LM317 datasheet(9/25 Pages) NSC

tên linh kiện	LM317

Giải thích chi tiết về linh kiện	3-Terminal Adjustable Regulator

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Application Hints (Continued)

when either the input or output is shorted. Internal to the

LM117 is a 50

Ω resistor which limits the peak discharge

current. No protection is needed for output voltages of 25V

or less and 10µF capacitance. Figure 3 shows an LM117

with protection diodes included for use with outputs greater

than 25V and high values of output capacitance.

When a value for

θ

(H−A) is found using the equation shown,

a heatsink must be selected that has a value that is less than

or equal to this number.

θ

(H−A) is specified numerically by the heatsink manufacturer

in the catalog, or shown in a curve that plots temperature rise

vs power dissipation for the heatsink.

HEATSINKING TO-263, SOT-223 AND TO-252 PACKAGE

PARTS

The TO-263 (“S”), SOT-223 (“MP”) and TO-252 (”DT”) pack-

ages use a copper plane on the PCB and the PCB itself as

a heatsink. To optimize the heat sinking ability of the plane

and PCB, solder the tab of the package to the plane.

Figure 4 shows for the TO-263 the measured values of

θ

(J−A)

for different copper area sizes using a typical PCB with 1

ounce copper and no solder mask over the copper area used

for heatsinking.

As shown in the figure, increasing the copper area beyond 1

square inch produces very little improvement. It should also

be observed that the minimum value of

θ

(J−A) for the TO-263

package mounted to a PCB is 32˚C/W.

As a design aid, Figure 5 shows the maximum allowable

power dissipation compared to ambient temperature for the

TO-263 device (assuming

θ

(J−A) is 35˚C/W and the maxi-

mum junction temperature is 125˚C).

Figure 6 and Figure 7 show the information for the SOT-223

package. Figure 7 assumes a

θ

(J−A) of 74˚C/W for 1 ounce

copper and 51˚C/W for 2 ounce copper and a maximum

junction temperature of 125˚C.

00906307

D1 protects against C1

D2 protects against C2

FIGURE 3. Regulator with Protection Diodes

00906355

FIGURE 4.

θ

(J−A) vs Copper (1 ounce) Area for the

TO-263 Package

00906356

FIGURE 5. Maximum Power Dissipation vs T

AMB for

the TO-263 Package

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Số phần tương tự - LM317

nhà sản xuất	tên linh kiện	bảng dữ liệu	Giải thích chi tiết về linh kiện
ON Semiconductor	LM317	132Kb / 12P	1.5 A Adjustable Output, Positive Voltage Regulator January, 2002 ??Rev. 3
Tiger Electronic Co.,Lt...	LM317	157Kb / 3P	3-Terminal Positive Adjustable Regulator
List of Unclassifed Man...	LM317	308Kb / 3P	3-TERMINAL 1.5A POSITIVE ADJUSTABLE VOLTAGE REGULATOR
E-Tech Electronics LTD	LM317	255Kb / 5P	HIGH CURRENT 1.3V TO 37V ADJUSTABLE VOLTAGE REGULATOR
STMicroelectronics	LM317	99Kb / 11P	1.2V TO 37V VOLTAGE REGULATOR

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Mô tả tương tự - LM317

nhà sản xuất	tên linh kiện	bảng dữ liệu	Giải thích chi tiết về linh kiện
National Semiconductor ...	LM337L	89Kb / 5P	3-Terminal Adjustable Regulator
Texas Instruments	LM317	1Mb / 32P	[Old version datasheet] 3-Terminal Adjustable Regulator
List of Unclassifed Man...	GM317	352Kb / 8P	3- TERMINAL ADJUSTABLE REGULATOR
Texas Instruments	LM317M	219Kb / 12P	[Old version datasheet] 3-TERMINAL ADJUSTABLE REGULATOR
Texas Instruments	LM317M_0701	369Kb / 14P	[Old version datasheet] 3-TERMINAL ADJUSTABLE REGULATOR
National Semiconductor ...	LM117HV	469Kb / 15P	3-Terminal Adjustable Regulator
Texas Instruments	LM317MQDCYRG4	868Kb / 17P	[Old version datasheet] 3-TERMINAL ADJUSTABLE REGULATOR
Tiger Electronic Co.,Lt...	LM317L	382Kb / 14P	3-TERMINAL ADJUSTABLE REGULATOR
Texas Instruments	LM317M	219Kb / 12P	[Old version datasheet] 3-TERMINAL ADJUSTABLE REGULATOR
National Semiconductor ...	LM317L	918Kb / 16P	3-Terminal Adjustable Regulator

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