LMS8117AMP-1.8/NOPB - NATIONAL SEMICONDUCTOR

10 F

Tantalum

INPUT

LMS8117A

OUTPUT

10 F

Tantalum

m(1) GND

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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LMS8117A

SNOS487F –MAY 2004–REVISED DECEMBER 2016

LMS8117A 1-A Low-Dropout Linear Regulator

1 Features

1• Available in 1.8-V, 3.3-V, and Adjustable Versions

• Space-Saving SOT-223 and TO-252 Packages

• Current Limiting and Thermal Protection

• Output Current: 1 A

• Temperature Range: 0°C to 125°C

• Line Regulation: 0.2% (Maximum)

• Load Regulation: 0.4% (Maximum)

2 Applications

• Post Regulator for Switching DC-DC Converters

• High Efficiency Linear Regulators

• Battery Chargers

• Battery-Powered Instrumentation

3 Description

The LMS8117A device is a series of low-dropout

voltage regulators with a dropout of 1.2 V at 1 A of

load current. The device has the same pinout as the

LM317.

The LMS8117A is available in an adjustable version,

which can set the output voltage from 1.27 V to

13.8 V with only two external resistors. In addition,

the device is also available in two fixed voltages,

1.8 V and 3.3 V.

The LMS8117A offers current limiting and thermal

shutdown. The device circuit includes a Zener

trimmed band-gap reference to assure output voltage

accuracy to within ±1%.

The LMS8117A is available in SOT-223 and TO-252

D-PAK packages. A 10-µF (minimum) tantalum

capacitor is required at the output to improve the

transient response and stability.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)

LMS8117A SOT-223 (4) 3.50 mm × 6.50 mm

TO-252 (3) 6.10 mm × 6.58 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Functional Block Diagram

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Table of Contents

1 Features.................................................................. 1

2 Applications ........................................................... 1

3 Description............................................................. 1

4 Revision History..................................................... 2

5 Pin Configuration and Functions......................... 3

6 Specifications......................................................... 3

6.1 Absolute Maximum Ratings ...................................... 3

6.2 ESD Ratings.............................................................. 3

6.3 Recommended Operating Conditions....................... 4

6.4 Thermal Information.................................................. 4

6.5 Electrical Characteristics........................................... 4

6.6 Typical Characteristics.............................................. 5

7 Detailed Description.............................................. 7

7.1 Overview................................................................... 7

7.2 Functional Block Diagram......................................... 7

7.3 Feature Description................................................... 7

7.4 Device Functional Modes.......................................... 8

8 Application and Implementation .......................... 9

8.1 Application Information.............................................. 9

8.2 Typical Applications .................................................. 9

9 Power Supply Recommendations...................... 13

10 Layout................................................................... 14

10.1 Layout Guidelines ................................................. 14

10.2 Layout Example .................................................... 14

10.3 Thermal Considerations........................................ 15

11 Device and Documentation Support................. 19

11.1 Documentation Support ........................................ 19

11.2 Receiving Notification of Documentation Updates 19

11.3 Community Resources.......................................... 19

11.4 Trademarks........................................................... 19

11.5 Electrostatic Discharge Caution............................ 19

11.6 Glossary................................................................ 19

12 Mechanical, Packaging, and Orderable

Information........................................................... 19

4 Revision History

NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

Changes from Revision E (April 2005) to Revision F Page

• Added Device Information table, Pin Configuration and Functions section, Specifications section, ESD Ratings table,

Recommended Operating Conditions table, Detailed Description section, Application and Implementation section,

Power Supply Recommendations section, Layout section, Device and Documentation Support section, and

Mechanical, Packaging, and Orderable Information section.................................................................................................. 1

• Deleted Ordering Information table; see Package Option Addendum at the end of the data sheet...................................... 1

• Deleted Soldering information from Absolute Maximum Ratings table.................................................................................. 3

• Added Thermal Information table........................................................................................................................................... 4

• Changed Junction-to-ambient, RθJA, values in Thermal Information table From: 136°C/W To: 61.4°C/W (SOT-223)

and From: 92°C/W To: 56.1°C/W(TO-252) ............................................................................................................................ 4

• Changed Junction-to-case, RθJC(top), values in Thermal Information table From: 15°C/W To: 43°C/W (SOT-223) and

From: 10°C/W To: 42.8°C/W (TO-252) .................................................................................................................................. 4

• Deleted duplicate paragraph from Output Voltage section................................................................................................... 10

OUTPUT

Not to scale

1ADJUST or GND

2OUTPUT

3INPUT

1ADJUST or GND

2OUTPUT

3INPUT

4 OUTPUT

Not to scale

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5 Pin Configuration and Functions

DCY Package

3-Pin SOT-223

Top View

NDP Package

3-Pin TO-252

Top View

Pin Functions

PIN I/O DESCRIPTION

NAME SOT-223 TO-252

ADJUST or 1 1 — Adjust pin for adjustable output version.

