Datasheet LT8640S-2, LT8643S-2 (Analog Devices) - 7

LT8640S-2/LT8643S-2
TYPICAL PERFORMANCE CHARACTERISTICS Top FET Current Limit vs Duty Cycle Top FET Current Limit Switch Drop vs Temperature
11.0 12 150 SWITCH CURRENT = 1A 10.5 125 10.0 11 9.5 100 9.0 TOP SWITCH 8.5 10 5% DC 75 8.0 CURRENT LIMIT (A) 50 7.5 CURRENT LIMIT (A) SWITCH DROP (mV) 9 7.0 25 BOTTOM SWITCH 6.5 6.0 8 0 0.1 0.3 0.5 0.7 0.9 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 DUTY CYCLE TEMPERATURE (°C) TEMPERATURE (°C) 8640s2 G19 8640s2 G20 8640s2 G21
Switch Drop vs Switch Current Dropout Voltage Minimum On-Time
500 600 44 VIN = 5V Burst Mode OPERATION 450 VOUT SET TO REGULATE AT 5V FORCED CONTINUOUS MODE 500 L = IHLP3232DZ-01, 1µH 40 400 350 400 36 300 TAGE (mV) 250 300 32 TOP SWITCH 200 28 SWITCH DROP (mV) 200 150 DROPOUT VOL MINIMUM ON–TIME (ns) 100 100 ILOAD = 2A 24 V 50 OUT = 0.97V BOTTOM SWITCH fSW = 3MHz 0 0 20 0 1 2 3 4 5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 –50 –25 0 25 50 75 100 125 SWITCH CURRENT (A) LOAD CURRENT (A) TEMPERATURE (°C) 8640s2 G22 8640s2 G23 8640s2 G24
Switching Frequency Burst Frequency LT8640S-2 Soft-Start Tracking
740 1200 1.2 RT = 60.4k 730 1000 1.0 720 800 0.8 710 700 600 0.6 690 400 FB VOLTAGE (V) 0.4 680 SWITCHING FREQUENCY (kHz) SWITCHING FREQUENCY (kHz) FRONT PAGE APPLICATION 200 0.2 670 VIN = 12V VOUT = 5V 660 0 0 –50 –25 0 25 50 75 100 125 0 100 200 300 400 500 600 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 TEMPERATURE (°C) LOAD CURRENT (mA) TR/SS VOLTAGE (V) 8640s2 G25 8640s2 G26 8640s2 G27 Rev 0 For more information www.analog.com 7 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION E LECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS BLOCK DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION TYPICAL APPLICATIONS RELATED PARTS