SineSemi is highlighting its automotive-grade SMT4005 MOSFET series for vehicle water pumps, where the design brief calls for smaller, more compact and more efficient drives. Parts in the series, including the dual-channel automotive MOSFET SMT4005AHPDQ, are AEC-Q101 qualified by SGS, with PPAP documentation available. Against comparable parts from European and US suppliers, on-resistance is roughly 10% lower and the figure of merit (FOM) improves by about 15%, which translates into higher efficiency, lower losses and lower temperature rise; the devices also carry added voltage margin and redundancy in the die's safety design.
Manufacturer key visual for the SMT4005 automotive MOSFET series. Image: SineSemi
In the application circuit the overall system power loss drops substantially, which suits sub-150 W three-phase BLDC motors in vehicles — water pumps, oil pumps, window lifts, sunroofs and tailgates. SMT4005AHPQ / SMT4005AHPDQ are shipping in volume to vehicle end customers.
Key parameters (typical, VGS=10 V): SMT4005AHPQ in PDFN5060-8L — VDS 40 V, RDS(ON) 3.9 mΩ, Qg 14.0 nC, FOM 54.6; the dual-channel SMT4005AHPDQ in PDFN5060-8L-D — VDS 40 V, RDS(ON) 4.6 mΩ, Qg 14.0 nC, FOM 64.4. Both list Ciss/Coss/Crss at 982 pF/593 pF/25 pF.
Parameter comparison of SMT4005AHPQ / SMT4005AHPDQ against benchmark parts. Image: SineSemi
The reference circuit is a standard three-phase BLDC drive: the A, B and C stator windings are star-connected and fed directly by the three-phase inverter. Q1 provides reverse-battery protection, and the inverter uses six MOSFETs — Q2, Q4 and Q6 on the high side, Q3, Q5 and Q7 on the low side. In SineSemi's schematic Q1 is an SMT4005AHPQ and each half-bridge leg uses the dual-channel SMT4005AHPDQ.
Bench results on a 70 W vehicle water pump cover motor phase current and MOSFET gate-drive waveforms, temperature rise and efficiency: the MOSFETs' temperature rise peaks at 54.7°C, pointing to low overall device loss, and system efficiency exceeds 90% at 72% load output — IE5 class against motor efficiency standards. In BLDC motor applications the FOMg figure of merit reflects the device's overall loss.
On the design-support side, SineSemi offers thermal simulation and circuit-level simulation with PSpice models, and the pump prototype has been through a 125°C system-level high-temperature endurance test.
Two EMI measures are applied. The first is a 2–10 nF capacitor across gate and source: it damps the VDS ringing generated by di/dt at turn-off; guards against shoot-through — false turn-on caused by dv/dt coupling through the Miller capacitance Cgd; moderately raises Ciss (newer-technology devices have a small Ciss) so the gate loop does not form an under-damped RLC oscillation on VGS; indirectly raises the Crss/Ciss ratio for better EMI; and shortens the Miller plateau. The second is an Rs–Cs network across gate and source to absorb the remaining VDS ringing. In third-party testing to CISPR 25, adding the RC snubber brought the peak near 90.4 MHz down from 62.55 dBµV to 50.98 dBµV.
Both SMT4005AHPQ and SMT4005AHPDQ are in mass production, with samples available on request from SineSemi; the datasheets for both parts are published by part number on its website.
Source: SineSemi Product News · www.sinesemi.com/cpxw/3736.html