Datasheet

TPS7101Q, TPS7133Q, TPS7148Q, TPS7150Q
TPS7101Y, TPS7133Y, TPS7148Y, TPS7150Y
LOW-DROPOUT VOLTAGE REGULATORS
SLVS092G – NOVEMBER 1994 – REVISED JANUARY 2003
27
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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
321
20
15
14
13
V
I
C1
0.1 µF
50 V
PG
ESR
V
O
10 µF
+
TPS71xx
†
C
O
†
TPS7133, TPS7148, TPS7150 (fixed-voltage options)
250 kΩ
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
V
ref
= reference voltage, 1.178 V typ