1.425V to 3.6V Input, 1A,
0.2V Dropout LDO Regulators
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-
ed in the device is P = IOUT ✕ (VIN - VOUT).
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 capacitor (CIN) lowers the source impedance of
the input supply. If input-supply source impedance is
high, place a larger input capacitor close to IN to prevent
VIN sagging due to load transients. Smaller output capac-
itors can be used for output currents less than 1A.
Calculate COUT as follows:
COUT = IOUT(MAX) × (1µF 200mA)
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.
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