Datasheet LTC3870 (Analog Devices) - 5

LTC3870
Typical perForMance characTerisTics Load Step (Discontinuous Load Step (Forced Continuous Conduction Mode) 4-Phase Mode) 4-Phase Operation Operation LTC3880 and LTC3870 LTC3880 and LTC3870 Inductor Current at Light Load
ILOAD ILOAD 20A/DIV 20A/DIV 0A TO 20A TO 0A 0A TO 20A TO 0A IL_3870(CH0) FORCED CONTINUOUS IL_3880(CH0) IL_3880(CH0) MODE 10A/DIV 10A/DIV 5A/DIV IL_3870(CH0) IL_3870(CH0) 10A/DIV 10A/DIV V V I OUT OUT L_3870(CH0) 100mV/DIV 100mV/DIV DISCONTINUOUS AC-COUPLED AC-COUPLED CONDUCTION MODE 5A/DIV 3870 G04 3870 G05 3870 G06 50µs/DIV 50µs/DIV 1µs/DIV V V V IN = 12V IN = 12V IN = 12V V V V OUT = 1.8V OUT = 1.8V OUT = 1.8V ILOAD = 1A
Start-Up Into a Pre-Biased Output 4-Phase Operation Current Sense Threshold LTC3880 and LTC3870 vs ITH Voltage INTVCC Line Regulation
80 6 RUN RANGE HIGH ALL RUN PINS RANGE LOW TIED TOGETHER 60 5 2V/DIV 40 4 VOUT (mV) TAGE (V) LTC3870 IN DCM 20 3 500mV/DIV VOL V ISENSE V CC 0 INT 2 3870 G07 –20 1 2ms/DIV VIN = 12V V –40 0 OUT = 1.8V 0 0.5 1 1.5 2 2.5 0 10 20 30 40 50 60 VITH (V) INPUT VOLTAGE (V) 3870 G08 3870 G09
Dynamic Current Sharing During DC Output Current Matching a Load Transient in a 4-Phase Quiescent Current vs Input Between LTC3880 and LTC3870 Operation LTC3880 and LTC3870 Voltage Without EXTVCC
25 3.5 3 20 IL_3880(CH0) 2.5 IL_3880(CH1) 15 IL_3870(CH0) 2 IL_3870(CH1) 5A/DIV 10 Y CURRENT (mA) 1.5 CHANNEL CURRENT (A) SUPPL 1 5 LTC3880 CH0 LTC3880 CH1 3870 G11 50µs/DIV 0.5 LTC3870 CH0 LTC3870 CH1 ILOAD 0A TO 32A TO 0A 0 0 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 TOTAL OUTPUT CURRENT (A) INPUT VOLTAGE (V) 3870 G10 3870 G12 3870fb For more information www.linear.com/LTC3870 5