Datasheet LT3514 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Triple Step-Down Switching Regulator with 100% Duty Cycle Operation |
| Pages / Page | 26 / 1 — FEATURES. DESCRIPTION. Wide Input Voltage Range: 3.2V to 36V. (40V … |
| File Format / Size | PDF / 482 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Wide Input Voltage Range: 3.2V to 36V. (40V Transient). Three Outputs: 2A, 1A, 1A
Model Line for this Datasheet
Text Version of Document
LT3514 Triple Step-Down Switching Regulator with 100% Duty Cycle Operation
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 3.2V to 36V
The LT®3514 consists of three buck regulators (2A, 1A,
(40V Transient)
1A output current). The device has a wide operating input n
Three Outputs: 2A, 1A, 1A
range of 3.2V to 36V. An on-chip boost regulator allows n
100% Duty Cycle Operation
each channel to operate up to 100% duty cycle. The LT3514 n
Resistor-Programmed Constant Frequency
is designed to minimize external component count and n
Short-Circuit Robust results in a simple and small application circuit. n Wide SYNC Range: 350kHz to 2.2MHz The LT3514 operates robustly in fault conditions. Cycle- n Anti-Phase Switching Reduces Ripple by-cycle peak current limit and catch diode current limit n Feedback Voltage: 800mV sensing protect the IC during overload conditions. Ther- n Independent Run/Soft-Start Pins mal shutdown protects the power switches at elevated n Shutdown with UVLO temperatures. Soft-start helps control the peak inductor n Internal Compensation current during startup. n Thermal Shutdown n Tiny 28-Lead (4mm × 5mm) Thermally Enhanced The LT3514 also features output voltage tracking and QFN Package sequencing, programmable frequency, programmable n 24-Lead Exposed Pad TSSOP undervoltage lockout, and a power good pin to indicate when all outputs are in regulation.
APPLICATIONS
The LT3514 has one fewer channel (CH2) than the LT3504, and has one channel (CH3) that outputs 2A instead of 1A. n Automotive Battery Regulation The LT3514 in QFN is pin compatible with the LT3504. The n Industrial Control Supplies LT3504 provides four 1A outputs. n Wall Transformer Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Distributed Supply Regulation of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION LT3514 Start-Up and Shutdown Triple Buck Regulator Waveform. VIN (Top Trace) Is Ramped from OV Up to 8V and Then Back Down
3.3µH
to 0V. The Other Three Traces Are the
SKY SW1 1.8V/1A
Output Voltages of All Three Channels
SW5 100pF 1µF 12.7k 22µF 10µH DA1 LT3514 10.2k FB1 VIN VIN 1V/DIV 5.4V TO 20V VIN 4.7µH 5V CHANNEL BEGINS TRANSIENT TO 40V 1µF V SW3 3.3V/2A 100% DC OPERATION ×2 IN EN/UVLO 47pF 31.6k 47µF 3.3V CHANNEL BEGINS DA3 CH4 1V/DIV PG PG 10.2k 100% DC OPERATION FB3 8.2µH RUN/SS1 UVLO = ~2.9V CH3 1V/DIV RUN/SS3 SW4 5V/1A PARTS SHUTS 22pF RUN/SS4 53.6k 22µF OFF CH1 1V/DIV 47nF DA4 10.2k RT/SYNC FB4 18.2k 1MHz GND 3514 TA01b 100ms/DIV 3514 TA01a 3514fa For more information www.linear.com/LT3514 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts
FEATURES DESCRIPTION
n
Wide Input Voltage Range: 3.2V to 36V
The LT®3514 consists of three buck regulators (2A, 1A,
(40V Transient)
1A output current). The device has a wide operating input n
Three Outputs: 2A, 1A, 1A
range of 3.2V to 36V. An on-chip boost regulator allows n
100% Duty Cycle Operation
each channel to operate up to 100% duty cycle. The LT3514 n
Resistor-Programmed Constant Frequency
is designed to minimize external component count and n
Short-Circuit Robust results in a simple and small application circuit. n Wide SYNC Range: 350kHz to 2.2MHz The LT3514 operates robustly in fault conditions. Cycle- n Anti-Phase Switching Reduces Ripple by-cycle peak current limit and catch diode current limit n Feedback Voltage: 800mV sensing protect the IC during overload conditions. Ther- n Independent Run/Soft-Start Pins mal shutdown protects the power switches at elevated n Shutdown with UVLO temperatures. Soft-start helps control the peak inductor n Internal Compensation current during startup. n Thermal Shutdown n Tiny 28-Lead (4mm × 5mm) Thermally Enhanced The LT3514 also features output voltage tracking and QFN Package sequencing, programmable frequency, programmable n 24-Lead Exposed Pad TSSOP undervoltage lockout, and a power good pin to indicate when all outputs are in regulation.
APPLICATIONS
The LT3514 has one fewer channel (CH2) than the LT3504, and has one channel (CH3) that outputs 2A instead of 1A. n Automotive Battery Regulation The LT3514 in QFN is pin compatible with the LT3504. The n Industrial Control Supplies LT3504 provides four 1A outputs. n Wall Transformer Regulation L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n Distributed Supply Regulation of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION LT3514 Start-Up and Shutdown Triple Buck Regulator Waveform. VIN (Top Trace) Is Ramped from OV Up to 8V and Then Back Down
3.3µH
to 0V. The Other Three Traces Are the
SKY SW1 1.8V/1A
Output Voltages of All Three Channels
SW5 100pF 1µF 12.7k 22µF 10µH DA1 LT3514 10.2k FB1 VIN VIN 1V/DIV 5.4V TO 20V VIN 4.7µH 5V CHANNEL BEGINS TRANSIENT TO 40V 1µF V SW3 3.3V/2A 100% DC OPERATION ×2 IN EN/UVLO 47pF 31.6k 47µF 3.3V CHANNEL BEGINS DA3 CH4 1V/DIV PG PG 10.2k 100% DC OPERATION FB3 8.2µH RUN/SS1 UVLO = ~2.9V CH3 1V/DIV RUN/SS3 SW4 5V/1A PARTS SHUTS 22pF RUN/SS4 53.6k 22µF OFF CH1 1V/DIV 47nF DA4 10.2k RT/SYNC FB4 18.2k 1MHz GND 3514 TA01b 100ms/DIV 3514 TA01a 3514fa For more information www.linear.com/LT3514 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts
