Datasheet LTC3857 (Analog Devices) - 5
| Hersteller | Analog Devices |
| Beschreibung | Low IQ, Dual, 2-Phase Synchronous Step-Down Controller |
| Seiten / Seite | 38 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS. Efficiency and Power Loss vs Output … |
| Dateiformat / Größe | PDF / 453 Kb |
| Dokumentensprache | Englisch |
TYPICAL PERFORMANCE CHARACTERISTICS. Efficiency and Power Loss vs Output Current. Efficiency vs Output Current
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LTC3857
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Output Current Efficiency vs Output Current Efficiency vs Input Voltage
100 10000 100 98 VIN = 12V VOUT = 3.3V 90 V 90 OUT = 3.3V V 96 ILOAD = 5A FIGURE 13 CIRCUIT IN = 5V 80 1000 80 94 POWER LOSS (mW) 70 70 VIN = 12V 92 60 100 60 90 50 50 88 40 10 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 86 30 30 20 1 20 84 10 10 VOUT = 3.3V 82 FIGURE 13 CIRCUIT 0 0.1 0 80 0.00001 0.0001 0.001 0.01 0.1 1 10 0.00001 0.0001 0.001 0.01 0.1 1 10 1 5 10 15 20 25 30 35 40 OUTPUT CURRENT (A) 38 57 G01 OUTPUT CURRENT (A) INPUT VOLTAGE (V) BURST EFFICIENCY BURST LOSS 3857 G02 3857 G03 PULSE-SKIPPING PULSE-SKIPPING EFFICIENCY LOSS CCM EFFICIENCY CCM LOSS
Load Step Load Step Load Step (Burst Mode Operation) (Forced Continuous Mode) (Pulse-Skipping Mode)
VOUT VOUT VOUT 100mV/DIV 100mV/DIV 100mV/DIV INDUCTOR INDUCTOR CURRENT INDUCTOR CURRENT 2A/DIV CURRENT 2A/DIV 2A/DIV VIN = 12V 20μs/DIV 3857 G04 VIN = 12V 20μs/DIV 3857 G05 VIN = 12V 20μs/DIV 3857 G06 VOUT = 3.3V VOUT = 3.3V VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT
Inductor Current at Light Load Soft Start-Up Tracking Start-Up
FORCED CONTINUOUS VOUT2 MODE 2V/DIV VOUT2 2V/DIV Burst Mode V OPERATION OUT1 2V/DIV 1A/DIV VOUT1 2V/DIV PULSE- SKIPPING MODE V 3857 G08 3857 G09 IN = 12V 5μs/DIV 3857 G07 20ms/DIV 20ms/DIV VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT ILOAD = 200μA FIGURE 13 CIRCUIT 3857fd 5 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Output Current Efficiency vs Output Current Efficiency vs Input Voltage
100 10000 100 98 VIN = 12V VOUT = 3.3V 90 V 90 OUT = 3.3V V 96 ILOAD = 5A FIGURE 13 CIRCUIT IN = 5V 80 1000 80 94 POWER LOSS (mW) 70 70 VIN = 12V 92 60 100 60 90 50 50 88 40 10 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 86 30 30 20 1 20 84 10 10 VOUT = 3.3V 82 FIGURE 13 CIRCUIT 0 0.1 0 80 0.00001 0.0001 0.001 0.01 0.1 1 10 0.00001 0.0001 0.001 0.01 0.1 1 10 1 5 10 15 20 25 30 35 40 OUTPUT CURRENT (A) 38 57 G01 OUTPUT CURRENT (A) INPUT VOLTAGE (V) BURST EFFICIENCY BURST LOSS 3857 G02 3857 G03 PULSE-SKIPPING PULSE-SKIPPING EFFICIENCY LOSS CCM EFFICIENCY CCM LOSS
Load Step Load Step Load Step (Burst Mode Operation) (Forced Continuous Mode) (Pulse-Skipping Mode)
VOUT VOUT VOUT 100mV/DIV 100mV/DIV 100mV/DIV INDUCTOR INDUCTOR CURRENT INDUCTOR CURRENT 2A/DIV CURRENT 2A/DIV 2A/DIV VIN = 12V 20μs/DIV 3857 G04 VIN = 12V 20μs/DIV 3857 G05 VIN = 12V 20μs/DIV 3857 G06 VOUT = 3.3V VOUT = 3.3V VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT
Inductor Current at Light Load Soft Start-Up Tracking Start-Up
FORCED CONTINUOUS VOUT2 MODE 2V/DIV VOUT2 2V/DIV Burst Mode V OPERATION OUT1 2V/DIV 1A/DIV VOUT1 2V/DIV PULSE- SKIPPING MODE V 3857 G08 3857 G09 IN = 12V 5μs/DIV 3857 G07 20ms/DIV 20ms/DIV VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT ILOAD = 200μA FIGURE 13 CIRCUIT 3857fd 5 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS