to this short
section, Infineon also provides a comprehensive application note regarding this topic - Linear Mode
Operation and Safe Operating Diagram of Power MOSFETs, where details regarding the linear mode
operation and the SOA diagram are discussed.
Safe operating area
ID=f(VDS); TC=25 °C; D=0
parameter: tp
Figure 5
Safe operating area ID=f(VDS)
Note: The SOA diagram is defined for single pulses. Mathematically, the duty cycle of a single pulse is
equivalent to zero (D=0) as the period (T) is infinite.
There are several limitations in this diagram and labels (A) to (E) are used to explain the boundary limits
using the 100 µs curve as an example.
A)
The top line is a limit of the maximum pulsed drain current.
B)
This area is limited by the on-state resistance RDS(on) at maximum junction temperature.
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Power MOSFET Datasheet Explanation
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C)
At fixed TC, the device is limited by the constant power line in this area. Depending on the applied power
pulse width, the maximum power loss varies according to the thermal impedance variation. Next section
(Section 2.4) discusses about maximum transient thermal impedance at a different pulse length.
D)
In linear mode operation, there is a risk of getting hot spots at low gate-source voltages due to thermal
run away. This effect becomes more important for latest trench technologies with high current densities,
where the “zero temperature coefficient” point of the transfer characteristic is shifted to higher drain
currents. More information can be found in the application note mentioned above Linear Mode
Operation and Safe Operating Diagram of Power MOSFETs
With the hot spot effect for higher VDS and longer pulse times considered, the SOA characteristic has a
different slope in this region (eq. (5)).
(5)
E)
I D (VDS ) =
T j − TC
VDS * Z thJC
The maximum breakdown voltage (V(BR)DSS), which is determined by the technology, limits the SOA
curve on the right hand side.
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
2.4
Application Note AN 2012-03
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Maximum transient thermal impedance ZthJC
Thermal impedance (Zth) consists of two components – thermal resistance (Rth) and thermal capacitance
(Cth).
RthJC is the thermal resistance from the junction of the die to the case. The heat through this path is
generated by the power loss in the device itself. This parameter is directly linked to the temperature that the
chip reaches relative to the case.
Transient thermal impedance (ZthJC) takes also the heat capacity (CthJC) of the device into account. It is used
to estimate the temperature resulted from transient power loss.
Max. transient thermal impedance
ZthJC=f(tp)
parameter: D=tp/T
Figure 6
Maximum transient thermal impedance ZthJC=f(tp)
Figure 6 shows that for each specified duty cycle (D=tp/T), the variation of the thermal resistance (ZthJC) as a
function of the loading time tp (pulse width).
To dissipate the heat out of the device, it has to pass several different layers of its characteristic thermal
resistances and capacitances. As a result, depending on the pulse width, either the thermal resistance or the
thermal capacitance dominates the behavior of the device. The increase of the junction temperature can be
calculated as shown in eq. (6). Before power pulse is applied, Tj,start is equal to TC at thermal equilibrium.
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Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
(6)
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T j = T j ,start + ∆T j = T j ,start + Z thJC (t P , D) ∗ Ptot
The maximum of RthJC is also listed in the table section of the datasheet as in Figure 7.
Thermal characteristics
Thermal resistance, junction - case
Figure 7
2.5
RthJC
bottom
-
-
1.1
K/W
Thermal characteristics
Typical output characteristics
Typical output characteristics graph, Figure 8, illustrates the drain current ID as a function of the drain-source
voltage VDS at given gate-source voltages VGS and chip temperature Tj of 25 °C.
Typ. output characteristics
ID=f(VDS); Tj=25 °C
parameter: VGS
Ohmic
Region
Figure 8
Typical output characteristics ID=f(VDS)
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Power MOSFET Datasheet Explanation
V1.1 March 2012
For optimal efficiency, the MOSFET should be operated in the “ohmic” region, which is shown in Figure 8
(Note that this diagram includes current range up to the maximum pulsed current limit). This boundary line
between ohmic and saturation region is defined by VDS = VGS – VGS(th). At any given gate-source voltage, the
drain current of the MOSFET saturates beyond the ohmic region. As the operating point goes into the
saturation region, any further increase in drain current leads to a significant rise in drain-source voltage
(linear operation mode) and as a result conduction loss increases. In this case, if the power dissipation is not
limited, the device may fail.
Gate-source voltage (VGS) is deterministic to the MOSFET’s output characteristics as shown in the diagram.
