Datasheet LT3973, LT3973-3.3, LT3973-5 (Analog Devices) - 9
| Manufacturer | Analog Devices |
| Description | 42V, 750mA Step-Down Regulator with 2.5μA Quiescent Current and Integrated Diodes |
| Pages / Page | 24 / 9 — PIN FUNCTIONS FB (Pin 1, LT3973 Only):. GND (Pin 5, Exposed Pad Pin 11):. … |
| File Format / Size | PDF / 479 Kb |
| Document Language | English |
PIN FUNCTIONS FB (Pin 1, LT3973 Only):. GND (Pin 5, Exposed Pad Pin 11):. SW (Pin 6):
Model Line for this Datasheet
- LT3973EDD#PBF LT3973EDD#TRPBF LT3973EDD-3.3#PBF LT3973EDD-3.3#TRPBF LT3973EDD-5#PBF LT3973EDD-5#TRPBF LT3973EMSE#PBF LT3973EMSE#TRPBF LT3973EMSE-3.3#PBF LT3973EMSE-3.3#TRPBF LT3973EMSE-5#PBF LT3973EMSE-5#TRPBF LT3973HDD#PBF LT3973HDD#TRPBF LT3973HDD-3.3#PBF LT3973HDD-3.3#TRPBF LT3973HDD-5#PBF LT3973HDD-5#TRPBF LT3973HMSE#PBF LT3973HMSE#TRPBF LT3973HMSE-3.3#PBF LT3973HMSE-3.3#TRPBF LT3973HMSE-5#PBF LT3973HMSE-5#TRPBF LT3973IDD#PBF LT3973IDD#TRPBF LT3973IDD-3.3#PBF LT3973IDD-3.3#TRPBF LT3973IDD-5#PBF LT3973IDD-5#TRPBF LT3973IMSE#PBF LT3973IMSE#TRPBF LT3973IMSE-3.3#PBF LT3973IMSE-3.3#TRPBF LT3973IMSE-5#PBF LT3973IMSE-5#TRPBF
Text Version of Document
LT3973/LT3973-3.3/LT3973-5
PIN FUNCTIONS FB (Pin 1, LT3973 Only):
The LT3973 regulates the FB
GND (Pin 5, Exposed Pad Pin 11):
Ground. The exposed pin to 1.21V. Connect the feedback resistor divider tap pad must be soldered to the PCB. to this pin.
SW (Pin 6):
The SW pin is the output of an internal power
VOUT (Pin 1, LT3973-3.3 and LT3973-5 Only):
The switch. Connect this pin to the inductor. LT3973-3.3 and LT3973-5 regulate the VOUT pin to 3.3V
BOOST (Pin 7):
This pin is used to provide a drive volt- and 5V, respectively. This pin connects to the internal age, higher than the input voltage, to the internal bipolar feedback divider that programs the fixed output voltage. NPN power switch.
OUT (Pin 2):
The LT3973 regulates the VIN to VOUT voltage
BD (Pin 8):
This pin connects to the anode of the boost for dropout conditions. It will also pull current from this diode. This pin also supplies current to the LT3973’s pin to charge the boost capacitor when needed. Connect internal regulator when BD is above 3.2V. this pin to the output. If programmed output is greater than 14V, tie this pin to GND.
PG (Pin 9):
The PG pin is the open-drain output of an internal comparator. PG remains low until the FB pin is
EN/UVLO (Pin 3):
The part is in shutdown when this pin is within 10% of the final regulation voltage. PG is valid when low and active when this pin is high. The threshold voltage V is 1.19V going up with 30mV of hysteresis. Tie to V IN is above 4.2V and EN/UVLO is high. IN if shutdown feature is not used. The EN/UVLO threshold is
RT (Pin 10):
A resistor is tied between RT and ground to accurate only when VIN is above 4.2V. If VIN is lower than set the switching frequency. 4.2V, ground EN/UVLO to place the part in shutdown.
VIN (Pin 4):
The VIN pin supplies current to the LT3973’s internal circuitry and to the internal power switch. This pin must be locally bypassed. 3973fb For more information www.linear.com/LT3973 9 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
PIN FUNCTIONS FB (Pin 1, LT3973 Only):
The LT3973 regulates the FB
GND (Pin 5, Exposed Pad Pin 11):
Ground. The exposed pin to 1.21V. Connect the feedback resistor divider tap pad must be soldered to the PCB. to this pin.
SW (Pin 6):
The SW pin is the output of an internal power
VOUT (Pin 1, LT3973-3.3 and LT3973-5 Only):
The switch. Connect this pin to the inductor. LT3973-3.3 and LT3973-5 regulate the VOUT pin to 3.3V
BOOST (Pin 7):
This pin is used to provide a drive volt- and 5V, respectively. This pin connects to the internal age, higher than the input voltage, to the internal bipolar feedback divider that programs the fixed output voltage. NPN power switch.
OUT (Pin 2):
The LT3973 regulates the VIN to VOUT voltage
BD (Pin 8):
This pin connects to the anode of the boost for dropout conditions. It will also pull current from this diode. This pin also supplies current to the LT3973’s pin to charge the boost capacitor when needed. Connect internal regulator when BD is above 3.2V. this pin to the output. If programmed output is greater than 14V, tie this pin to GND.
PG (Pin 9):
The PG pin is the open-drain output of an internal comparator. PG remains low until the FB pin is
EN/UVLO (Pin 3):
The part is in shutdown when this pin is within 10% of the final regulation voltage. PG is valid when low and active when this pin is high. The threshold voltage V is 1.19V going up with 30mV of hysteresis. Tie to V IN is above 4.2V and EN/UVLO is high. IN if shutdown feature is not used. The EN/UVLO threshold is
RT (Pin 10):
A resistor is tied between RT and ground to accurate only when VIN is above 4.2V. If VIN is lower than set the switching frequency. 4.2V, ground EN/UVLO to place the part in shutdown.
VIN (Pin 4):
The VIN pin supplies current to the LT3973’s internal circuitry and to the internal power switch. This pin must be locally bypassed. 3973fb For more information www.linear.com/LT3973 9 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
