SUM60N04-12LT-E3 Vishay/Siliconix, SUM60N04-12LT-E3 Datasheet - Page 7

• Manufacturer Part Number: SUM60N04-12LT-E3
• Description: MOSFET 40V 60A 110W
• Manufacturer: Vishay/Siliconix

Specifications of SUM60N04-12LT-E3

• Product Category: MOSFET
• Rohs: yes
• Transistor Polarity: N-Channel
• Drain-source Breakdown Voltage: 40 V
• Gate-source Breakdown Voltage: +/- 20 V
• Continuous Drain Current: 60 A
• Resistance Drain-source Rds (on): 9 mOhms
• Configuration: Single
• Maximum Operating Temperature: + 175 C
• Mounting Style: SMD/SMT
• Package / Case: D2PAK-5
• Fall Time: 20 ns
• Minimum Operating Temperature: - 55 C
• Power Dissipation: 3.75 W
• Rise Time: 70 ns
• Factory Pack Quantity: 800
• Tradename: TrenchFET
• Typical Turn-off Delay Time: 35 ns

APPLICATIONS
The SUM60N04-12LT provides a non-committed diode to
allow temperature sensing of the actual MOSFET chip. The
addition of one simple comparator and a few other
components is all that is required to implement a
temperature protected MOSFET. Since it has a very tight
tolerance on forward voltage, the forward voltage of the
diode can be used to provide to shutdown signal. The diode
forward voltage falls to around 0.4 V with a bias current of
250 µA when the MOSFET chip is close to the maximum
permitted temperature value. The external comparator used
to detect over temperature can also be used as a driver stage
for the MOSFET, meaning that the on/off input is logic
compatible, and can be driven from a logic gate.
A typical circuit is shown in Figure 1. Here a LMV321
operational amplifier is used to drive the MOSFET, and as a
comparator to when the maximum junction temperature is
reached. The circuit will turn on once more when the chip has
cooled to approximately 110 °C, and can cycle on and off
until the fault is cleared or the power is removed. This circuit
has assumed a 5 V rail is available, but the circuit could
easily be adapted for a 12 V rail, for example.
The LMV321 op amp was selected to give reasonable output
current to drive the MOSFET at a reasonable price. The
SC-70 package means that the protection circuit uses very
little board space. However the limited output current means
that it can only be used in slow switching applications, where
one microsecond switching time and limited dv/dt immunity
can be accepted. For PWM and other faster applications, a
buffer should be added to drive the MOSFET, or the
schematic in Figure 2 used to give fast switching speed.
Document Number: 71620
S-80272-Rev. C, 11-Feb-08
INPUT
+ 5 V
0.1 µF
C2
R3, 18 kΩ
180 kΩ
22 kΩ
Signal Ground
1 %
1 %
R1
R2
560 pF
IC1, LMV321
R7
10 kΩ
1 %
C1
0.1 µF
C3
R4, 560 kΩ, 1 %
-
+
Figure 1.
The reference voltage for the trip point is derived from the 5 V
rail, which should have reasonable voltage accuracy and
stability (± 0.5 V). A voltage reference could be added if
required, but the circuit is only intended to make the
MOSFET invulnerable to drastic faults that might otherwise
cause it to fail, not to give a precise shutdown point. 1 %
resistors are used to provide a reference voltage of 0.545 V,
giving a nominal rising trip point of around 155 °C, allowing
for the hysteresis drop over R7.
A 560 pF capacitor across the inputs of the comparator
provides some noise immunity and gives a response time of
around a micro second, just faster than the switching speed
of the MOSFET in this circuit (faster response has
diminishing returns as the turn-off time is fixed). This does
have a side effect of introducing such a delay at turn-on. If
this is an issue (although if this delay is an issue, the
switching time should be reviewed also), a separate driver
could be added using a comparator for over temperature
detection only as shown in Figure 2. The diode is then left
biased whenever the power is applied to the load and there
is no turn-on delay. In a very noisy environment C1 should be
increased and additional capacitors may also be required
from each input of the comparator to ground and on the logic
input.
R5, 18 kΩ
R6, 560 Ω
Gate
Output
Signal
SUM60N04-12LT
Vishay Siliconix
Power Ground
www.vishay.com
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