APPLICATION NOTE
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The NIV3071 eFuse Advantages
in Automotive Applications
AND90247/D
Introduction

does not need to be replaced in the event of a fault as its
protection features will protect both the device and the load,
enabling a distributed zonal architecture throughout thevehicle. There are two versions of this device, latching andauto−retry. In the event of a fault, a latching device will latch
off until a command is sent by toggling the EN pin or power
cycling. An auto−retry device will wait either 3 ms or ifentering the thermal shutdown protection enough time tocool the die down before attempting to turn back on.
Another advantage over traditional fuses is the NIV3071
has a very fast short circuit response time of 6 ms in the eventof a fault. This severally reduces the peak current and power
dissipation when compared to traditional fuses as seen inFigure 1, which benefits the peak current and power ratingof any associated wire harness. Additionally, the quick
response time prevents the input power supply fromsagging, which will protect any safety critical and otherloads that are using the same power supply as illustrated inFigure 2.

The electrification in automobiles has driven thereplacement of mechanical relays and melting fuses withelectronic fuses “eFuses” to enable more compact andefficient solutions. The NIV3071 eFuse protects
downstream circuitry from overcurrent, overtemperatureand short to ground events, and can provide a fault indicatorwith the open drain FAULT pin. This device has four
integrated high side channels, which can be controlled
independently with the EN pins or paralleled together forlarger loads. The device has both a configurable current limit
and turn−on time, allowing for a wide variety of loads.
NIV3071 in Automotive Applications

There are several advantages to using the NIV3071 inautomotive applications. The device is in a 6x5 mm package,
greatly reducing the board area needed when compared
traditional solutions such as mechanical relays and melting
fuses. In comparison to these traditional solutions the eFuse

Figure 1. Left Blade Fuse, Center PTC, Right NIV3071 eFuse© Semiconductor Components Industries, LLC, 2023

August, 2023 − Rev. 01Publication Order Number:AND90247/D

AND90247/D

Figure 2. Multiple eFuses on the same Power Supply

The NIV3071 is made up of four integrated channels
which can be driven either independently or paralleled
together to supply more load current, described in Figure 3.
The inputs can be powered by different supplies or acommon supply. With this flexibility, the NIV3071 caneasily support both 48 V and 12 V loads through the samedevice. This is extremely beneficial in automotive
applications, where the presence of 48 V and 12 V loads inan ECU (electronic control unit) could be protected throughone device.

Figure 3. Configurations of the NIV3071

This device is intended to be used with regulated power
supplies. Other automotive applications where cold crankand load dump are required are not recommended due to theUVLO and lack of reverse current protection on this device.

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AND90247/D
Dynamic Features and Considerations

the event of any momentary voltage spike on the EN pin or
if the microcontroller has a small delay when powering up
in sending the correct logic signal, ensuring a safe start into
the load at the time it is designed to be engaged.
The Turn−on Time feature can be configured by an
external capacitor. To properly use the Turn−on Time feature
the type of load must be considered. While there is a benefit
to increasing the Turn−on Time for capacitive loads byreducing the inrush current spike, a resistive load will draw
a continuous increasing current as the output is rising. From
this dc current and the prolonged output Turn−on Time inwhich creates a voltage gradient across the device, thedevice will dissipate a large amount of power and potentiallyenter thermal shutdown to protect the die before the device
can fully turn on. This will be dependent on the input
voltage, output voltage Turn−on Time, load current profile
and ambient temperature.

Turn−on Timing
The NIV3071 has a controlled turn on which can bedescribed by the On Delay Time (Tdly(On)) and Turn-on
Time (tRAMP(On)), seen in Figure 4:

Inrush Current Control
The NIV3071 and other eFuse’s at onsemi have an inrush
current control feature to limit the peak current seen whenturning on capacitive loads. This feature is governed by an
external pin which can be left open or with a low value
ceramic capacitor between the dvdt pin and ground. By
adding capacitance to this pin, the output Turn-on Time iselongated which allows for lower peak currents, which canbe expressed by:

Figure 4. Turn−on Timing of the NIV3071

The On Delay Time is defined as the time between the EN
pin reaching 90% of its maximum value to 10% of thenominal voltage on the output. The Turn-on Time is definedas the time between 10% to 90% of the nominal voltage on
the output. The On Delay Time is used as a deglitch filter inI peak + C load

dv outdtThe following relation can be used to control the peakcurrent with a given Cload:

Figure 5. Turn−on Time vs dv/dt Pin Capacitance

Using above equation and Figure 5., the user can set a max
inrush current when turning on into a capacitive load. A test
case is provided below in Figures 6 and 7:

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AND90247/DFigure 6. Test Case for Inrush Current Control

Figure 7. Measured Result from Test Casewww.onsemi.com
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turn off, creating a reverse voltage across the device as theoutput capacitor maintains the voltage on the output before
fully discharging. The negative voltage at the same timebiases the Schottky, providing a path to discharge around thedevice as seen in the measurement in Figure 9.

Large Capacitive Loads and SchottkyWith larger capacitive loads (and low current DC loads),a Schottky diode can be placed from output to input as seenin Figure 8. to protect the body diode of eFuse against
excessive reverse current when powering down the device.
Once the input voltage falls below UVLO the device will

IN x

OUT x
NIS(V)3071

Current measurement

CLOAD

Figure 8. Using a Schottky to Protect Against Reverse Current Conditions

Figure 9. Measurement of Current through the Device and through the External Schottky Diode

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5RLOADAND90247/D
Additionally, a RC snubber circuit can be used in parallelwith load. If the application has an expected inductance over
5 uH, an external Schottky or snubber is highly
recommended.

Switching Off with Inductive Loading
During a short to ground or overcurrent fault event on theoutput, the NIV3071 is designed to quickly turn off toprotect both device and downstream circuitry. If there are
significant inductances in the power path, such as cabling,
the quick turn off will result in voltage spikes that can exceed
the devices voltage ratings. To mitigate these voltage spikes
several options can be used. A TVS diode could be placed
between the input and ground, while a Schottky diode can beplaced in parallel with the load as a freewheeling diode.

Summary

The NIV3071 has many advantages in automotiveapplications as the trend of electrification trends and theprevalence of 48 V systems continues to increase in theautomotive markets.

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