The allowable range of VGS is specified in the table section of the datasheet as shown in Figure 9. The
effects of gate-source voltage on drain-source on-state resistance will be discussed in the Section 2.6.
VGS
Gate source voltage
Figure 9
2.6
±20
V
Gate source voltage limit
Drain-source on-state resistance as a function of Drain current
In Figure 10, for each gate-source voltage, the drain source on-state resistances over drain current curve is
directly calculated from the typical output characteristic diagram (Figure 8a) using Ohms Law, eq. (7).
(7)
RDS ( on ) ( I D ) =
VDS
ID
Notice that VGS plays an important role in this diagram. The on-resistance curves change tremendously while
a different level of VGS is applied. To fully turn on a device, a VGS of 10V is required. For normal level
devices, 10V is recommended for efficiency-optimized low drain-source on-state resistance. For logic level
devices, shifted RDS(on) curves (Figure 8b) make a lower-than-10V VGS acceptable for fast switching
applications, whereas the conduction loss due to higher RDS(on) is less critical. An example application could
be synchronous rectification at low load.
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Power MOSFET Datasheet Explanation
Application Note AN 2012-03
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b) Typ. drain-source on resistance
a) Typ. drain-source on resistance
RDS(on)=f(ID); Tj=25 °C
parameter: VGS
Figure 10
2.7
RDS(on)=f(ID); Tj=25 °C
parameter: VGS
Typical drain-source on-state resistance RDS(on)=f(ID) for a) normal level device and b)
logic level device (BSC010N04LS)
Transfer characteristics
This diagram shows the typical drain current as a function of the applied gate-source voltage. Normally the
graphs at different junction temperatures are given. For example, Figure 11 has one curve at 25°C and the
other at 175°C. All the graphs should intersect at one point, the so-called temperature stable operating point.
When the gate-source voltage applied to the MOSFET is below this point (in the example VGS < 5.2V), the
MOSFET operates with a positive temperature coefficient, meaning with increasing junction temperature the
drain current will also increase. Operating at this condition with constant VGS should be avoided due to the
possibility of thermal runaway.
Beyond the temperature stable operating point the temperature coefficient is negative, meaning that with
increasing junction temperature the drain current decreases. The MOSFET self-limits its current handling
capability at high temperatures. Operating in this region is generally safe as long as the junction temperature
stays within specification.
Note: For current level higher than the specified maximum continuous conduction current, only pulsed
currents are allowed.
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Power MOSFET Datasheet Explanation
Application Note AN 2012-03
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Typ. transfer characteristics
ID=f(VGS); |VDS|>2|ID|RDS(on)max
parameter: Tj
Figure 11
Typical transfer characteristics ID=f(VGS)
To approximate the maximum or minimum rating of this characteristic the curves can be moved in parallel
according to the min-max ratings of the threshold voltage (+/- 1V for normal level devices).
2.8
Forward transconductance
Transconductance (gfs) is a measure of sensitivity of the drain current to the variation of the gate-source
voltage. Figure 12 shows the typical forward transconductance as a function of drain current at junction
temperature of 25°C.
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Power MOSFET Datasheet Explanation
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Typ. forward transconductance
gfs=f(ID); Tj=25 °C
Figure 12
Typical forward transconductance gfs=f(ID)
The forward transconductance (gfs) can be calculated from the typical transfer characteristics diagram from
Figure 11 using eq. (8).
(8)
g fs ( I D ) =
∆I D
∆VGS
VDS
The minimum and typical values of gfs at the test current are listed in Figure 13.
Transconductance
Figure 13
gfs
|VDS|>2|ID|RDS(on)max,
ID=100 A
Transconductance in Static Characteristics section
16
80
160
-
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Application Note AN 2012-03
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
2.9
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Drain-source on-state resistance
The drain-source on-state resistance is one of the key parameters of a MOSFET. In the datasheet there are
two sections dealing with this parameter. In the table section, the typical and maximum ratings at room
temperature are listed as in Figure 14. These values are determined during production testing at the
specified conditions.
For a surface-mount device (SMD), the resistance is measured between the source pin and the backside
drain contact of the device. For a through-hole package, the RDS(on) is specified between the drain and
source pins at a defined soldering point (approx. 4.5 mm lead lengths for TO-220), which results in an
additional 0.3 mΩ of parasitic resistance.
