Datasheet LTC3879 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | Fast, Wide Operating Range No RSENSE Step-Down Controller |
| Pages / Page | 28 / 3 — ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply … |
| File Format / Size | PDF / 314 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply over the full operating
Model Line for this Datasheet
Text Version of Document
LTC3879
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 15V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop
Input Operating Voltage Range 4 38 V IQ Input DC Supply Current Normal 1350 2000 μA Shutdown Supply Current 18 35 μA VFBREF Feedback Reference Voltage ITH = 1.2V (Note 3) l 0.594 0.6 0.606 V Feedback Voltage Line Regulation VIN = 4V to 30V, ITH = 1.2V (Note 3) 0.005 %/V Feedback Voltage Load Regulation ITH = 0.5V to 1.9V (Note 3) l –0.05 –0.3 % IFB Feedback Input Current VFB = 0.6V –5 ±50 nA gm(EA) Error Amplifi er Transconductance ITH = 1.2V (Note 3) 1.4 1.7 2 mS VMODE MODE Threshold 0.76 0.8 0.84 V MODE Pin Current VMODE = 0.8V 0 ±1 μA tON On-Time ION = 30μA 198 233 268 ns ION = 15μA 370 440 510 ns tON(MIN) Minimum On-Time ION = 180μA 43 75 ns tOFF(MIN) Minimum Off-Time ION = 30μA 220 300 ns VSENSE(MAX) Valley Current Sense Threshold VRNG = 1V, VFB = 0.56V l 108 133 165 mV VPGND – VSW VRNG = 0V, VFB = 0.56V l 22 30 48 mV Peak Current = Valley + Ripple VRNG = INTVCC, VFB = 0.56V l 62 75 98 mV VSENSE(MIN) Minimum Current Sense Threshold VRNG = 1V, VFB = 0.64V –61 mV VPGND – VSW VRNG = 0V, VFB = 0.64V –12 mV Force Continuous Operation VRNG = INTVCC, VFB = 0.64V –33 mV VRUN RUN On Threshold VRUN Rising 1.3 1.5 1.7 V IRUN RUN Pull-Up Current VRUN = 0V –1.2 μA ITRACK/SS Soft-Start Charging Current VTRACK/SS = 0V –0.45 –1 –2 μA INTVCC Undervoltage Lockout Falling l 3.3 3.9 V INTVCC Undervoltage Lockout Release Rising l 3.6 4 V TG Driver Pull-Up On-Resistance TG High 2.5 Ω TG Driver Pull-Down On-Resistance TG Low 1.2 Ω BG Driver Pull-Up On-Resistance BG High 2.5 Ω BG Driver Pull-Down On-Resistance BG Low 0.7 Ω TG Rise Time CLOAD = 3300pF (Note 5) 20 ns TG Fall Time CLOAD = 3300pF (Note 5) 20 ns BG Rise Time CLOAD = 3300pF (Note 5) 20 ns BG Fall Time CLOAD = 3300pF (Note 5) 20 ns Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver (Note 5) 15 ns Synchronous Switch-On Delay Time Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver (Note 5) 15 ns Top Switch-On Delay Time 3879f 3
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 15V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop
Input Operating Voltage Range 4 38 V IQ Input DC Supply Current Normal 1350 2000 μA Shutdown Supply Current 18 35 μA VFBREF Feedback Reference Voltage ITH = 1.2V (Note 3) l 0.594 0.6 0.606 V Feedback Voltage Line Regulation VIN = 4V to 30V, ITH = 1.2V (Note 3) 0.005 %/V Feedback Voltage Load Regulation ITH = 0.5V to 1.9V (Note 3) l –0.05 –0.3 % IFB Feedback Input Current VFB = 0.6V –5 ±50 nA gm(EA) Error Amplifi er Transconductance ITH = 1.2V (Note 3) 1.4 1.7 2 mS VMODE MODE Threshold 0.76 0.8 0.84 V MODE Pin Current VMODE = 0.8V 0 ±1 μA tON On-Time ION = 30μA 198 233 268 ns ION = 15μA 370 440 510 ns tON(MIN) Minimum On-Time ION = 180μA 43 75 ns tOFF(MIN) Minimum Off-Time ION = 30μA 220 300 ns VSENSE(MAX) Valley Current Sense Threshold VRNG = 1V, VFB = 0.56V l 108 133 165 mV VPGND – VSW VRNG = 0V, VFB = 0.56V l 22 30 48 mV Peak Current = Valley + Ripple VRNG = INTVCC, VFB = 0.56V l 62 75 98 mV VSENSE(MIN) Minimum Current Sense Threshold VRNG = 1V, VFB = 0.64V –61 mV VPGND – VSW VRNG = 0V, VFB = 0.64V –12 mV Force Continuous Operation VRNG = INTVCC, VFB = 0.64V –33 mV VRUN RUN On Threshold VRUN Rising 1.3 1.5 1.7 V IRUN RUN Pull-Up Current VRUN = 0V –1.2 μA ITRACK/SS Soft-Start Charging Current VTRACK/SS = 0V –0.45 –1 –2 μA INTVCC Undervoltage Lockout Falling l 3.3 3.9 V INTVCC Undervoltage Lockout Release Rising l 3.6 4 V TG Driver Pull-Up On-Resistance TG High 2.5 Ω TG Driver Pull-Down On-Resistance TG Low 1.2 Ω BG Driver Pull-Up On-Resistance BG High 2.5 Ω BG Driver Pull-Down On-Resistance BG Low 0.7 Ω TG Rise Time CLOAD = 3300pF (Note 5) 20 ns TG Fall Time CLOAD = 3300pF (Note 5) 20 ns BG Rise Time CLOAD = 3300pF (Note 5) 20 ns BG Fall Time CLOAD = 3300pF (Note 5) 20 ns Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver (Note 5) 15 ns Synchronous Switch-On Delay Time Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver (Note 5) 15 ns Top Switch-On Delay Time 3879f 3
