Datasheet LTC3729 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | 550kHz, PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulator |
| Pages / Page | 30 / 3 — ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply … |
| File Format / Size | PDF / 356 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply over the full operating
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LTC3729
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 15V, VRUN/SS = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop
VEAIN Regulated Feedback Voltage (Note 3); ITH Voltage = 1.2V l 0.792 0.800 0.808 V V – SENSEMAX Maximum Current Sense Threshold VSENSE = 5V l 62 75 88 mV VSENSE1, 2 = 5V 65 75 85 mV IINEAIN Feedback Current (Note 3) –5 –50 nA VLOADREG Output Voltage Load Regulation (Note 3) Measured in Servo Loop; ITH Voltage = 0.7V l 0.1 0.5 % Measured in Servo Loop; ITH Voltage = 2V l –0.1 –0.5 % VREFLNREG Reference Voltage Line Regulation VIN = 3.6V to 30V (Note 3) 0.002 0.02 %/V VOVL Output Overvoltage Threshold Measured at VEAIN l 0.84 0.86 0.88 V UVLO Undervoltage Lockout VIN Ramping Down 3 3.5 4 V gm Transconductance Amplifier gm ITH = 1.2V; Sink/Source 5µA; (Note 3) 3 mmho gmOL Transconductance Amplifier Gain ITH = 1.2V; (gmxZL; No Ext Load); (Note 3) 1.5 V/mV IQ Input DC Supply Current (Note 4) Normal Mode EXTVCC Tied to VOUT; VOUT = 5V 580 µA Shutdown VRUN/SS = 0V 20 40 µA IRUN/SS Soft‑Start Charge Current VRUN/SS = 1.9V –0.5 –1.2 µA VRUN/SS RUN/SS Pin ON Threshold VRUN/SS Rising 1.0 1.5 1.9 V VRUN/SSLO RUN/SS Pin Latchoff Arming VRUN/SS Rising from 3V 3.8 4.5 V ISCL RUN/SS Discharge Current Soft Short Condition VEAIN = 0.5V; VRUN/SS = 4.5V 0.5 2 4 µA ISDLDO Shutdown Latch Disable Current VEAIN = 0.5V 1.6 5 µA I – – + + SENSE Total Sense Pins Source Current Each Channel; VSENSE1 , 2 = VSENSE1 , 2 = 0V –85 –60 µA DFMAX Maximum Duty Factor In Dropout 98 99.5 % Top Gate Transition Time: TG1, 2 tr Rise Time CLOAD = 3300pF 30 90 ns TG1, 2 tf Fall Time CLOAD = 3300pF 40 90 ns Bottom Gate Transition Time: BG1, 2 tr Rise Time CLOAD = 3300pF 30 90 ns BG1, 2 tf Fall Time CLOAD = 3300pF 20 90 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch‑On Delay Time CLOAD = 3300pF Each Driver 90 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch‑On Delay Time CLOAD = 3300pF Each Driver 90 ns tON(MIN) Minimum On‑Time Tested with a Square Wave (Note 5) 100 ns
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V; VEXTVCC = 4V 4.8 5.0 5.2 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA; VEXTVCC = 4V 0.2 1.0 % VLDO EXT EXTVCC Voltage Drop ICC = 20mA; VEXTVCC = 5V 80 160 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive l 4.5 4.7 V VLDOHYS EXTVCC Switchover Hysteresis ICC = 20mA, EXTVCC Ramping Negative 0.2 V
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VPLLFLTR = 1.2V 360 400 440 kHz fLOW Lowest Frequency VPLLFLTR = 0V 230 260 290 kHz fHIGH Highest Frequency VPLLFLTR ≥ 2.4V 480 550 590 kHz RPLLIN PLLIN Input Resistance 50 kΩ 3729fb 3 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions functional Diagram Operation 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 = 15V, VRUN/SS = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop
VEAIN Regulated Feedback Voltage (Note 3); ITH Voltage = 1.2V l 0.792 0.800 0.808 V V – SENSEMAX Maximum Current Sense Threshold VSENSE = 5V l 62 75 88 mV VSENSE1, 2 = 5V 65 75 85 mV IINEAIN Feedback Current (Note 3) –5 –50 nA VLOADREG Output Voltage Load Regulation (Note 3) Measured in Servo Loop; ITH Voltage = 0.7V l 0.1 0.5 % Measured in Servo Loop; ITH Voltage = 2V l –0.1 –0.5 % VREFLNREG Reference Voltage Line Regulation VIN = 3.6V to 30V (Note 3) 0.002 0.02 %/V VOVL Output Overvoltage Threshold Measured at VEAIN l 0.84 0.86 0.88 V UVLO Undervoltage Lockout VIN Ramping Down 3 3.5 4 V gm Transconductance Amplifier gm ITH = 1.2V; Sink/Source 5µA; (Note 3) 3 mmho gmOL Transconductance Amplifier Gain ITH = 1.2V; (gmxZL; No Ext Load); (Note 3) 1.5 V/mV IQ Input DC Supply Current (Note 4) Normal Mode EXTVCC Tied to VOUT; VOUT = 5V 580 µA Shutdown VRUN/SS = 0V 20 40 µA IRUN/SS Soft‑Start Charge Current VRUN/SS = 1.9V –0.5 –1.2 µA VRUN/SS RUN/SS Pin ON Threshold VRUN/SS Rising 1.0 1.5 1.9 V VRUN/SSLO RUN/SS Pin Latchoff Arming VRUN/SS Rising from 3V 3.8 4.5 V ISCL RUN/SS Discharge Current Soft Short Condition VEAIN = 0.5V; VRUN/SS = 4.5V 0.5 2 4 µA ISDLDO Shutdown Latch Disable Current VEAIN = 0.5V 1.6 5 µA I – – + + SENSE Total Sense Pins Source Current Each Channel; VSENSE1 , 2 = VSENSE1 , 2 = 0V –85 –60 µA DFMAX Maximum Duty Factor In Dropout 98 99.5 % Top Gate Transition Time: TG1, 2 tr Rise Time CLOAD = 3300pF 30 90 ns TG1, 2 tf Fall Time CLOAD = 3300pF 40 90 ns Bottom Gate Transition Time: BG1, 2 tr Rise Time CLOAD = 3300pF 30 90 ns BG1, 2 tf Fall Time CLOAD = 3300pF 20 90 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch‑On Delay Time CLOAD = 3300pF Each Driver 90 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch‑On Delay Time CLOAD = 3300pF Each Driver 90 ns tON(MIN) Minimum On‑Time Tested with a Square Wave (Note 5) 100 ns
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V; VEXTVCC = 4V 4.8 5.0 5.2 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA; VEXTVCC = 4V 0.2 1.0 % VLDO EXT EXTVCC Voltage Drop ICC = 20mA; VEXTVCC = 5V 80 160 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive l 4.5 4.7 V VLDOHYS EXTVCC Switchover Hysteresis ICC = 20mA, EXTVCC Ramping Negative 0.2 V
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VPLLFLTR = 1.2V 360 400 440 kHz fLOW Lowest Frequency VPLLFLTR = 0V 230 260 290 kHz fHIGH Highest Frequency VPLLFLTR ≥ 2.4V 480 550 590 kHz RPLLIN PLLIN Input Resistance 50 kΩ 3729fb 3 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
