Datasheet LT8311 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Synchronous Rectifier Controller with Opto-Coupler Driver for Forward Converters |
| Pages / Page | 48 / 4 — ELECTRICAL. CHARACTERISTICS The. denotes the specifications which apply … |
| File Format / Size | PDF / 744 Kb |
| Document Language | English |
ELECTRICAL. CHARACTERISTICS The. denotes the specifications which apply over the full operating
Model Line for this Datasheet
Text Version of Document
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 Supply
VIN Operating Range l 3.7 30 V VIN UVLO VIN Rising l 3.6 3.7 V Hysteresis 50 100 150 mV Quiescent Current Not Switching 4.5 5.5 mA
Error Amplifier
Feedback Reference Voltage VIN = 12V l 1.209 1.227 1.245 V Feedback Voltage Line Regulation 3.7V ≤ VIN ≤ 30V, % of FB Ref Voltage 0.015 0.1 % Feedback Voltage Load Regulation 1.3V ≤ COMP ≤ 1.8V, % of FB Ref Voltage 0.05 0.1 % Feedback Pin Bias Current Current Out of FB pin 120 200 nA Error Amplifier Transconductance 1.3V ≤ COMP ≤ 1.8V 370 µmhos Error Amplifier Voltage Gain 1.3V ≤ COMP ≤ 1.8V 65 dB Error Amplifier Output Swing High FB = 1V 1.9 2.3 2.8 V Error Amplifier Output Swing Low FB = 1.5V 0.75 1 1.25 V
Power Good
Power NOT Good (Outside This Window) % Relative to FB Ref Voltage ±4 ±10 ±16 % Power Good (Inside This Window) % Relative to FB Ref Voltage ±7 % Power Good Indicator Wait Time Minimum Time That FB Must Stay within Power Good Window 175 µs Before PGOOD Pin Goes Low Power Good Leakage PGOOD = 30V ±1 µA Power Good Output Low Voltage Current into PGOOD Pin = 1mA l 0.2 0.3 V
Soft-Start (SS)
SS Wake-Up Slew Current Current Exists Upon Part Wake Up, Shuts Off After SS Wake Up 1 mA Offset Voltage Is Satisfied (Note 6) SS Wake-Up Offset Voltage VFB – VSS, Upon Part Wake Up SS Is Slewed Up to an Offset 16 mV Voltage Below FB by SS Wake-Up Slew Current SS Charge Current SS = 0V, FB = 0.6V (Note 9) l 9 10 11 µA SS Pull-Down Amplifier Offset Voltage VSS – VFB, Pull-Down Amplifier Prevents SS from Rising Beyond 100 mV This Offset Voltage Above FB When the FB Pin Voltage Is Below 50% of the FB Reference Voltage SS Pull-Down Amplifier Maximum SS = 1.5V, FB = 0.6V (Note 7) 13 mA Sink Current SS High Clamp Voltage 1.8 2 V
Opto Driver
COMP Buffer Input Offset Voltage 1.3V ≤ COMP (Note 5) 0.9 V Opto-Driver Reference Voltage (Note 5) 1 V Opto-Driver DC Gain (Note 5) –7 V/V 8311f 4 For more information www.linear.com/LT8311 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
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 Supply
VIN Operating Range l 3.7 30 V VIN UVLO VIN Rising l 3.6 3.7 V Hysteresis 50 100 150 mV Quiescent Current Not Switching 4.5 5.5 mA
Error Amplifier
Feedback Reference Voltage VIN = 12V l 1.209 1.227 1.245 V Feedback Voltage Line Regulation 3.7V ≤ VIN ≤ 30V, % of FB Ref Voltage 0.015 0.1 % Feedback Voltage Load Regulation 1.3V ≤ COMP ≤ 1.8V, % of FB Ref Voltage 0.05 0.1 % Feedback Pin Bias Current Current Out of FB pin 120 200 nA Error Amplifier Transconductance 1.3V ≤ COMP ≤ 1.8V 370 µmhos Error Amplifier Voltage Gain 1.3V ≤ COMP ≤ 1.8V 65 dB Error Amplifier Output Swing High FB = 1V 1.9 2.3 2.8 V Error Amplifier Output Swing Low FB = 1.5V 0.75 1 1.25 V
Power Good
Power NOT Good (Outside This Window) % Relative to FB Ref Voltage ±4 ±10 ±16 % Power Good (Inside This Window) % Relative to FB Ref Voltage ±7 % Power Good Indicator Wait Time Minimum Time That FB Must Stay within Power Good Window 175 µs Before PGOOD Pin Goes Low Power Good Leakage PGOOD = 30V ±1 µA Power Good Output Low Voltage Current into PGOOD Pin = 1mA l 0.2 0.3 V
Soft-Start (SS)
SS Wake-Up Slew Current Current Exists Upon Part Wake Up, Shuts Off After SS Wake Up 1 mA Offset Voltage Is Satisfied (Note 6) SS Wake-Up Offset Voltage VFB – VSS, Upon Part Wake Up SS Is Slewed Up to an Offset 16 mV Voltage Below FB by SS Wake-Up Slew Current SS Charge Current SS = 0V, FB = 0.6V (Note 9) l 9 10 11 µA SS Pull-Down Amplifier Offset Voltage VSS – VFB, Pull-Down Amplifier Prevents SS from Rising Beyond 100 mV This Offset Voltage Above FB When the FB Pin Voltage Is Below 50% of the FB Reference Voltage SS Pull-Down Amplifier Maximum SS = 1.5V, FB = 0.6V (Note 7) 13 mA Sink Current SS High Clamp Voltage 1.8 2 V
Opto Driver
COMP Buffer Input Offset Voltage 1.3V ≤ COMP (Note 5) 0.9 V Opto-Driver Reference Voltage (Note 5) 1 V Opto-Driver DC Gain (Note 5) –7 V/V 8311f 4 For more information www.linear.com/LT8311 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
