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DC-DC Conversion Cookbook Slide 31

The L7985 and L7986 are examples of step down converters that operate from a maximum input voltage of 38 V (45 V absolute maximum rating). These are non-synchronous converters, which means they require an external diode for operation and the maximum DC output current capability is 2 A and 3 A, respectively. Most typical applications are in the industrial segment, anywhere a step down conversion from an input voltage of up to 38 V is required. As can be seen on the slide, the L7985 has a maximum current specification of 2 A and the L7986 is rated for 3 A. Both devices have a maximum operating voltage of 38 V. These are P-channel power MOS devices which provide two benefits: no need for a bootstrap diode, and the ability to drive the high side at 100% duty cycle, achieving very low drop operation. Other features include adjustable switching frequency and synchronization, an internal soft-start that limits the in-rush current at start up, and overcurrent and over-temperature protection. Both devices are stable with low ESR ceramic capacitors. An “A” suffix on the part number identifies the SO8 package with exposed pad for improved heat transfer. Additionally these parts are available in automotive grade (AECQ100 qualified) versions (A7985, A7986).

PTM Published on: 2013-04-11