Datasheet LT1185 (Analog Devices) - 3

LT1185
ELECTRICAL CHARACTERISTICS The
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denotes specifications which apply over the operating temperature range, otherwise specifications are at TA = 25
°
C. Adjustable version, VIN = 7.4V, VOUT = 5V, IOUT = 1mA, RLIM = 4.02k, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
Load Regulation (Note 7) IOUT = 5mA to 3A 0.05 0.3 % VIN – VOUT = 1.5V to 10V, VOUT = 5V Line Regulation (Note 7) VIN – VOUT = 1V to 20V, VOUT = 5V 0.002 0.01 %/V Minimum Input Voltage IOUT = 1A (Note 4), VOUT = VREF 4.0 V IOUT = 3A 4.3 V Internal Current Limit (See Graph for 1.5V ≤ VIN – VOUT ≤ 10V 3.3 3.6 4.2 A Guaranteed Curve) (Note 12) ● 3.1 4.4 A VIN – VOUT = 15V ● 2.0 3.0 4.2 A VIN – VOUT = 20V ● 1.0 1.7 2.6 A VIN – VOUT = 30V ● 0.2 0.4 1.0 A External Current Limit 5k ≤ RLIM ≤ 15k, VOUT = 1V ● 15k A•Ω Programming Constant (Note 11) External Current Limit Error 1A ≤ ILIM ≤ 3A 0.02 ILIM 0.06 ILIM + 0.03 A RLIM = 15k • A/ILIM ● 0.04 ILIM 0.09 ILIM + 0.05 A Quiescent Supply Current IOUT = 5mA, VOUT = VREF ● 2.5 3.5 mA 4V ≤ VIN ≤ 25V (Note 5) Supply Current Change with Load VIN – VOUT = VSAT (Note 10) ● 25 40 mA/A VIN – VOUT ≥ 2V ● 10 25 mA/A REF Pin Shutoff Current ● 0.4 2 7 µA Thermal Regulation (See Applications VIN – VOUT = 10V 0.005 0.014 %/W Information) IOUT = 5mA to 2A Reference Voltage Temperature Coefficient (Note 8) 0.003 0.01 %/°C Thermal Resistance Junction to Case TO-3 Control Area 1 °C/W Power Transistor 3 °C/W TO-220 Control Area 1 °C/W Power Transistor 3 °C/W
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 6:
The 25W power level is guaranteed for an input-output voltage of may cause permanent damage to the device. Exposure to any Absolute 8.3V to 17V. At lower voltages the 3A limit applies, and at higher voltages Maximum Rating condition for extended periods may affect device the internal power limiting may restrict regulator power below 25W. See reliability and lifetime. graphs.
Note 2:
Reference voltage is guaranteed both at nominal conditions (no
Note 7:
Line and load regulation are measured on a pulse basis with a load, 25°C) and at worst-case conditions of load, line, power and pulse width of ≈ 2ms, to minimize heating. DC regulation will be affected temperature. An intermediate value can be calculated by adding the effects by thermal regulation and temperature coefficient of the reference. See of these variables in the actual application. See the Applications Applications Information section for details. Information section of this data sheet.
Note 8:
Guaranteed by design and correlation to other tests, but not
Note 3:
Dropout voltage is tested by reducing input voltage until the tested. output drops 1% below its nominal value. Tests are done at 0.5A and 3A.
Note 9:
TJMIN = 0°C for the LT1185C, – 40°C for LT1185I, and –55°C for The power transistor looks basically like a pure resistance in this range so the LT1185M. Power transistor area and control circuit area have different that minimum differential at any intermediate current can be calculated by maximum junction temperatures. Control area limits are TJMAX = 125°C for interpolation; VDROPOUT = 0.25V + 0.25Ω • IOUT. For load current less than the LT1185C and LT1185I and 150°C for the LT1185M. Power area limits 0.5A, see graph. are 150°C for LT1185C and LT1185I and 175°C for LT1185M.
Note 4:
“Minimum input voltage” is limited by base emitter voltage drive
Note 10:
VSAT is the maximum specified dropout voltage; of the power transistor section, not saturation as measured in Note 3. For 0.25V + 0.25 • IOUT. output voltages below 4V, “minimum input voltage” specification may limit
Note 11:
Current limit is programmed with a resistor from REF pin to GND dropout voltage before transistor saturation limitation. pin. The value is 15k/ILIM.
Note 5:
Supply current is measured on the ground pin, and does not
Note 12:
For VIN – VOUT = 1.5V; VIN = 5V, VOUT = 3.5V. VOUT = 1V for all include load current, RLIM, or output divider current. other current limit tests. 1185ff 3