Datasheet LT3581 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 3.3A Boost/Inverting DC/DC Converter with Fault Protection |
| Pages / Page | 36 / 1 — FEATURES. DESCRIPTION. 3.3A, 42V Combined Power Switch. Master/Slave … |
| File Format / Size | PDF / 472 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. 3.3A, 42V Combined Power Switch. Master/Slave (1.9A/1.4A) Switch Design. Output Short Circuit Protection
Model Line for this Datasheet
Text Version of Document
LT3581 3.3A Boost/Inverting DC/DC Converter with Fault Protection
FEATURES DESCRIPTION
n
3.3A, 42V Combined Power Switch
The LT®3581 is a PWM DC/DC converter with built-in fault n
Master/Slave (1.9A/1.4A) Switch Design
protection features to aid in protecting against output n
Output Short Circuit Protection
shorts, input/output overvoltages, and overtemperature n
Wide Input Range: 2.5V to 22V Operating,
conditions. The part consists of a 42V master switch, and
40V Maximum Transient
a 42V slave switch that can be tied together for a total n Switching Frequency Up to 2.5MHz current limit of 3.3A. n Easily Configurable as a Boost, SEPIC, Inverting or The LT3581 is ideal for many local power supply designs. It Flyback Converter can be easily configured in Boost, SEPIC, Inverting or Flyback n User Configurable Undervoltage Lockout configurations, and is capable of generating 12V at 830mA, n Low VCESAT Switch: 250mV at 2.75A (Typical) or –12V at 625mA from a 5V input. In addition, the LT3581’s n Can be Synchronized to External Clock slave switch allows the part to be configured in high voltage, n Can Be Synchronized to other Switching Regulators high power charge pump topologies that are very efficient n High Gain SHDN Pin Accepts Slowly Varying Input and require fewer components than traditional circuits. Signals n 14-Pin 4mm × 3mm DFN and 16-Lead MSE Packages The LT3581’s switching frequency range can be set bet ween 200kHz and 2.5MHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to ground, or it may be synchronized to an external clock. A buffered
APPLICATIONS
version of the clock signal is driven out of the CLKOUT n Local Power Supply pin, and may be used to synchronize other compatible n Vacuum Fluorescent Display (VFD) Bias Supplies switching regulator ICs to the LT3581. n TFT-LCD Bias Supplies The LT3581 also features innovative SHDN pin circuitry that n Automotive Engine Control Unit (ECU) Power allows for slowly varying input signals and an adjustable L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. undervoltage lockout function. Additional features such Protected by U.S. Patents, including 7579816. as frequency foldback and soft-start are integrated. The LT3581 is available in 14-Pin 4mm × 3mm DFN and 16- Lead MSE packages.
TYPICAL APPLICATION Efficiency and Power Loss vs Load Current Output Short Protected, 5V to 12V Boost Converter Operating at 2MHz
100 2000 95 1800 1.5µH V VOUT IN 90 1600 5V 12V POWER LOSS (mW) 4.7µF 830mA 85 1400 6.04k SW1 SW2 80 1200 18.7k VIN FB 100k 130k 75 1000 FAULT GATE VIN 70 800 4.7µF SHDN CLKOUT EFFICIENCY (%) 65 600 RT LT3581 VC 4.7µF 10k SYNC SS 56pF 60 400 10.5k 43.2k GND 0.1µF 55 200 1nF 50 0 3581 TA01 0 200 400 600 800 1000 LOAD CURRENT (mA) 3581 TA01b 3581fb For more information www.linear.com/LT3581 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram State Diagram Operation Applications Information Appendix Typical Applications Typical Application Related Parts
FEATURES DESCRIPTION
n
3.3A, 42V Combined Power Switch
The LT®3581 is a PWM DC/DC converter with built-in fault n
Master/Slave (1.9A/1.4A) Switch Design
protection features to aid in protecting against output n
Output Short Circuit Protection
shorts, input/output overvoltages, and overtemperature n
Wide Input Range: 2.5V to 22V Operating,
conditions. The part consists of a 42V master switch, and
40V Maximum Transient
a 42V slave switch that can be tied together for a total n Switching Frequency Up to 2.5MHz current limit of 3.3A. n Easily Configurable as a Boost, SEPIC, Inverting or The LT3581 is ideal for many local power supply designs. It Flyback Converter can be easily configured in Boost, SEPIC, Inverting or Flyback n User Configurable Undervoltage Lockout configurations, and is capable of generating 12V at 830mA, n Low VCESAT Switch: 250mV at 2.75A (Typical) or –12V at 625mA from a 5V input. In addition, the LT3581’s n Can be Synchronized to External Clock slave switch allows the part to be configured in high voltage, n Can Be Synchronized to other Switching Regulators high power charge pump topologies that are very efficient n High Gain SHDN Pin Accepts Slowly Varying Input and require fewer components than traditional circuits. Signals n 14-Pin 4mm × 3mm DFN and 16-Lead MSE Packages The LT3581’s switching frequency range can be set bet ween 200kHz and 2.5MHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to ground, or it may be synchronized to an external clock. A buffered
APPLICATIONS
version of the clock signal is driven out of the CLKOUT n Local Power Supply pin, and may be used to synchronize other compatible n Vacuum Fluorescent Display (VFD) Bias Supplies switching regulator ICs to the LT3581. n TFT-LCD Bias Supplies The LT3581 also features innovative SHDN pin circuitry that n Automotive Engine Control Unit (ECU) Power allows for slowly varying input signals and an adjustable L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. undervoltage lockout function. Additional features such Protected by U.S. Patents, including 7579816. as frequency foldback and soft-start are integrated. The LT3581 is available in 14-Pin 4mm × 3mm DFN and 16- Lead MSE packages.
TYPICAL APPLICATION Efficiency and Power Loss vs Load Current Output Short Protected, 5V to 12V Boost Converter Operating at 2MHz
100 2000 95 1800 1.5µH V VOUT IN 90 1600 5V 12V POWER LOSS (mW) 4.7µF 830mA 85 1400 6.04k SW1 SW2 80 1200 18.7k VIN FB 100k 130k 75 1000 FAULT GATE VIN 70 800 4.7µF SHDN CLKOUT EFFICIENCY (%) 65 600 RT LT3581 VC 4.7µF 10k SYNC SS 56pF 60 400 10.5k 43.2k GND 0.1µF 55 200 1nF 50 0 3581 TA01 0 200 400 600 800 1000 LOAD CURRENT (mA) 3581 TA01b 3581fb For more information www.linear.com/LT3581 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram State Diagram Operation Applications Information Appendix Typical Applications Typical Application Related Parts
