LT1375/LT1376 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25 ° C. TJ = 25 ° C, VIN = 15V, VC = 1.5V, boost open, switch open,unless otherwise noted.PARAMETERCONDITIONSMINTYPMAXUNITS Shutdown Thresholds VC Open Device Shutting Down ● 0.15 0.37 0.60 V Device Starting Up ● 0.25 0.45 0.60 V VC Open LT1375HV/LT1376HV Device Shutting Down ● 0.15 0.37 0.70 V LT1375HV/LT1376HV Device Starting Up ● 0.25 0.45 0.70 V Minimum Synchronizing Amplitude (LT1375 Only) VIN = 5V ● 1.5 2.2 V Synchronizing Range (LT1375 Only) 580 900 kHz SYNC Pin Input Resistance 40 kΩ Note 1: Stresses beyond those listed under Absolute Maximum Ratings 5V. Total input referred supply current is calculated by summing input may cause permanent damage to the device. Exposure to any Absolute supply current (ISI) with a fraction of output supply current (ISO): Maximum Rating condition for extended periods may affect device ITOT = ISI + (ISO)(VOUT/VIN)(1.15) reliability and lifetime. With VIN = 15V, VOUT = 5V, ISI = 0.9mA, ISO = 3.6mA, ITOT = 2.28mA. Note 2: Gain is measured with a VC swing equal to 200mV above the low For the LT1375, quiescent current is equal to: clamp level to 200mV below the upper clamp level. ITOT = ISI + ISO(1.15) Note 3: Minimum input voltage is not measured directly, but is guaranteed because the BIAS pin is internally connected to V by other tests. It is defined as the voltage where internal bias lines are still IN. For LT1375 or BIAS open circuit, input supply current is the sum of input regulated so that the reference voltage and oscillator frequency remain + output supply currents. constant. Actual minimum input voltage to maintain a regulated output will depend on output voltage and load current. See Applications Information. Note 7: Switch-on resistance is calculated by dividing VIN to VSW voltage by the forced current (1.5A). See Typical Performance Characteristics for Note 4: This is the minimum voltage across the boost capacitor needed to the graph of switch voltage at other currents. guarantee full saturation of the internal power switch. Note 8: Transconductance and voltage gain refer to the internal amplifier Note 5: Boost current is the current flowing into the BOOST pin with the exclusive of the voltage divider. To calculate gain and transconductance pin held 5V above input voltage. It flows only during switch-on time. refer to sense pin on fixed voltage parts. Divide values shown by the ratio Note 6: Input supply current is the bias current drawn by the input pin V when the BIAS pin is held at 5V with switching disabled. Output supply OUT/2.42. current is the current drawn by the BIAS pin when the bias pin is held at WUTYPICAL PERFORMANCE CHARACTERISTICSInductor Core LossSwitch Peak Current LimitFeedback Pin Voltage and Current 1.0 20 2.5 2.44 2.0 VOUT = 5V, VIN = 10V, IOUT = 1A 12 8 CORE LOSS (% OF 5W LOAD) TYPICAL 2.0 4 TYPE 52 2.43 1.5 POWDERED IRON 0.1 2 CURRENT ( GUARANTEED MINIMUM 1.2 1.5 Kool Mµ® 0.8 VOLTAGE 2.42 1.0 0.4 µ PERMALLOY 1.0 A) CORE LOSS (W) 0.01 µ = 125 0.2 CORE LOSS IS CURRENT 0.12 FEEDBACK VOLTAGE (V) INDEPENDENT OF LOAD 2.41 0.5 0.08 SWITCH PEAK CURRENT (A) 0.5 CURRENT UNTIL LOAD CURRENT FALLS LOW ENOUGH FOR CIRCUIT TO GO INTO 0.04 DISCONTINUOUS MODE 0.001 0.02 0 2.40 0 0 5 10 15 20 25 0 20 40 60 80 100 –50 –25 0 25 50 75 100 125 INDUCTANCE (µH) DUTY CYCLE (%) JUNCTION TEMPERATURE (°C) 1375/76 G01 1375/76 G08 1375/76 G09 13756fd 4