Datasheet LTC3772B (Analog Devices) - 3
| 制造商 | Analog Devices |
| 描述 | Micropower No RSENSE Constant Frequency Step-Down DC/DC Controller |
| 页数 / 页 | 20 / 3 — ELECTRICAL CHARACTERISTICS The. indicates specifications which apply over … |
| 文件格式/大小 | PDF / 331 Kb |
| 文件语言 | 英语 |
ELECTRICAL CHARACTERISTICS The. indicates specifications which apply over the full operating
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LTC3772B
ELECTRICAL CHARACTERISTICS The
●
indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 4.2V unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS
VFB Input Current (Note 5) –10 2 10 nA Overvoltage Protect Threshold Measured at VFB 0.850 0.880 0.910 V Overvoltage Protect Hysteresis 40 mV Oscillator Frequency Normal Operation VFB = 0.8V 500 550 650 kHz Output Short Circuit VFB = 0V 200 kHz Gate Drive Rise Time CLOAD = 3000pF 40 ns Gate Drive Fall Time CLOAD = 3000pF 40 ns Peak Current Sense Voltage IPRG = GND (Note 6) ● 55 70 85 mV IPRG = Floating ● 120 138 155 mV IPRG = VIN ● 190 208 225 mV Default Soft-Start Time Time for VFB to Ramp from 0.05V to 0.75V 0.8 ms
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings dissipation PD according to the following formula: may cause permanent damage to the device. Exposure to any Absolute TJ = TA + (PD • θJA°C/W) Maximum Rating condition for extended periods may affect device
Note 4:
Dynamic supply current is higher due to the gate charge being reliability and lifetime. delivered at the switching frequency.
Note 2:
The LTC3772BETS8/LTC3772BEDDB are guaranteed to meet
Note 5:
The LTC3772B is tested in a feedback loop that servos VFB to the specifications from 0°C to 70°C. Specifications over the –40°C to 85°C output of the error amplifier while maintaining ITH/RUN at the midpoint of operating temperature range are assured by design, characterization and the current limit range. correlation with statistical process controls.
Note 6:
Peak current sense voltage is reduced dependent on duty cycle as
Note 3:
TJ is calculated from the ambient temperature TA and power given in Figure 1.
W U TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current (No Load) Quiescent Current (No Load) Quiescent Current (Shutdown) vs Input Voltage vs Temperature vs Input Voltage
225 250 25 VIN = 5V 220 230 20 µA) µA) µA) 215 15 210 210 190 10 205 QUIESCENT CURRENT ( QUIESCENT CURRENT ( QUIESCENT CURRENT ( 170 200 5 195 150 0 2 3 4 5 6 7 8 9 10 –60 –40 –20 0 20 40 60 80 100 2 3 4 5 6 7 8 9 10 VIN (V) TEMPERATURE (°C) INPUT VOLTAGE (V) 3772B G01 3772B G02 3772B G03 3772bfa 3
ELECTRICAL CHARACTERISTICS The
●
indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 4.2V unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS
VFB Input Current (Note 5) –10 2 10 nA Overvoltage Protect Threshold Measured at VFB 0.850 0.880 0.910 V Overvoltage Protect Hysteresis 40 mV Oscillator Frequency Normal Operation VFB = 0.8V 500 550 650 kHz Output Short Circuit VFB = 0V 200 kHz Gate Drive Rise Time CLOAD = 3000pF 40 ns Gate Drive Fall Time CLOAD = 3000pF 40 ns Peak Current Sense Voltage IPRG = GND (Note 6) ● 55 70 85 mV IPRG = Floating ● 120 138 155 mV IPRG = VIN ● 190 208 225 mV Default Soft-Start Time Time for VFB to Ramp from 0.05V to 0.75V 0.8 ms
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings dissipation PD according to the following formula: may cause permanent damage to the device. Exposure to any Absolute TJ = TA + (PD • θJA°C/W) Maximum Rating condition for extended periods may affect device
Note 4:
Dynamic supply current is higher due to the gate charge being reliability and lifetime. delivered at the switching frequency.
Note 2:
The LTC3772BETS8/LTC3772BEDDB are guaranteed to meet
Note 5:
The LTC3772B is tested in a feedback loop that servos VFB to the specifications from 0°C to 70°C. Specifications over the –40°C to 85°C output of the error amplifier while maintaining ITH/RUN at the midpoint of operating temperature range are assured by design, characterization and the current limit range. correlation with statistical process controls.
Note 6:
Peak current sense voltage is reduced dependent on duty cycle as
Note 3:
TJ is calculated from the ambient temperature TA and power given in Figure 1.
W U TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current (No Load) Quiescent Current (No Load) Quiescent Current (Shutdown) vs Input Voltage vs Temperature vs Input Voltage
225 250 25 VIN = 5V 220 230 20 µA) µA) µA) 215 15 210 210 190 10 205 QUIESCENT CURRENT ( QUIESCENT CURRENT ( QUIESCENT CURRENT ( 170 200 5 195 150 0 2 3 4 5 6 7 8 9 10 –60 –40 –20 0 20 40 60 80 100 2 3 4 5 6 7 8 9 10 VIN (V) TEMPERATURE (°C) INPUT VOLTAGE (V) 3772B G01 3772B G02 3772B G03 3772bfa 3