MOSFET drivers cut passives down to size

Four new high-speed, half-bridge N-channel MOSFET driver ICs are designed for use in high-frequency, high-current, single- and multiphase DC/DC switching power supplies.

Siliconix has four new high-speed, half-bridge N-channel MOSFET driver ICs designed for use in high-frequency, high-current, single- and multiphase DC/DC switching power supplies, including one driver with a brake for brushless motor control applications.

The new SiP41103, SiP41104 and SiP41105 dual MOSFET drivers, which drive both the lower and upper MOSFETs in a half-bridge configuration, work in systems with supply voltages from 4.5 to 50V.

Designed to supply output currents up to 1A, these three drivers operate at switching frequencies of 250kHz to 1MHz with a driver impedance of less than 1ohm, allowing for reduced capacitor and inductor size.

The new SiP42101, which is equipped with a brake function for motor drive applications, operates at 50kHz.

The family's break-before-make logic prevents shoot-through currents in the external MOSFETs as well as the internal bootstrap diode, which drives an N-channel high-side MOSFET that reduces the number of external components.

A shutdown/control pin is used to enable the drivers, and a synchronous enable pin is additionally provided on the SiP41103 and SiP41105 to allow disabling of the low-side or "synchronous rectifier" MOSFET to maximise efficiency at light power loads.

An undervoltage lockout feature prevents driving of the MOSFET gates when the supply voltage (at VDD) is less than is specified, thereby ensuring that output MOSFETs are only turned on when sufficient gate voltage is present.

The devices have a shutdown quiescent current of less than 5uA.

All four new MOSFET drivers are available in both standard and lead (Pb)-free packages.

The SiP42101 and SiP41103 have an MLP33-10 package, whereas the SiP41104 has an SO8 package and the SiP41105 a TSSOP-16 PowerPAK.

They are rated for operation over the -40 to +85C industrial temperature range, with applications including high-current synchronous buck (step-down) convertors, multiphase DC/DC convertors, asynchronous-to-synchronous adaptations and computer DC/DC convertors.

The SiP42101 joins Siliconix's existing family of motor drivers, including the popular Si9986, which has integrated 1A MOSFETs.

Samples and production quantities of the SiP42101, SiP41103, SiP41104 and SiP41105 are available now, with lead times of 8 to 10 weeks for larger orders.

Pricing for US delivery in 1000-piece quantities is $1.96 for the SiP41101 and $1.83 for the SiP41103, SiP41104, SiP41105 and SiP42101.

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