Operating Region and Power Dissipation

The maximum power dissipation depends on the ther-

mal resistance of the IC package and circuit board, the

temperature difference between the die junction and

ambient air, and the rate of airflow. The power dissipat-

The package features an exposed thermal pad on its

underside. This pad lowers the thermal resistance of

the package by providing a direct heat conduction

path from the die to the PCB.

Additionally, the ground pins (GND) perform the dual

function of providing an electrical connection to system

ground and channeling heat away. Connect the

exposed backside pad and GND to the system ground

using a large pad or ground plane, or multiple vias to

the ground plane layer.

Applications Information

Capacitor Selection and

Regulator Stability

Capacitors are required at the MAX8516/MAX8517/

MAX8518 inputs and outputs for stable operation over the

full temperature range and with load currents up to 1A.

Connect a 1µF capacitor between IN and ground and a

4.7µF capacitor with low equivalent series resistance

(ESR) between OUT and ground for 1A output current.

the input supply. If input-supply source impedance is

high, place a larger input capacitor close to IN to prevent

itors can be used for output currents less than 1A.

Noise, PSRR, and Transient Response

The MAX8516/MAX8517/MAX8518 are designed to

operate with low dropout voltages and low quiescent

currents while still maintaining good noise, transient

response, and AC rejection (see the

Typical Operating

Characteristics for a plot of Power-Supply Rejection

Ratio (PSRR) vs. Frequency). When operating from

noisy sources, improved supply-noise rejection and

transient response can be achieved by increasing the

values of the input and output bypass capacitors and

through passive filtering techniques. The MAX8516/

MAX8517/MAX8518 load-transient response graphs

(see the

Typical Operating Characteristics) show two

components of the output response: a DC shift from the

output impedance due to the load current change, and

the transient response. A typical transient overshoot for

a step change in the load current from 20mA to 1A is

45mV. Use larger output ceramic capacitors greater

than 4.7µF up to 50µF to attenuate the overshoot.

CI

F

mA

OUT

OUT MAX

()

()

=×

µ

1

200

1.425V to 3.6V Input, 1A,

0.2V Dropout LDO Regulators

8

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