Datasheet LT3744 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | High Current Synchronous Step-Down LED Driver |
| Pages / Page | 32 / 4 — e lecTrical characTerisTics The. denotes the specifications which apply … |
| File Format / Size | PDF / 782 Kb |
| Document Language | English |
e lecTrical characTerisTics The. denotes the specifications which apply over the full operating
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LT3744
e lecTrical characTerisTics The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 2V, SGND = VEE = 0V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS NMOS FET Drivers
Non-Overlap Time TG to BG 50 ns Non-Overlap Time BG to TG 50 ns Minimum On-Time BG (Note 3) 50 ns Minimum On-Time TG (Note 3) 160 ns Top Gate Driver Switch RON VBOOST – VSW = 5V Gate Pull Up 3 Ω Gate Pull Down 1.5 Ω Bottom Gate Driver Switch RON VINTVCC = 5V Gate Pull Up 2.5 Ω Gate Pull Down 1.5 Ω
PWM Out Drivers
PWM_OUT Switch RON VINTVCC = 5V, VFNEG = –15V Gate Pull Up 5 Ω Gate Pull Down 1.65 Ω PWMX High To PWM_OUTX High Delay 175 ns PWMX Low To PWM_OUTX Low Delay 80 ns
Oscillator
Switching Frequency Range 100 1000 kHz RT Pin Current Limit 66 μA SYNC Input High Referenced to SGND 2.0 V SYNC Input Low Referenced to SGND 0.8 V SYNC Pin Current SYNC = 2.0V 25 nA SYNC Range Tested at 190kHz and 1.1MHz with RT = 422kΩ 90 900 kHz
Switching Frequency
fSW RT = 40.2kΩ l 950 1000 1050 kHz RT = 422kΩ 95 104 120 kHz
Soft-Start
Charge Current PWM1 = 2V, SS, PWM2 and PWM3 = 0V l 4.8 5 5.2 μA
Fault
Lower Fault Falling VFB Threshold l 240 250 260 mV Lower Fault Rising VFB Hysteresis 30 mV Upper Fault Rising VFB Threshold l 1.06 1.100 1.14 V Upper Fault Falling VFB Hysteresis –30 mV Fault Voltage Low IFAULT = 2mA 0.1 V Fault Leakage Current 50 nA 3744fa 4 For more information www.linear.com/LT3744 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
e lecTrical characTerisTics The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 2V, SGND = VEE = 0V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS NMOS FET Drivers
Non-Overlap Time TG to BG 50 ns Non-Overlap Time BG to TG 50 ns Minimum On-Time BG (Note 3) 50 ns Minimum On-Time TG (Note 3) 160 ns Top Gate Driver Switch RON VBOOST – VSW = 5V Gate Pull Up 3 Ω Gate Pull Down 1.5 Ω Bottom Gate Driver Switch RON VINTVCC = 5V Gate Pull Up 2.5 Ω Gate Pull Down 1.5 Ω
PWM Out Drivers
PWM_OUT Switch RON VINTVCC = 5V, VFNEG = –15V Gate Pull Up 5 Ω Gate Pull Down 1.65 Ω PWMX High To PWM_OUTX High Delay 175 ns PWMX Low To PWM_OUTX Low Delay 80 ns
Oscillator
Switching Frequency Range 100 1000 kHz RT Pin Current Limit 66 μA SYNC Input High Referenced to SGND 2.0 V SYNC Input Low Referenced to SGND 0.8 V SYNC Pin Current SYNC = 2.0V 25 nA SYNC Range Tested at 190kHz and 1.1MHz with RT = 422kΩ 90 900 kHz
Switching Frequency
fSW RT = 40.2kΩ l 950 1000 1050 kHz RT = 422kΩ 95 104 120 kHz
Soft-Start
Charge Current PWM1 = 2V, SS, PWM2 and PWM3 = 0V l 4.8 5 5.2 μA
Fault
Lower Fault Falling VFB Threshold l 240 250 260 mV Lower Fault Rising VFB Hysteresis 30 mV Upper Fault Rising VFB Threshold l 1.06 1.100 1.14 V Upper Fault Falling VFB Hysteresis –30 mV Fault Voltage Low IFAULT = 2mA 0.1 V Fault Leakage Current 50 nA 3744fa 4 For more information www.linear.com/LT3744 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
