Datasheet LTC1871 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Wide Input Range, No RSENSE Current Mode Boost, Flyback and SEPIC Controller |
| Pages / Page | 36 / 7 — PIN FUNCTIONS. RUN (Pin 1):. GND (Pin 6):. GATE (Pin 7):. INTVCC (Pin … |
| File Format / Size | PDF / 534 Kb |
| Document Language | English |
PIN FUNCTIONS. RUN (Pin 1):. GND (Pin 6):. GATE (Pin 7):. INTVCC (Pin 8):. TH (Pin 2):. FB (Pin 3):. IN (Pin 9):. SENSE (Pin 10):
Model Line for this Datasheet
Text Version of Document
LTC1871
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.
I INTVCC (Pin 8):
The Internal 5.20V Regulator Output.
TH (Pin 2):
Error Amplifi er Compensation Pin. The current comparator input threshold increases with this The gate driver and control circuits are powered from control voltage. Nominal voltage range for this pin is 0V this voltage. Decouple this pin locally to the IC ground to 1.40V. with a minimum of 4.7μF low ESR tantalum or ceramic capacitor.
FB (Pin 3):
Receives the feedback voltage from the external
V
resistor divider across the output. Nominal voltage for
IN (Pin 9):
Main Supply Pin. Must be closely decoupled to ground. this pin in regulation is 1.230V.
SENSE (Pin 10):
The Current Sense Input for the Control
FREQ (Pin 4):
A resistor from the FREQ pin to ground Loop. Connect this pin to the drain of the power MOSFET programs the operating frequency of the chip. The nominal for V voltage at the FREQ pin is 0.6V. DS sensing and highest effi ciency. 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. 1871fe 7
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.
I INTVCC (Pin 8):
The Internal 5.20V Regulator Output.
TH (Pin 2):
Error Amplifi er Compensation Pin. The current comparator input threshold increases with this The gate driver and control circuits are powered from control voltage. Nominal voltage range for this pin is 0V this voltage. Decouple this pin locally to the IC ground to 1.40V. with a minimum of 4.7μF low ESR tantalum or ceramic capacitor.
FB (Pin 3):
Receives the feedback voltage from the external
V
resistor divider across the output. Nominal voltage for
IN (Pin 9):
Main Supply Pin. Must be closely decoupled to ground. this pin in regulation is 1.230V.
SENSE (Pin 10):
The Current Sense Input for the Control
FREQ (Pin 4):
A resistor from the FREQ pin to ground Loop. Connect this pin to the drain of the power MOSFET programs the operating frequency of the chip. The nominal for V voltage at the FREQ pin is 0.6V. DS sensing and highest effi ciency. 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. 1871fe 7
