Datasheet LTC3868-1 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Low IQ, Dual 2-Phase Synchronous Step-Down Controller |
| Pages / Page | 38 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS. Effi ciency and Power Loss vs Output … |
| File Format / Size | PDF / 475 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. Effi ciency and Power Loss vs Output Current. Effi ciency vs Load Current. Load Step
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LTC3868-1
TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency and Power Loss vs Output Current Effi ciency vs Load Current
100 10000 100 FIGURE 12 CIRCUIT 90 V 90 IN = 12V VIN = 5V V 80 OUT = 3.3V 1000 80 POWER LOSS (mW) 70 70 VIN = 12V 60 100 60 50 50 40 10 40 EFFICIENCY (%) EFFICIENCY (%) 30 Burst Mode 30 OPERATION 20 1 20 PULSE- 10 SKIPPING 10 VOUT = 3.3V FCM FIGURE 12 CIRCUIT 0 0.1 0 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 OUTPUT CURRENT (A) OUTPUT CURRENT (A) 38681 G01 38681 G02
Load Step Effi ciency vs Input Voltage Load Step (Burst Mode Operation) (Forced Continuous Mode)
98 FIGURE 12 CIRCUIT 96 VOUT = 3.3V I V V OUT = 4A OUT OUT 94 100mV/DIV 100mV/DIV AC- AC- 92 COUPLED COUPLED 90 88 EFFICIENCY (%) 86 IL I 2A/DIV L 2A/DIV 84 82 80 0 5 10 15 20 25 28 20μs/DIV 38681 G04 VOUT = 3.3V 20μs/DIV 38681 G05 VOUT = 3.3V INPUT VOLTAGE (V) FIGURE 12 CIRCUIT FIGURE 12 CIRCUIT 38681 G03
Load Step (Pulse-Skipping Mode) Inductor Current at Light Load Soft Start-Up
VOUT FORCED 100mV/DIV VOUT2 CONTINUOUS AC- 2V/DIV MODE COUPLED Burst Mode VOUT1 OPERATION 2V/DIV 2A/DIV IL 2A/DIV PULSE- SKIPPING MODE 20μs/DIV 38681 G06 VOUT = 3.3V 2μs/DIV 38681 G07 VOUT = 3.3V 20ms/DIV 38681 G08 FIGURE 12 CIRCUIT ILOAD = 200μA FIGURE 12 CIRCUIT FIGURE 12 CIRCUIT 38681fd 5
TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency and Power Loss vs Output Current Effi ciency vs Load Current
100 10000 100 FIGURE 12 CIRCUIT 90 V 90 IN = 12V VIN = 5V V 80 OUT = 3.3V 1000 80 POWER LOSS (mW) 70 70 VIN = 12V 60 100 60 50 50 40 10 40 EFFICIENCY (%) EFFICIENCY (%) 30 Burst Mode 30 OPERATION 20 1 20 PULSE- 10 SKIPPING 10 VOUT = 3.3V FCM FIGURE 12 CIRCUIT 0 0.1 0 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 OUTPUT CURRENT (A) OUTPUT CURRENT (A) 38681 G01 38681 G02
Load Step Effi ciency vs Input Voltage Load Step (Burst Mode Operation) (Forced Continuous Mode)
98 FIGURE 12 CIRCUIT 96 VOUT = 3.3V I V V OUT = 4A OUT OUT 94 100mV/DIV 100mV/DIV AC- AC- 92 COUPLED COUPLED 90 88 EFFICIENCY (%) 86 IL I 2A/DIV L 2A/DIV 84 82 80 0 5 10 15 20 25 28 20μs/DIV 38681 G04 VOUT = 3.3V 20μs/DIV 38681 G05 VOUT = 3.3V INPUT VOLTAGE (V) FIGURE 12 CIRCUIT FIGURE 12 CIRCUIT 38681 G03
Load Step (Pulse-Skipping Mode) Inductor Current at Light Load Soft Start-Up
VOUT FORCED 100mV/DIV VOUT2 CONTINUOUS AC- 2V/DIV MODE COUPLED Burst Mode VOUT1 OPERATION 2V/DIV 2A/DIV IL 2A/DIV PULSE- SKIPPING MODE 20μs/DIV 38681 G06 VOUT = 3.3V 2μs/DIV 38681 G07 VOUT = 3.3V 20ms/DIV 38681 G08 FIGURE 12 CIRCUIT ILOAD = 200μA FIGURE 12 CIRCUIT FIGURE 12 CIRCUIT 38681fd 5
