Datasheet LT3681 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 36V, 2A, 2.8MHz Step-Down Switching Regulator with Integrated Power Schottky Diode |
| Pages / Page | 24 / 1 — FEATURES. DESCRIPTIO. Wide Input Voltage Range: 3.6V to 34V Operating,. … |
| File Format / Size | PDF / 381 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. Wide Input Voltage Range: 3.6V to 34V Operating,. 36V Maximum. 2A Maximum Output Current
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Text Version of Document
LT3681 36V, 2A, 2.8MHz Step-Down Switching Regulator with Integrated Power Schottky Diode
U FEATURES DESCRIPTIO
■
Wide Input Voltage Range: 3.6V to 34V Operating,
The LT®3681 is an adjustable frequency (300kHz to 2.8MHz)
36V Maximum
monolithic buck switching regulator that accepts input ■
2A Maximum Output Current
voltages up to 34V (36V maximum). A high effi ciency ■
Low Ripple Burst Mode® Operation
0.18Ω switch is included on the die along with a boost
50µA I
Schottky diode and the necessary oscillator, control, and
Q at 12VIN to 3.3VOUT Output Ripple < 15mV
logic circuitry. An undedicated power Schottky diode is
P-P
■
Adjustable Switching Frequency: 300kHz to 2.8MHz
integrated into the LT3681 to minimize the solution size. ■
Low Shutdown Current: I
Current mode topology is used for fast transient response
Q < 1µA
■
Integrated Boost Diode
and good loop stability. Low ripple Burst Mode operation ■
Integrated Power Schottky Diode
maintains high effi ciency at low output currents while ■ Power Good Flag keeping output ripple below 15mV in a typical application. ■ Saturating Switch Design: 0.18Ω On-Resistance In addition, the LT3681 can further enhance low output ■ 1.265V Feedback Reference Voltage current effi ciency by drawing bias current from the output ■ Output Voltage: 1.265V to 20V when VOUT is above 3V. Shutdown reduces input supply ■ Soft-Start Capability current to less than 1µA while a resistor and capacitor on ■ Small 14-Pin Thermally Enhanced the RUN/SS pin provide a controlled output voltage ramp (4mm x 3mm) DFN Package (soft-start). A power good fl ag signals when VOUT reaches
U
90% of the programmed output voltage. The LT3681
APPLICATIO S
is available in 14-Pin 4mm x 3mm DFN package with exposed pads for low thermal resistance. ■ Automotive Battery Regulation , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ Power for Portable Products Burst Mode is a registered trademark of Linear Technology Corporation. All other ■ Distributed Supply Regulation trademarks are the property of their respective owners. ■ Industrial Supplies ■ Wall Transformer Regulation
U TYPICAL APPLICATIO 5V Step-Down Converter Effi ciency
VIN VOUT 100 10.0000 6.3V TO 5V 34V 2A 90 VIN BD 80 1.0000 OFF ON RUN/SS BOOST 0.47mF L 70 POWER LOSS (W) 6.8mH 20k 60 0.1000 V LT3681 SW C 4.7mF 50 DC 40 RT 0.0100 DA EFFICIENCY (%) 330pF 30 PG BIAS V 20 IN = 12V 0.0010 V 590k OUT = 3.3V 60.4k FB 10 L = 4.7mH GND F = 800 kHz 0 200k 22mF 0.0001 0.0001 0.001 0.01 0.1 1 10 ILOAD (A) 3681 TA01b 3681 TA01 L: NEC PLC-0745-6R8 3681f 1
U FEATURES DESCRIPTIO
■
Wide Input Voltage Range: 3.6V to 34V Operating,
The LT®3681 is an adjustable frequency (300kHz to 2.8MHz)
36V Maximum
monolithic buck switching regulator that accepts input ■
2A Maximum Output Current
voltages up to 34V (36V maximum). A high effi ciency ■
Low Ripple Burst Mode® Operation
0.18Ω switch is included on the die along with a boost
50µA I
Schottky diode and the necessary oscillator, control, and
Q at 12VIN to 3.3VOUT Output Ripple < 15mV
logic circuitry. An undedicated power Schottky diode is
P-P
■
Adjustable Switching Frequency: 300kHz to 2.8MHz
integrated into the LT3681 to minimize the solution size. ■
Low Shutdown Current: I
Current mode topology is used for fast transient response
Q < 1µA
■
Integrated Boost Diode
and good loop stability. Low ripple Burst Mode operation ■
Integrated Power Schottky Diode
maintains high effi ciency at low output currents while ■ Power Good Flag keeping output ripple below 15mV in a typical application. ■ Saturating Switch Design: 0.18Ω On-Resistance In addition, the LT3681 can further enhance low output ■ 1.265V Feedback Reference Voltage current effi ciency by drawing bias current from the output ■ Output Voltage: 1.265V to 20V when VOUT is above 3V. Shutdown reduces input supply ■ Soft-Start Capability current to less than 1µA while a resistor and capacitor on ■ Small 14-Pin Thermally Enhanced the RUN/SS pin provide a controlled output voltage ramp (4mm x 3mm) DFN Package (soft-start). A power good fl ag signals when VOUT reaches
U
90% of the programmed output voltage. The LT3681
APPLICATIO S
is available in 14-Pin 4mm x 3mm DFN package with exposed pads for low thermal resistance. ■ Automotive Battery Regulation , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ Power for Portable Products Burst Mode is a registered trademark of Linear Technology Corporation. All other ■ Distributed Supply Regulation trademarks are the property of their respective owners. ■ Industrial Supplies ■ Wall Transformer Regulation
U TYPICAL APPLICATIO 5V Step-Down Converter Effi ciency
VIN VOUT 100 10.0000 6.3V TO 5V 34V 2A 90 VIN BD 80 1.0000 OFF ON RUN/SS BOOST 0.47mF L 70 POWER LOSS (W) 6.8mH 20k 60 0.1000 V LT3681 SW C 4.7mF 50 DC 40 RT 0.0100 DA EFFICIENCY (%) 330pF 30 PG BIAS V 20 IN = 12V 0.0010 V 590k OUT = 3.3V 60.4k FB 10 L = 4.7mH GND F = 800 kHz 0 200k 22mF 0.0001 0.0001 0.001 0.01 0.1 1 10 ILOAD (A) 3681 TA01b 3681 TA01 L: NEC PLC-0745-6R8 3681f 1
