Datasheet LTC7821 (Analog Devices) - 7

LTC7821
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Regulated Feedback Voltage TIMER Pin Current vs Temperature TEMP Pin Current vs Temperature vs Temperature
7.5 10 804 7.0 VTIMER = 0V 803 6.5 1 6.0 802 5.5 0.1 (µA) VTEMP = 1V 5.0 (nA) (mV) 801 I TIMER 4.5 I TEMP 0.01 V FB 800 4.0 3.5 0.001 VTIMER = 2.8V 799 3.0 EXT_REF = INTVCC 2.5 0.0001 798 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 7821 G10 7821 G11 7821 G12
Regulated Feedback Voltage Oscillator Frequency Oscillator Frequency vs Temperature vs Input Voltage vs Temperature
600.50 600 800 575 700 600.20 550 600 599.90 525 500 (mV) 500 400 V FB 599.60 475 300 TOR FREQUENCY (kHz) FREQUENCY (kHz) 450 200 599.30 OSCILLA 425 100 EXT_REF = 0.6V RFREQ = 68kΩ RFREQ = 68kΩ 599.00 400 0 –50 –25 0 25 50 75 100 125 0 10 20 30 40 50 60 70 80 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) INPUT VOLTAGE (V) TEMPERATURE (°C) 7821 G13 7821 G14 7821 G15
Switching Frequency INTVCC Line Regulation Current Sense Threshold vs Voltage at FREQ Pin (Supply from EXTVCC) vs ITH Voltage
1800.0 6.50 60 1600.0 50 6.25 1400.0 40 1200.0 6.00 30 1000.0 (V) 20 VCC 5.75 800.0 10 V INT 600.0 5.50 0 400.0 –10 SWITCHING FREQUENCY (kHz) 5.25 CURRENT SENSE THRESHOLD (mV) 200.0 –20 0 5.00 –30 0 0.5 1 1.5 2 2.5 6 10 14 18 22 26 30 34 38 0 0.4 0.8 1.2 1.6 2 FREQ PIN VOLTAGE (V) EXTVCC VOLTAGE (V) ITH VOLTAGE (V) 7821 G16 7821 G17 7821 G18 Rev A For more information www.analog.com 7 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Related Parts