link to page 16 link to page 16 LT8640S/LT8643S elecTrical characTerisTics The l denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C.PARAMETERCONDITIONSMINTYPMAXUNITS 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 Output Sink Current in Forced Continuous VFB = 1.01V, L = 6.8µH, RT = 60.4k 0.25 0.6 1.1 A Mode VIN to Disable Forced Continuous Mode VIN Rising 35 37 39 V Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: θ values determined per JEDEC 51-7, 51-12. See the Applications may cause permanent damage to the device. Exposure to any Absolute Information section for information on improving the thermal resistance Maximum Rating condition for extended periods may affect device and for actual temperature measurements of a demo board in typical reliability and lifetime. operating conditions. Note 2: The LT8640SE/LT8643SE is guaranteed to meet performance Note 4: This IC includes overtemperature protection that is intended to specifications from 0°C to 125°C junction temperature. Specifications over protect the device during overload conditions. Junction temperature will the –40°C to 125°C operating junction temperature range are assured by exceed 150°C when overtemperature protection is active. Continuous design, characterization, and correlation with statistical process controls. operation above the specified maximum operating junction temperature The LT8640SI/LT8643SI is guaranteed over the full –40°C to 125°C will reduce lifetime. operating junction temperature range. The junction temperature (TJ, in °C) is calculated from the ambient temperature (TA in °C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD • θJA) where θJA (in °C/W) is the package thermal impedance. 8640sfa 4 For more information www.linear.com/LT8640S Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Applications Related Parts