LTC1844 Series ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25 ° C. VIN = VOUT + 0.5V, unless otherwise noted. (Note 2)SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITS LTC1844-1.5 IOUT = 50mA ● 115 160 mV IOUT = 150mA ● 350 450 mV LTC1844-BYP IOUT = 50mA ● 45 75 mV IOUT = 150mA ● 135 200 mV LTC1844-SD IOUT = 50mA ● 45 75 mV IOUT = 150mA ● 135 200 mV ILIM Output Current Limit ● 160 350 mA en Output Voltage Noise f = 10Hz to 100kHz, CBP = 0.1µF, COUT = 10µF, IL = 150mA 60 µVRMS f = 10Hz to 100kHz, CBP = 0.1µF, COUT = 1µF, IL = 150mA 65 µVRMS VSHDN SHDN Input Threshold ● 0.35 0.65 0.9 V tDELAY Shutdown Exit Delay CBP = 0.01µF, COUT = 1µF, No load 70 100 µs CBP = 0.01µF, COUT = 1µF, No load ● 200 µs TSHDN Thermal Shutdown Limit 155 °C ∆TSHDN Thermal Shutdown Hysteresis 10 °C IADJ ADJ Pin Bias Current (Notes 3, 8) ● 30 100 nA IIRL Input Reverse Leakage Current LTC1844-3.3, LTC1844-2.8, LTC1844-2.5, LTC1844-1.8, ● 200 500 µA LTC1844-1.5, VIN = –5V, VOUT = 0V LTC1844-BYP, LTC1844-SD, VIN = –5V, VOUT = 0V ● 1000 1500 µA IORL Output Reverse Leakage Current VIN = 0V, VOUT = VOUT(NOMINAL) 0.01 0.1 µA (Note 9) VIN = 0V, VOUT = VOUT(NOMINAL) ● 1.2 µA VOSH Start-Up Overshoot RL = 1k, SHDN Rise Time ≤ 1µs 2 %VOUT VRP Output Ripple Rejection (VIN – VOUT) = 1V (Avg), VRIPPLE = 0.5VP-P, 50 dB fRIPPLE = 120Hz, ILOAD = 100mA Note 1: Absolute Maximum Ratings are those values beyond which the life Note 6: To ensure adequate input supply voltage, the LTC1844 adjustable of a device may be impaired. versions are tested and specified for these conditions with an external Note 2: The LTC1844 is tested and specified under pulse load conditions resistor divider (two 100k resistors) for an output voltage of 2.50V. The such that T external resistor divider will add a 5µA load on the output. J ≈ TA. The LTC1844E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the – 40°C to 125°C Note 7: Dropout voltage is (VIN – VOUT) when VOUT falls to 100mV below operating junction temperature range are assured by design, its nominal value measured at VIN = VOUT + 0.5V. For example, the characterization and correlation with statistical process controls. LTC1844-3.3 is tested by measuring the VOUT at VIN = 3.8V, then VIN is Note 3: The LTC1844 adjustable versions are tested and specified for lowered until VOUT falls 100mV below the measured value. The difference these conditions with the ADJ pin connected to the OUT pin for a (VIN – VOUT) is then measured and defined as ∆VDO. VOUT(NOMINAL) of 1.25V. Note 8: ADJ pin bias current flows into the ADJ pin. Note 4: Operating conditions are limited by maximum junction Note 9: Output reverse leakage current is tested with the IN pin grounded temperature. The regulated output voltage specification will not apply for and the OUT pin forced to the rated output voltage. all possible combinations of input voltage and output current. When Note 10: This IC includes overtemperature protection that is intended to operating at maximum input voltage, the output current range must be protect the device during momentary overload conditions. Junction limited. When operating at maximum output current, the input voltage temperature will exceed 125°C when overtemperature protection is active. range must be limited. Continuous operation above the specified maximum operating junction Note 5: The LTC1844’s high precision degrades slightly at high temperature may impair device reliability. temperatures (TJ > 70°C) with input voltages below 2.2V. The lower output voltage versions have been split into higher and lower accuracy input voltage ranges to reflect this. 1844fa 4