Datasheet LT3434 (Analog Devices)

LT3434 High Voltage 3A, 200kHz Step-Down Switching Regulator with 100µA Quiescent Current
U FEATURES DESCRIPTIO
■
Wide Input Range: 3.3V to 60V
The LT®3434 is a 200kHz monolithic buck switching ■
3A Peak Switch Current
regulator that accepts input voltages up to 60V. A high ■
Burst Mode® Operation: 100
µ
A Quiescent Current**
efficiency 3A, 0.1Ω switch is included on the die along with ■
Low Shutdown Current: IQ < 1
µ
A
all the necessary oscillator, control and logic circuitry. ■
Power Good Flag with Programmable Threshold
Current mode topology is used for fast transient response ■
Load Dump Protection to 60V
and good loop stability. ■ 200kHz Switching Frequency Innovative design techniques integrated in a new high ■ Saturating Switch Design: 0.1Ω voltage process achieve high efficiency over a wide input ■ Peak Switch Current Maintained Over range. Efficiency is maintained over a wide output current Full Duty Cycle Range* range by employing Burst Mode operation at low currents, ■ 1.25V Feedback Reference Voltage utilizing the output to bias the internal circuitry, and by ■ Easily Synchronizable using a supply boost capacitor to fully saturate the power ■ Soft-Start Capability switch. Patented circuitry maintains peak switch current ■ Small 16-Pin Thermally Enhanced TSSOP Package
U
over the full duty cycle range.* Shutdown reduces input
APPLICATIO S
supply current to less than 1µA. External synchronization can be implemented by driving the SYNC pin with logic-level ■ High Voltage Power Conversion inputs. A single capacitor from the CSS pin to the output ■ 14V and 42V Automotive Systems provides a controlled output voltage ramp (soft-start). The ■ Industrial Power Systems device also has a power good flag with a programmable ■ Distributed Power Systems threshold and time-out, and thermal shutdown protection. ■ Battery-Powered Systems The LT3434 is available in a 16-pin TSSOP package with , LTC and LT are registered trademarks of Linear Technology Corporation. All other Exposed Pad leadframe for low thermal resistance. trademarks are the property of their respective owners. Burst Mode is a registered trademark of Linear Technology Corporation. *Protected by U.S. Patents including 6498466. **See Burst Mode Operation section for conditions.
U TYPICAL APPLICATIO Supply Current vs Efficiency and Power Loss 14V to 3.3V Step-Down Converter with Input Voltage vs Load Current 100
µ
A No Load Quiescent Current
150 100 10 VOUT = 3.3V VIN = 12V VOUT = 5V VOUT 125 EFFICIENCY VIN VIN BOOST 3.3V 75 1 4.7µF 0.68µF 33µH 4148 2A POWER LOSS (W) SHDN µA) 100V SW 100 VOUT = 3.3V CER LT3434 0.1µF 30MQ100 CSS 75 V 50 0.1 C 4700pF 470pF VBIAS 165k EFFICIENCY (%) TYPICAL POWER 27pF 50 FB 1% LOSS 10k 100µF SUPPLY CURRENT ( C 25 0.01 T PGFB 6.3V 1µF SYNC TANT 25 100k PG GND 1% 0 0 0.001 3434 TA01 0 10 20 30 40 50 60 0.0001 0.001 0.01 0.1 1 10 INPUT VOLTAGE (V) LOAD CURRENT (A) 3434 TA02a 3434 TA02b 3434fb 1