Datasheet LTC3727, LTC3727-1 (Analog Devices) - 3

LTC3727/LTC3727-1
ELECTRICAL CHARACTERISTICS The
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denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 15V, VRUN/SS1, 2 = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VLOADREG Output Voltage Load Regulation (Note 4) Measured in Servo Loop; ΔITH Voltage = 1.2V to 0.7V ● 0.1 0.5 % Measured in Servo Loop; ΔITH Voltage = 1.2V to 2.0V ● – 0.1 – 0.5 % gm1, 2 Transconductance Amplifier gm ITH1, 2 = 1.2V; Sink/Source 5μA (Note 4) 1.3 mmho gmGBW1, 2 Transconductance Amplifier GBW ITH1, 2 = 1.2V (Note 4) 3 MHz IQ Input DC Supply Current (Note 5) Normal Mode VIN = 15V, EXTVCC Tied to VOUT1, VOUT1 = 8.5V 670 μA Shutdown VRUN/SS1, 2 = 0V 20 35 μA VFCB Forced Continuous Threshold ● 0.76 0.800 0.84 V IFCB Forced Continuous Pin Current VFCB = 0.85V – 0.30 – 0.18 – 0.05 μA VBINHIBIT Burst Inhibit (Constant Frequency) Measured at FCB pin 6.8 7.3 V Threshold UVLO Undervoltage Lockout VIN Ramping Down ● 3.5 4 V VOVL Feedback Overvoltage Lockout Measured at VOSENSE1, 2 ● 0.84 0.86 0.88 V ISENSE Sense Pins Total Source Current (Each Channel) VSENSE1–, 2– = VSENSE1+, 2+ = 0V – 85 – 60 μA DFMAX Maximum Duty Factor In Dropout 98 99.4 % IRUN/SS1, 2 Soft-Start Charge Current VRUN/SS1, 2 = 1.9V 0.5 1.2 μA VRUN/SS1, 2 ON RUN/SS Pin ON Threshold VRUN/SS1, VRUN/SS2 Rising 1.0 1.5 1.9 V VRUN/SS1, 2 LT RUN/SS Pin Latchoff Arming Threshold VRUN/SS1, VRUN/SS2 Rising from 3V (LTC3727 Only) 4.1 4.5 V ISCL1, 2 RUN/SS Discharge Current Soft-Short Condition VOSENSE1, 2 = 0.5V, 0.5 2 4 μA VRUN/SS1, 2 = 4.5V (LTC 3727 Only) ISDLHO Shutdown Latch Disable Current VOSENSE1, 2 = 0.5V (LTC3727 Only) 1.6 5 μA VSENSE(MAX) Maximum Current Sense Threshold VOSENSE1, 2 = 0.7V,VSENSE1–, 2– = 12V ● 105 135 165 mV TG Transition Time: (Note 6) TG1, 2 tr Rise Time CLOAD = 3300pF 50 90 ns TG1, 2 tf Fall Time CLOAD = 3300pF 50 90 ns BG Transition Time: (Note 6) BG1, 2 tr Rise Time CLOAD = 3300pF 40 90 ns BG1, 2 tf Fall Time CLOAD = 3300pF 40 80 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver 90 ns Synchronous Switch-On Delay Time BG/TG t2D Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver 90 ns Top Switch-On Delay Time tON(MIN) Minimum On-Time Tested with a Square Wave (Note 7) 180 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 8.5V < VIN < 30V, VEXTVCC = 6V 7.2 7.5 7.8 V VLDO INT INTVCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 6V 0.2 1.0 % VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 8.5V 70 160 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive ● 6.9 7.3 V VLDOHYS EXTVCC Hysteresis 0.3 V
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VPLLFLTR = 1.2V 350 380 430 kHz fLOW Lowest Frequency VPLLFLTR = 0V 220 255 290 kHz fHIGH Highest Frequency VPLLFLTR ≥ 2.4V 460 530 580 kHz 3727fc 3