Datasheet LTC7860 (Analog Devices) - 3

LTC7860
e lecTrical characTerisTics The
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denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. (Note 3) VIN = 12V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Input Supply
VIN Input Voltage Operating Range 3.5 60 V VUVLO Undervoltage Lockout (VIN-VCAP) Ramping Up Threshold l 3.25 3.50 3.8 V (VIN-VCAP) Ramping Down Threshold l 3.00 3.25 3.50 V Hysteresis 0.25 V IQ Input DC Supply Current FREQ = 0V, VFB = 0.83V (No Load) 0.77 1.2 mA Shutdown Supply Current RUN = 0V 7 12 µA
Output Sensing
VREG Regulated Feedback Voltage VREG = (VFB – VFBN) VITH = 1.2V (Note 4) l 0.791 0.800 0.809 V Feedback Voltage Line Regulation VIN = 3.8V to 60V (Note 4) –0.005 0.005 %/V Feedback Voltage Load Regulation VITH = 0.6V to 1.8V (Note 4) –0.1 –0.015 0.1 % gm(EA) Error Amplifier Transconductance VITH = 1.2V, ∆IITH = ±5µA (Note 4) 1.8 mS IFB Feedback Input Bias Current –50 –10 50 nA IFBN Feedback Negative Input Bias Current –50 –10 50 nA
Current Sensing
VILIM Current Limit Threshold (VIN-VSENSE) VFB = 0.77V l 85 95 103 mV ISENSE SENSE Pin Input Current VSENSE = VIN 0.1 2 µA
Start-Up and Shutdown
VRUN RUN Pin Enable Threshold VRUN Rising l 1.22 1.26 1.32 V RUN Pin Hysteresis 150 mV ISS Soft-Start Pin Charging Current VSS = 0V 10 µA
Fault Timer
ITPU TMR Pull-Up Current TMR = 1.1V, VFB = 0.83V l –35 –30 –25 µA ITPDR TMR Pull-Down Current Restart TMR = 1.1V, VFB = 0.77V 40 µA ITPDC TMR Pull-Down Current Cool Down TMR = 1.1V, VFB = 0.77V 1.0 1.3 1.6 µA VGTH TMR Gate Off Threshold VFB = 0.77V l 1.25 1.29 1.35 V VRTH TMR Restart Threshold VFB = 0.77V 240 mV TSETI(1µF) TMR Set Time Initial for Fault Detection for 1µF l 37 44 50 ms/µF (TSETI = VGTH/ITPU) TSETR(1µF) TMR Set Time Repeat for Fault Detection for 1µF 32 ms/µF (TSETI = (VGTH – VRTH)/ITPU) TRSTC(1µF) TMR Restart Cool Down Time for 1µF 732 ms/µF (TRSTC = (VGTH – VRTH)/ITPDC) DTYTSTR TMR Restart Duty Cycle in a Sustained Fault l 3.5 4.5 5.5 % (DTYTSTR = TSETR/TRSTC)
Switching Frequency
7860f For more information www.linear.com/LTC7860 3