IR's DOL Packaging Boosts Thermal and Electrical Performance for EPS, EHPS and Other Automotive Motion Control Applications
International Rectifier (IR) introduced an innovative, new power packaging technology to solve design challenges found in electro-hydraulic power steering (EHPS), electric power steering (EPS) and automotive motion control applications.
"International Rectifier's die-on-leadframe (DOL) packaging sets new standards in thermal and electrical performance while reducing size and weight, delivering a viable path to automakers looking to migrate to more sophisticated systems like the transition from hydraulic steering systems to EHPS and full electric systems," said Ivo Jurek, Vice President, International Rectifier Automotive Products.
For example, EPS is an enabling technology for four-wheel steering systems and improved vehicle stability control (VSC). However, limitations in electrical efficiency, the availability of current on the vehicle bus, and torque ripple which adversely affects "steering feel," have delayed the proliferation into higher curb-weight vehicles.
IR's new patent-pending DOL concept in power inverter packaging delivers the lowest package inductance and resistance by minimizing the number of material layers to improve thermal performance while reducing the number of interconnections. Lower thermal resistance allows the use of smaller silicon devices. The significantly lower inverter electrical resistance allows for higher current capabilities with smaller die sizes and lower torque ripple.
For medium to high power applications, DOL packaging offers better electrical conductivity and increased thermal performance than alternative packaging methods using insulated metal substrate (IMS), direct-bonded copper (DBC) to a ceramic substrate, thick film substrates or PCB-based modules, which primarily utilize discrete power devices.
A DOL power module includes silicon devices directly soldered to a copper leadframe within an injection-molded shell. The internal components are connected directly to outside terminals, eliminating intermediate insulation and conductive layers.
The first IR devices to use DOL technology are IR's automotive power modules for EPS and EHPS applications. The IR11867-E02 is a 120A module while the IR11867-E01 is a 160A module. The current ratings are continuous capability at maximum junction temperature of 175°C and include built-in temperature-sense feedback and bus-current sensing.
Other features include high frequency, low inductance package for electromagnetic compatibility (EMC) and an integrated de-coupling capacitor across negative and positive bus for EMI suppression at high frequencies. The DOL modules are housed in a compact plastic package, 60mm x 36mm x 8mm.
| IR Module Part Number | IR Die Part Number | VDS (V) | MOSFETs RDS(on) @25°C | IRMS Max** | Rthjc °C/W | Module Loop Resistance# | Package Resistance | Package Inductance |
| IR11867-E01 | IRFC2804 | 40* | ~0.85mOhm* | 160A | ~0.40 | ~3.8 mOhm | ~1.95 mOhm | ~25nH |
| IR11867-E02 | IRFC1404Z | 40* | ~1.65 mOhm* | 120A | ~0.60 | ~5.6 mOhm | ~2.15 mOhm | ~30nH |
| Notes * Parameter depends on the MOSFET chosen and can be changed to meet application requirements. ** Values correspond to base-plate temperature of 100°C and Rthjs = 0.8°C/W (with IRFC2804) or Rthjs = 1.1 °C/W (with IRFC1404Z) # Values include a 0.3mohm current sense resistor, which can be changed to meet application requirements. Loop resistance is the electrical resistance between battery plus and a battery minus terminal when phase terminals are shorted. |
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