5V/3.3V or Adjustable, Low-Dropout,

12

______________________________________________________________________________________

The filter capacitor’s size depends primarily on the

desired power-up time and load-transient responses.

Load-transient response is improved by using larger

output capacitors.

The output capacitor’s equivalent series resistance

(ESR) will not affect stability as long as the minimum

capacitance requirement is observed. The type of

capacitor selected is not critical, but it must remain

above the minimum value over the full operating temper-

ature range.

Input Bypass Capacitor

Normally, use 0.1µF to 10µF capacitors on the MAX882/

MAX883/MAX884 input. The best value depends pri-

and line transients. Larger input capacitor values pro-

vide better supply-noise rejection and line-transient

response, as well as improved performance, when the

supply has a high AC impedance. The type of input

bypass capacitor used is not critical.

Noise

noise during normal operation. This is negligible in

most applications. When using the MAX882/MAX883/

MAX884 for applications that include analog-to-digital

converters (ADCs) with resolutions greater than 12 bits,

consider the ADC’s power-supply rejection specifica-

tions. See the output noise plot in the Typical Operating

Characteristics section.

PSRR and Operation from

Sources Other than Batteries

The MAX882/MAX883/MAX884 are designed to

achieve low dropout voltages and low quiescent cur-

rents in battery-powered systems. However, to gain

these benefits, the devices must trade away power-

supply noise rejection, as well as swift response to sup-

ply variations and load transients. For a 1mA load

current, power-supply rejection ranges from 60dB

down to 20dB at 2kHz. At higher frequencies, the cir-

cuit depends primarily on the characteristics of the out-

put capacitor, and the PSRR increases (Figure 8).

0

60

50

40

30

20

10

FREQUENCY (Hz)

μF

μF

μF

A

B

C

MAX883

μF

0

80

70

60

50

40

30

20

10

FREQUENCY (Hz)

MAX884

μF

μF

Figure 8b. Power-Supply Rejection Ratio vs. Ripple Frequency

for Various Output Capacitances

Figure 8a. Power-Supply Rejection Ratio vs. Ripple Frequency

for Light and Heavy Loads