LT3437

Features:

Wide Input Range: 3.3V to 60V
Load Dump (Input Transient) Protection to 80V
500mA Peak Switch Current
Burst Mode® Operation: 100µA Quiescent Current**
Low Shutdown Current: IQ < 1µA
Burst Mode Operation Defeat
200kHz Switching Frequency
Saturating Switch Design: 0.8Ω On-Resistance
Peak Switch Current Maintained Over Full Duty Cycle Range*
1.25V Feedback Reference Voltage
Easily Synchronizable
Soft-Start Capability
Small 10-Pin Thermally Enhanced DFN Package


Application

High Voltage Power Conversion
14V and 42V Automotive Systems
Industrial Power Systems
Distributed Power Systems
Battery-Powered Systems
Powered Ethernet


Specifications

VIN, SHDN, BIAS, SW Operating ............................. 60V
VIN, SHDN 100ms Transient, <15% Duty Cycle ....... 80V
BOOST Pin Above SW ............................................ 35V
BOOST Pin Voltage Operating ................................. 75V
BOOST Pin 100ms Transient, <15% Duty Cycle ...... 85V
SYNC, CSS, FB .......................................................... 6V
Operating Junction Temperature Range
LT3437EDD (Note 2) ....................... 40°C to 125°C
LT3437IDD (Note 2) ........................ 40°C to 125°C
LT3437EFE (Note 2) ........................ 40°C to 125°C
LT3437IFE (Note 2) ......................... 40°C to 125°C
Storage Temperature Range ................. 65°C to 125°C

Description

The LT®3437 is a 200kHz monolithic buck switching regulator that accepts input voltages up to 80V. A high efficiency 500mA, 0.8Ω switch is included on the die along with all the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Innovative design techniques along with a new high voltage process achieve high efficiency over a wide input range. Efficiency of LT3437 is maintained over a wide output current range by employing Burst Mode operation at low currents, utilizing the output to bias the internal circuitry, and by using a supply boost capacitor to fully saturate the power switch. Burst Mode operation can be defeated by a logic high signal on the SYNC pin which results in lower light load ripple at the expense of light load efficiency. Patented circuitry maintains peak switch current over the full duty cycle range.* Shutdown reduces input supply current to less than 1µA. External synchronization can be implemented by driving the SYNC pin with logic-level inputs. A single capacitor from the CSS pin to the output provides a controlled output voltage ramp (soft-start).

The LT3437 is available in a low profile (0.75mm) 3mm 3mm 10-pin DFN package or a 16-Pin TSSOP Package both with exposed pad leadframes for low thermal resistance.