GND Ground pin for fixed output versions.

INPUT 3 3 I Input voltage (VI) pin for the regulator.

OUTPUT 2, Tab (4) 2, Tab O Output voltage (VO) pin for the regulator.

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended

Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and

specifications.

(3) The maximum power disspation is a function of TJ(MAX), RθJA, and TA. The maximum allowable power dissipation at any ambient

temperature is PD= (TJ(MAX) – TA) / RθJA. All numbers apply for packages soldered directly onto a PCB.

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)

MIN MAX UNIT

Maximum input voltage (all versions), VIN 20 V

Power dissipation(3) Internally limited

Junction temperature, TJ(MAX) 150 °C

Storage temperature, Tstg –65 150 °C

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

(2) For testing purposes, ESD was applied using human body model, 1.5-kΩresistor in series iwth 100-pF capacitor.

6.2 ESD Ratings VALUE UNIT

V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)(2) ±2000 V

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6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT

Input voltage (all versions) 15 V

Junction temperature, TJ0 125 °C

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report.

6.4 Thermal Information

THERMAL METRIC(1) LMS8117A

UNITDCY (SOT-223) NDP (TO-252)

4 PINS 3 PINS

RθJA Junction-to-ambient thermal resistance 61.4 56.1 °C/W

RθJC(top) Junction-to-case (top) thermal resistance 43 42.8 °C/W

RθJB Junction-to-board thermal resistance 10 29.4 °C/W

ψJT Junction-to-top characterization parameter 2.4 5.4 °C/W

ψJB Junction-to-board characterization parameter 9.9 28.9 °C/W

RθJC(bot) Junction-to-case (bottom) thermal resistance — 4.1 °C/W

(1) Line and load regulation are measured at constant junction room temperature.

(2) The dropout voltage is the input and output differential at which the circuit ceases to regulate against further reduction in input voltage. It

is measured when the output voltage drops 100 mV from the nominal value obtained by VIN = VOUT + 1.5 V.

(3) The minimum output current required to maintain regulation.

6.5 Electrical Characteristics

Typical values apply for TJ= 25°C and Minimum and Maximum limits apply for TJ= 0°C to 125°C (unless otherwise noted).

Typical values represent the most likely parametric norm. All limits are guaranteed using by testing or statistical analysis.

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

VREF Reference voltage Adjustable version IOUT = 10 mA, VIN – VOUT = 2 V, TJ= 25°C 1.238 1.25 1.262 V

IOUT = 10 mA to 1 A, VIN – VOUT = 1.4 V to 10 V 1.225 1.27

VOUT Output voltage

1.8-V version IOUT = 10 mA, VIN = 3.8 V, TJ= 25°C 1.782 1.8 1.818

IOUT = 0 A to 1 A, VIN = 3.2 V to 10 V 1.746 1.854

3.3-V version IOUT = 10 mA, VIN = 5 V, TJ= 25°C 3.267 3.3 3.333

IOUT = 0 A to 1 A, VIN = 4.75 V to 10 V 3.235 3.365

ΔVOUT

Line regulation(1) Adjustable version, IOUT = 10 mA, VIN – VOUT = 1.5 V to 13.75 V 0.035% 0.2%

1.8-V version, IOUT = 0 mA, VIN = 3.2 V to 10 V 1 6 mV

3.3-V version, IOUT = 0 mA , VIN = 4.75 V to 15 V 1 6

Load regulation(1) Adjustable version, IOUT = 10 mA to 1 A, VIN – VOUT = 3 V 0.2% 0.4%

