Datasheet LTC3836 (Analog Devices) - 3

LTC3836
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 = 3.3V unless otherwise specifi ed. PARAMETER CONDITIONS MIN TYP MAX UNITS
Undervoltage Lockout Threshold VIN Falling l 1.95 2.25 2.55 V VIN Rising l 2.15 2.45 2.75 V Shutdown Threshold at RUN/SS 0.45 0.65 0.85 V Start-Up Current Source RUN/SS = 0V 0.4 0.65 1 μA Regulated Feedback Voltage –40°C to 85°C (Note 5) l 0.591 0.6 0.609 V Output Voltage Line Regulation 2.75V < VIN < 4.5V (Note 5) 0.05 0.2 mV/V Output Voltage Load Regulation ITH = 0.9V (Note 5) 0.12 0.5 % ITH = 1.7V –0.12 –0.5 % VFB1,2 Input Current (Note 5) 10 50 nA TRACK/SS2 Input Current TRACK/SS2 = 0V 1 1.5 2.2 μA Overvoltage Protect Threshold Measured at VFB 0.66 0.68 0.7 V Overvoltage Protect Hysteresis 20 mV Auxiliary Feedback Threshold SYNC/FCB Ramping Positive 0.525 0.6 0.675 V Top Gate (TG) Drive 1, 2 Rise Time CL = 3000pF 40 ns Top Gate (TG) Drive 1, 2 Fall Time CL = 3000pF 40 ns Bottom Gate (BG) Drive 1, 2 Rise Time CL = 3000pF 50 ns Bottom Gate (BG) Drive 1, 2 Fall Time CL = 3000pF 40 ns Maximum Current Sense Voltage (∆VSENSE(MAX)) IPRG = Floating l 110 122 135 mV (SENSE+ – SW) IPRG = 0V l 70 82 95 mV IPRG = VIN l 185 202 220 mV Maximum Duty Cycle In Dropout 97 % Soft-Start Time Time for VFB1 to Ramp from 0.05V to 0.55V 0.6 0.8 1 ms
Oscillator and Phase-Locked Loop
Oscillator Frequency Unsynchronized (SYNC/FCB Not Clocked) PLLLPF = Floating 480 550 600 kHz PLLLPF = 0V 260 300 340 kHz PLLLPF = VIN 650 750 825 kHz Phase-Locked Loop Lock Range SYNC/FCB Clocked Minimum Synchronizable Frequency l 200 250 kHz Maximum Synchronizable Frequency l 850 1150 kHz Phase Detector Output Current Sinking fOSC > fSYNC/FCB –4 μA Sourcing fOSC > fSYNC/FCB 4 μA
PGOOD Output
PGOOD Voltage Low IPGOOD Sinking 1mA 140 mV PGOOD Trip Level VFB with Respect to Set Output Voltage VFB < 0.6V, Ramping Positive –13 –10.0 –7 % VFB < 0.6V, Ramping Negative –16 –13.3 –10 % VFB > 0.6V, Ramping Negative 7 10.0 13 % VFB > 0.6V, Ramping Positive 10 13.3 16 %
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
TJ is calculated from the ambient temperature TA and power dissi- may cause permanent damage to the device. Exposure to any Absolute pation PD according to the following formula: TJ = TA + (PD • θJA°C/W) Maximum Rating condition for extended periods may affect device
Note 4:
Dynamic supply current is higher due to gate charge being reliability and lifetime. delivered at the switching frequency.
Note 2:
The LTC3836 is guaranteed to meet specifi ed performance from
Note 5:
The LTC3836 is tested in a feedback loop that servos ITH to a 0°C to 85°C. Specifi cations over the –40°C to 85°C operating range are specifi ed voltage and measures the resultant VFB voltage. assured by design, characterization and correlation with statistical process
Note 6:
Peak current sense voltage is reduced dependent on duty cycle to controls. a percentage of value as shown in Figure 1. 3836fb 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 RELATED PARTS