VCTA25201B-R33MS6 datasheet(21/50 Pages) RICHTEK

21 / 50 page

RTQ2134-QA

is a registered trademark of Richtek Technology Corporation.

DSQ2134-QA-02

May

2022

www.richtek.com

value and case size. Most ceramic capacitors lose 50%

or more of their rated values when used near their

rated voltage.

Transient performance can be improved with a higher

value

output

capacitor.

Increasing

the

output

capacitance will also decrease the output voltage

ripple.

The recommended output capacitors are shown in

Typical Application Circuit section.

Thermal Considerations

In many applications, the RTQ2134 does not generate

much heat due to its high efficiency and low thermal

resistance of its WQFN- 30L 4.5x5 package. However,

in applications where the RTQ2134 runs at a high

ambient temperature and high input voltage or high

switching frequency, the generated heat may exceed

the maximum junction temperature of the part.

The junction temperature should never exceed the

absolute maximum junction temperature TJ(MAX), listed

under Absolute Maximum Ratings, to avoid permanent

damage to the device. If the junction temperature

reaches approximately 160°C, the RTQ2134 stops

switching the power MOSFETs until the temperature

cools down by 30°C.

The maximum power dissipation can be calculated by

the following formula :

PD(MAX) = (TJ(MAX)

− TA) /JA(EFFECTIVE)

where

TJ(MAX) is the maximum allowed junction temperature

of the die. For recommended operating condition

specifications, the maximum junction temperature is

125°C. TA is the ambient operating temperature,

JA(EFFECTIVE) is the system-level junction to ambient

thermal resistance. It can be estimated from thermal

modeling or measurements in the system.

The thermal resistance of the device strongly depends

on the surrounding PCB layout and can be improved by

providing a heat sink of surrounding copper ground.

The addition of backside copper with thermal vias,

stiffeners, and other enhancements can also help

reduce thermal resistance.

Experiments in the Richtek thermal lab show that

simply set

JA(EFFECTIVE) as 110% to 120% of the JA

is reasonable to obtain the allowed PD(MAX).

The power loss of system can be found in the efficiency

measurement and the formula below can be used to

determine the power loss of IC by removing the loss of

inductor including DC loss and AC loss.

Two-phase converter power loss :

OUT

loss

OUT

core_loss

= (V

) ((

)

DCR) 2

ACR

2 (

) ) 2

12 L



−



−



−

 −





Single-phase converter power loss :

loss

OUT

core_loss

OUT

= (V

) I

DCR P

ACR

)

12 L



−



−



−



−

 −



Where

Pcore_loss and ACR need to be obtained from inductor

supplier.

Total loss of IC cannot be larger than maximum power

loss. If the application requires a higher ambient

temperature and/or higher switching frequency, care

should be taken to reduce the temperature rise of the

part by using a heat sink or air flow. Note that the

over-temperature protection is intended to protect the

device during momentary overload conditions. The

protection

activated

outside

the

absolute

maximum range of operation as a secondary fail-safe

and therefore should not be relied upon operationally.

Continuous operation above the specified absolute

maximum operating junction temperature may impair

device reliability or permanently damage the device.

Layout Guidelines

When laying out the printed circuit board, the following

checklist should be used to ensure proper operation of

the RTQ2134 :



Four-layer or six-layer PCB with maximum ground

plane is strongly recommended for good thermal

performance.



Keep the traces of the main current paths wide and

short.

VCTA25201B-R33MS6 数据表(PDF) 21 Page - Richtek Technology Corporation

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