1.8-V version, IOUT = 0 mA to 1 A, VIN = 3.2 V 1 10 mV

3.3-V version, IOUT = 0 mA to 1 A, VIN = 4.75 V 1 10

VIN – VOUT Dropout voltage(2) IOUT = 100 mA 1.1 1.15

VIOUT = 500 mA 1.15 1.2

IOUT = 1 A 1.1 1.25

ILIMIT Current limit VIN – VOUT = 5 V, TJ= 25°C 1 1.4 1.9 A

Minimum load current(3) Adjustable version, VIN = 15 V 1.7 5 mA

Quiescent current 1.8-V and 3.3-V versions, VIN ≤15 V 5 10 mA

Thermal regulation 30-ms pulse, TA= 25°C 0.01% 0.1% W

Ripple regulation fRIPPLE = 120 Hz, VIN – VOUT = 3 V, VRIPPLE = 1 VPP 60 75 dB

ADJUST pin current 60 120 µA

ADJUST pin current

change IOUT = 10 mA to 1 A, VIN – VOUT = 1.4 V to 10 V 0.2 5 µA

Temperature stability 0.5%

Long term stability 1000 hrs, TA= 125°C 0.3%

RMS output noise Percentage of VOUT, f = 10 Hz to 10 kHz 0.003%

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6.6 Typical Characteristics

Figure 1. Dropout Voltage Figure 2. Short-Circuit Current

Figure 3. Load Regulation

Adjustable version

Figure 4. Ripple Regulation vs Current

Adjustable version

Figure 5. Ripple Rejection Figure 6. Temperature Stability

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Typical Characteristics (continued)

Figure 7. ADJUST Pin Current

1.8 V version

Figure 8. Load Transient Response

3.3 V version

Figure 9. Load Transient Response

1.8 V version

Figure 10. Line Transient Response

3.3 V version

Figure 11. Line Transient Response

ADJUST (ADJUSTABLE OUTPUT)

VOUT

GND (FIXED OUTPUT)

Current

Limit

Thermal

Limit

Substrate

VIN

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7 Detailed Description

7.1 Overview

The LMS8117A device is a positive-voltage regulator available in 1.8-V, 3.3-V, and adjustable versions. For the

adjustable version, the output voltage ranges from 1.25 V to 13.8 V and is set with only two external resistors.

This device is capable of supplying up to 1-A output current for an input voltage up to 15 V.

Because this device has a low-dropout voltage of 1.25 V over a junction temperature from 0°C to 125°C, the

input voltage can be as low as 2.5 V for proper regulation over the entire temperature range. The LMS8117A

also features current limiting and thermal overload protection to help protect the device and is available in the

space-saving SOT-223 and TO-252 packages.

The LMS8117A device is versatile in its applications, including uses in programmable output regulation and local

on-card regulation. Or, by connecting a fixed resistor between the ADJUST and OUTPUT pins, the device can

function as a precision current regulator. An optional output capacitor can be added to improve transient

response. The ADJUST pin can be bypassed to achieve very high ripple-rejection ratios, which are difficult to

achieve with standard regulators.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Protection

This device provides current limiting and thermal protection to protect the device against overload or damage

from operating in excessive heat.

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Feature Description (continued)

7.3.2 Programmable Feedback

The ADJUST pin for adjustable versions provide easy output voltage or current (not both) programming. For

current regulation applications, a single resistor whose resistance value is 1.25 V/IOand power rating is greater

than (1.25 V)2/R must be used. For voltage regulation applications, two resistors set the output voltage.

7.4 Device Functional Modes

7.4.1 Normal Operation

For the adjustable version, the OUTPUT pin sources current as necessary to make VOUT 1.25 V greater than

VREF to provide output regulation. For the fixed version, the OUTPUT pin sources current as necessary to make

VOUT greater than the GND pin voltage by the specific fixed voltage (version dependent) to provide output

regulation.

7.4.2 Operation With Low Input Voltage

The device requires up to 1.25-V headroom (VIN – VOUT) to operate in regulation. With less headroom, the device

may dropout and OUTPUT voltage is equal to INPUT voltage minus the dropout voltage.

7.4.3 Operation at Light Loads

The device passes its bias current to the OUTPUT pin. The load or feeedback must consume this minimum

current for regulation or the output may be too high.

7.4.4 Operation in Self Protection

When an overload occurs the device will shut down or reduce the output current to prevent device damage. The

device will automatically reset from the overload. The output may be reduced or alternate between ON and OFF

states until the overload is removed.

10 F

Tantalum

INPUT

LMS8117A

OUTPUT

10 F

Tantalum

m(1) GND

LMS8117A

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LMS8117A is a versatile and high-performance linear regulator with a wide temperature range and tight line

and load regulation operation. An output capacitor is required to further improve transient response and stability.

