Datasheet LT3845A (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency |
| Pages / Page | 26 / 3 — ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply … |
| File Format / Size | PDF / 295 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply over the full operating
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LT3845A
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 20V, VCC = BOOST = BURST_EN = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE– = SENSE+ = 10V, SGND = PGND = SW = SYNC = 0V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Operating Voltage Range (Note 4) l 4 60 V VIN Minimum Start Voltage l 7.5 V VIN UVLO Threshold (Falling) l 3.6 3.8 4 V VIN UVLO Threshold Hysteresis 670 mV VIN Supply Current VCC > 9V 20 µA VIN Burst Mode Current VBURST_EN = 0V, VFB = 1.35V 20 µA VIN Shutdown Current VSHDN = 0V l 9 15 µA BOOST Operating Voltage Range l 75 V BOOST Operating Voltage Range (Note 5) VBOOST – VSW l 20 V BOOST UVLO Threshold (Rising) VBOOST – VSW 5 V BOOST UVLO Threshold Hysteresis VBOOST – VSW 400 mV BOOST Supply Current (Note 6) 1.4 mA BOOST Burst Mode Current VBURST_EN = 0V 0.1 µA BOOST Shutdown Current VSHDN = 0V 0.1 µA VCC Operating Voltage Range (Note 5) l 20 V VCC Output Voltage Over Full Line and Load Range l 8 8.3 V VCC UVLO Threshold (Rising) 6.25 V VCC UVLO Threshold Hysteresis 500 mV VCC Supply Current (Note 6) l 3 3.7 mA VCC Burst Mode Current VBURST_EN = 0V 100 µA VCC Shutdown Current VSHDN = 0V 20 µA VCC Current Limit l –40 –150 mA Error Amp Reference Voltage Measured at VFB Pin 1.224 1.231 1.238 V l 1.215 1.245 V VFB Pin Input Current VFB = 1.231V 25 nA SHDN Enable Threshold (Rising) l 1.3 1.35 1.4 V SHDN Threshold Hysteresis 120 mV Sense Pins Common Mode Range l 0 36 V Current Limit Sense Voltage V + – SENSE – VSENSE l 90 100 115 mV Reverse Protect Sense Voltage V + – SENSE – VSENSE , VBURST_EN = VCC –100 mV Reverse Current Inhibit Offset VBURST_EN = 0V or VBURST_EN = VFB 10 mV Input Current (I + – SENSE + ISENSE ) VSENSE(CM) = 0V 800 µA VSENSE(CM) = 2V –20 µA VSENSE(CM) > 4V –300 µA Operating Frequency l 270 300 330 kHz Minimum Programmable Frequency l 100 kHz Maximum Programmable Frequency l 500 kHz External Sync Frequency Range l 100 600 kHz SYNC Input Resistance 40 kΩ SYNC Voltage Threshold l 1.4 2 V Soft-Start Capacitor Control Current 2 µA Error Amp Transconductance l 270 340 410 µS Error Amp DC Voltage Gain 62 dB Error Amp Sink/Source Current ±30 µA 3845afa 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History 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 = 20V, VCC = BOOST = BURST_EN = 10V, SHDN = 2V, RSET = 49.9kΩ, SENSE– = SENSE+ = 10V, SGND = PGND = SW = SYNC = 0V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Operating Voltage Range (Note 4) l 4 60 V VIN Minimum Start Voltage l 7.5 V VIN UVLO Threshold (Falling) l 3.6 3.8 4 V VIN UVLO Threshold Hysteresis 670 mV VIN Supply Current VCC > 9V 20 µA VIN Burst Mode Current VBURST_EN = 0V, VFB = 1.35V 20 µA VIN Shutdown Current VSHDN = 0V l 9 15 µA BOOST Operating Voltage Range l 75 V BOOST Operating Voltage Range (Note 5) VBOOST – VSW l 20 V BOOST UVLO Threshold (Rising) VBOOST – VSW 5 V BOOST UVLO Threshold Hysteresis VBOOST – VSW 400 mV BOOST Supply Current (Note 6) 1.4 mA BOOST Burst Mode Current VBURST_EN = 0V 0.1 µA BOOST Shutdown Current VSHDN = 0V 0.1 µA VCC Operating Voltage Range (Note 5) l 20 V VCC Output Voltage Over Full Line and Load Range l 8 8.3 V VCC UVLO Threshold (Rising) 6.25 V VCC UVLO Threshold Hysteresis 500 mV VCC Supply Current (Note 6) l 3 3.7 mA VCC Burst Mode Current VBURST_EN = 0V 100 µA VCC Shutdown Current VSHDN = 0V 20 µA VCC Current Limit l –40 –150 mA Error Amp Reference Voltage Measured at VFB Pin 1.224 1.231 1.238 V l 1.215 1.245 V VFB Pin Input Current VFB = 1.231V 25 nA SHDN Enable Threshold (Rising) l 1.3 1.35 1.4 V SHDN Threshold Hysteresis 120 mV Sense Pins Common Mode Range l 0 36 V Current Limit Sense Voltage V + – SENSE – VSENSE l 90 100 115 mV Reverse Protect Sense Voltage V + – SENSE – VSENSE , VBURST_EN = VCC –100 mV Reverse Current Inhibit Offset VBURST_EN = 0V or VBURST_EN = VFB 10 mV Input Current (I + – SENSE + ISENSE ) VSENSE(CM) = 0V 800 µA VSENSE(CM) = 2V –20 µA VSENSE(CM) > 4V –300 µA Operating Frequency l 270 300 330 kHz Minimum Programmable Frequency l 100 kHz Maximum Programmable Frequency l 500 kHz External Sync Frequency Range l 100 600 kHz SYNC Input Resistance 40 kΩ SYNC Voltage Threshold l 1.4 2 V Soft-Start Capacitor Control Current 2 µA Error Amp Transconductance l 270 340 410 µS Error Amp DC Voltage Gain 62 dB Error Amp Sink/Source Current ±30 µA 3845afa 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
