Integrated LDO controller targets automotive apps

Milpitas, Calif. — Linear Technology has introduced the LT3500, a 2-A, 36-V step-down switching regulator and a linear controller in a 3 x 3-mm DFN package. The LT3500 operates from a VIN range of 3 V to 36 V (40 V max), making it suitable for load dump and cold-crank conditions found in automotive applications.

The 2.3-A internal switch can deliver up to 2 amps of continuous output current at voltages as low as 0.8 V. Switching frequency is user programmable from 250 kHz to 2.2 MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands, said Linear.

The integrated LDO controller, combined with an NPN transistor, ensures very low noise output from the primary channel or as a second channel. The LT3500's small DFN-10 package and high switching frequency, which keeps external capacitors and inductor small, delivers a compact, thermally-efficient footprint.

The device's main switcher uses a high-efficiency 2.3-A, 450 mV CESAT switch, with the necessary oscillator, control, logic circuitry and LDO controller integrated into a single die. Special design techniques enable high efficiency over a wide input voltage range while its current mode topology enables fast transient response and excellent loop stability, said Linear. Other features include a power good flag and soft-start capability.

The LT3500IDD and LT3500HDD devices are tested and guaranteed to operate from operating junction temperature ranges of -40°C to 125°C and -40°C to 150°C, respectively.

Pricing: The LT3500EDD starts at $3.25 each in quantities of 1,000; the LT3500IDD is priced at $3.90 each, and the LT3500HDD is priced at $4.15 each.
Availability: All versions are available from stock.
Product information: LT3500

Linear Technology Corp. , 1-408-432-1900,

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