R

1

+

V

OUT

V

REF

*1

R

2

(2)

IN

EN

FB/NC

OUT

RESET

RESET Output

GND

+

C

OUT

10 F

m

V

OUT

V

IN

250kW

TPS767D301

0.1 F

m

R

2

R

1

>2.7V

<0.5V

OUTPUTVOLTAGE

PROGRAMMINGGUIDE

2.5V

3.3V

3.6V

4.75V

33.2

53.6

61.9

90.8

30.1

30.1

30.1

30.1

R

2

R

1

OUTPUT

VOLTAGE

UNIT

kW

kW

kW

kW

RESET INDICATOR

REGULATOR PROTECTION

TPS767D3xx

SLVS209H – JULY 1999 – REVISED AUGUST 2008......................................................................................................................................................... www.ti.com

The recommended design procedure is to choose R2 = 30.1 kΩ to set the divider current at 40µA and then

calculate R1 using:

Figure 26. TPS767D301 Adjustable LDO Regulator Programming

The TPS767D3xx features a RESET output that can be used to monitor the status of the regulator. The internal

comparator monitors the output voltage: when the output drops to 95% (typical) of its regulated value, the

RESET output transistor turns on, taking the signal low. The open-drain output requires a pullup resistor. If not

used, it can be left floating. RESET can be used to drive power-on reset circuitry or as a low-battery indicator.

The TPS767D3xx PMOS-pass transistor has a built-in back-gate diode that safely conducts reverse currents

when the 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 limited. When extended reverse voltage is anticipated, external

limiting may be appropriate.

The TPS767D3xx also features internal current limiting and thermal protection. During normal operation, the

TPS767D3xx limits output current to approximately 1.7A. When current limiting engages, the output voltage

scales back linearly until the overcurrent condition ends. While current limiting is designed to prevent gross

device failure, care should be taken not to exceed the power dissipation ratings of the package. If the

temperature of the device exceeds +150°C (typ), thermal-protection circuitry shuts it down. Once the device has

cooled below +130°C (typ), regulator operation resumes.

12

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