Datasheet

OUTPUT VOLTAGE
PROGRAMMING GUIDE
OUTPUT
VOLTAGE
R1 R2 C1
GND
FB
IN OUT
EN
V
IN
V
OUT
R1
C1
R2
TPS79601
1 µF
1.8 V
3.6V
14.0 kΩ
57.9 kΩ
30.1 kΩ
30.1 kΩ
33 pF
15 pF
2.2 µF
C1 +
(3 x 10
–7
) x (R1 ) R2)
(R1 x R2)
R1 +
ǒ
V
OUT
V
REF
*1
Ǔ
R2
TPS796
SLVS351O –SEPTEMBER 2002–REVISED NOVEMBER 2013 www.ti.com
The recommended design procedure is to choose Regulator Protection
R2 = 30.1kΩ to set the divider current at 40μA, C1 =
The TPS796xx PMOS-pass transistor has a built-in
15pF for stability, and then calculate R1 using
back diode that conducts reverse current when the
Equation 2:
input voltage drops below the output voltage (for
example, during power-down). Current is conducted
from the output to the input and is not internally
(2)
limited. If extended reverse voltage operation is
anticipated, external limiting might be appropriate.
In order to improve the stability of the adjustable
version, it is suggested that a small compensation
The TPS796xx features internal current limiting and
capacitor be placed between OUT and FB. The
thermal protection. During normal operation, the
approximate value of this capacitor can be calculated
TPS796xx limits output current to approximately 2.8A.
as Equation 3:
When current limiting engages, the output voltage
scales back linearly until the overcurrent condition
ends. While current limiting is designed to prevent
(3)
gross device failure, care should be taken not to
The suggested value of this capacitor for several
exceed the power dissipation ratings of the package.
resistor ratios is shown in the table in Figure 23. If
If the temperature of the device exceeds
this capacitor is not used (such as in a unity-gain
approximately +165°C, thermal-protection circuitry
configuration) then the minimum recommended
shuts it down. Once the device has cooled down to
output capacitor is 2.2μF instead of 1μF.
below approximately +140°C, regulator operation
resumes.
Figure 23. TPS79601 Adjustable LDO Regulator Programming
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