The LM2645 is a dual synchronous controller, a linear regulator controller and a fixed 3.3V, 50mA linear regulator in a single 48-pin TSSOP. The synchronous controllers operate at either 200kHz or 300kHz clock rate and are 180° out of phase. This out of phase operation reduces the peak current and thus reduces the size and cost of the inductors and input capacitor. The switching controllers can also be operated in parallel as a dual-phase controller for higher current requirements. The input voltage range is 4.5V-30V, which makes the part ideal for supplying many of the required voltages in embedded computer systems that have a single distributed 5V, 12V, 19V or higher rail.
- Synchronous rectification
- Improved efficiency over a wide input voltage range
- 200kHz or 300kHz oscillator
- User can choose the best efficiency/size/cost operation point
- Power good and enable on both switching channels
- Easy solution to power supply sequencing
- Switchers operate out of phase
- Smaller, cheaper input/output capacitors and inductors
- Current mode without sense resistors
- Lower cost and simpler design
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Laptop PC
There are many requirements for video processor, audio and other non-core processor voltages. The LM2645 can convert efficiently down from the available 19V rail and provide cost-effective, high-performance local regulation.
Set-Top Boxes
Core logic needs ~2V at 2 Amps. The IO is usually 3.3V. There is a 5V digital rail and a separate 5V analog rail. Systems with a HDD need 12V with 2.5 Amp capability. All these needs can be addressed with a LM2645.
Internet Appliances
Internet appliances take many forms, but most have power supply needs like a notebook computer. The LM2645 is ideally suited to supply the power in these systems from a single higher-voltage input like 19V.
Multi-Market Applications
There are many multi-market applications that incorporate >200 MIPS processors. These systems have many of the same multiple voltage requirements as Internet appliances. Typical of such systems are process controllers, factory automation, data acquisition systems and communication systems.
The LM2645 is available in the following package:
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