AN938 application note describes the design of L4973 3.5A high efficiency DC-DC converter, which uses BCD60 II technology and adopts continuous mode step-down topology. The input voltage range is 8V-55V, and the output voltage is 60V in no-load condition. The internal current limiting and thermal shutdown are considered as standard protection functions for safe load supply, and an oscillator with voltage feed-forward improves line regulation and overall control loop. The soft-start function prevents output overvoltage at turn-on, and the synchronization function can reduce EMI problems in multi-output power supplies. The inhibit function, introduced for power management in equipment having standby features, when active (high), reduces device power consumption by a few tens of µA.
This document describes the L4973 family of 3.5 A monolithic DC-DC converters operating in step-down topology. It covers two versions, the L4973V3.3 and L4973V5.1, which set output voltages at 3.3 V and 5.1 V respectively, with the ability to control higher voltages using an external divider. The device operates with an input supply voltage ranging from 8 V to 55 V.
| Output current | 3.5 A |
|---|---|
| Topology | Step-down |
| Input voltage range | 8 V to 55 V |
| Absolute maximum input voltage | 60 V |
| Output voltage (L4973V3.3) | 3.3 V |
| Output voltage (L4973V5.1) | 5.1 V |
| Internal reference voltage | 5.1 V |
| Packages | DIP18 and SO20 |
The L4973V3.3 sets the output voltage at 3.3 V, and the L4973V5.1 sets it at 5.1 V.
Yes, both regulators can control higher output voltage values by using an external voltage divider.
The operating input supply voltage ranges from 8 V to 55 V.
Yes, a demonstration board is available through order code EVAL4973.