Drain-source on-state resistance
Figure 14
RDS(on)
VGS=10 V, ID=100 A
-
2.7
2.9
VGS=6 V, ID=25 A
-
5.4
-
mΩ
Drain to Source on-state resistance
In addition to the table, the datasheet contains a diagram of the on-state resistance as a function of the
junction temperature (Figure 15). The higher the junction temperature, the higher the RDS(on) will be. Due to
this positive temperature coefficient, it is possible to use multiple devices in parallel. Note that typical and
maximum RDS(on) values are shown in the diagram.
Drain-source on-state resistance
RDS(on)=f(Tj); ID=100 A; VGS=10 V
Figure 15
Typical drain-source on-state resistance RDS(on)=f(Tj)
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Power MOSFET Datasheet Explanation
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To calculate the dependency of the junction temperature, the following formula is used:
(9)
RDS ( on ) (T j ) = RDS ( on ), 25°C ⋅ (1 +
α is a technology dependent constant. For OptiMOS
RDS(on) approximation.
TM
α
100
)
T j − 25°C
Power MOSFET, α value of 0.4 can be used for
2.10 Gate threshold voltage
The gate threshold voltage defines the required gate-source voltage at a specified drain current. During the
production, the threshold voltage is measured at room temperature with VDS = VGS and test drain currents in
the µA range. The minimum, typical, and maximum ratings are specified in the table as shown in Figure 16.
VGS(th)
Gate threshold voltage
Figure 16
VDS=VGS, ID=75 µA
2.0
2.8
3.6
V
Threshold voltage
The threshold voltage decreases with increasing junction temperature. This dependency at typical condition
as specified in the table section is illustrated in the Figure 17.
Typ. gate threshold voltage
VGS(th)=f(Tj); VGS=VDS
Figure 17
Typical gate threshold voltage VGS(th)=f(Tj)
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Power MOSFET Datasheet Explanation
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2.11 Capacitances
The capacitances of the MOSFETs are defined both in the table and the diagram sections of the data sheet.
The table specifies the ranges for the capacitances (Figure 18), and the diagram shows the dependencies of
the drain-source voltage on the capacitances (Figure 19).
The gate-source, gate-drain, and drain-source capacitances cannot be measured directly; however, they can
be calculated from the measurable input, output, and reverse transfer capacitances. The three equations
(10) below describe the relationships among them.
C iss = C GS + C GD
(10)
C oss = C DS + C GD
C rss = C GD
Dynamic characteristics
Input capacitance
Ciss
Output capacitance
Coss
Reverse transfer capacitance
Crss
Figure 18
VGS=0 V, VDS=30 V,
f=1 MHz
Dynamic characteristics: capacitances
19
-
4100
-
-
980
-
-
39
-
pF
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Power MOSFET Datasheet Explanation
Application Note AN 2012-03
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In the diagram section of the datasheet, the typical capacitances as a function of the drain-source voltage
are defined. Clear dependencies of the voltages are shown for reverse (Crss) and output (Coss) capacitances.
This is due to the change in the space charge region during the switching transition of the MOSFET
Typ. capacitances
C=f(VDS); VGS=0 V; f=1 MHz
Figure 19
Capacitance C=f(VDS)
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Power MOSFET Datasheet Explanation
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2.12 Reverse diode characteristics
The characteristics of the MOSFET’s body diode are given both in the table and the diagram sections.
In the table section, as in Figure 20, the minimum, typical and the maximum values of the diode parameters
are given.
Reverse Diode
Diode continuous forward current
IS
Diode pulse current
IS,pulse
Diode forward voltage
VSD
Reverse recovery time
trr
Reverse recovery charge
Qrr
Figure 20
TC=25 °C
VGS=0 V, IF=100 A,
Tj=25 °C
VR=30 V, IF=100 A,
diF/dt=100 A/µs
-
-
120
A
-
-
480
-
1.0
1.2
V
-
37
-
ns
-
44
-
nC
Diode characteristics
•
Diode continuous forward current: The maximum permissible DC forward current of the body diode
at the specified case temperature TC =25°C, which is normally equal to the MOSFET’s continuous
current limit.
•
Diode pulse current: The maximum permissible pulsed forward current of the inverse diode at the
specified case temperature TC =25°C, which is normally equal to the MOSFET’s pulse current limit.
•
Diode forward voltage: The source-to-drain voltage during diode’s on-state (MOSFET off-state) at
test diode forward current (IF), zero gate-source voltage (VGS) and junction temperature (Tj) of 25°C.
