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LTC1773 3 1773fb Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC1773 is guaranteed to meet performance specifications from 0 °C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: TJis calculated from the ambient temperature TAand power dissipation PD according to the following formula: LTC1773: TJ = TA + (PD • 120°C/W) Note 4: The LTC1773 is tested in a feedback loop which servos VFB to the balance point for the error amplifier (VITH = 0.8V) Note 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. Note 6: Rise and fall times are measured using 10% and 90% levels. ELECTRICAL CHARACTERISTICS TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Input Voltage Efficiency vs Load Current Efficiency vs Load Current Load Regulation VIN-VOUT Dropout Voltage vs Load Current Input and Shutdown Currents vs Input Voltage OUTPUT CURRENT (mA) 1 1773 G01 10 100 1000 5000 100 90 80 70 60 50 FORCED CONTINUOUS VIN = 5V VOUT = 2.5V SEE FIGURE 1 Burst Mode OPERATION SYNC(750kHz) INPUT VOLTAGE (V) 100 95 90 85 80 75 24 6 8 1773 G03 10 VOUT = 2.5V SEE FIGURE 1 IOUT = 100mA IOUT = 1A LOAD CURRENT (mA) 0 400 350 300 250 200 150 100 50 0 2000 1773 G05 500 1000 1500 2500 RSENSE = 0.025Ω VOUT = 1.8V Si9801DY INPUT VOLTAGE (V) 2 10 1773 G06 4 6 8 500 450 400 350 300 250 200 150 100 50 0 SYNC TO 750kHz Burst Mode OPERATION SHUTDOWN VOUT = 1.8V Si9801DY RSENSE = 0.025Ω L = CDRH6D28-3RO OUTPUT CURRENT (mA) 1 100 90 80 70 60 50 1773 G02 10 100 1000 VOUT = 2.5V SEE FIGURE 1 VIN = 5V VIN = 3.3V VIN = 8V 10,000 LOAD CURRENT (A) 0 0 – 0.05 – 0.10 – 0.15 – 0.20 – 0.25 – 0.30 1.5 2.5 1773 G16 0.5 1.0 2.0 3.0 3.5 RSENSE = 0.025Ω SEE FIGURE 1 |
