Datasheet LTC1871X (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Wide Input Range, No RSENSE Current Mode Boost, Flyback and SEPIC Controller |
| Pages / Page | 32 / 7 — PIN FUNCTIONS RUN (Pin 1):. GND (Pin 6):. GATE (Pin 7):. ITH (Pin 2):. … |
| File Format / Size | PDF / 777 Kb |
| Document Language | English |
PIN FUNCTIONS RUN (Pin 1):. GND (Pin 6):. GATE (Pin 7):. ITH (Pin 2):. INTVCC (Pin 8):. FB (Pin3):. VIN (Pin 9):. FREQ (Pin 4):
Model Line for this Datasheet
Text Version of Document
LTC1871X
PIN FUNCTIONS RUN (Pin 1):
The RUN pin provides the user with an operating frequency to an external clock. If the MODE/ accurate means for sensing the input voltage and pro- SYNC pin is connected to ground, Burst Mode operation gramming the start-up threshold for the converter. The is enabled. If the MODE/SYNC pin is connected to INTVCC, falling RUN pin threshold is nominally 1.248V and the or if an external logic-level synchronization signal is ap- comparator has 100mV of hysteresis for noise immunity. plied to this input, Burst Mode operation is disabled and When the RUN pin is below this input threshold, the IC the IC operates in a continuous mode. is shut down and the VIN supply current is kept to a low
GND (Pin 6):
Ground Pin. value (typ 10μA). The Absolute Maximum Rating for the voltage on this pin is 7V.
GATE (Pin 7):
Gate Driver Output.
ITH (Pin 2):
Error Amplifier Compensation Pin. The current
INTVCC (Pin 8):
The Internal 5.20V Regulator Output. The comparator input threshold increases with this control gate driver and control circuits are powered from this voltage. Nominal voltage range for this pin is 0V to 1.40V. voltage. Decouple this pin locally to the IC ground with a minimum of 4.7μF low ESR tantalum or ceramic capacitor.
FB (Pin3):
Receives the feedback voltage from the external resistor divider across the output. Nominal voltage for this
VIN (Pin 9):
Main Supply Pin. Must be closely decoupled pin in regulation is 1.230V. to ground.
FREQ (Pin 4):
A resistor from the FREQ pin to ground
SENSE (Pin 10):
The Current Sense Input for the Control programs the operating frequency of the chip. The nominal Loop. Connect this pin to the drain of the power MOSFET voltage at the FREQ pin is 0.6V. for VDS sensing and highest efficiency. Alternatively, the SENSE pin may be connected to a resistor in the source
MODE/SYNC (Pin 5):
This input controls the operating of the power MOSFET. Internal leading edge blanking is mode of the converter and allows for synchronizing the provided for both sensing methods. 1871xf For more information www.linear.com/LTC1871X 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 Typical Application Related Parts
PIN FUNCTIONS RUN (Pin 1):
The RUN pin provides the user with an operating frequency to an external clock. If the MODE/ accurate means for sensing the input voltage and pro- SYNC pin is connected to ground, Burst Mode operation gramming the start-up threshold for the converter. The is enabled. If the MODE/SYNC pin is connected to INTVCC, falling RUN pin threshold is nominally 1.248V and the or if an external logic-level synchronization signal is ap- comparator has 100mV of hysteresis for noise immunity. plied to this input, Burst Mode operation is disabled and When the RUN pin is below this input threshold, the IC the IC operates in a continuous mode. is shut down and the VIN supply current is kept to a low
GND (Pin 6):
Ground Pin. value (typ 10μA). The Absolute Maximum Rating for the voltage on this pin is 7V.
GATE (Pin 7):
Gate Driver Output.
ITH (Pin 2):
Error Amplifier Compensation Pin. The current
INTVCC (Pin 8):
The Internal 5.20V Regulator Output. The comparator input threshold increases with this control gate driver and control circuits are powered from this voltage. Nominal voltage range for this pin is 0V to 1.40V. voltage. Decouple this pin locally to the IC ground with a minimum of 4.7μF low ESR tantalum or ceramic capacitor.
FB (Pin3):
Receives the feedback voltage from the external resistor divider across the output. Nominal voltage for this
VIN (Pin 9):
Main Supply Pin. Must be closely decoupled pin in regulation is 1.230V. to ground.
FREQ (Pin 4):
A resistor from the FREQ pin to ground
SENSE (Pin 10):
The Current Sense Input for the Control programs the operating frequency of the chip. The nominal Loop. Connect this pin to the drain of the power MOSFET voltage at the FREQ pin is 0.6V. for VDS sensing and highest efficiency. Alternatively, the SENSE pin may be connected to a resistor in the source
MODE/SYNC (Pin 5):
This input controls the operating of the power MOSFET. Internal leading edge blanking is mode of the converter and allows for synchronizing the provided for both sensing methods. 1871xf For more information www.linear.com/LTC1871X 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 Typical Application Related Parts
