Date: 08/12/2008

36V, 1.5A buck and boost regulator combined with a linear (LDO) controller

Linear Technology Corporation launched the LT3570, a 36V, 1.5A(ISW) buck and boost regulator combined with a linear controller. The LT3570 operates from a input range of 2.5V to 36V (40VMAX), making it ideal for the load dump and cold-crank conditions commonly found in automotive applications.
Independent input pins of the device can be tied together to run from a single input or can be run from independent input rails. The buck regulator can deliver up to 1A of continuous output current at voltages as low as 0.8V whereas the boost converter can deliver output voltages as high as 38V.

The LDO controller combined with an external NPN transistor can be run from the output of the buck regulator for maximum efficiency or via an independent input pin for design flexibility, either way providing low noise operation. Both the LT3570's buck and boost switchers utilize 1.5A, 240mVCESAT switches, with the necessary oscillator, control, logic circuitry and LDO controller integrated into a single die.

Summary of Features of LT 3570

1. 2.5V to 36V Input Voltage Range
2. User programmable switching frequency from 500kHz to 2MHz
3. Synchronizable Up to 2.5MHz
4. Buck VOUT(MIN) = 0.8V
5. Boost : VOUT(MAX) = 38V
6. Independent Soft-Start for Each Converter
7. Separate VIN Supplies for Each Converter
8. Duty Cycle Range: 0% to 90% at 1MHz
9. Thermal shutdown facility
10. Guaranteed to operate from a -40°C to 125°C operating junction temperature

Packaging & pricing:

1. The LT3570EUF is packaged in a 4mm x 4mm QFN and pricing starts at $2.95 each, for 1,000-piece quantities.
2. The LT3570EFE is packaged in a thermally enhanced TSSOP-20 and pricing starts at $3.05 each, for 1,000-piece quantities.
3. The LT3570IUF and LT3570IFE are priced at $3.39 each and $3.51each, respectively for 1,000-piece quantities.

Availability: All versions are available from stock.

For further information visit: www.linear.com