For the adjustable version, the ADJUST pin can also be bypassed to achieve very high ripple-rejection ratios.

The LMS8117A is versatile in its applications, including uses as a post regulator for DC-DC converters, batter

chargers, and microprocessor supplies.

8.2 Typical Applications

8.2.1 Output Regulator

(1) Required if the regulator is placed far from the power supply filter.

Figure 12. Fixed Output Regulator

8.2.1.1 Design Requirements

The device component count is very minimal, employing two resistors as part of a voltage divider circuit for the

adjustable version and an output capacitor for load regulation. A 10-µF tantalum capacitor on the input is suitable

for almost all applications and is required if the regulator is located far from the power-supply filter. An optional

bypass capacitor across R2 can also be used to improve PSRR.

8.2.1.2 Detailed Design Procedure

8.2.1.2.1 External Capacitors and Stability

8.2.1.2.1.1 Input Bypass Capacitor

TI recommends an input capacitor. A 10-µF tantalum on the input is a suitable input bypassing for almost all

applications.

8.2.1.2.1.2 ADJUST Pin Bypass Capacitor

The ADJUST pin can be bypassed to ground with a bypass capacitor (CADJ) to improve ripple rejection. This

bypass capacitor prevents ripple from being amplified as the output voltage is increased. At any ripple frequency,

the impedance of the CADJ must be less than R1 to prevent the ripple from being amplified in Equation 1.

1 / (2 × π× fRIPPLE × CADJ) < R1 (1)

The R1 is the resistor between the OUTPUT and the ADJUST pins. Its value is normally from 100 Ωto 200 Ω.

For example, with R1 = 124 Ωand fRIPPLE = 120 Hz, the CADJ must be > 11 µF.

INPUT

LMS8117A

OUTPUT

VIN

VOUT

GND

Rt1 IL

VLOAD RLOAD

Rt2

100 Fm

INPUT

LMS8117A

OUTPUT

10 Fm

VIN VOUT

VREF

ADJUST

IADJ

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Typical Applications (continued)

8.2.1.2.1.3 Output Capacitor

The output capacitor is critical in maintaining regulator stability, and must meet the required conditions for both

minimum amount of capacitance and ESR (Equivalent Series Resistance). The minimum output capacitance

required by the LMS8117A is 10 µF, if a tantalum capacitor is used. Any increase of the output capacitance

merely improves the loop stability and transient response. The ESR of the output capacitor must be greater than

0.5 Ωand less than 5 Ω. In the case of the adjustable regulator, when the CADJ is used, a larger output

capacitance (22-µF tantalum) is required.

8.2.1.2.2 Output Voltage

The LMS8117A adjustable version develops a 1.25-V reference voltage (VREF) between the OUTPUT and the

ADJUST pins. As shown in Figure 13, this voltage is applied across resistor R1 to generate a constant current I1.

The current IADJ from the ADJUST pin could introduce error to the output. Because it is very small (60 µA)

compared with the I1 and very constant with line and load changes, the error can be ignored. The constant

current I1 then flows through the output set resistor R2 and sets the output voltage to the desired level.

For fixed voltage devices, R1 and R2 are integrated inside the devices.

Figure 13. Basic Adjustable Regulator

VOUT is calculated using Equation 2. IADJ is typically 60 µF and negligible in most applications.

VOUT = VREF × (1 + R2 / R1) + (IADJ × R2) (2)

8.2.1.2.3 Load Regulation

The LMS8117A regulates the voltage that appears between its OUTPUT and GROUND pins, or between its

OUTPUT and ADJUST pins. In some cases, line resistances can introduce errors to the voltage across the load.

To obtain the best load regulation, a few precautions are required.

Figure 14 shows a typical application using a fixed output regulator. The RT1 and RT2 are the line resistances. It

is obvious that the VLOAD is less than the VOUT by the sum of the voltage drops along the line resistances (as

seen in Equation 3). In this case, the load regulation seen at the RLOAD would be degraded from the data sheet

specification. To improve this, the load must be tied directly to the OUTPUT pin on the positive side and directly

tied to the GROUND pin on the negative side.

