Datasheet LT8640, LT8640-1 (Analog Devices) - 7

LT8640/LT8640-1
TYPICAL PERFORMANCE CHARACTERISTICS Dropout Voltage Switching Frequency Burst Frequency
600 740 1200 R FRONT PAGE APPLICATION V T = 60.4k IN = 5V V V 730 IN = 12V 500 OUT SET TO REGULATE AT 5V 1000 V L = IHLP3232DZ-01, 1µH OUT = 5V 720 400 800 710 300 700 600 690 200 400 DROPOUT VOLTAGE (mV) 680 100 SWITCHING FREQUENCY (kHz) SWITCHING FREQUENCY (kHz) 200 670 0 660 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 –50 –25 0 25 50 75 100 125 150 0 100 200 300 400 LOAD CURRENT (A) TEMPERATURE (°C) LOAD CURRENT (mA) 8640 G19 8640 G20 8640 G21
Minimum Load to Full Frequency (Pulse-Skipping Mode) Frequency Foldback Soft-Start Tracking
100 800 1.2 FRONT PAGE APPLICATION VOUT = 3.3V VOUT = 5V 700 VIN = 12V fSW = 1MHz VSYNC = 0V 1.0 80 600 RT = 60.4k 0.8 500 60 400 0.6 40 300 FB VOLTAGE (V) 0.4 LOAD CURRENT (mA) 200 20 SWITCHING FREQUENCY (kHz) 0.2 100 0 0 0 5 10 15 20 25 30 35 40 45 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 INPUT VOLTAGE (V) FB VOLTAGE (V) TR/SS VOLTAGE (V) 8640 G22 8640 G23 8640 G24
Soft-Start Current PG High Thresholds PG Low Thresholds
2.2 10.0 –6.0 VSS = 0.5V 2.1 (%) 9.5 (%) –6.5 REF REF 2.0 9.0 –7.0 1.9 8.5 –7.5 FB RISING 1.8 8.0 FB RISING –8.0 1.7 7.5 FB FALLING –8.5 FB FALLING SS PIN CURRENT (µA) 1.6 7.0 –9.0 1.5 6.5 –9.5 PG THRESHOLD OFFSET FROM V PG THRESHOLD OFFSET FROM V 1.4 6.0 –10.0 –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) 8640 G25 8640 G26 8640 G27 Rev. D 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 Typical Applications Package Description Revision History Typical Application Related Parts