TPS7101Q, TPS7133Q, TPS7148Q, TPS7150Q

TPS7101Y, TPS7133Y, TPS7148Y, TPS7150Y

LOW-DROPOUT VOLTAGE REGULATORS

SLVS092G – NOVEMBER 1994 – REVISED JANUARY 2003

27

POST OFFICE BOX 655303

APPLICATION INFORMATION

external capacitor requirements (continued)

As with most LDO regulators, the TPS71xx family requires an output capacitor for stability. A 10-

µF

solid-tantalum capacitor connected from the regulator output to ground is sufficient to ensure stability over the

full load range (see Figure 43). Adding high-frequency ceramic or film capacitors (such as power-supply bypass

capacitors for digital or analog ICs) can cause the regulator to become unstable unless the ESR of the tantalum

capacitor is less than 1.2

Ω over temperature. Where component height and/or mounting area is a problem,

physically smaller, 10-

µF devices can be screened for ESR. Figures 34 through 41 show the stable regions of

operation using different values of output capacitance with various values of ceramic load capacitance.

In applications with little or no high-frequency bypass capacitance (< 0.2

µF), the output capacitance can be

reduced to 4.7

µF, provided ESR is maintained between the values shown in figures 34 through 41. Because

minimum capacitor ESR is seldom if ever specified, it may be necessary to add a 0.5-

Ω to 1-Ω resistor in series

with the capacitor and limit ESR to 1.5

Ω maximum.

SENSE

PG

OUT

OUT

9

8

6

10

IN

IN

IN

EN

GND

3

2

1

20

15

14

13

VI

C1

0.1

µF

50 V

PG

ESR

VO

10

µF

+

TPS71xx†

CO

† TPS7133, TPS7148, TPS7150 (fixed-voltage options)

250 k

Ω

Figure 43. Typical Application Circuit

programming the TPS7101 adjustable LDO regulator

Programming the adjustable regulators is accomplished using an external resistor divider as shown in

Figure 44. The equation governing the output voltage is:

V

O +

V

ref @

1

) R1

R2

where