Electric tool motor drive: explosive power of TOLT packaged MOSFET

——IMWTEK UP009N10LT vs. Competitors: Practical Comparison

I. Application Scenarios and Technical Challenges

The motor drive systems of electric tools (such as drills and angle grinders) need to withstand instantaneous pulse currents of up to several hundred amperes while facing harsh environments like frequent start-stops, vibrations, and high temperatures. Traditional TO-220 packaged MOSFETs, due to their large size and high thermal resistance, are difficult to meet the requirements of high power density. However, the TOLT (TO-Leadless Top-side cooling) package, through its top-side cooling design, reduces thermal resistance by over 40%, becoming the preferred choice for the new generation of brushless motor drives.

Core Pain Points:

1. Instantaneous Peak Current: The current during drill startup can reach 5-10 times the rated value, requiring the MOSFET to have low RDS(on) and high surge current capability.
2. Thermal Limitations: The internal temperature of enclosed tools can reach over 80°C, and traditional packages cause junction temperatures to rise rapidly due to long thermal paths.
3. Space Compression: Cordless tools are trending towards miniaturization, and MOSFETs need to achieve multi-parallel connections within smaller PCB areas.

II. Product Comparison: IMWTEK UP009N10LT vs. Infineon IPB030N10N

III. Practical Testing: Performance Verification of Drill Motor Drives

Testing Platform:

• Motor Model: BLDC 18V/500W brushless motor
• Control Scheme: FOC algorithm, PWM frequency of 20kHz
• Cooling Conditions: Fanless passive cooling, ambient temperature of 25°C

Testing Items:

1. Start-up Response Time: Acceleration time from 0 to rated speed (load torque of 5N·m).
2. Temperature Rise Comparison: MOSFET case temperature after 10 minutes of full-load operation.
3. Efficiency Curve: Overall system efficiency at different loads.

Testing Results:

• Start-up Response: IMWTEK UP009N10LT: Acceleration time of 82ms (Infineon's solution is 92ms), benefiting from lower Qg and RDS(on), which shortened the current rise time.
• Key Waveform: Figure 1 shows that the VGS rising edge of UP009N10LT is 15ns faster than the competitor's, reducing conduction loss during the switching transition period.
• Temperature Rise Performance: IMWTEK UP009N10LT: Case temperature of 68°C (Infineon's solution is 78°C), with TOLT packaging directly contacting the heatsink for a shorter thermal path.
• Thermal Imaging: Figure 2 compares and shows that Infineon's hot spots are concentrated in the chip center, while IMWTEK's heat is evenly distributed to the package edges.
• System Efficiency: IMWTEK UP009N10LT: Peak efficiency of 93.5% (Infineon's is 92.1%), with the efficiency gap widening to 2.3% at 50% load.

IV. Design Suggestions: How to Optimize TOLT Package Layout

Thermal Design:

• Use a 0.5mm-thick thermal pad to adhere the TOLT top to the metal case, reducing thermal resistance further to 28°C/W.
• Avoid placing vias on the thermal path to prevent heat flow from being blocked by PCB inner layers.

Parallel Current Sharing:

• Due to the low parasitic inductance of the TOLT package, when four UP009N10LTs are paralleled, it is recommended to adopt a symmetrical star layout (Figure 3) to ensure that the current deviation of each tube is less than 3%.
• Match the drive resistors to ±5% accuracy to suppress parallel oscillation risks.

EMI Suppression:

• By series-connecting a 2.2Ω resistor and paralleling a 100pF capacitor at the gate, the switching noise (dV/dt) can be reduced from 50V/ns to 30V/ns.
• Measured comparison (Figure 4): The radiation noise of the IMWTEK solution in the 30MHz band is 4dBμV lower than Infineon's.

V. Cost and Reliability Analysis

BOM Cost:

• The price of a single UP009N10LT is approximately 12% lower than Infineon's IPB030N10N, and due to efficiency improvements, the use of heatsinks can be reduced. With an annual usage of 100K sets, the annual cost savings can reach $15,000.

Reliability Verification:

• High-Temperature and High-Humidity Testing: Continuous operation for 500 hours at 85°C/85%RH with RDS(on) drift less than 2%.
• Mechanical Vibration: Passed the 10-2000Hz random vibration test (IEC 60068-2-64) without pin fracture.

VI. Industry Trends and Competitor Summary

As electric tools develop towards higher voltages (20V→40V), the margin design of 100V MOSFETs will become mainstream. IMWTEK UP009N10LT, with its structural innovation and superior performance parameters of the TOLT package, has been successfully introduced into the next-generation platforms of multiple top tool manufacturers.