Datasheet LTC3879 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Fast, Wide Operating Range No RSENSE Step-Down Controller |
| Pages / Page | 28 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS. Transient Response FCM. (Forced … |
| File Format / Size | PDF / 314 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. Transient Response FCM. (Forced Continuous Mode). Positive Load Step. Negative Load Step
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LTC3879
TYPICAL PERFORMANCE CHARACTERISTICS Transient Response FCM Transient Response FCM Transient Response FCM (Forced Continuous Mode) Positive Load Step Negative Load Step
VSW VSW 20V/DIV 20V/DIV VOUT (AC) 50mV/DIV VOUT (AC) VOUT (AC) 50mV/DIV 50mV/DIV IL I 10A/DIV IL L 10A/DIV 10A/DIV ILOAD ILOAD ILOAD 10A/DIV 10A/DIV 10A/DIV 50μs/DIV 3879 G01 5μs/DIV 3879 G02 5μs/DIV 3879 G03 LOAD STEP 0A TO 10A TO 0A LOAD STEP 0A TO 10A LOAD STEP 10A TO 0A VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V VOUT = 1.2V MODE = 0V MODE = 0V MODE = 0V SW FREQ = 400kHz SW FREQ = 400kHz SW FREQ = 400kHz FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT
Transient Response DCM Normal Start-Up, RUN Pin Start-Up Into a Pre-Biased Output (Discontinuous Mode) Released from GND RUN Pin Released from GND
I RUN L V 5A/DIV OUT (AC) 5V/DIV 50mV/DIV VOUT V I OUT 0.5V/DIV L 0.5V/DIV 10A/DIV ILOAD TRACK/SS TRACK/SS 10A/DIV 0.5V/DIV 0.5V/DIV 3879 G05 50μs/DIV 3879 G04 20ms/DIV 20ms/DIV 3879 G06 LOAD STEP 1A TO 11A TO 1A VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V VOUT = 1.2V SW FREQ = 400kHz SW FREQ = 400kHz MODE = INTVCC FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT SW FREQ = 400kHz FIGURE 10 CIRCUIT
Start-Up After Input Undervoltage Coincident Rail Tracking 1.2V VIN Cycled Low to High VOUT Tracks External 1.8V Supply Effi ciency vs Load Current
100 VIN VMASTER 90 DISCONTINUOUS 10V/DIV 0.5V/DIV MODE 80 TRACK/SS 5V/DIV 70 VOUT 0.5V/DIV 60 CONTINUOUS MODE VOUT 50 1V/DIV 40 EFFICIENCY (%) 100ms/DIV 3879 G07 5ms/DIV 3879 G08 30 VIN = 12V VIN = 12V VIN = 12V V 20 OUT = 1.2V VOUT = 1.2V VOUT = 1.2V SW FREQ = 400kHz SW FREQ = 400kHz 10 SW FREQ = 400kHz FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT 0 0.01 0.1 1 10 100 LOAD CURRENT (A) 3879 G09 3879f 5
TYPICAL PERFORMANCE CHARACTERISTICS Transient Response FCM Transient Response FCM Transient Response FCM (Forced Continuous Mode) Positive Load Step Negative Load Step
VSW VSW 20V/DIV 20V/DIV VOUT (AC) 50mV/DIV VOUT (AC) VOUT (AC) 50mV/DIV 50mV/DIV IL I 10A/DIV IL L 10A/DIV 10A/DIV ILOAD ILOAD ILOAD 10A/DIV 10A/DIV 10A/DIV 50μs/DIV 3879 G01 5μs/DIV 3879 G02 5μs/DIV 3879 G03 LOAD STEP 0A TO 10A TO 0A LOAD STEP 0A TO 10A LOAD STEP 10A TO 0A VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V VOUT = 1.2V MODE = 0V MODE = 0V MODE = 0V SW FREQ = 400kHz SW FREQ = 400kHz SW FREQ = 400kHz FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT
Transient Response DCM Normal Start-Up, RUN Pin Start-Up Into a Pre-Biased Output (Discontinuous Mode) Released from GND RUN Pin Released from GND
I RUN L V 5A/DIV OUT (AC) 5V/DIV 50mV/DIV VOUT V I OUT 0.5V/DIV L 0.5V/DIV 10A/DIV ILOAD TRACK/SS TRACK/SS 10A/DIV 0.5V/DIV 0.5V/DIV 3879 G05 50μs/DIV 3879 G04 20ms/DIV 20ms/DIV 3879 G06 LOAD STEP 1A TO 11A TO 1A VIN = 12V VIN = 12V VIN = 12V VOUT = 1.2V VOUT = 1.2V VOUT = 1.2V SW FREQ = 400kHz SW FREQ = 400kHz MODE = INTVCC FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT SW FREQ = 400kHz FIGURE 10 CIRCUIT
Start-Up After Input Undervoltage Coincident Rail Tracking 1.2V VIN Cycled Low to High VOUT Tracks External 1.8V Supply Effi ciency vs Load Current
100 VIN VMASTER 90 DISCONTINUOUS 10V/DIV 0.5V/DIV MODE 80 TRACK/SS 5V/DIV 70 VOUT 0.5V/DIV 60 CONTINUOUS MODE VOUT 50 1V/DIV 40 EFFICIENCY (%) 100ms/DIV 3879 G07 5ms/DIV 3879 G08 30 VIN = 12V VIN = 12V VIN = 12V V 20 OUT = 1.2V VOUT = 1.2V VOUT = 1.2V SW FREQ = 400kHz SW FREQ = 400kHz 10 SW FREQ = 400kHz FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT FIGURE 10 CIRCUIT 0 0.01 0.1 1 10 100 LOAD CURRENT (A) 3879 G09 3879f 5
