Datasheet LT8640S-2, LT8643S-2 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | 42V, 6A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current |
| Pages / Page | 30 / 7 — TYPICAL PERFORMANCE CHARACTERISTICS. Top FET Current Limit vs Duty Cycle. … |
| File Format / Size | PDF / 2.6 Mb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. Top FET Current Limit vs Duty Cycle. Top FET Current Limit. Switch Drop vs Temperature
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Text Version of Document
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
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
