LOW DROPOUT
REGULATOR
Austin Semiconductor, Inc.
AS1185
ABSOLUTE MAXIMUM RATINGS1
InputVoltage ..................................................................................................................................................................................................... 35V
Input-Output Differential ................................................................................................................................................................................. 30V
FBVoltage .......................................................................................................................................................................................................... 7V
REFVoltage ........................................................................................................................................................................................................ 7V
OutputVoltage .................................................................................................................................................................................................. 30V
Output ReverseVoltage .................................................................................................................................................................................. 2V
OperatingAmbient Temperature Range
AS1185M ........................................................................................................................................................................... -55°C to 125°C
Operating Junction Temperature Range
Control Section
AS1185/IT ......................................................................................................................................................................... –40°C to 125°C
AS1185M/XT and /Mil .................................................................................................................................................. –55°C to 150°C
Power Transistor Section
AS1185/IT ........................................................................................................................................................................ –40°C to 150°C
AS1185M/XT and /MIL.................................................................................................................................................. –55°C to 175°C
StorageTemperature Range .......................................................................................................................................................... –65°C to 150°C
LeadTemperature (Soldering, 10 sec)........................................................................................................................................................... 300°C
Theta J/C................................................................................................................................................................................................8.11°C/W
Max Power Dissipation (Tc = +125°C).......................................................................................................................................................3.0W
NOTES:
1. Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only
and functional operation of the device at these or any other conditions above those indicated in the operation section of this specification is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
2. Reference voltage is quaranteed both at nominal conditions (no load, 25°C) and at worst-case conditions of load, line, power, and temperature.
An intermediate value can be calculated by adding the effects of these variables in the actual application.
3. Dropout voltage is tested by reducing input voltage until the output drops 1% below its nominal value. Tests are done at 0.5A and 2.7A. The
power transistor looks basically like a pure resistance in this range so that minimum differential at any intermediate current can be calculated by
interpolation; VDROPOUT = 0.25V + 0.25W • IOUT
. For load current less than 0.5A, see graph.
4. “Minimum input voltage” is limited by base emitter voltage drive of the power transistor section, not saturation as measured in Note 3. For
output voltages below 4V, “minimum input voltage” specification may limit dropout voltage before transistor saturation limitation.
5. Supply current is measured on the ground pin, and does not include load current, RLIM, or output divider current.
6. The 25W power level is guaranteed for an input-output voltage of 8.3V to 17V. At lower voltages the 2.7A limit applies, and at higher voltages
the internal power limiting may restrict regulator power below 25W. See graphs.
7. Line and load regulation are measured on a pulse basis with a pulse width of »2ms, to minimize heating. DC regulation will be affected by thermal
regulation and temperature coefficient of the reference.
8. Guaranteed by design and correlation to other tests, but not tested.
9. TJMIN
= – 40°C for AS1185I and –55°C for the AS1185M. Power transistor area and control circuit area have different maximum junction
temperatures. Control area limits are TJMAX = 125°C for the LT1185C and LT1185I and 150°C for the LT1185M. Power area limits are 150°C for
AS1185I and 175°C for AS1185M.
10. VSAT is the maximum specified dropout voltage; 0.25V + 0.25 • IOUT
.
11. Current limit is programmed with a resistor from REF pin to GND pin. The value is 15k/ILIM
12. For VIN – VOUT = 1.5V; VIN = 5V, VOUT = 3.5V. VOUT = 1V for all other current limit tests.
.
AS1185
AustinSemiconductor,Inc.reservestherighttochangeproductsorspecificationswithoutnotice.
Rev. 1.1 6/05
2
AUSTIN [ AUSTIN SEMICONDUCTOR ]
