New Industry Products

Alpha and Omega Semiconductor Launches MOSFET Devices for Hot Swap Applications

January 13, 2021 by Gary Elinoff

The 150V devices, featuring high safe operating areas and low RDS(ON)s, are aimed at challenging telecomm hot swap tasks

The AOTL66518 and AOB66518L are N-channel 150 volt MOSFETs that can serve to protect the load from high inrush current in soft-start and eFuse applications, as well as to satisfy difficult hot swap requirements.


The AOB66518L
The AOB66518L. Image courtesy of the AOB66518L datasheet


The AOB66518L from Alpha and Omega Semiconductor (AOS) is offered in a TO-263 (D2PAK) package. Alternatively, the AOTL66518 is furnished in a TOLL package that employs clip bond technology; this involves replacing multiple wires with a solid copper bridge. 

The result is that the AOTL66518, in its TOLL package, has a higher current capability than does the AOB66518L in its TO-263 package. The TOLL package also takes up 30% less board space than the TO-263 package does.


The AOTL66518.
The AOTL66518. Image courtesy of the AOTL66518 datasheet


The AOTL66518 in its TOLL package, when compared to T0-263, also features a lower thermal resistance from silicon junction to the bottom of the package case (Rthjc) compared to TO-263. 

As per AOS’s Peter H. Wilson,  “High reliability and robust linear mode performance are critical metrics in Telecommunications. AOTL66518 and AOB66518L have high SOA with low on-resistance to meet these demanding requirements,” 


What is a MOSFET’s  Safe Operating Area (SOA)?

The SOA is a critical feature for any power semiconductor device. It can be illustrated graphically by plotting voltage the “X” axis  and allowable current for that voltage on the “Y” axis. Voltages and currents below the plotted line(s) are considered “safe.”


Safe operating area of the AOB66518L.
Safe operating area of the AOB66518L. Image courtesy of the AOB66518L datasheet


“Safe” voltage/current combinations are related to the duration that they must be carried. For example, in the plot above, at 100 volts, 0.8 amps can be safely carried for 100m seconds, while about 200 amps can be safely borne for 100µ seconds


Key Comparisons for the AOTL66518 and the AOB66518L 


  Package ID IDMAX Maximum RTHJC   Maximum RDS(ON) at VGS = 10 Volts
AOTL65518 TOLL 214 Amps 710 Amps 0.3 (°C/W) 4.3 mΩ
AOB66518L TO-263 120 Amps 480 Amps 0.4 (°C/W) 5.0 mΩ


Dynamic Parameters for Both Units

For VGS = 0V, VDS =75V and f=1MHz 

  • Input capacitance: 6460pF (typical)
  • Output capacitance: 820 pF (typical)
  • Reverse transfer capacitance: 5pF (typical)
  • Gate resistance (VGS  and VDS not specified): 2.3Ω (typical)


Switching Parameters for both MOSFETS

These are typical values. Caveats are specified in detail in the data sheets.

  • Total gate charge: 80nc
  • Gate source charge: 32nc
  • Gate drain charge: 15nc
  • Output charge: 273nc
  • Turn-on delay time: 27ns
  • Turn-on rise time: 20ns
  • Turn-off fall time: 20ns


Absolute Maximums for the AOTL66518 and the AOB66518L

  • Both devices handle up to 150 volts. 
  • VGS is ±20 volts and maximum junction temperature is 175℃.  
  • Maximum avalanche current for both units is 70 amps, and avalanche energy is 735 mJ.



  • Motor control
  • Load switches
  • Battery management systems


Environmental and Physical Considerations

Both devices are “Green” products

  • 100% UIS Tested
  • 100% Rg Tested 
  • RoHS compliant
  • Halogen free

Both MOSFETs operate over a temperature range of -55 to 175℃.

1 Comment
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