POWER AND LINEAR IC SOLUTIONS

High Performance Transistors Increase PSU Power Density

Zetex Semiconductors has introduced a series of miniature NPN and PNP transistors for MOSFET gate driving in advanced Power Supply Units (PSUs). These are the first bipolars to be provided in the SOT23FF package, with a footprint of 2.5mm x 3mm and an off-board height of just 1mm.



As well as the small size, the ZXTN and ZXTP series transistors offer improved saturation voltage and current-gain hold-up specifications, leading to improved circuit efficiency and cooler running.

Covering the operating voltage range from 20V through to 100V, the transistors are able to drive MOSFET gates faster and more efficiently than CMOS alternatives. Being immune to latch-up, they also offer an improvement in overall system reliability. The use of the SOT23FF package allows the devices to sit as close as possible to the MOSFET, helping to minimise track inductance and ringing effects.

The 20V ZXTN19020CFF and ZXTP19020CFF have guaranteed gains of 100 at 7A and 110 at 5A, respectively. When connected in a common emitter configuration they provide extremely fast switching, with propagation times less than 2ns and rise and fall times between 10ns and 20ns. With a peak current performance up to 15A, they offer a highly cost effective alternative to dedicated gate driver ICs.

In saturated switch applications based on the Royer and push pull topologies used in Point of Load (PoL) DC/DC modules and emergency lighting, the transistors’ low saturation voltage provides a significant advantage. As an illustration, the 60V rated ZXTN19060CFF NPN has a saturation voltage of just 150mV at 1A with a base drive of 10mA, or 135mV at 2A and a base drive of 40mA.

Features

• NPN and PNP transistors in 2.5mm x 3mm x 1mm SOT23FF package
• 20V to 100V versions
• Improved saturation voltage
  • 150mV at 1A with a base drive of 10mA, 135mV at 2A and a base drive of 40mA (60V version)
• Fast switching
  • Propagation times less than 2ns (20V version)
  • Rise and fall times between 10ns and 20ns (20V version)
• Better current gain hold up
• Immune to latch-up

Applications

• High frequency gate drives
• Power supplies
• Switching DC/DC converters

For further information, including Datasheets for featured products, please click here