Low-Noise Operation (MAX8882)

An external 0.01µF bypass capacitor at BP, in conjunc-

tion with an internal resistor, creates a lowpass filter.

Noise Spectral Density graph in the Typical Operating

Characteristics.)

Applications Information

Capacitor Selection and

Regulator Stability

Use a 2.2µF capacitor on the MAX8882/MAX8883 input

and a 2.2µF capacitor on the outputs. Larger input

capacitor values and lower ESRs provide better supply-

noise rejection and line-transient response. To reduce

noise, improve load transients, and for loads up to

160mA, use larger output capacitors (up to 10µF). For

stable operation over the full temperature range and

with load currents up to 80mA, use 2.2µF.

Note that some ceramic dielectrics exhibit large capac-

itance and ESR variation with temperature. With

dielectrics such as Z5U and Y5V, it may be necessary

to use 4.7µF or more to ensure stability at temperatures

below -10°C. With X7R or X5R dielectrics, 2.2µF is suffi-

cient at all operating temperatures. These regulators

are optimized for ceramic capacitors, and tantalum

capacitors are not recommended.

Use a 0.01µF bypass capacitor at BP (MAX8882) for

low output voltage noise. Increasing the capacitance

will slightly decrease the output noise, but increase the

startup time. (See the Shutdown Response graph in the

Typical Operating Characteristics.)

PSRR and Operation from Sources

Other than Batteries

The MAX8882/MAX8883 are designed to deliver low

dropout voltages and low quiescent currents in battery-

powered systems. Power-supply rejection is 62dB at

low frequencies and rolls off above 100kHz. (See the

PSRR vs. Frequency graph in the Typical Operating

Characteristics.)

When operating from sources other than batteries,

improved supply-noise rejection and transient response

can be achieved by increasing the values of the input

and output bypass capacitors and through passive fil-

tering techniques.

Dropout Voltage

A regulator’s minimum input-output voltage differential

(or dropout voltage) determines the lowest usable sup-

ply voltage. In battery-powered systems, this deter-

mines the useful end-of-life battery voltage. Because

the MAX8882/MAX8883 use a P-channel MOSFET pass

transistor, their dropout voltage is a function of drain-to-

current (see the Typical Operating Characteristics).

Chip Information

TRANSISTOR COUNT: 493

PROCESS: BiCMOS

Dual, Low-Noise, Low-Dropout, 160mA Linear

Regulators in SOT23

_______________________________________________________________________________________

7

TOP VIEW

GND

SHDNB

SHDNA

16

OUTA

5

IN

OUTB

MAX8883

SOT23-6

2

34