Datasheet LT8636, LT8637 (Analog Devices) - 4

link to page 16 link to page 16 LT8636/LT8637
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum On-Time ILOAD = 1.5A, SYNC = 0V l 30 50 ns ILOAD = 1.5A, SYNC = 2V l 30 45 ns Minimum Off-Time 80 110 ns Oscillator Frequency RT = 221k l 180 210 240 kHz RT = 60.4k l 665 700 735 kHz RT = 18.2k l 1.8 1.95 2.1 MHz Top Power NMOS On-Resistance ISW = 1A 66 mΩ Top Power NMOS Current Limit l 7.5 10 12.5 A Bottom Power NMOS On-Resistance VINTVCC = 3.4V, ISW = 1A 27 mΩ SW Leakage Current VIN = 42V, VSW = 0V, 42V –3 3 µA EN/UV Pin Threshold EN/UV Rising l 0.94 1.0 1.06 V EN/UV Pin Hysteresis 40 mV EN/UV Pin Current VEN/UV = 2V –20 20 nA PG Upper Threshold Offset from VFB VFB Falling l 5 7.5 10.25 % PG Lower Threshold Offset from VFB VFB Rising l –10.75 –8 –5.25 % PG Hysteresis 0.2 % PG Leakage VPG = 3.3V –80 80 nA PG Pull-Down Resistance VPG = 0.1V l 700 2000 Ω SYNC/MODE Threshold SYNC/MODE DC and Clock Low Level Voltage l 0.7 0.9 V SYNC/MODE Clock High Level Voltage l 1.2 1.4 V SYNC/MODE DC High Level Voltage l 2.2 2.55 2.9 V Spread Spectrum Modulation RT = 60.4k, VSYNC = 3.3V 22 % Frequency Range Spread Spectrum Modulation Frequency VSYNC = 3.3V 3 kHz TR/SS Source Current l 1.2 1.9 2.6 µA TR/SS Pull-Down Resistance Fault Condition, TR/SS = 0.1V 200 Ω VIN to Disable Forced Continuous Mode VIN Rising 35 37 39 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings lifetime is derated at junction temperatures greater than 125°C. The junction may cause permanent damage to the device. Exposure to any Absolute temperature (TJ, in °C) is calculated from the ambient temperature (TA in Maximum Rating condition for extended periods may affect device °C) and power dissipation (PD, in Watts) according to the formula: reliability and lifetime. TJ = TA + (PD • θJA)
Note 2:
The LT8636E is guaranteed to meet performance specifications where θJA (in °C/W) is the package thermal impedance. from 0°C to 125°C junction temperature. Specifications over the –40°C
Note 3:
θ values determined per JEDEC 51-7, 51-12. See the Applications to 125°C operating junction temperature range are assured by design, Information section for information on improving the thermal resistance characterization, and correlation with statistical process controls. The and for actual temperature measurements of a demo board in typical LT8636J and LT8636H are guaranteed over the full –40°C to 150°C operating conditions. operating junction temperature range. High junction temperatures degrade operating lifetimes. The LT8636MP is 100% tested and guaranteed over
Note 4:
This IC includes overtemperature protection that is intended to the full –55°C to 150°C operating junction temperature range. Operating protect the device during overload conditions. Junction temperature will exceed 150°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature will reduce lifetime. Rev. C 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Applications Related Parts