Datasheet LTC7810 (Analog Devices) - 4

link to page 36 link to page 36 LTC7810
ELECTRICAL CHARACTERISTICS The
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denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, RUN1,2 = 5V, EXTVCC = 0V, DRVSET = INTVCC unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Input Supply (VIN)
VIN Input Supply Operating Range (Note 11) 4.5 140 V VOUT1,2 Regulated Output Voltage Set Point 1 60 V IVIN VIN Current in Regulation Figure 14 Circuit, 48V to 12V and 3.3V, 16 μA No Load Figure 14 Circuit, 12V to 3.3V, 32 μA No Load, RUN2 = 0V IQ No-Load DC Supply Current (Note 5) Shutdown VIN Current RUN1,2 = 0V 1.5 5 μA Sleep Mode V – IN Current (Note 3) VSENSE1 ≥ 3.2V, VEXTVCC = 12V 4 8 µA V – SENSE1 ≥ 3.2V, VEXTVCC = 0V 25 50 µA V – SENSE1 < 3.2V 40 75 µA Sleep Mode SENSE1– Current (Note 3) V – SENSE1 ≥ 3.2V 16 30 μA Sleep Mode EXTVCC Current (Note 3) VEXTVCC = 12V 23 45 μA Low I – Q Dropout (One Channel On) VFB = 0.97V, VIN = VSENSE ≥ 8V, No Load 78 130 μA Combined V – IN and VSENSE DC Supply Current Low I – Q Dropout (Both Channels On) VFB1,2 = 0.97V, VIN = VSENSE1,2 ≥ 8V, No Load 110 160 μA Combined V – IN and VSENSE DC Supply Current Pulse-Skipping or Forced Continuous Mode One Channel On 1.7 mA Both Channels On 2.4 mA RUN Pin ON Threshold VRUN1, VRUN2 Rising l 1.17 1.22 1.27 V RUN Pin Hysteresis 120 mV OVLO Pin OFF Threshold VOVLO Rising l 1.17 1.22 1.27 V OVLO Pin Hysteresis 65 mV
Controller Operation
VFB1,2 Regulated Feedback Voltage (Note 4) VIN = 4.5V to 150V, ITH1 = 0.6V to 1.2V l 0.985 1.0 1.015 V –40°C to 85°C, All Grades 0.990 1.0 1.010 V Feedback Current (Note 4) –5 ±50 nA Feedback Overvoltage Threshold Relative to Regulated VFB1,2 7 10 13 % gm1,2 Transconductance Amplifier gm (Note 4) ITH1,2 = 1.2V, Sink/Source = 5μA 2 mmho V – SENSE(MAX) Maximum Current Sense Threshold VFB1,2 = 0.9V, VSENSE1,2 = 3.3V l 67 75 83 mV Current Sense Threshold Matching Between V – FB1,2 = 0.9V, VSENSE1,2 = 3.3V –5 0 5 mV Channels I + + SENSE1,2 SENSE1,2+ Pin Current VSENSE1,2 = 3V ±1 μA I – SENSE1 SENSE1– Pin Current V – SENSE1 < 3V 6 μA 3.2V ≤ V – SENSE1 < INTVCC – 0.5V 60 μA V – SENSE1 > INTVCC + 0.5V 540 μA V – SENSE1 ≥ 8V, in Low IQ Dropout 25 μA I – – SENSE2 SENSE2– Pin Current VSENSE2 < INTVCC – 0.5V 4 μA V – SENSE2 > INTVCC + 0.5V 480 μA V – SENSE2 ≥ 8V, in Low IQ Dropout 4 μA ITRACK/SS1,2 Soft-Start Charge Current VTRACK/SS1,2 = 0V 8 10 12 µA Rev. A 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Main Control Loop Power and Bias Supplies (VIN, NDRV, EXTVCC, DRVCC, REGSD) Boost Supply and Dropout (BOOST and SW pins) Start-Up and Shutdown (RUN, TRACK/SS, OVLO Pins) Light Load Operation: Burst Mode Operation, Pulse Skipping or Forced Continuous Mode (MODE Pin) Frequency Selection, Spread Spectrum, and Phase-Locked Loop (FREQ and PLLIN/SPREAD Pins) Applications Information Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Sensing Setting the Operating Frequency Selecting the Light-Load Operating Mode Inductor Value Calculation Inductor Core Selection Power MOSFET Selection CIN and COUT Selection Setting the Output Voltage RUN Pins and Overvoltage/Undervoltage Lockout Tracking and Soft-Start (TRACK/SS1, TRACK/SS2 Pins) Single Output Two-Phase Operation DRVCC Regulators Topside MOSFET Driver Supply (CB, DB) Burst Clamp Programming Fault Conditions: Current Limit and Current Foldback Fault Conditions: Overvoltage Protection (Crowbar) Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations Efficiency Considerations Checking Transient Response Design Example PC Board Layout Checklist PC Board Layout Debugging Typical Applications Package Description Revision History Typical Application Related Parts