Power design drives reliability

Power design engineers play a vital role in protecting their companies’ reputations for quality – just ask any electronics repair centre how many field failures are related to power components. Selecting a reliable power MOSFET, in particular, is a critical decision. These advanced devices need to switch many tens of amps continually, resulting in junction temperatures that would destroy many other components. Such operating extremes stress MOSFET packages to the limit of their thermal and mechanical capabilities.

Increased challenges in a miniature world

The trend to miniaturization, cramming more and more into smaller and smaller spaces never ends. It drives the need for MOSFET packages that can reliably handle system power requirements whilst minimizing the PCB real estate required. NXP rose to this challenge with the creation of LFPAK56, ‘The toughest Power-S08’. Now we have done it again with LFPAK33 – tougher just got smaller.

LFPAK33 designed for reliability

Unlike some MOSFET packages that have their roots in more benign applications, LFPAK33 has been designed from the bottom up to be an ultra-reliable power solution. For example, in LFPAK33, gone are the compromises associated with glue and wire bonds: NXP’s solder die-attach and copper clip technologies for source and gate allow a market-leading junction temperature of 175 ºC.

Furthermore, LFPAK33’s unique construction allows the exposed SOURCE and GATE pins to ‘flex’ and safely absorb thermally and mechanically induced stresses. Similar stresses on a QFN or micro-lead device can cause solder joint failure and/or cracking of the plastic case, leading to moisture ingress, contamination and ultimately component breakdown.
 

A question of compatibility

Independent research has shown that the NXP LFPAK33 is 100% compatible with layout and soldering footprints of leading competitor QFN3333 types. It is also compatible with automated vision inspection systems and can be processed alongside competitor QFN devices. NXP has also developed a ‘universal’ 3.3 x 3.3 mm footprint that allows engineers to create designs that can accept LFPAK33 and competitive types, enabling a full multi-sourcing strategy to be deployed.

Key features and benefits

• Unique rugged construction, specifically designed for space-constrained power applications
• No wire bonds, best-in-class thermal performance Tj(max) = 175 ºC
• Uniquely resilient to mechanical and thermal stresses
• Exposed leads for improved optical inspection of solder joints
• Low 0.85 mm package height
• Footprint compatible with QFN3333 / DFN3333
• Proven pedigree: Derived from LFPAK56 – ‘The toughest Power SO-8’
• Available with NextPower SuperJunction MOSFET technology

LFPAK33 products released

Related links

• LFPAK33 Outline drawing
• Understanding Power MOS datasheet parameters
• LFPAK Thermal Design Guide
• LFPAK Thermal Design Guide 2
• Power MOSFET selection Guide 2013