Figure 14. Basic Fixed Output Regulator

VLOAD = VOUT – IL× (RT1 + RT2) (3)

INPUT

LMS8117A

OUTPUT

VIN VOUT

ADJUST

10 F

ADJ

100 F

OUT

1N4002

(Optional)

INPUT

LMS8117A

OUTPUT

VIN VOUT

VREF R1

ADJUST

Rt1

VREF

Rt2

RLOAD

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Typical Applications (continued)

When the adjustable regulator is used (Figure 15), the best performance is obtained with the positive side of the

resistor R1 tied directly to the OUTPUT pin of the regulator rather than near the load (as seen in Equation 4).

This eliminates line drops from appearing effectively in series with the reference and degrading regulation. For

example, a 5-V regulator with 0.05-Ωresistance between the regulator and load has a load regulation due to line

resistance of 0.05 Ω× IL. If R1 (125 Ω) is connected near the load, the effective line resistance is 0.05 Ω(1 + R2

/ R1) or in this case, it is 4 times worse. In addition, the ground side of the resistor R2 can be returned near the

ground of the load to provide remote ground sensing and improve load regulation.

Figure 15. Best Load Regulation Using Adjustable Output Regulator

VLOAD = VREF × (R1 + R2) / R1 – (IL× RT1) (4)

8.2.1.2.4 Protection Diodes

Under normal operation, the LMS8117A regulators do not require any protection diode. With the adjustable

device, the internal resistance between the ADJUST and OUTPUT pins limit the current. No diode is required to

divert the current around the regulator even with capacitor on the ADJUST pin. The ADJUST pin can take a

transient signal of ±25 V with respect to the output voltage without damaging the device.

When a output capacitor is connected to a regulator and the input is shorted to ground, the output capacitor

discharges into the output of the regulator. The discharge current depends on the value of the capacitor, the

output voltage of the regulator, and rate of decrease of VIN. In the LMS8117A regulators, the internal diode

between the OUTPUT and INPUT pins can withstand microsecond surge currents of 10 A to 20 A. With an

extremely large output capacitor (≥1000 µF), and with input instantaneously shorted to ground, the regulator

could be damaged.

In this case, TI recommends an external diode between the OUTPUT and INPUT pins to protect the regulator, as

shown in Figure 16.

Figure 16. Regulator With Protection Diode

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Typical Applications (continued)

8.2.1.3 Application Curves

SOT-223 package

Figure 17. RθJA vs 1-oz Copper Area

TO-252 package

Figure 18. RθJA vs 2-oz Copper Area

SOT-223 package

Figure 19. Maximum Allowable Power Dissipation

vs Ambient Temperature

TO-252 package

Figure 20. Maximum Allowable Power Dissipation

vs Ambient Temperature

SOT-223 package

Figure 21. Maximum Allowable Power Dissipation

vs 1-oz Copper Area

TO-252 package

Figure 22. Maximum Allowable Power Dissipation

vs 2-oz Copper Area

INPUT

LMS8117A

OUTPUT

VIN VOUT

ADJUST

100 Fm

240

5 V

720

TTL

1 k

2N2219

10 F

Tantalum

INPUT

LMS8117A

OUTPUT

VIN VOUT

ADJUST

10 Fm

100 Fm

121 W

CADJ

(1)

1 k

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Typical Applications (continued)

8.2.2 Other Application Circuits

Figure 23 and Figure 24 show application circuit examples using the LMS8117A devices. Customers must fully

validate and test any circuit before implementing a design based on an example in this section. Unless otherwise

noted, the design procedures in Output Regulator are applicable.

(1) CADJ is optional, however it will improve ripple rejection.

Figure 23. 1.25-V to 10-V Adjustable Regulator With Improved Ripple Rejection

VOUT = 1.25 × (1 + R2 / R1) (5)

(1) Minimum output is approximately 1.25 V.

Figure 24. 5-V Logic Regulator With Electronic Shutdown

9 Power Supply Recommendations

The input supply to the LMS8117A must be kept at a voltage level such that its maximum rating is not exceeded.

The minimum dropout voltage must also be met, with extra headroom when possible, to keep the device in

regulation. TI recommends an input capacitor; see External Capacitors and Stability for more information on

capacitor selection.

OUTPUT

INPUT

OUTPUT

ADJ/GND

Cadj

COUT

0.1 Fμ 10 Fμ

Ground

High

Frequency

Bypass

Capacitor

High Input

Bypass

Capacitor

Power

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10 Layout

10.1 Layout Guidelines

• TI recommends bypassing the input pin to ground with a bypass capacitor.

