Datasheet LT3431 (Analog Devices) - 3

LT3431
ELECTRICAL CHARACTERISTICS The
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denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25
°
C. VIN = 15V, VC = 1.5V, SHDN = 1V, BOOST open circuit, SW open circuit, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage (Note 3) ● 4.6 5.5 V Minimum Boost Voltage (Note 4) ISW ≤ 2.5A ● 1.8 3 V Boost Current (Note 5) BOOST = VIN + 5V, ISW = 0.75A ● 25 50 mA BOOST = VIN + 5V, ISW = 2.5A ● 75 120 mA Input Supply Current (IVIN) (Note 6) VBIAS = 5V 1.5 2.2 mA Bias Supply Current (IBIAS) (Note 6) VBIAS = 5V 3.1 4.2 mA Shutdown Supply Current SHDN = 0V, VIN ≤ 60V, SW = 0V, VC Open 30 100 µA ● 200 µA Lockout Threshold VC Open, ● 2.30 2.42 2.53 V Shutdown Thresholds VC Open, Shutting Down ● 0.15 0.37 0.58 V VC Open, Starting Up ● 0.25 0.42 0.6 V Minimum SYNC Amplitude ● 1.5 2.2 V SYNC Frequency Range 580 700 kHz SYNC Input Resistance 20 kΩ
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 7:
Switch on resistance is calculated by dividing VIN to SW voltage by of a device may be impaired. the forced current (3A). See Typical Performance Characteristics for the
Note 2:
Gain is measured with a V graph of switch voltage at other currents. C swing equal to 200mV above the low clamp level to 200mV below the upper clamp level.
Note 8:
The LT3431EFE is guaranteed to meet performance specifications
Note 3:
Minimum input voltage is not measured directly, but is guaranteed from 0°C to 125°C junction temperature. Specifications over the –40°C to by other tests. It is defined as the voltage where internal bias lines are still 125°C operating junction temperature range are assured by design, regulated so that the reference voltage and oscillator remain constant. characterization and correlation with statistical process controls. The Actual minimum input voltage to maintain a regulated output will depend LT3431IFE is guaranteed over the full –40°C to 125°C operating junction upon output voltage and load current. See Applications Information. temperature range.
Note 4:
This is the minimum voltage across the boost capacitor needed to
Note 9:
See Typical Performance Graph of Peak Switch Current Limit vs guarantee full saturation of the internal power switch. Junction Temperature.
Note 5:
Boost current is the current flowing into the BOOST pin with the
Note 10.
This IC includes overtemperature protection that is intended to pin held 5V above input voltage. It flows only during switch on time. protect the device during momentary overload conditions. Junction
Note 6:
Input supply current is the quiescent current drawn by the input temperature will exceed 125°C when overtemperature protection is active. pin when the BIAS pin is held at 5V with switching disabled. Bias supply Continuous operation above the specified maximum operating junction current is the current drawn by the BIAS pin when the BIAS pin is held at temperature may impair device reliability. 5V. Total input referred supply current is calculated by summing input supply current (IVIN) with a fraction of bias supply current (IBIAS): ITOTAL = IVIN + (IBIAS)(VOUT/VIN) With VIN = 15V, VOUT = 5V, IVIN = 1.5mA, IBIAS = 3.1mA, ITOTAL = 2.5mA. sn3431 3431fs 3