Datasheet LTC3446 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Monolithic Buck Regulator with Dual VLDO Regulators |
| Pages / Page | 20 / 7 — pin FuncTions. MODESEL (Pin 1):. LVFB1 (Pin 10):. ENLDO1/ENLDO2 (Pin … |
| File Format / Size | PDF / 290 Kb |
| Document Language | English |
pin FuncTions. MODESEL (Pin 1):. LVFB1 (Pin 10):. ENLDO1/ENLDO2 (Pin 11/Pin 8):. VIN (Pin 2):. BUCKFB (Pin 12):. ITH (Pin 3):
Model Line for this Datasheet
Text Version of Document
LTC3446
pin FuncTions MODESEL (Pin 1):
Chooses Between Burst Mode Operation
LVFB1 (Pin 10):
Feedback Pin for the First VLDO Regulator. and Pulse-Skipping Operation at Light Loads. Forcing this An output divider should be connected from LVOUT1 to LVFB1 pin below 0.3V allows the buck converter to automatically to set the desired LVOUT1 regulated output voltage. enter Burst Mode operation at light loads. Forcing this pin
ENLDO1/ENLDO2 (Pin 11/Pin 8):
Enable Pin for the First above 1V disallows entering Burst Mode operation; the and Second VLDO Regulators, Respectively. Forcing this buck converter will cycle skip at light loads. Do not leave pin above 1V enables the corresponding VLDO regulator this pin floating. This is a MOS gate input. and forcing this pin below 0.3V shuts it down. Each VLDO
VIN (Pin 2):
Input Supply to the LTC3446. Must be regulator draws <1µA of supply current in shutdown. Do closely decoupled to GND with a 10µF or greater ceramic not leave this pin floating. This is a MOS gate input. capacitor.
BUCKFB (Pin 12):
Buck Converter’s Feedback Pin. Receives
ITH (Pin 3):
Buck Error Amplifier Output and Servo-Loop the feedback voltage from an external resistive divider Compensation Point. across the output. External resistance from this pin to
PGOOD (Pin 4):
Supply Monitor Output, Open-Drain ground should be equal to or less than 50k. NMOS.
ENBUCK (Pin 13):
Enable Pin for the LTC3446’s Buck
LV
Converter Circuit. Forcing this pin above 1V enables the
OUT1 (Pin 5):
Output of the First VLDO Regulator. buck converter and forcing this pin below 0.3V shuts down
LVIN (Pin 6):
Input Supply to the LTC3446’s VLDO Circuits. the converter. In shutdown, the buck converter draws <1µA Bypass LVIN to GND with at least a 1µF low ESR ceramic of supply current. Do not leave this pin floating. This is a capacitor. Typical LTC3446 application circuits wil connect MOS gate input. this pin to the output of the buck converter but this is not required. The VLDO regulators may be used independently
SW (Pin 14):
Switch Node Connection to Inductor. This of the buck converter. pin connects to the drains of the internal main and syn- chronous power MOSFET switches.
LVOUT2 (Pin 7):
Output of the Second VLDO Regulator.
GND (Exposed Pad, Pin 15):
Ground. The Exposed Pad is
LVFB2 (Pin 9):
Feedback Pin for the Second VLDO Regulator. the only ground and must connect to the PCB ground for An output divider should be connected from LVOUT2 to LVFB2 electrical contact and rated thermal performance. to set the desired LVOUT2 regulated output voltage. 3446ff 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 Package Description Revision History Typical Application Related Parts
pin FuncTions MODESEL (Pin 1):
Chooses Between Burst Mode Operation
LVFB1 (Pin 10):
Feedback Pin for the First VLDO Regulator. and Pulse-Skipping Operation at Light Loads. Forcing this An output divider should be connected from LVOUT1 to LVFB1 pin below 0.3V allows the buck converter to automatically to set the desired LVOUT1 regulated output voltage. enter Burst Mode operation at light loads. Forcing this pin
ENLDO1/ENLDO2 (Pin 11/Pin 8):
Enable Pin for the First above 1V disallows entering Burst Mode operation; the and Second VLDO Regulators, Respectively. Forcing this buck converter will cycle skip at light loads. Do not leave pin above 1V enables the corresponding VLDO regulator this pin floating. This is a MOS gate input. and forcing this pin below 0.3V shuts it down. Each VLDO
VIN (Pin 2):
Input Supply to the LTC3446. Must be regulator draws <1µA of supply current in shutdown. Do closely decoupled to GND with a 10µF or greater ceramic not leave this pin floating. This is a MOS gate input. capacitor.
BUCKFB (Pin 12):
Buck Converter’s Feedback Pin. Receives
ITH (Pin 3):
Buck Error Amplifier Output and Servo-Loop the feedback voltage from an external resistive divider Compensation Point. across the output. External resistance from this pin to
PGOOD (Pin 4):
Supply Monitor Output, Open-Drain ground should be equal to or less than 50k. NMOS.
ENBUCK (Pin 13):
Enable Pin for the LTC3446’s Buck
LV
Converter Circuit. Forcing this pin above 1V enables the
OUT1 (Pin 5):
Output of the First VLDO Regulator. buck converter and forcing this pin below 0.3V shuts down
LVIN (Pin 6):
Input Supply to the LTC3446’s VLDO Circuits. the converter. In shutdown, the buck converter draws <1µA Bypass LVIN to GND with at least a 1µF low ESR ceramic of supply current. Do not leave this pin floating. This is a capacitor. Typical LTC3446 application circuits wil connect MOS gate input. this pin to the output of the buck converter but this is not required. The VLDO regulators may be used independently
SW (Pin 14):
Switch Node Connection to Inductor. This of the buck converter. pin connects to the drains of the internal main and syn- chronous power MOSFET switches.
LVOUT2 (Pin 7):
Output of the Second VLDO Regulator.
GND (Exposed Pad, Pin 15):
Ground. The Exposed Pad is
LVFB2 (Pin 9):
Feedback Pin for the Second VLDO Regulator. the only ground and must connect to the PCB ground for An output divider should be connected from LVOUT2 to LVFB2 electrical contact and rated thermal performance. to set the desired LVOUT2 regulated output voltage. 3446ff 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 Package Description Revision History Typical Application Related Parts
