Datasheet LTC1772B (Analog Devices) - 3

LTC1772B
ELECTRICAL CHARACTERISTICS The
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denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 4.2V unless otherwise specifi ed. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS
VFB Input Current (Note 5) 10 50 nA Overvoltage Protect Threshold Measured at VFB 0.820 0.860 0.895 V Overvoltage Protect Hysteresis 20 mV Oscillator Frequency VFB = 0.8V 500 550 650 kHz VFB = 0V 120 kHz Gate Drive Rise Time CLOAD = 3000pF 40 ns Gate Drive Fall Time CLOAD = 3000pF 40 ns Peak Current Sense Voltage (Note 6) 105 mV
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
TJ is calculated from the ambient temperature TA and power may cause permanent damage to the device. Exposure to any Absolute dissipation PD according to the following formula: Maximum Rating condition for extended periods may affect device TJ = TA + (PD • θJA°C/W) reliability and lifetime.
Note 4:
Dynamic supply current is higher due to the gate charge being
Note 2:
The LTC1772BE is guaranteed to meet specifi cations from 0°C to delivered at the switching frequency. 85°C. Specifi cations over the –40°C to 85°C operating temperature range
Note 5:
The LTC1772B is tested in a feedback loop that servos VFB to the are assured by design, characterization and correlation with statistical output of the error amplifi er. process controls. The LTC1772BI is guaranteed to meet specifi cations over
Note 6:
Peak current sense voltage is reduced dependent on duty cycle to the full –40°C to 85°C operating temperature range. a percentage of value as given in Figure 2. 1772bfa 3