Datasheet LTC1874 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Dual Constant Frequency Current Mode Step-Down DC/DC Controller |
| Pages / Page | 12 / 4 — PIN FUNCTIONS. VIN1 (Pin 1):. VIN2 (Pin 9):. SENSE1– (Pin 2):. SENSE2– … |
| File Format / Size | PDF / 190 Kb |
| Document Language | English |
PIN FUNCTIONS. VIN1 (Pin 1):. VIN2 (Pin 9):. SENSE1– (Pin 2):. SENSE2– (Pin 10):. GND1 (Pin 3):. GND2 (Pin 11):. VFB1 (Pin 4):
Model Line for this Datasheet
Text Version of Document
LTC1874
U U U PIN FUNCTIONS VIN1 (Pin 1):
Main Supply Pin for Controller #1. This pin
VIN2 (Pin 9):
Main Supply Pin for Controller #2. This pin delivers the Input DC Supply Current (listed in the Electri- delivers the Input DC Supply Current (listed in the Electri- cal Characteristics table) plus a small amount of logic cal Characteristics table) plus a small amount of logic switching current. Must be connected to PVIN1 (Pin 16) switching current. Must be connected to PVIN2 (Pin 8) and and closely decoupled to GND1 (Pin 3). closely decoupled to GND2 (Pin 11).
SENSE1– (Pin 2):
The Negative Input to the Current
SENSE2– (Pin 10):
The Negative Input to the Current Comparator of Controller #1. Comparator of Controller #2.
GND1 (Pin 3):
Signal Ground for Controller #1. Must be
GND2 (Pin 11):
Signal Ground for Controller #2. Must be connected to PGND1 (Pin 14). connected to PGND2 (Pin 6).
VFB1 (Pin 4):
Receives the feedback voltage from an
VFB2 (Pin 12):
Receives the feedback voltage from an external resistive divider across the output of Controller external resistive divider across the output of Controller #1. #2.
ITH/RUN2 (Pin 5):
This pin performs two functions. It
ITH/RUN1 (Pin 13):
This pin performs two functions. It serves as the error amplifier compensation point as well as serves as the error amplifier compensation point as well as the run control input of Controller #2. The current com- the run control input of Controller #1. The current com- parator threshold increases with this control voltage. parator threshold increases with this control voltage. Nominal voltage range for this pin is 0.7V to 1.9V. Forcing Nominal voltage range for this pin is 0.7V to 1.9V. Forcing this pin below 0.35V causes Controller #2 to be shut down. this pin below 0.35V causes Controller #1 to be shut down. In shutdown, all functions of Controller #2 are disabled In shutdown, all functions of Controller #1 are disabled and PGATE2 (Pin 7) is held high. and PGATE1 (Pin 15) is held high.
PGND2 (Pin 6):
Power Ground for Controller #2. Must be
PGND1 (Pin 14):
Power Ground for Controller #1. Must be connected to GND2 (Pin 11). connected to GND1 (Pin 3).
PGATE2 (Pin 7):
Gate Drive for the External P-Channel
PGATE1 (Pin 15):
Gate Drive for the External P-Channel MOSFET of Controller #2. This pin swings from 0V to the MOSFET of Controller #1. This pin swings from 0V to the voltage of PVIN2. voltage of PVIN1.
PVIN2 (Pin 8):
Power Supply Pin for Controller #2. This pin
PVIN1 (Pin 16):
Power Supply Pin for Controller #1. This delivers the dynamic switching current that drives the gate pin delivers the dynamic switching current that drives the of the external P-channel MOSFET of Controller #2. Must gate of the external P-channel MOSFET of Controller #1. be connected to VIN2 (Pin 9) and closely decoupled to Must be connected to VIN1 (Pin 1) and closely decoupled PGND2 (Pin 6). to PGND1 (Pin 14). 4
U U U PIN FUNCTIONS VIN1 (Pin 1):
Main Supply Pin for Controller #1. This pin
VIN2 (Pin 9):
Main Supply Pin for Controller #2. This pin delivers the Input DC Supply Current (listed in the Electri- delivers the Input DC Supply Current (listed in the Electri- cal Characteristics table) plus a small amount of logic cal Characteristics table) plus a small amount of logic switching current. Must be connected to PVIN1 (Pin 16) switching current. Must be connected to PVIN2 (Pin 8) and and closely decoupled to GND1 (Pin 3). closely decoupled to GND2 (Pin 11).
SENSE1– (Pin 2):
The Negative Input to the Current
SENSE2– (Pin 10):
The Negative Input to the Current Comparator of Controller #1. Comparator of Controller #2.
GND1 (Pin 3):
Signal Ground for Controller #1. Must be
GND2 (Pin 11):
Signal Ground for Controller #2. Must be connected to PGND1 (Pin 14). connected to PGND2 (Pin 6).
VFB1 (Pin 4):
Receives the feedback voltage from an
VFB2 (Pin 12):
Receives the feedback voltage from an external resistive divider across the output of Controller external resistive divider across the output of Controller #1. #2.
ITH/RUN2 (Pin 5):
This pin performs two functions. It
ITH/RUN1 (Pin 13):
This pin performs two functions. It serves as the error amplifier compensation point as well as serves as the error amplifier compensation point as well as the run control input of Controller #2. The current com- the run control input of Controller #1. The current com- parator threshold increases with this control voltage. parator threshold increases with this control voltage. Nominal voltage range for this pin is 0.7V to 1.9V. Forcing Nominal voltage range for this pin is 0.7V to 1.9V. Forcing this pin below 0.35V causes Controller #2 to be shut down. this pin below 0.35V causes Controller #1 to be shut down. In shutdown, all functions of Controller #2 are disabled In shutdown, all functions of Controller #1 are disabled and PGATE2 (Pin 7) is held high. and PGATE1 (Pin 15) is held high.
PGND2 (Pin 6):
Power Ground for Controller #2. Must be
PGND1 (Pin 14):
Power Ground for Controller #1. Must be connected to GND2 (Pin 11). connected to GND1 (Pin 3).
PGATE2 (Pin 7):
Gate Drive for the External P-Channel
PGATE1 (Pin 15):
Gate Drive for the External P-Channel MOSFET of Controller #2. This pin swings from 0V to the MOSFET of Controller #1. This pin swings from 0V to the voltage of PVIN2. voltage of PVIN1.
PVIN2 (Pin 8):
Power Supply Pin for Controller #2. This pin
PVIN1 (Pin 16):
Power Supply Pin for Controller #1. This delivers the dynamic switching current that drives the gate pin delivers the dynamic switching current that drives the of the external P-channel MOSFET of Controller #2. Must gate of the external P-channel MOSFET of Controller #1. be connected to VIN2 (Pin 9) and closely decoupled to Must be connected to VIN1 (Pin 1) and closely decoupled PGND2 (Pin 6). to PGND1 (Pin 14). 4
