CS8151YT7G View Datasheet(PDF) - ON Semiconductor

Part Name

Description

Manufacturer

CS8151YT7G

5.0 V, 100 mA Low Dropout Linear Regulator with Watchdog, RESET, and Wake Up

ON Semiconductor 

CS8151

temperatures. The ESR of the capacitor should be less than

50% of the maximum allowable ESR found in step 3 above.

Calculating Power Dissipation

In a Single Output Linear Regulator

The maximum power dissipation for a single output

regulator (Figure 9) is:

PD(max) + (VIN(max) * VOUT(min))IOUT(max) (1)

) VIN(max)IQ

where:

VIN(max) is the maximum input voltage,

VOUT(min) is the minimum output voltage,

IOUT(max) is the maximum output current for the

application, and

IQ is the quiescent current the regulator consumes at

IOUT(max).

Once the value of PD(max) is known, the maximum

permissible value of RqJA can be calculated:

RqJA

+

150°C *

PD

TA

(2)

The value of RqJA can then be compared with those in the

package section of the data sheet. Those packages with

RqJA’s less than the calculated value in equation 2 will keep

the die temperature below 150°C.

IIN

VIN

SMART

REGULATOR®

IOUT

VOUT

} Control

Features

IQ

In some cases, none of the packages will be sufficient to

dissipate the heat generated by the IC, and an external

heatsink will be required.

A heat sink effectively increases the surface area of the

package to improve the flow of heat away from the IC and

into the surrounding air.

Heat Sinks

Each material in the heat flow path between the IC and the

outside environment will have a thermal resistance. Like

series electrical resistances, these resistances are summed to

determine the value of RqJA:

(3)

RqJA + RqJC ) RqCS ) RqSA

where:

RqJC = the junction−to−case thermal resistance,

RqCS = the case−to−heatsink thermal resistance, and

RqSA = the heatsink−to−ambient thermal resistance.

RqJC appears in the package section of the data sheet. Like

RqJA, it too is a function of package type. RqCS and RqSA are

functions of the package type, heatsink and the interface

between them. These values appear in heatsink data sheets

of heatsink manufacturers.

Figure 9. Single Output Regulator with Key

Performance Parameters Labeled

Battery

C1

CDelay

VIN

VOUT

CS8151

WDI

CDelay

RESET

GND Wake Up

VCC

C2

Microprocessor

I/O

RESET

I/O

Figure 10. Application Diagram

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