Datasheet LTC3670 (Analog Devices) - 6

LTC3670
PIN FUNCTIONS SW (Pin 1):
Buck Regulator Switch Node Connection to In-
LDO2_FB (Pin 8):
Feedback Voltage Input for the Second ductor. This pin connects to the drains of the buck regulator’s Low Dropout Linear Regulator (LDO2). Typically, an ex- main PMOS and synchronous NMOS switches. ternal resistor divider feeds a fraction of the LDO2 output
GND (Pin 2):
Ground. voltage to this pin.
ENLDO1 (Pin 3):
Enables the First Low Dropout Linear
LDO1_FB (Pin 9):
Feedback Voltage Input for the First Low Regulator (LDO1) When High. This is a MOS gate input. Dropout Linear Regulator (LDO1). Typically, an external There is an internal 4MΩ pull-down. resistor divider feeds a fraction of the LDO1 output volt- age to this pin.
ENLDO2 (Pin 4):
Enables the Second Low Dropout Linear Regulator (LDO2) When High. This is a MOS gate input.
LDO1 (Pin 10):
Output of the First Low Dropout Linear There is an internal 4MΩ pull-down. Regulator. This pin must be bypassed to ground with a 1µF or greater ceramic capacitor.
ENBUCK (Pin 5):
Enables the Buck Converter When High. This is a MOS gate input. There is an internal 4MΩ pull-
LDO2 (Pin 11):
Output of the Second Low Dropout Linear down. Regulator. This pin must be bypassed to ground with a 1µF or greater ceramic capacitor.
BUCKFB (Pin 6):
Feedback Voltage Input for the Buck Regulator. Typically, an external resistor divider feeds a
VIN (Pin 12):
Input Supply. This pin should be bypassed fraction of the buck output voltage to this pin. to ground with a 2.2µF or greater ceramic capacitor.
PGOOD (Pin 7):
Power Good Open-Drain NMOS Output.
Exposed Pad (Pin 13):
Ground. This pin must be soldered The PGOOD pin goes Hi-Z when all enabled outputs are to the PCB. within 8% of final value. Rev A 6 For more information www.analog.com Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Application Related Parts