Datasheet LT3514 (Analog Devices) - 8
| 制造商 | Analog Devices |
| 描述 | Triple Step-Down Switching Regulator with 100% Duty Cycle Operation |
| 页数 / 页 | 26 / 8 — TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. … |
| 文件格式/大小 | PDF / 482 Kb |
| 文件语言 | 英语 |
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Operating Waveforms,. Discontinuous Mode
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LT3514
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Operating Waveforms, Operating Waveforms, Discontinuous Mode Continuous Mode
SW1 SW1 10V/DIV 10V/DIV SW3 SW3 10V/DIV 10V/DIV SW4 SW4 10V/DIV 10V/DIV 500ns/DIV 3514 G29 500ns/DIV 3514 G30 IOUT1,3,4 = 40mA IOUT1,3,4 = 0.5A VOUT1,3,4 = 5V VOUT1,3,4 = 5V
PIN FUNCTIONS (QFN/TSSOP) NC (Pins 1, 2, 14, 22/Pins 2, 10):
No Connection. These
RUN/SS (Pins 12, 13, 15/Pins 13, 14, 15):
The RUN/SS pins have no connection to internal circuitry. They can be pins are used to soft start each channel and to allow grounded or left floating. each channel to track other outputs. Output tracking is
DA (Pins 3, 6, 8/Pins 3, 7, 9):
Return the Schottky catch implemented by connecting a resistor divider to this pin diode anode to the diode anode (DA) pin. An internal com- from the tracked output. For soft start, tie a capacitor from parator senses the diode current and prevents switching this pin to ground. An internal 1.3µA soft-start current when the diode current is higher than the DA pin current charges the capacitor to create a voltage ramp at the pin. limit. Each channel can be individually shut down by pulling RUN/SS below 0.1V.
SW (Pins 4, 5, 7/Pins 4, 5, 6, 8):
The SW pins are the output of the internal power switches. Connect each SW
EN/UVLO (Pin 16/Pin 16):
The EN/UVLO pin is used to pin to an inductor and Schottky catch diode cathode. start up the internal regulator to power the reference and oscillator. It also starts up the internal boost regulator. Pull
VIN (Pins 9, 11, 26, 28/Pins 1, 11, 12):
The VIN pins sup- the EN/UVLO pin below 1.44V to shut down the LT3514. ply current to the LT3514’s internal regulator and to the The LT3514 will draw less than 10µA of current from the internal power switches. The VIN pins should be locally VIN pin when EN/UVLO is less than 1.44V. Pull EN/UVLO bypassed with a capacitor to ground, preferably to pins pin below 0.7V to put the LT3514 in a state where the part 27 and 10. They must be tied to the same input source. draws 0µA from the VIN pin. The threshold can function
GND (Pins 10, 18, 27, Exposed Pad Pin 29/Pin 22,
as an accurate undervoltage lockout (UVLO), preventing
Exposed Pad Pin 25):
Tie the GND pins to a local ground the regulator from operating until the input voltage has plane below the LT3514 and the circuit components. The reached the programmed level. Do not drive the EN/UVLO exposed pad must be soldered to the PCB and electrically pin more than 5V above VIN. connected to ground. Use a large ground plane and thermal vias to optimize thermal performance. 3514fa 8 For more information www.linear.com/LT3514 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
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Operating Waveforms, Operating Waveforms, Discontinuous Mode Continuous Mode
SW1 SW1 10V/DIV 10V/DIV SW3 SW3 10V/DIV 10V/DIV SW4 SW4 10V/DIV 10V/DIV 500ns/DIV 3514 G29 500ns/DIV 3514 G30 IOUT1,3,4 = 40mA IOUT1,3,4 = 0.5A VOUT1,3,4 = 5V VOUT1,3,4 = 5V
PIN FUNCTIONS (QFN/TSSOP) NC (Pins 1, 2, 14, 22/Pins 2, 10):
No Connection. These
RUN/SS (Pins 12, 13, 15/Pins 13, 14, 15):
The RUN/SS pins have no connection to internal circuitry. They can be pins are used to soft start each channel and to allow grounded or left floating. each channel to track other outputs. Output tracking is
DA (Pins 3, 6, 8/Pins 3, 7, 9):
Return the Schottky catch implemented by connecting a resistor divider to this pin diode anode to the diode anode (DA) pin. An internal com- from the tracked output. For soft start, tie a capacitor from parator senses the diode current and prevents switching this pin to ground. An internal 1.3µA soft-start current when the diode current is higher than the DA pin current charges the capacitor to create a voltage ramp at the pin. limit. Each channel can be individually shut down by pulling RUN/SS below 0.1V.
SW (Pins 4, 5, 7/Pins 4, 5, 6, 8):
The SW pins are the output of the internal power switches. Connect each SW
EN/UVLO (Pin 16/Pin 16):
The EN/UVLO pin is used to pin to an inductor and Schottky catch diode cathode. start up the internal regulator to power the reference and oscillator. It also starts up the internal boost regulator. Pull
VIN (Pins 9, 11, 26, 28/Pins 1, 11, 12):
The VIN pins sup- the EN/UVLO pin below 1.44V to shut down the LT3514. ply current to the LT3514’s internal regulator and to the The LT3514 will draw less than 10µA of current from the internal power switches. The VIN pins should be locally VIN pin when EN/UVLO is less than 1.44V. Pull EN/UVLO bypassed with a capacitor to ground, preferably to pins pin below 0.7V to put the LT3514 in a state where the part 27 and 10. They must be tied to the same input source. draws 0µA from the VIN pin. The threshold can function
GND (Pins 10, 18, 27, Exposed Pad Pin 29/Pin 22,
as an accurate undervoltage lockout (UVLO), preventing
Exposed Pad Pin 25):
Tie the GND pins to a local ground the regulator from operating until the input voltage has plane below the LT3514 and the circuit components. The reached the programmed level. Do not drive the EN/UVLO exposed pad must be soldered to the PCB and electrically pin more than 5V above VIN. connected to ground. Use a large ground plane and thermal vias to optimize thermal performance. 3514fa 8 For more information www.linear.com/LT3514 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