LT1129 Linear Technology, LT1129 Datasheet
LT1129
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LT1129 Summary of contents
Page 1
... The quiescent current does not rise in dropout as it does with many other low dropout PNP regulators. Other features of the LT1129 /LT1129-3.3/LT1129-5 in- clude the ability to operate with small output capacitors. They are stable with only 3 the output while most older devices require between 10 F and 100 F for stabil- ity ...
Page 2
... Storage Temperature Range ................ – 150 C Operating Junction Temperature Range (Note 2) LT1129C-X ......................................... 125 C LT1129C-X Extended Temperature Range (Note 11) ....................................... – 125 C LT1129I-X ..................................... – 125 C Lead Temperature (Soldering, 10 sec).................. 300 C * For applications requiring input voltage ratings greater than 30V, contact the factory. ...
Page 3
... Note 10: Reverse output current is tested with the input pin grounded. The output pin and the sense pin are forced to the rated output voltage. This current flows into the sense pin and out of the ground pin. For the LT1129 (adjustable version) the sense pin is internally tied to the ...
Page 4
... Quiescent Current OPEN (HI) SHDN SHDN 10 0 125 50 100 –50 – TEMPERATURE (°C) 1129 G10 LT1129 Quiescent Current 250 = 0 225 = 200 175 150 V = OPEN (HI) SHDN 125 100 SHDN ...
Page 5
... LOAD I = 300mA* LOAD 10 *For V = 3.3V OUT INPUT VOLTAGE (V) 1129 G21 Ground Pin Current 3.3V (LT1129-3. (LT1129- 3.75V (LT1129) IN DEVICE IS OPERATING 50 IN DROPOUT T = 125° 25° –50° 0.1 0.2 0.3 0.4 0.5 0.6 0.7 OUTPUT CURRENT (A) 1129 G15 LT1129/LT1129-3 ...
Page 6
... TEMPERATURE (°C) 1129 G25 Reverse Output Current (LT1129-5) OUT SENSE 3.3V (LT1129-3.3) OUT SENSE 3.75V (LT1129) OUT ADJ –50 – 100 125 TEMPERATURE (°C) 1129 G29 Reverse Output Current 100 T = 25°C, V ...
Page 7
... In the case of a reversed input, which can happen if a battery is plugged in backwards, the LT1129 will act as if there is a diode in series with its input. There will be no reverse current flow into the LT1129 and no reverse voltage will appear at the load ...
Page 8
... The device is protected against reverse input voltages. In battery backup applications where the output can be held backup battery when the input is pulled to ground, the LT1129 acts like it has a diode in series with its output and prevents reverse current flow. Adjustable Operation The adjustable version of the LT1129 has an output voltage range of 3 ...
Page 9
... Ground Pin Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the two components listed above. The LT1129 series regulators have internal thermal limit- ing designed to protect the device during overload condi- tions. For continuous normal load conditions the maxi- mum junction temperature rating of 125 C must not be exceeded ...
Page 10
... 37 87.2 C JMAX Output Capacitance and Transient Performance The LT1129 is designed to be stable with a wide range of output capacitors. The minimum recommended value is 3.3 F with an ESR less. The LT1129 is a micropower device and output transient response will be a function of output capacitance ...
Page 11
... When the input of the LT1129 is forced to a voltage below its nominal output voltage and its output is held high, the output current will follow the curve shown in Figure 6 . This Table 4 ...
Page 12
... LT1129/LT1129-3.3/LT1129-5 PACKAGE DESCRIPTIO 0.401 ± 0.015 0.060 (10.185 ± 0.381) (1.524) 15° TYP +0.012 0.331 –0.020 +0.305 8.407 –0.508 0.067 ± 0.010 +0.012 (1.702 ± 0.254) 0.143 –0.020 0.032 ± 0.008 +0.305 3.632 (0.813 ± 0.203) –0.508 10° ...