Datasheet LTC1871X (Analog Devices) - 3

LTC1871X
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = VINTVCC = 5V, VRUN = 1.5V, RFREQ = 80k, VMODE/SYNC = 0V, unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop
VIN(MIN) Minimum Input Voltage 2.5 V (Note 2) l 2.5 V IQ Input Voltage Supply Current (Note 4) Continuous Mode VMODE/SYNC = 5V, VFB = 1.4V, VITH = 0.75V 550 1000 μA VMODE/SYNC = 5V, VFB = 1.4V, VITH = 0.75V, l 550 1200 μA (Note 2) Burst Mode Operation, No Load VMODE/SYNC = 0V, VITH = 0.2V (Note 5) 250 500 μA VMODE/SYNC = 0V, VITH = 0.2V (Note 5), (Note 2) l 250 650 μA Shutdown Mode VRUN = 0V 10 20 μA VRUN = 0V, (Note 2) l 10 65 μA V + RUN Rising RUN Input Threshold Voltage 1.348 V V – RUN Falling RUN Input Threshold Voltage 1.223 1.248 1.273 V (Note 2) l 1.179 1.465 V VRUN(HYST) RUN Pin Input Threshold Hysteresis 50 100 150 mV (Note 2) l 35 400 mV IRUN RUN Input Current 1 60 nA VFB Feedback Voltage VITH = 0.2V (Note 5) 1.218 1.230 1.242 V VITH = 0.2V (Note 5), (Note 2) l 1.205 1.255 V IFB FB Pin Input Current VITH = 0.2V (Note 5) 18 60 nA ∆VFB Line Regulation 3.5V ≤ VIN ≤ 30V 0.002 0.02 %/V ∆VIN 3.5V ≤ VIN ≤ 30V, (Note 2) l 0.002 0.02 %/V ∆VFB Load Regulation VMODE/SYNC = 0V, VITH = 0.5V to 0.9V (Note 5) –1 –0.1 % ∆VITH VMODE/SYNC = 0V, VITH = 0.5V to 0.9V (Note 5) l –1 –0.1 % (Note 2) ∆VFB(OV) ∆FB Pin,Overvoltage Lockout VFB(OV) – VFB(NOM) in Percent 2.5 6 10 % gm Error Amplifier Transconductance ITH Pin Load = ±5μA (Note 5) 650 μmho VITH(BURST) Burst Mode Operation ITH Pin Voltage Falling ITH Voltage (Note 5) 0.3 V VSENSE(MAX) Maximum Current Sense Input Threshold Duty Cycle < 20% 115 150 185 mV Duty Cycle < 20%, (Note 2) l 100 200 mV ISENSE(ON) SENSE Pin Current (GATE High) VSENSE = 0V 35 50 μA ISENSE(OFF) SENSE Pin Current (GATE Low) VSENSE = 30V 0.1 5 μA
Oscillator
fOSC Oscillator Frequency RFREQ = 80k 250 300 350 kHz RFREQ = 80k, (Note 2) l 240 300 375 kHz Oscillator Frequency Range 50 1000 kHz (Note 2) l 65 900 kHz DMAX Maximum Duty Cycle 87 92 97 % (Note 2) l 87 92 97 % 1871xf For more information www.linear.com/LTC1871X 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts