Datasheet LTC7138 (Analog Devices) - 3

LTC7138
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) LTC7138E, LTC7138I l 0.792 0.800 0.808 V LTC7138H, LTC7138MP 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 540 610 680 mA 100k Resistor from ISET to GND l 270 310 350 mA ISET Shorted to GND l 140 170 200 mA IVAL Valley Current Comparator Threshold ISET Floating l 50 60 70 % Relative to IPEAK 100k Resistor from ISET to GND l 45 60 70 % ISET Shorted to GND l 45 60 75 % 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 LTC7138 is tested under pulsed load conditions such that where θJA is 40°C/W for the MSOP package. TJ ≈ TA. The LTC7138E 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 LTC7138I is guaranteed other environmental factors. over the –40°C to 125°C operating junction temperature range, the LTC7138H 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 LTC7138MP 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. 7138f For more information www.linear.com/LTC7138 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