Datasheet LT3474, LT3474-1 (Analog Devices) - 3
| 制造商 | Analog Devices |
| 描述 | Step-Down 1A LED Driver |
| 页数 / 页 | 20 / 3 — ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply … |
| 文件格式/大小 | PDF / 226 Kb |
| 文件语言 | 英语 |
ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply over the full operating
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LT3474/LT3474-1
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V, VBOOST = 16V, VOUT = 4V unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference Voltage Line Regulation 5V < VIN < 36V 0.01 %/V Reference Voltage Load Regulation 0 < IREF < 250μA 0.0002 %/μA VADJ Pin Bias Current (Note 4) l 20 400 nA Switching Frequency RT = 80.6k 470 500 530 kHz l 450 540 kHz Maximum Duty Cycle RT = 80.6k l 90 95 % RT = 10k 76 % RT = 232k 98 % Foldback Frequency RT = 80.6k, VOUT = 0V 70 kHz SHDN Threshold (to Switch) 2.6 2.65 2.7 V SHDN Pin Current (Note 5) VSHDN = SHDN Threshold 8.3 10.3 12.3 μA PWM Threshold 0.4 0.9 1.2 V VC Switching Threshold 0.8 V VC Source Current VC = 1V 100 μA VC Sink Current VC = 1V 100 μA LED to VC Current Gain 1.5 μA/mA LED to VC Transresistance 1 V/mA VC to Switch Current Gain 2 A/V VC Clamp Voltage 1.9 V VC Pin Current in PWM Mode VC = 1V, VPWM = 0.3V l 0.01 1 μA OUT Pin Clamp Voltage (LT3474) 13.2 13.8 14.5 V OUT Pin Current in PWM Mode VOUT = 4V, VPWM = 0.3V l 0.1 10 μA Switch Current Limit (Note 6) –40°C to 85°C l 1.6 2.1 3.2 A LT3474I, LT3474I-1 at 125°C 1.5 3.2 A Switch VCESAT ISW = 1A 380 500 mV Boost Pin Current ISW = 1A 30 50 mA Switch Leakage Current 0.01 1 μA Minimum Boost Voltage (Note 7) 1.9 2.5 V Boost Diode Forward Voltage IDIO = 100mA 600 mV
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings operating temperature range are assured by design, characterization and may cause permanent damage to the device. Exposure to any Absolute correlation with statistical process controls. The LT3474I and LT3474I-1 Maximum Rating condition for extended periods may affect device are guaranteed to meet performance specifi cations over the –40°C to reliability and lifetime. 125°C operating temperature range.
Note 2:
This IC includes overtemperature protection that is intended
Note 4:
Current fl ows out of pin. to protect the device during momentary overload conditions. Junction
Note 5:
Current fl ows into pin. temperature will exceed 125°C when overtemperature protection is active.
Note 6:
Current limit is guaranteed by design and/or correlation to static Continuous operation above the specifi ed maximum operating junction test. Slope compensation reduces current limit at higher duty cycles. temperature may impair device reliability.
Note 7:
This is the minimum voltage across the boost capacitor needed to
Note 3:
The LT3474E and LT3474E-1 are guaranteed to meet performance guarantee full saturation of the internal power switch. specifi cations from 0°C to 70°C. Specifi cations over the –40°C to 85°C 3474fd 3
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V, VBOOST = 16V, VOUT = 4V unless otherwise noted (Note 3). PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference Voltage Line Regulation 5V < VIN < 36V 0.01 %/V Reference Voltage Load Regulation 0 < IREF < 250μA 0.0002 %/μA VADJ Pin Bias Current (Note 4) l 20 400 nA Switching Frequency RT = 80.6k 470 500 530 kHz l 450 540 kHz Maximum Duty Cycle RT = 80.6k l 90 95 % RT = 10k 76 % RT = 232k 98 % Foldback Frequency RT = 80.6k, VOUT = 0V 70 kHz SHDN Threshold (to Switch) 2.6 2.65 2.7 V SHDN Pin Current (Note 5) VSHDN = SHDN Threshold 8.3 10.3 12.3 μA PWM Threshold 0.4 0.9 1.2 V VC Switching Threshold 0.8 V VC Source Current VC = 1V 100 μA VC Sink Current VC = 1V 100 μA LED to VC Current Gain 1.5 μA/mA LED to VC Transresistance 1 V/mA VC to Switch Current Gain 2 A/V VC Clamp Voltage 1.9 V VC Pin Current in PWM Mode VC = 1V, VPWM = 0.3V l 0.01 1 μA OUT Pin Clamp Voltage (LT3474) 13.2 13.8 14.5 V OUT Pin Current in PWM Mode VOUT = 4V, VPWM = 0.3V l 0.1 10 μA Switch Current Limit (Note 6) –40°C to 85°C l 1.6 2.1 3.2 A LT3474I, LT3474I-1 at 125°C 1.5 3.2 A Switch VCESAT ISW = 1A 380 500 mV Boost Pin Current ISW = 1A 30 50 mA Switch Leakage Current 0.01 1 μA Minimum Boost Voltage (Note 7) 1.9 2.5 V Boost Diode Forward Voltage IDIO = 100mA 600 mV
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings operating temperature range are assured by design, characterization and may cause permanent damage to the device. Exposure to any Absolute correlation with statistical process controls. The LT3474I and LT3474I-1 Maximum Rating condition for extended periods may affect device are guaranteed to meet performance specifi cations over the –40°C to reliability and lifetime. 125°C operating temperature range.
Note 2:
This IC includes overtemperature protection that is intended
Note 4:
Current fl ows out of pin. to protect the device during momentary overload conditions. Junction
Note 5:
Current fl ows into pin. temperature will exceed 125°C when overtemperature protection is active.
Note 6:
Current limit is guaranteed by design and/or correlation to static Continuous operation above the specifi ed maximum operating junction test. Slope compensation reduces current limit at higher duty cycles. temperature may impair device reliability.
Note 7:
This is the minimum voltage across the boost capacitor needed to
Note 3:
The LT3474E and LT3474E-1 are guaranteed to meet performance guarantee full saturation of the internal power switch. specifi cations from 0°C to 70°C. Specifi cations over the –40°C to 85°C 3474fd 3