Datasheet LT8311 (Analog Devices) - 5

LT8311
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, VINTVCC = 8V, PMODE = 5V, CCG = CFG = 100pF, unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS
Inverting DC Gain From COMP Pin to (∆VOPTO/∆VCOMP), 1.290V ≤ COMP ≤ 1.310V –5 V/V OPTO Pin (∆VOPTO/∆VCOMP), 1.490V ≤ COMP ≤ 1.510V –5.9 V/V (∆VOPTO/∆VCOMP), 1.890V ≤ COMP ≤ 1.910V –6.2 V/V Opto-Driver –3dB Bandwidth No Load (Note 5) 400 kHz Opto-Driver Output Swing Low FB = 1V, COMP = SS = OPTO = Open l 0.5 0.85 V Opto-Driver Output Swing High VIN = 3.7V, FB = 1.5V, COMP = SS = Open, IOPTO = 10mA l VIN – 1.7 VIN – 1.4 V VIN = 30V, FB = 1.5V, COMP = SS = Open, IOPTO = 10mA l 5.2 6.5 V Opto-Driver Output Short-Circuit Current VIN = 30V, FB = 1.5V, COMP = SS = Open, OPTO = 0V (Note 6) l 10.5 15 18 mA Opto-Driver Output Sink Current FB = 1V, OPTO = 1.2V (Note 7) l 200 300 420 µA
Internal Linear Regulator
INTVCC Regulation Voltage No Load l 6.5 7 7.5 V INTVCC Load Regulation (∆VINTVCC/∆IINTVCC), 0A ≤ IINTVCC ≤ 20mA 1.8 3 mV/mA INTVCC UVLO Rising l 4.6 4.8 V INTVCC UVLO Falling l 4.1 4.3 V INTVCC OVLO Rising l 16.5 17.5 V INTVCC OVLO Falling l 14 15 V INTVCC Current Limit INTVCC > IINTVCC_UVLO_RISING (= 4.6V) l 38 48 58 mA INTVCC < IINTVCC_UVLO_FALLING (= 4.3V) 20 mA INTVCC Dropout Voltage VIN = 6V, IINTVCC = 10mA, Not Switching 400 mV
CG and FG Gate Drivers
Driver Output Rise Time CCG = CFG = 3.3nF, INTVCC = 8V (Note 4) 25 ns Driver Output Fall Time CCG = CFG = 3.3nF, INTVCC = 8V (Note 4) 25 ns Driver Output High Voltage l VINTVCC V – 0.2 Driver Output Low Voltage l 0.7 V
PMODE Selection
PMODE Trip Voltage PMODE Ramp Up l 1 1.2 1.4 V Hysteresis 30 mV PMODE Input Current PMODE = 18V l 60 90 µA
Preactive Mode (Tie PMODE to 0V)
Preactive Mode Operating l 100 300 kHz Frequency Range CSW High Trip Voltage CSW Ramp Up l 1 1.2 1.4 V CSW High Input Current CSW = 150V (Note 7) l 250 500 µA CSW Low Trip Voltage CSW Ramp Down l –250 –150 –50 mV FSW Trip Voltage l 1 1.2 1.4 V FSW High Input Current FSW = 150V (Note 7) l 250 500 µA CG Falling Edge to CSW Rising Edge CSW = 150kHz (Note 10), FSW = 0V, CSP = –500mV l 5 100 300 ns Prediction Delay CG Falling Edge Delay to FG Rising Edge CSW = 150kHz (Note 10), FSW = 0V, CSP = –500mV l 10 50 80 ns 8311f For more information www.linear.com/LT8311 5 Document Outline Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation FUNDAMENTALS OF FORWARD CONVERTER OPERATION IN CCM LT8311 SYNCHRONOUS CONTROL SCHEMES PREACTIVE MODE SYNCHRONOUS CONTROL SYNC MODE SYNCHRONOUS CONTROL OPTO-COUPLER CONTROL Applications Information VIN BIAS SUPPLY INTVCC BIAS SUPPLY LT8311 OPTO CONTROL FUNDAMENTALS LT8311 SYNCHRONOUS CONTROL FUNDAMENTALS PREACTIVE MODE SYNCHRONOUS CONTROL SYNC MODE SYNCHRONOUS CONTROL Typical Applications Package Description Typical Application Related Parts