•
Reverse recovery time: The time needed for the reverse recovery charge to be removed. The
graphical explanation of trr is given in Figure 21.
•
Reverse recovery charge: The charge stored in the diode during its on-state. This charge needs to
be completely removed immediately following the diode conduction period before the diode’s
blocking capability resumes as shown in Figure 21. The higher the switching rate of the current (di/dt
on the order of 100A/µs or more), the higher the reverse recovery charge. The graphical explanation
of Qrr is also given in Figure 21.
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Power MOSFET Datasheet Explanation
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Figure 21 demonstrates that during device turn-on, the diode forward current (IF) drops from the on-state
drain current (ID(on)) to beneath zero. IF then recovers back to zero before the drain-source voltage (VDS)
starts to decrease (discharging of Coss). Reverse recovery occurs during the time IF is below zero, and the
charge (Qrr) can be approximated using the area between IF negative and the zero current line.
VDD
ID(on)+Irr
ID(on)
Qrr
ID
VDS
Qrr
ID(on)-Irr
Figure 21
IF
trr
Explanation of Qrr and trr
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Power MOSFET Datasheet Explanation
Application Note AN 2012-03
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Figure 22 illustrates the typical diode forward currents, IF, of the functions of source-drain voltages, VSD, at
junction temperatures, Tj, of 25°C and 175°C.
Forward characteristics of reverse diode
IF=f(VSD)
parameter: Tj
Figure 22
Typical forward diode characteristics IF=f(VSD)
2.13 Avalanche characteristics
The dependence of the pulsed avalanche current IAV on the time in avalanche tAV is presented in Figure 23.
Operating MOSFET under the conditions below the curve is allowed with consideration of the maximum
junction temperature. This characteristic is bounded by the total avalanche energy of a pulse. The longer the
avalanche pulse, the lower the maximum allowed avalanche current.
This figure also includes multiple curves for different junction temperatures at the start of the avalanche
event. It shows that with higher temperature, the avalanche capability decreases.
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Power MOSFET Datasheet Explanation
Application Note AN 2012-03
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Avalanche characteristics
IAS=f(tAV); RGS=25 Ω
parameter: Tj(start)
Figure 23
Avalanche characteristics IAS=f(tAV)
The table section of the datasheet provides the maximum single-pulse avalanche energy at a given
avalanche current and the maximum allowable single-pulse current in avalanche.
Avalanche energy, single pulse
Figure 24
EAS
ID=100 A, RGS=25 Ω
110
mJ
Avalanche energy and current
2.14 Drain-source breakdown voltage
The diagram in Figure 25 shows the linear temperature dependence of the typical minimum value of the
drain-to-source breakdown voltage over the complete allowable temperature range (-55°C…+175°C). The
table as shown in Figure 26 gives the minimum value of the breakdown voltage at 25°C.
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Power MOSFET Datasheet Explanation
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Drain-source breakdown voltage
VBR(DSS)=f(Tj); ID=1 mA
Figure 25
Drain-source breakdown voltage VBR(DSS)=f(Tj)
Drain-source breakdown voltage
Figure 26
V(BR)DSS
VGS=0 V, ID=1 mA
60
-
-
V
Drain-source breakdown voltage VBR(DSS)=f(Tj)
2.15 Typical gate charge
Figure 27 includes two diagrams: 1) typical gate charge diagram and 2) gate charge waveform.
The typical gate charge diagram shows the typical variation of the requisite gate charge to switch on a
MOSFET at given gate-source voltages and drain-source supply voltages (Vdd). The on-state current is given
as a parameter.
25
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
Application Note AN 2012-03
V1.1 March 2012
As indicated in gate charge waveform, the gate charge (Qg) comprises the gate-source charge (Qgs), the
gate-drain charge (Qgd), and the charge required to increase VGS from the plateau to the desired VGS level.
Qgs is the charge required for charging the gate-source capacitance (CGS) to the plateau level. During this
period, the drain current (ID) rises up to the load value after the gate threshold voltage (Vgs(th)) has been
reached. The drain-source voltage (VDS) behaves differently based on different loads. For resistive loads, the
drain-source voltage falls simultaneously with the rise of the drain current. For inductive loads, VDS starts
falling after the drain current reaches the load level. Before the voltage VDS falls to its on-state value (VDS =
RDS(on) *ID), the gate-to-drain capacitance (CGD), the Miller capacitance, has to be discharged. This
component is defined as the gate-to-drain charge (Qgd).
