LT3745-1 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 5: The SYNC frequency must be higher than the RT programmed may cause permanent damage to the device. Exposure to any Absolute oscillator frequency, and is suggested to be around 20% higher. Any SYNC Maximum Rating condition for extended periods may affect device frequency higher than the suggested value may introduce sub-harmonic reliability and lifetime. oscillation in the converter due to insufficient slope compensation. See Note 2: The LT3745E-1 is guaranteed to meet performance specifications Application Information section. from 0°C to 125°C junction temperature. Specifications over the –40°C Note 6: The current mismatch between channels is calculated as to 125°C operating junction temperature range are assured by design, Equation 1 in Table 1. characterization and correlation with statistical process controls. The Note 7: The current mismatch between devices is calculated as LT3745I-1 is guaranteed over the full –40°C to 125°C operating junction Equations 2 and 3 in Table 1. temperature range. Note 8: The LED current line regulation is calculated as Equation 4 in Note 3: This IC includes thermal shutdown protection that is intended Table 1. to protect the device during momentary overload conditions. Junction Note 9: The LED current load regulation is calculated as Equation 5 in temperature will exceed 125°C when thermal shutdown protection is Table 1. active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 10: The specifications of single-ended input SI apply to the LDI pin. Note 4: The V Note 11: The specifications of differential inputs DI+/DI– apply to SCKI+/ CC supply current with LED channel on highly depends on the LED current setting and LEDxx pin voltage; its test condition is SCKI–, SDI+/SDI– and PWMCK+/PWMCK–; the specifications of differential R outputs DO+/DO– apply to SCKO+/SCKO– and SDO+/SDO–. The parameters ISET = 60.4k, REGDC = 0x3F, REGGS = 0xFFF, VISP = VISN = 5V, V VID, VCM, VOD and VOS are defined in Equations 6 to 9 and measured in the LEDxx = 1V. The VCC supply current with serial data interface on highly depends on V Parameter Test Setup. CC supply voltage, SCKI+/SCKI– clock frequency, SCKO+/SCKO–, SDO+/SDO– loading capacitance, and PWMCK+/PWMCK– clock frequency; its test condition is VCC = 3.3V, fSCKI+/SCKI– = 30MHz, CSCKO+/SCKO– = CSDO+/SDO– = 15pF, fPWMCK+/PWMCK– = 409.6KHz. Parameter Test Setup CL DO+ D RL DO– CL 37451 PT 37451f 6 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Timing Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Package Description Typical Application Related Parts