Datasheet LTC3638 (Analog Devices) - 3

LTC3638
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 12V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Output Supply (VFB)
VFB(ADJ) Feedback Comparator Threshold VFB Rising, VPRG1 = VPRG2 = 0V (Adjustable Output) LTC3638E, LTC3638I l 0.792 0.800 0.808 V LTC3638H, LTC3638MP l 0.788 0.800 0.812 V VFBH Feedback Comparator Hysteresis VFB Falling, VPRG1 = VPRG2 = 0V l 3 5 9 mV (Adjustable Output) IFB Feedback Pin Current VFB = 1V, VPRG1 = VPRG2 = 0V –10 0 10 nA VFB(FIXED) Feedback Comparator Thresholds VFB Rising, VPRG1 = SS, VPRG2 = 0V l 4.94 5.015 5.09 V (Fixed Output) VFB Falling, VPRG1 = SS, VPRG2 = 0V l 4.91 4.985 5.06 V VFB Rising, VPRG1 = 0V, VPRG2 = SS l 3.25 3.31 3.37 V VFB Falling, VPRG1 = 0V, VPRG2 = SS l 3.23 3.29 3.35 V VFB Rising, VPRG1 = VPRG2 = SS l 1.78 1.81 1.84 V VFB Falling, VPRG1 = VPRG2 = SS l 1.77 1.80 1.83 V
Operation
IPEAK Peak Current Comparator Threshold ISET Floating l 500 575 650 mA 100k Resistor from ISET to GND l 250 300 350 mA ISET Shorted to GND l 40 60 80 mA RON Power Switch On-Resistance ISW = –100mA 1.8 Ω ILSW Switch Pin Leakage Current VIN = 140V, SW = 0V 0.1 1 μA ISS Soft-Start Pin Pull-Up Current VSS < 2.5V 4 5 6 μA tINT(SS) Internal Soft-Start Time SS Pin Floating 1 ms
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
The junction temperature (TJ, in °C) is calculated from the ambient may cause permanent damage to the device. Exposure to any Absolute temperature (TA, in °C) and power dissipation (PD, in Watts) according to Maximum Rating condition for extended periods may affect device the formula: reliability and lifetime. TJ = TA + (PD • θJA)
Note 2:
The LTC3638 is tested under pulsed load conditions such that where θJA is 40°C/W for the MSOP package. TJ ≈ TA. The LTC3638E is guaranteed to meet performance specifications Note that the maximum ambient temperature consistent with these from 0°C to 85°C. Specifications over the –40°C to 125°C operating specifications is determined by specific operating conditions in junction temperature range are assured by design, characterization and conjunction with board layout, the rated package thermal impedance and correlation with statistical process controls. The LTC3638I is guaranteed other environmental factors. over the –40°C to 125°C operating junction temperature range, the LTC3638H is guaranteed over the –40°C to 150°C operating junction
Note 4:
This IC includes overtemperature protection that is intended to temperature range and the LTC3638MP is tested and guaranteed over the protect the device during momentary overload conditions. The maximum –55°C to 150°C operating junction temperature range. rated junction temperature will be exceeded when this protection is active. Continuous operation above the specified absolute maximum operating High junction temperatures degrade operating lifetimes; operating lifetime junction temperature may impair device reliability or permanently damage is derated for junction temperatures greater than 125°C. Note that the the device. The overtemperature protection level is not production tested. maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board
Note 5:
Dynamic supply current is higher due to the gate charge being layout, the rated package thermal impedance and other environmental delivered at the switching frequency. See Applications Information. factors. 3638fa For more information www.linear.com/LTC3638 3 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 Typical Applications Package Description Typical Application Related Parts