The BD3550HFN, BD3551HFN, and BD3552HFN are a series of high-performance regulator ICs designed for PCs. They feature ultra-low dropout and linear regulation, making them ideal for low input voltage to low output voltage applications. These ICs incorporate a built-in N-MOSFET power transistor to minimize the voltage differential and achieve high current output with reduced conversion loss. This eliminates the need for a switching regulator and its components, resulting in package profile downsizing and cost reduction.
The BD3550HFN series from ROHM are ultra‑low‑dropout linear regulators designed for PC and consumer‑electronics applications. They operate from a low input voltage and provide a selectable output voltage from 0.65 V to 2.7 V while delivering up to 2.0 A of current.
The document includes absolute maximum ratings, electrical characteristics, pin layout, block diagram, and reference waveforms. It also lists typical applications such as notebook computers, desktop computers, LCD‑TVs and other digital appliances.
| Output voltage range | 0.65 V – 2.7 V |
|---|---|
| Maximum output current | 2.0 A (BD3552HFN) |
| Package size | 2.9 mm × 3 mm × 0.6 mm (HSONS) |
| ON‑resistance of internal MOSFET | 100 mΩ |
| Typical dropout voltage | 200 mV – 300 mV |
The regulators can be set to any voltage between 0.65 V and 2.7 V.
BD3552HFN can deliver up to 2.0 A of continuous output current.
They are offered in a small HSONS package measuring 2.9 mm × 3 mm × 0.6 mm.
The internal N‑MOSFET driver has a low ON‑resistance of about 100 mΩ.