LTC3446 elecTrical characTerisTicsNote 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: Minimum operating VIN voltage required for the VLDO regulators may cause permanent damage to the device. Exposure to any Absolute to stay in regulation is: Maximum Rating condition for extended periods may affect device VIN ≥ LVOUT(MAX) + 1.4V and VIN ≥ 2.7V reliability and lifetime. Note 4: Dynamic supply current is higher due to the internal gate charge Note 2: The LTC3446 is tested under pulsed load conditions such that being delivered at the switching frequency. TJ ≈ TA. The LTC3446E is guaranteed to meet performance specifications Note 5: The LTC3446 is tested in a feedback loop that connects the from 0°C to 85°C operating junction temperature. Specifications over BUCKFB pin to the output of the buck converter’s error amplifier (i.e., the the –40°C to 125°C operating junction temperature range are assured by I design characterization and correlation with statistical process controls. TH pin). The LTC3446I is guaranteed to meet performance specifications over Note 6: Minimum operating LVIN voltage required for the VLDO regulators the –40°C to 125°C operating junction temperature range. Note that the to stay in regulation is: maximum ambient temperature consistent with these specifications is LVIN ≥ LVOUT(MAX) + 100mV and LVIN ≥ 0.9V determined by specific operating conditions in conjunction with board Note 7: Operating conditions are limited by maximum junction layout, the rated package thermal impedance and other environmental temperature. The regulated output voltage specification will not apply factors. The junction temperature (TJ, in °C) is calculated from the ambient for all possible combinations of input voltage and output current. When temperature (TA, in °C) and power dissipation (PD, in Watts) according to operating at maximum input voltage, the output current range must be the formula: limited. When operating at maximum output current, the input voltage T range must be limited. J = TA + (PD • θJA) where θ Note 8: PGOOD assertion indicates that the feedback voltages of all JA (in °C/W) is the package thermal impedance. enabled supplies are within the specified percentage of their target values. Note 9: Dropout voltage in the DFN package is assured by design, characterization and statistical process control. Typical perForMance characTerisTicsBuck Regulated Feedback VoltageLDO1 Regulated FeedbackLDO2 Regulated Feedbackvs TemperatureVoltage vs TemperatureVoltage vs Temperature 808 408 408 806 406 406 804 404 404 802 402 402 (mV) (mV) (mV) 800 400 400 V BUCKFB 798 V LVFB1 V LVFB2 398 398 796 VIN = 2.7V 396 V 396 IN = 2.7V VIN = 2.7V VIN = 3.6V VIN = 3.6V VIN = 3.6V 794 VIN = 4.2V 394 VIN = 4.2V 394 VIN = 4.2V VIN = 5.5V VIN = 5.5V VIN = 5.5V 792 392 392 –50 –30 –10 10 30 50 70 90 110 130 –50 –30 –10 10 30 50 70 90 110 130 –50 –30 –10 10 30 50 70 90 110 130 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 3446 G01 3446 G02 3446 G03 3446ff 4 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts