Datasheet LTC1871-7 (Analog Devices) - 6

LTC1871-7
Typical perForMance characTerisTics Maximum Sense Threshold Frequency vs Temperature vs Temperature SENSE Pin Current vs Temperature
325 160 35 GATE HIGH 320 VSENSE = 0V 315 155 310 305 300 150 30 295 290 GATE FREQUENCY (kHz) 145 SENSE PIN CURRENT (µA) 285 MAX SENSE THRESHOLD (mV) 280 275 140 25 –50 –25 0 25 50 75 100 125 150 –50 –25 0 25 50 75 100 125 150 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 18717 G13 18717 G14 18717 G15
INTVCC Dropout Voltage INTVCC Load Regulation INTVCC Line Regulation vs Current, Temperature
7.2 500 VIN = 8V 450 150°C 7.0 400 125°C 7.1 350 75°C 300 25°C 250 VOLTAGE (V) VOLTAGE (V) CC 6.9 CC 200 7.0 0°C INTV INTV 150 DROPOUT VOLTAGE (mV) –50°C 100 50 6.8 6.9 0 0 10 20 30 40 50 60 70 80 0 5 10 15 20 25 30 35 40 0 5 10 15 20 VIN (V) INTVCC LOAD (mA) 18717 G16 18717 G17 18717 G18
pin FuncTions RUN (Pin 1):
The RUN pin provides the user with an
ITH (Pin 2):
Error Amplifier Compensation Pin. The current accurate means for sensing the input voltage and pro- comparator input threshold increases with this control gramming the start-up threshold for the converter. The voltage. Nominal voltage range for this pin is 0V to 1.40V. falling RUN pin threshold is nominally 1.248V and the
FB (Pin 3):
Receives the feedback voltage from the external comparator has 100mV of hysteresis for noise immunity. resistor divider across the output. Nominal voltage for this When the RUN pin is below this input threshold, the IC pin in regulation is 1.230V. is shut down and the VIN supply current is kept to a low value (typ 10µA). The Absolute Maximum Rating for the
FREQ (Pin 4):
A resistor from the FREQ pin to ground voltage on this pin is 7V. programs the operating frequency of the chip. The nominal voltage at the FREQ pin is 0.6V. 18717fd 6 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 Typical Applications Package Description Revision History Typical Application Related Parts