Datasheet LTC3549 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | 250mA Low VIN Buck Regulator in 2mm × 3mm DFN |
| Pages / Page | 16 / 7 — PI FU CTIO S. VIN (Pin 1):. RUN (Pin 5):. GND (Pin 2):. SW (Pin 3):. FB … |
| File Format / Size | PDF / 370 Kb |
| Document Language | English |
PI FU CTIO S. VIN (Pin 1):. RUN (Pin 5):. GND (Pin 2):. SW (Pin 3):. FB (Pin 6):. GND (Pin 7):. MODE (Pin 4):. FU CTIO AL DIAGRA
Model Line for this Datasheet
Text Version of Document
LTC3549
U U U PI FU CTIO S VIN (Pin 1):
Main Supply Pin. Must be closely decoupled
RUN (Pin 5):
Run Control Input. Forcing this pin above 1.1V to GND, Pins 2 and 7, with a 4.7µF or greater ceramic enables the part. Forcing this pin below 0.3V shuts down capacitor. the device. In shutdown, all functions are disabled drawing <1µA supply current. Do not leave RUN fl oating.
GND (Pin 2):
N/C. Ground this pin.
V SW (Pin 3):
Switch Node Connection to Inductor. This pin
FB (Pin 6):
Feedback Pin. Receives the feedback voltage from an external resistive divider across the output. connects to the drains of the internal main and synchronous power MOSFET switches.
GND (Pin 7):
Exposed Pad. The Exposed Pad is ground. It must be soldered to PCB ground to provide both electrical
MODE (Pin 4):
Mode Select Input. To select pulse-skip- contact and optimum thermal performance. ping mode, force this pin above 1.1V. Forcing this pin below 0.3V selects Burst Mode operation. Do not leave MODE fl oating.
U U W FU CTIO AL DIAGRA
MODE 4 SLOPE COMP 0.65V OSCILLATOR OSC 1 VIN – VFB EN + – 6 SLEEP + 0.611V 5Ω – 0.4V + – + I EA COMP BURST S Q SOFT- R Q START SWITCHING RS LATCH LOGIC VIN AND ANTI- BLANKING SHOOT- THRU 3 SW RUN CIRCUIT + 5 REFERENCE OV OVDET 0.671 – + SHUTDOWN IRCMP– 2 GND 7 GND 3549 FD 3549f 7
U U U PI FU CTIO S VIN (Pin 1):
Main Supply Pin. Must be closely decoupled
RUN (Pin 5):
Run Control Input. Forcing this pin above 1.1V to GND, Pins 2 and 7, with a 4.7µF or greater ceramic enables the part. Forcing this pin below 0.3V shuts down capacitor. the device. In shutdown, all functions are disabled drawing <1µA supply current. Do not leave RUN fl oating.
GND (Pin 2):
N/C. Ground this pin.
V SW (Pin 3):
Switch Node Connection to Inductor. This pin
FB (Pin 6):
Feedback Pin. Receives the feedback voltage from an external resistive divider across the output. connects to the drains of the internal main and synchronous power MOSFET switches.
GND (Pin 7):
Exposed Pad. The Exposed Pad is ground. It must be soldered to PCB ground to provide both electrical
MODE (Pin 4):
Mode Select Input. To select pulse-skip- contact and optimum thermal performance. ping mode, force this pin above 1.1V. Forcing this pin below 0.3V selects Burst Mode operation. Do not leave MODE fl oating.
U U W FU CTIO AL DIAGRA
MODE 4 SLOPE COMP 0.65V OSCILLATOR OSC 1 VIN – VFB EN + – 6 SLEEP + 0.611V 5Ω – 0.4V + – + I EA COMP BURST S Q SOFT- R Q START SWITCHING RS LATCH LOGIC VIN AND ANTI- BLANKING SHOOT- THRU 3 SW RUN CIRCUIT + 5 REFERENCE OV OVDET 0.671 – + SHUTDOWN IRCMP– 2 GND 7 GND 3549 FD 3549f 7
