TPS761 Datasheet, PDF (9/16 Pages) Texas Instruments – TPS76130, TPS76132, TPS76133, TPS76138, TPS76150 LOW-POWER 100-mA LOW-DROPOUT LINEAR REGULATORS

TPS76130, TPS76132, TPS76133, TPS76138, TPS76150
LOW-POWER 100-mA LOW-DROPOUT LINEAR REGULATORS
SLVS178B – DECEMBER 1998 – REVISED MAY 2001
APPLICATION INFORMATION
IN
CI = 1 µF
EN
1
5
TPS761xx
3
2 _GND
OUT
Co = 4.7 µF
over current protection
Figure 17. TPS761xx Typical Application
The over current protection circuit forces the TPS761xx into a constant current output mode when the load is
excessive or the output is shorted to ground. Normal operation resumes when the fault condition is removed.
NOTE:
An overload or short circuit may also activate the over temperature protection if the fault
condition persists.
over temperature protection
The thermal protection system shuts the TPS761xx down when the junction temperature exceeds 160°C. The
device recovers and operates normally when the temperature drops below 150°C.
input capacitor
A 1-µF or larger ceramic decoupling capacitor with short leads connected between IN and GND is
recommended. The decoupling capacitor may be omitted if there is a 1 µF or larger electrolytic capacitor
connected between IN and GND and located reasonably close to the TPS761xx. However, the small ceramic
device is desirable even when the larger capacitor is present, if there is a lot of high frequency noise present
in the system.
output capacitor
Like all low dropout regulators, the TPS761xx requires an output capacitor connected between OUT and GND
to stabilize the internal control loop. The minimum recommended capacitance value is 4.7 µF and the ESR
(equivalent series resistance) must be between 0.1 Ω and 10 Ω. Solid tantalum electrolytic, aluminum
electrolytic, and multilayer ceramic capacitors are all suitable, provided they meet the requirements described
above. Most of the commercially available 4.7-µF surface-mount solid-tantalum capacitors, including devices
from Sprague, Kemet, and Nichicon, meet the ESR requirements stated above. Multilayer ceramic capacitors
should have minimum values of 4.7 µF over the full operating temperature range of the equipment.
enable (EN)
A logic zero on the enable input shuts the TPS761xx off and reduces the supply current to less than 1 µA. Pulling
the enable input high causes normal operation to resume. If the enable feature is not used, EN should be
connected to IN to keep the regulator on all of the time. The EN input must not be left floating.
reverse current path
The power transistor used in the TPS761xx has an inherent diode connected between IN and OUT as shown
in the functional block diagram. This diode conducts current from the OUT terminal to the IN terminal whenever
IN is lower than OUT by a diode drop. This condition does not damage the TPS761xx provided the current is
limited to 150 mA.
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