Datasheet LTC3850-2 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | Dual, 2-Phase Synchronous Step-Down Switching Controller |
| Pages / Page | 36 / 3 — ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply … |
| File Format / Size | PDF / 417 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply over the full operating
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LTC3850-2
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 = 15V, VRUN1,2 = 5V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loops
VFB1,2 Regulated Feedback Voltage ITH1,2 Voltage = 1.2V; (Note 4) l 0.792 0.800 0.808 V IFB1,2 Feedback Current (Note 4) –10 –50 nA VREFLNREG Reference Voltage Line Regulation VIN = 6V to 24V (Note 4) 0.002 0.02 %/V VLOADREG Output Voltage Load Regulation (Note 4) Measured in Servo Loop; ΔITH Voltage = 1.2V to 0.7V l 0.01 0.1 % Measured in Servo Loop; ΔITH Voltage = 1.2V to 1.6V l –0.01 –0.1 % gm1,2 Transconductance Amplifi er gm ITH1,2 = 1.2V; Sink/Source 5μA; (Note 4) 2.2 mmho IQ Input DC Supply Current (Note 5) Normal Mode VIN = 15V; EXTVCC Tied to VOUT1; VOUT1 = 5V 850 μA Shutdown VRUN1,2 = 0V 30 50 μA UVLO Undervoltage Lockout on INTVCC VINTVCC Ramping Down 3 V UVLOHYS UVLO Hysteresis 0.5 V DFMAX Maximum Duty Factor In Dropout 96 97.2 % VOVL Feedback Overvoltage Lockout Measured at VFB1,2 l 0.84 0.86 0.88 V ISENSE Sense Pin Bias Current (Each Channel) VSENSE1,2 = 3.3V ±1 ±2 μA ITK/SS1,2 Soft-Start Charge Current VTK/SS1,2 = 0V 0.9 1.3 1.7 μA VRUN1,2 RUN Pin ON Threshold VRUN1, VRUN2 Rising l 1.1 1.22 1.35 V VRUN1,2HYS RUN Pin ON Hysteresis 80 mV VSENSE(MAX) Maximum Current Sense Threshold VFB1,2 = 0.7V, VSENSE1,2 = 3.3V l 40 50 60 mV TG RUP TG Driver Pull-Up On-Resistance TG High 2.6 Ω TG RDOWN TG Driver Pulldown On-Resistance TG Low 1.5 Ω BG RUP BG Driver Pull-Up On-Resistance BG High 2.4 Ω BG RDOWN BG Driver Pulldown On-Resistance BG Low 1.1 Ω TG Transition Time: (Note 6) TG1,2 tr Rise Time CLOAD = 3300pF 25 ns TG1,2 tf Fall Time CLOAD = 3300pF 25 ns BG Transition Time: (Note 6) BG1,2 tr Rise Time CLOAD = 3300pF 25 ns BG1,2 tf Fall Time CLOAD = 3300pF 25 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver 30 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch-On Delay Time CLOAD = 3300pF Each Driver 30 ns tON(MIN) Minimum On-Time (Note 7) 90 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 7V < VIN < 24V 4.8 5 5.2 V VLDO INT INTVCC Load Regulation ICC = 0mA to 50mA 0.5 2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 50 100 mV VLDOHYS EXTVCC Hysteresis 200 mV 38502f 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 = 15V, VRUN1,2 = 5V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loops
VFB1,2 Regulated Feedback Voltage ITH1,2 Voltage = 1.2V; (Note 4) l 0.792 0.800 0.808 V IFB1,2 Feedback Current (Note 4) –10 –50 nA VREFLNREG Reference Voltage Line Regulation VIN = 6V to 24V (Note 4) 0.002 0.02 %/V VLOADREG Output Voltage Load Regulation (Note 4) Measured in Servo Loop; ΔITH Voltage = 1.2V to 0.7V l 0.01 0.1 % Measured in Servo Loop; ΔITH Voltage = 1.2V to 1.6V l –0.01 –0.1 % gm1,2 Transconductance Amplifi er gm ITH1,2 = 1.2V; Sink/Source 5μA; (Note 4) 2.2 mmho IQ Input DC Supply Current (Note 5) Normal Mode VIN = 15V; EXTVCC Tied to VOUT1; VOUT1 = 5V 850 μA Shutdown VRUN1,2 = 0V 30 50 μA UVLO Undervoltage Lockout on INTVCC VINTVCC Ramping Down 3 V UVLOHYS UVLO Hysteresis 0.5 V DFMAX Maximum Duty Factor In Dropout 96 97.2 % VOVL Feedback Overvoltage Lockout Measured at VFB1,2 l 0.84 0.86 0.88 V ISENSE Sense Pin Bias Current (Each Channel) VSENSE1,2 = 3.3V ±1 ±2 μA ITK/SS1,2 Soft-Start Charge Current VTK/SS1,2 = 0V 0.9 1.3 1.7 μA VRUN1,2 RUN Pin ON Threshold VRUN1, VRUN2 Rising l 1.1 1.22 1.35 V VRUN1,2HYS RUN Pin ON Hysteresis 80 mV VSENSE(MAX) Maximum Current Sense Threshold VFB1,2 = 0.7V, VSENSE1,2 = 3.3V l 40 50 60 mV TG RUP TG Driver Pull-Up On-Resistance TG High 2.6 Ω TG RDOWN TG Driver Pulldown On-Resistance TG Low 1.5 Ω BG RUP BG Driver Pull-Up On-Resistance BG High 2.4 Ω BG RDOWN BG Driver Pulldown On-Resistance BG Low 1.1 Ω TG Transition Time: (Note 6) TG1,2 tr Rise Time CLOAD = 3300pF 25 ns TG1,2 tf Fall Time CLOAD = 3300pF 25 ns BG Transition Time: (Note 6) BG1,2 tr Rise Time CLOAD = 3300pF 25 ns BG1,2 tf Fall Time CLOAD = 3300pF 25 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver 30 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch-On Delay Time CLOAD = 3300pF Each Driver 30 ns tON(MIN) Minimum On-Time (Note 7) 90 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 7V < VIN < 24V 4.8 5 5.2 V VLDO INT INTVCC Load Regulation ICC = 0mA to 50mA 0.5 2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 50 100 mV VLDOHYS EXTVCC Hysteresis 200 mV 38502f 3
