VPOL5A-5-SMT, VPORT 0402220KV05, VPORT0402100KV05

Electrical Description

A block diagram of the VPOL5A-5-SMT Series converter is shown in Figure 1. Extremely high efficiency power conversion is achieved through the use of synchronous rectification and drive techniques.

Essentially, the powerful VPOL5A-5-SMT series topology is based on a non-isolated synchronous buck converter. The control loop is optimized for unconditional stability, fast transient response and a very tight line and load regulation. In a typical pre-bias application the VPOL5A-5- SMT series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.75 to 3.63vdc, using the TRIM pin with a external resistor. The converter can be shut down via a remote on/off input that is referenced to ground. This input is compatible with popular logic devices; a 'positive' logic input is supplied as standard. Positive logic implies that the converter is enabled if the remote on/off input is high (or floating), and disabled if it is low.

The converter is also protected against over-temperature conditions. If the converter is overloaded or the ambient temperature gets too high, the converter will shut down to protect the unit.

Thermal Packaging and Physical Design.

The VPOL5A-5-SMT series uses a multi-layer FR4 PCB construction. All surface mount power components are placed on one side of the PCB, and all low-power control components are placed on the other side. Thus, the Heat dissipation of the power components is optimized, ensuring that control components are not thermally stressed. The converter is an open-frame product and has no case or case pin. The open-frame design has several advantages over encapsulated closed devices. Among these advantages are: Efficient Thermal Management: the heat is removed from the heat generating components without heating more sensitive, small signal control components.

Environmental: Lead free open-frame converters are more easily re-cycled.

Cost Efficient: No encapsulation. Cost efficient open-frame construction.

Reliable: Efficient cooling provided by open frame construction offers high reliability and easy diagnostics.