Datasheet LTC3728L, LTC3728LX (Analog Devices) - 4

LTC3728L/LTC3728LX
elecTrical characTerisTics The
l
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 Main Control Loops
VOSENSE1, 2 Regulated Feedback Voltage (Note 3); ITH1, 2 Voltage = 1.2V (LTC3728LC) ● 0.792 0.800 0.808 V (Note 3); ITH1, 2 Voltage = 1.2V ● 0.788 0.800 0.812 V (LTC3728LE/LTC3728LX/LTC3728LI) IVOSENSE1, 2 Feedback Current (Note 3) –5 –50 nA VREFLNREG Reference Voltage Line Regulation VIN = 3.6V to 30V (Note 3) 0.002 0.02 %/V VLOADREG Output Voltage Load Regulation (Note 3) 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 3) 1.3 mmho gmGBW1, 2 Transconductance Amplifier GBW ITH1, 2 = 1.2V (Note 8) 3 MHz IQ Input DC Supply Current (Note 4) Normal Mode VIN = 15V; EXTVCC Tied to VOUT1; VOUT1 = 5V 450 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 –0.50 –0.18 –0.1 µA VBINHIBIT Burst Inhibit (Constant-Frequency) Measured at FCB Pin 4.3 4.8 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 –90 –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 2.0 V VRUN/SS1, 2 LT RUN/SS Pin Latchoff Arming VRUN/SS1, VRUN/SS2 Rising from 3V 4.1 4.75 V Threshold ISCL1, 2 RUN/SS Discharge Current Soft-Short Condition VOSENSE1, 2 = 0.5V; 0.5 2 4 µA VRUN/SS1, 2 = 4.5V ISDLHO Shutdown Latch Disable Current VOSENSE1, 2 = 0.5V 1.6 5 µA VSENSE(MAX) Maximum Current Sense Threshold VOSENSE1, 2 = 0.7V, VSENSE1–, 2– = 5V 65 75 85 mV VOSENSE1, 2 = 0.7V, VSENSE1–, 2– = 5V ● 62 75 88 mV TG Transition Time: (Note 5) TG1, 2 tr Rise Time CLOAD = 3300pF 55 100 ns TG1, 2 tf Fall Time CLOAD = 3300pF 55 100 ns BG Transition Time: (Note 5) BG1, 2 tr Rise Time CLOAD = 3300pF 45 100 ns BG1, 2 tf Fall Time CLOAD = 3300pF 45 90 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver 80 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch-On Delay Time CLOAD = 3300pF Each Driver 80 ns tON(MIN) Minimum On-Time Tested with a Square Wave (Note 6) 100 ns 3728lxff 4 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts