Datasheet LT3990, LT3990-3.3, LT3990-5 (Analog Devices) - 7
| Fabricante | Analog Devices |
| Descripción | 62V, 350mA Step-Down Regulator with 2.5μA Quiescent Current and Integrated Diodes |
| Páginas / Página | 22 / 7 — TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. … |
| Formato / tamaño de archivo | PDF / 307 Kb |
| Idioma del documento | Inglés |
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Switching Waveforms,. Switching Waveforms, Full
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- LT3990EDD#PBF LT3990EDD#TRPBF LT3990EMSE#PBF LT3990EMSE#TRPBF LT3990EMSE-3.3#PBF LT3990EMSE-3.3#TRPBF LT3990EMSE-5#PBF LT3990EMSE-5#TRPBF LT3990EMSE-5#WTRPBF LT3990HMSE#PBF LT3990HMSE#TRPBF LT3990HMSE-3.3#PBF LT3990HMSE-3.3#TRPBF LT3990HMSE-5#PBF LT3990HMSE-5#TRPBF LT3990IDD#PBF LT3990IDD#TRPBF LT3990IMSE#PBF LT3990IMSE#TRPBF LT3990IMSE-3.3#PBF LT3990IMSE-3.3#TRPBF LT3990IMSE-5#PBF LT3990IMSE-5#TRPBF
Versión de texto del documento
LT3990/LT3990-3.3/LT3990-5
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Switching Waveforms, Switching Waveforms, Full Burst Mode Operation Frequency Continuous Operation
VSW VSW 5V/DIV 5V/DIV IL IL 100mA/DIV 200mA/DIV VOUT VOUT 5mV/DIV 5mV/DIV 2µs/DIV 3990 G28 1µs/DIV 3990 G29 FRONT PAGE APPLICATION FRONT PAGE APPLICATION VIN = 12V VIN = 12V VOUT = 5V VOUT = 5V ILOAD = 10mA ILOAD = 350mA f = 600kHz f = 600kHz
PIN FUNCTIONS (DFN, MSOP) FB (Pin 1/Pins 1, 2 LT3990 Only):
The LT3990 regulates
GND (Pins 4, 5, Exposed Pad Pin 11/Pin 8, Exposed
the FB pin to 1.21V. Connect the feedback resistor divider
Pad Pin 17):
Ground. The exposed pad must be soldered tap to this pin. The two FB pins on the MSE package are to the PCB. connected internally and provide a redundant path for the
SW (Pin 6/Pin 9):
The SW pin is the output of an internal feedback divider. Tie the divider to both pins. power switch. Connect this pin to the inductor.
VOUT (Pins 1, 2, LT3990-X Only):
The LT3990-3.3 and
BOOST (Pin 7/Pin 11):
This pin is used to provide a drive LT3990-5 regulate the VOUT pin to 3.3V and 5V, respec- voltage, higher than the input voltage, to the internal bipolar tively. This pin connects to the internal feedback divider NPN power switch. that programs the fixed output voltage. The two VOUT pins are connected internally and provide a redundant path to
BD (Pin 8/Pin 13):
This pin connects to the anode of the the output. Tie the output to both pins. boost diode. This pin also supplies current to the LT3990’s internal regulator when BD is above 3.2V.
EN/UVLO (Pin 2/Pin 4):
The part is in shutdown when this pin is low and active when this pin is high. The threshold
PG (Pin 9/Pin 14):
The PG pin is the open-drain output of voltage is 1.19V going up with 35mV of hysteresis. Tie to an internal comparator. PG remains low until the FB pin VIN if shutdown feature is not used. The EN/UVLO threshold is within 10% of the final regulation voltage. PG is valid is accurate only when VIN is above 4.2V. If VIN is lower when VIN is above 4.2V and EN/UVLO is high. than 4.2V, ground EN/UVLO to place the part in shutdown.
RT (Pin 10/Pin 16):
A resistor is tied between RT and
VIN (Pin 3/Pin 6):
The VIN pin supplies current to the ground to set the switching frequency. LT3990’s internal circuitry and to the internal power switch.
NC (Pins 3, 5, 7, 10, 12, 15, MSOP Only):
No Connects. This pin must be locally bypassed. These pins are not connected to internal circuitry and must be left floating to ensure fault tolerance. 3990fa 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Switching Waveforms, Switching Waveforms, Full Burst Mode Operation Frequency Continuous Operation
VSW VSW 5V/DIV 5V/DIV IL IL 100mA/DIV 200mA/DIV VOUT VOUT 5mV/DIV 5mV/DIV 2µs/DIV 3990 G28 1µs/DIV 3990 G29 FRONT PAGE APPLICATION FRONT PAGE APPLICATION VIN = 12V VIN = 12V VOUT = 5V VOUT = 5V ILOAD = 10mA ILOAD = 350mA f = 600kHz f = 600kHz
PIN FUNCTIONS (DFN, MSOP) FB (Pin 1/Pins 1, 2 LT3990 Only):
The LT3990 regulates
GND (Pins 4, 5, Exposed Pad Pin 11/Pin 8, Exposed
the FB pin to 1.21V. Connect the feedback resistor divider
Pad Pin 17):
Ground. The exposed pad must be soldered tap to this pin. The two FB pins on the MSE package are to the PCB. connected internally and provide a redundant path for the
SW (Pin 6/Pin 9):
The SW pin is the output of an internal feedback divider. Tie the divider to both pins. power switch. Connect this pin to the inductor.
VOUT (Pins 1, 2, LT3990-X Only):
The LT3990-3.3 and
BOOST (Pin 7/Pin 11):
This pin is used to provide a drive LT3990-5 regulate the VOUT pin to 3.3V and 5V, respec- voltage, higher than the input voltage, to the internal bipolar tively. This pin connects to the internal feedback divider NPN power switch. that programs the fixed output voltage. The two VOUT pins are connected internally and provide a redundant path to
BD (Pin 8/Pin 13):
This pin connects to the anode of the the output. Tie the output to both pins. boost diode. This pin also supplies current to the LT3990’s internal regulator when BD is above 3.2V.
EN/UVLO (Pin 2/Pin 4):
The part is in shutdown when this pin is low and active when this pin is high. The threshold
PG (Pin 9/Pin 14):
The PG pin is the open-drain output of voltage is 1.19V going up with 35mV of hysteresis. Tie to an internal comparator. PG remains low until the FB pin VIN if shutdown feature is not used. The EN/UVLO threshold is within 10% of the final regulation voltage. PG is valid is accurate only when VIN is above 4.2V. If VIN is lower when VIN is above 4.2V and EN/UVLO is high. than 4.2V, ground EN/UVLO to place the part in shutdown.
RT (Pin 10/Pin 16):
A resistor is tied between RT and
VIN (Pin 3/Pin 6):
The VIN pin supplies current to the ground to set the switching frequency. LT3990’s internal circuitry and to the internal power switch.
NC (Pins 3, 5, 7, 10, 12, 15, MSOP Only):
No Connects. This pin must be locally bypassed. These pins are not connected to internal circuitry and must be left floating to ensure fault tolerance. 3990fa 7 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts