The A6861 and A6862 are N-channel power MOSFET drivers capable of controlling MOSFETs to replace a 3-phase solid state relay in phase-isolation applications. In safety critical applications where redundancy is required, motor isolation is a critical safety requirement which is currently addressed with discrete circuitry or relays. Allegro A2-SILTM products include specific features that compliment proper system design, allowing users to achieve up to ASIL-D system rating.
The A6861 and A6862 have three independent floating gate drive outputs to maintain the power MOSFETs in the ON state over the full supply range while tolerating the high phase-voltage slew rates. An integrated charge pump regulator provides the above battery supply voltage necessary to maintain the power MOSFETs in the ON state continuously when the phase voltage is equal to the battery voltage. The charge pump will maintain sufficient gate drive (>7.5 V) for battery voltages down to 4.5 V with 100 kΩ gate-source resistors.
The three gate drives can be independently controlled by a logic level control input (A6861) or by an ignition/enable input (A6862.) In typical applications, the MOSFETs will be switched on within 8 μs and will switch off within 1 μs. An under voltage monitor checks that the pumped supply voltage is high enough to ensure that the MOSFETs are maintained in a safe conducting state.
The A6861 and A6862 are supplied in a 16-lead TSSOP (LP) with exposed pad for enhanced thermal dissipation. They are lead (Pb) free, with 100% matte-tin leadframe plating.
Typical Applications:
- 3-phase disconnect for up to ASIL D level systems
- 3-phase solid-state relay driver
- Electric power steering (EPS)
- Electric braking
