TPS76301, TPS76316, TPS76318, TPS76325, TPS76327

TPS76328, TPS76330, TPS76333, TPS76338, TPS76350

LOW POWER 150mA LOW DROPOUT LINEAR REGULATORS

SLVS181H − DECEMBER 1998 − REVISED JANUARY 2004

www.ti.com

13

APPLICATION INFORMATION

external capacitor requirements

Although not required, a 0.047

µF or larger ceramic bypass input capacitor, connected between IN and GND and located

close to the TPS763xx, is recommended to improve transient response and noise rejection. A higher-value electrolytic input

capacitor may be necessary if large, fast-rise-time load transients are anticipated and the device is located several inches

from the power source.

Like all low dropout regulators, the TPS763xx requires an output capacitor connected between OUT and GND to stabilize

the internal loop control. The minimum recommended capacitance value is 4.7

µF and the ESR (equivalent series

resistance) must be between 0.3

Ω and 10 Ω. Capacitor values 4.7 µF or larger are acceptable, provided the ESR is less

than 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 Nichico, meet the ESR requirements stated above.

CAPACITOR SELECTION

PART NO.

MFR.

VALUE

SIZE (H

T494B475K016AS

KEMET

4.7

µF

1.5

Ω

1.9

× 3.5 × 2.8

195D106x0016x2T

SPRAGUE

10

µF

1.5

Ω

1.3

× 7.0 × 2.7

695D106x003562T

SPRAGUE

10

µF

1.3

Ω

2.5

× 7.6 × 2.5

TPSC475K035R0600

AVX

4.7

µF

0.6

Ω

2.6

× 6.0 × 3.2

(1) Size is in mm. ESR is maximum resistance in ohms at 100 kHz and TA = 25°C. Listings are sorted by height.

output voltage programming

The output voltage of the TPS76301 adjustable regulator is programmed using an external resistor divider as shown in

Figure 21. The output voltage is calculated using:

V

O +

0.995

V

ref

1

) R1

R2

(1)

Where:

0.995 is a constant used to center the load regulator (1%)

Resistors R1 and R2 should be chosen for approximately 7-

µA divider current. Lower value resistors can be used but offer

no inherent advantage and waste more power. Higher values should be avoided as leakage currents at FB increase the

output voltage error. The recommended design procedure is to choose R2 = 169 k

Ω to set the divider current at 7 µA and

then calculate R1 using:

R1

+

V

O

0.995

V

ref

* 1

R2

(2)