Good for buck converters

Fairchild Semiconductor’s FDS7066SN3 is the first in a new family of MOSFETs that use Fairchild’s FLMP (Flip Leaded Moulded Package) and SyncFET silicon technology.

The 30V, 19A N-Channel device is targeted for the low-side switch used in synchronous buck DC/DC converter applications.

With an integrated Schottky diode, the device’s SyncFET technology offers similar performance (high power and current handling) of a separate MOSFET and Schottky rectifier in one package.

By using Fairchild’s FLMP SO-8 packaging combined with the SyncFET technology, the device offers a thermal efficiency (thermal resistance junction-to-case of 0.5 degrees C per Watt) and a very low RDS(on) (4.5mOhms typical at 10Vgs).

Making use of technology patented by Fairchild, the SyncFET monolithic die solution incorporates a titanium Schottky diode with a PowerTrench MOSFET, allowing Fairchild to match the performance of the Schottky to the requirements of the MOSFET to prevent the MOSFET body diode from turning on. This greatly improves reverse recovery gate charge (QRR) and reverse recovery time (trr) characteristics – with the FDS7066SN3 having a QRR of only 28 nC and a trr of 26.6 ns (both at IF = 19 A, di/dt = 300 A/us). Reducing the reverse recovery charge also helps to increase the overall operating efficiency in the DC/DC converters. In addition, replacing the lower MOSFETs with a SyncFET of the same on-resistance can result in efficiency improvements upwards of 5%, according to the company.

Fairchild’s FLMP package offers the thermal performance and very low RDS(on) of a larger TO-263 in a standard SO-8 package outline. This packaging allows the FDS7066SN3 to achieve thermal resistance junction-to-case of 0.5 degrees C per Watt compared to the 25 degrees per Watt of a standard SO-8. It also improves power dissipation: a standard SO-8 dissipates 2.5W versus a FLMP, which dissipates 3W.

The new device is priced at $2.14 in 1,000 piece quantities.