The HM076R68, introduced by HeroMicro, is a high-performance 70V, 70A N-channel power MOSFET. It employs advanced high-cell-density Trench technology to achieve an ultra-low on-resistance (RDS(ON)) and optimized switching characteristics. This device is specifically designed for applications demanding high efficiency and high power density, making it an ideal choice for Switch-Mode Power Supplies (SMPS), motor drives, battery management systems, and more.
1. Key Features Overview
Based on the datasheet provided by HeroMicro (HM076R68.pdf), key specifications are:
High Voltage & High Current Capability:
Drain-Source Breakdown Voltage (VDS): 70V
Continuous Drain Current (ID): 70A (TC=25°C), 52A (TC=100°C)
Pulsed Drain Current (IDM): Up to 320A
Ultra-Low Conduction Losses:
On-Resistance (RDS(ON)): Typical 6.6mΩ, Max 8.6mΩ (@ VGS=10V, ID=30A)
Excellent Switching Performance:
Low Gate Charge (Qg): Typical 33nC (@ VGS=10V, VDS=30V), helping to reduce drive losses.
Fast Switching Speed: Typical turn-on time (td(on)+tr) is 103ns, and turn-off time (td(off)+tf) is 73ns.
High Reliability & Thermal Performance:
Wide Operating Junction Temperature Range: -55°C to +175°C.
High Power Dissipation: 116W (TC=25°C).
Low Thermal Resistance: Junction-to-Case (RθJC) is only 0.85°C/W, ensuring efficient heat transfer to a heatsink.
Package: TO-252 (DPAK), a surface-mount package with an exposed thermal pad, offering excellent electrical and thermal performance.
2. Pin Configuration
The HM076R68 uses a standard TO-252 (DPAK) 3-pin package:
| Pin | Symbol | Function |
|---|---|---|
| 1 | Gate (G) | Gate |
| 2 | Drain (D) | Drain (connected to the exposed thermal pad) |
| 3 | Source (S) | Source |
Critical Note: The Drain (D) is internally connected directly to the exposed metal thermal pad on the bottom of the package. For optimal thermal performance, this pad must be soldered to a large copper area on the PCB, which also serves as part of the main power path.
3. Critical Design Guidelines
(1) Gate Drive Design
Recommended Drive Voltage (VGS): To achieve the lowest RDS(ON) and best efficiency, +10V drive is strongly recommended.
Drive Current Capability: With a total gate charge (Qg) of 33nC, the driver circuit must have sufficient peak current output to enable fast switching transitions, minimizing switching losses. A typical gate resistor (RG) value is 6Ω (as per the datasheet test conditions).
Preventing False Turn-On: In high di/dt or dv/dt switching environments, the Miller capacitance (Crss) can cause the gate voltage to rise, leading to false turn-on. It's advisable to place a small resistor (e.g., 10kΩ) between gate and source, or use a dedicated driver IC with a "Miller clamp" feature.
(2) Body Diode Characteristics
The HM076R68 has an internal body diode from Source (S) to Drain (D).
Forward Voltage (VSD): Max 1.2V (@ IS=80A).
Reverse Recovery: Reverse recovery time (Trr) is 78ns, and reverse recovery charge (Qrr) is 51nC. In hard-switching applications, this recovery process generates additional losses and voltage spikes, which must be accounted for in the design.
(3) PCB Layout & Thermal Management (Critical!)
Thermal Pad Handling: This is key to a successful design. A sufficiently large copper pour must be designed for the TO-252's exposed pad, connected to inner or back-side ground/power planes with multiple vias to maximize heat dissipation. The copper area directly determines the device's real-world power handling capability.
Minimize Power Loop: The high-frequency power loop, consisting of the input capacitor, MOSFET, and freewheeling diode (or sync FET), should be as short and wide as possible to minimize parasitic inductance, thereby reducing switching noise and voltage overshoot.
Kelvin Connection (Optional but Recommended): For precise current sensing or applications with strict switching waveform requirements, consider using a separate, small-signal trace from the Source (Pin 3) to the driver or controller IC. This avoids the L*di/dt voltage drop from the high current in the source trace affecting the drive signal.
(4) Safe Operating Area (SOA)
The "Maximum Safe Operating Area" curve (Figure 9 in the datasheet) defines the safe operating boundaries under various voltage and current combinations. When designing startup, overload, or short-circuit protection strategies, ensure all operating points stay within this curve, especially limiting time spent in the linear (constant current) region to avoid thermal runaway damage.
(5) Absolute Maximum Ratings
Gate-Source Voltage (VGS): ±20V. Exceeding this can cause permanent gate oxide breakdown.
Operating Temperature: Maximum junction temperature is +175°C. While high, designs should include ample margin, typically keeping the steady-state junction temperature below 125°C for long-term reliability.
4. Typical Applications
AC-DC / DC-DC Switch-Mode Power Supplies (especially synchronous rectified Buck, Boost, Half-Bridge topologies)
BLDC/PMSM Motor Drives (inverter legs)
Power Tools and Drone ESCs (Electronic Speed Controllers)
Server and Telecom VRMs (Voltage Regulator Modules)
Solar Microinverters and Optimizers
5. Summary
HeroMicro's HM076R68 is a power MOSFET that combines high voltage rating, high current capability, ultra-low on-resistance, and excellent thermal performance. By providing a strong +10V drive, meticulously designing the PCB thermal solution, and following good high-frequency layout practices, engineers can fully leverage its performance advantages to achieve outstanding designs in high-power-density and high-efficiency power and motor drive applications.