Qgs and Qgs are not sufficient to fully switch on the transistor, because the drain-source on-state resistance is
not yet minimized. Only with a charge corresponding to a full gate-source voltage (typically VGS = 10 V for
both normal level and logic level MOSFETs), the full turn-on resistance is reached, and thus static loss is
optimized. The complete gate-charge waveform changes with the drain-source voltage level (or the supply
voltage level). The parameters relevant to gate charge are also listed in the table section as shown in Figure
28.
Note: The plateau level is not fixed. It varies with load conditions.
26
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
Typ. gate charge
Gate charge waveforms
VGS=f(Qgate); ID=100 A pulsed
parameter: VDD
Figure 27
Typical gate charge VGS=f(Qgate) and gate charge waveforms
27
Application Note AN 2012-03
V1.1 March 2012
Application Note AN 2012-03
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
V1.1 March 2012
Gate Charge Characteristics5)
Gate to source charge
Qgs
-
20
-
Gate charge at threshold
Qg(th)
-
11
-
Gate to drain charge
Qgd
-
11
-
Switching charge
Qsw
-
19
-
Gate charge total
Qg
-
56
-
Gate plateau voltage
Vplateau
-
4.8
-
V
Gate charge total, sync. FET
Qg(sync)
VDS=0.1 V,
VGS=0 to 10 V
-
49
-
nC
Output charge
Qoss
VDD=30 V, VGS=0 V
-
65
-
Figure 28
VDD=30 V, ID=100 A,
VGS=0 to 10 V
nC
Gate charge and plateau voltage
2.16 Leakage Currents
There are two types of leakage currents specified for a MOSFET (Figure 29):
1) IDSS is the drain-source leakage current at a specified drain-source voltage (typically the minimum
drain-source breakdown voltage) and at VGS = 0V.
2) IGSS is the gate-source leakage current at a specified gate-source voltage (typically the maximum
gate-source voltage) and at VDS = 0V.
Zero gate voltage drain current
Gate-source leakage current
Figure 29
IDSS
IGSS
VDS=60 V, VGS=0 V,
Tj=25 °C
-
0.5
1
VDS=60 V, VGS=0 V,
Tj=125 °C
-
10
100
VGS=20 V, VDS=0 V
-
10
100
Leakage Currents
28
µA
nA
Application Note AN 2012-03
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
V1.1 March 2012
2.17 Other important parameters
2.17.1 Switching Times
Figure 30 shows the switching time parameters listed in the table section of the datasheet.
Turn-on delay time
td(on)
Rise time
tr
Turn-off delay time
td(off)
Fall time
tf
Figure 30
VDD=30 V, VGS=10 V,
ID=100 A, RG=3 Ω
-
17
-
-
15
-
-
30
-
-
8
-
ns
Switching Times
The turn-on time (ton) of a MOSFET is the sum of the turn-on delay time (td(on)) and the rise time (tr). td(on) is
measured between the 10% value of the gate-source voltage and the 90% value of the drain-source voltage.
tr is measured between the 90% value and the 10% value of the drain-source voltage.
The turn-off time (toff) of a MOSFET is the sum of the turn-off delay time (td(off)) and the fall time (tf). td(off) is
measured between the 90% value of the gate-source voltage and the 10% value of the drain-source voltage.
tf is measured between the 10% value and the 90% value of the drain-source voltage.
Figure 31 graphically defines the above mentioned parameters.
Figure 31
Definition of switching times
Note: this diagram is used for definition only and the real-life waveforms do not necessary look alike due to
different application conditions. For a better representation of the switching waveform, please refer to gate
charge waveform in Figure 27.
29
Application Note AN 2012-03
Infineon OptiMOSTM
Power MOSFET Datasheet Explanation
V1.1 March 2012
2.17.2 Gate resistance
Internal gate resistance is also listed in the datasheet as in Figure 32.
Gate resistance
Figure 32
RG
-
1.3
-
Ω
Gate resistance
2.17.3 Additional maximum ratings
The maximum ratings section of the datasheet also lists operating and storage temperature and the IEC
climate category as in Figure 33.
Operating and storage temperature
Tj, Tstg
-55 ... 175
IEC climatic category; DIN IEC 68-1
Figure 33
55/175/56
Additional maximum ratings
30
°C
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