9.2.2.6 Input Capacitor Selection

The LMR50410-Q1 device requires a high frequency input decoupling capacitor or capacitor. The typical

recommended value for the high frequency decoupling capacitor is 2.2 µF or higher. A high-quality ceramic type

X5R or X7R with sufficiency voltage rating is recommended. The voltage rating must be greater than the

maximum input voltage. To compensate the derating of ceramic capacitors, a voltage rating of twice the

maximum input voltage is recommended. For this design, one 2.2-µF, X7R dielectric capacitor rated for 50 V is

used for the input decoupling capacitor. The equivalent series resistance (ESR) is approximately 10 mΩ, and the

current rating is 1 A. Include a capacitor with a value of 0.1 µF for high-frequency filtering and place it as close

as possible to the device pins.

9.2.2.7 Bootstrap Capacitor

0.1 µF and rated at 16 V or higher. The bootstrap capacitor is located between the SW pin and the CB pin. The

bootstrap capacitor must be a high-quality ceramic type with X7R or X5R grade dielectric for temperature

stability.

9.2.2.8 Undervoltage Lockout Set-Point

ENT

ENB

IN_RISING

ENH

ENB

R

+ R

V

= V

×

R

(13)

can be calculated using Equation 14:

IN_RISING

ENT

ENB

ENH

V

R

=

- 1 × R

V

§

·

¨

¸

¨

¸

©

¹

(14)

The above equation yields a value of 775.6 kΩ, a standard value of 768 kΩ is selected. The resulting falling

V (typical).

ENT

ENB

IN_FALLING

ENH

EN_HYS

ENB

R

+ R

V

= V

- V

×

R

(15)

9.2.2.9 Maximum Ambient Temperature

As with any power conversion device, the LMR50410-Q1 dissipates internal power while operating. The effect of

this power dissipation is to raise the internal temperature of the converter above ambient. The internal die

limited to 150°C. This establishes a limit on the maximum device power dissipation and, therefore, the load

current. Equation 16 shows the relationships between the important parameters. It is easy to see that larger

converter efficiency can be estimated by using the curves provided in this data sheet. If the desired operating

conditions cannot be found in one of the curves, then interpolation can be used to estimate the efficiency.

Alternatively, the EVM can be adjusted to match the desired application requirements and the efficiency can be

purposes and must not be used to estimate the thermal performance of the application. The values reported in

that table were measured under a specific set of conditions that are rarely obtained in an actual application.

LMR50410-Q1

SLUSDW4 – JULY 2020

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