• The optimum placement of the bypass capacitor is as close as possible to the input pin and the system

ground. Take care to minimize the loop area formed by the bypass capacitor connection, the input pin, and

the system GND.

• TI recommends using wide trace lengths to eliminate I × R drop and heat dissipation.

10.2 Layout Example

Figure 25. SOT-223 Layout Example for LMS8117A Adjustable Version (Schematic View)

Figure 26. TO-252 Layout Example for LMS8117A Adjustable Version (PCB View)

RθJC

RθCA

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10.3 Thermal Considerations

10.3.1 Heat Sink Requirements

When an integrated circuit operates with an appreciable current, its junction temperature is elevated. It is

important to quantify its thermal limits to achieve acceptable performance and reliability. This limit is determined

by summing the individual parts consisting of a series of temperature rises from the semiconductor junction to the

operating environment. A one-dimensional steady-state model of conduction heat transfer is demonstrated in

Figure 27. The heat generated at the device junction flows through the die to the die attach pad, through the lead

frame to the surrounding case material, to the printed-circuit board, and eventually to the ambient environment.

There are several variables that may affect the thermal resistance and in turn the need for a heat sink, which

include the following.

Component variables (RθJC)

• Leadframe size and material

• Number of conduction pins

• Die size

• Die attach material

• Molding compound size and material

Application variables (RθCA)

• Mounting pad size, material, and location

• Placement of mounting pad

• PCB size and material

• Traces length and width

• Adjacent heat sources

• Volume of air

• Ambient temperature

• Shape of mounting pad

The case temperature is measured at the point where the leads contact the mounted pad surface.

Figure 27. Cross-Sectional View of Integrated Circuit Mounted on a Printed-Circuit Board

The LMS8117A regulator has internal thermal shutdown to protect the device from overheating. Under all

possible operating conditions, the junction temperature of the LMS8117A must be within 0°C to 125°C. A heat

sink may be required depending on the maximum power dissipation and maximum ambient temperature of the

application. To determine if a heat sink is required, the power dissipated by the regulator (PD) is calculated using

Equation 6.

IIN = IL+ IG(6)

PD= (VIN – VOUT)×IL+ (VIN × IG) (7)

Figure 28 shows the voltages and currents which are present in the circuit.

VIN

GND

INPUT OUTPUT

INVOUT

LOAD

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Thermal Considerations (continued)

(1) Tab of device is attached to top-side copper.

Figure 28. Power Dissipation Diagram

The next parameter which must be calculated is the maximum allowable temperature rise (TR(MAX))inEquation 8.

TR(MAX) = TJ(MAX) – TA(MAX)

where

• TJ(MAX) is the maximum allowable junction temperature (125°C)

• TA(MAX) is the maximum ambient temperature encountered in the application (8)

Using the calculated values for TR(MAX) and PD, the maximum allowable value for the junction-to-ambient thermal

resistance (RθJA) can be calculated with Equation 9.

RθJA = TR(MAX) / PD(9)

If the maximum allowable value for RθJA is found to be ≥61.4°C/W for SOT-223 package or ≥56.1°C/W for

TO-252 package, no heat sink is required because the package alone dissipates enough heat to satisfy these

requirements. If the calculated value for RθJA falls below these limits, a heat sink is required.

As a design aid, Table 1 shows the value of the RθJA of SOT-223 and TO-252 for different heat sink area. The

copper patterns that we used to measure these RθJA are shown Figure 29 and Figure 30.Figure 17 and

Figure 18 reflect the same test results as what are in the Table 1.

Figure 19 and Figure 20 show the maximum allowable power dissipation versus ambient temperature for the

SOT-223 and TO-252 device packages. Figure 21 and Figure 22 show the maximum allowable power dissipation

versus copper area (in.2) for the SOT-223 and TO-252 device packages. For power enhancement techniques to

be used with SOT-223 and TO-252 packages, see AN–1028 Maximum Power Enhancement Techniques for

Power Packages (SNVA036).

Table 1. RθJA Different Heat Sink Area

LAYOUT COPPER AREA (in2) THERMAL RESISTANCE: RθJA (°C/W)

TOP SIDE(1) BOTTOM SIDE SOT-223 T0-252

1 0.0123 0 136 103

2 0.066 0 123 87

3 0.3 0 84 60

4 0.53 0 75 54

5 0.76 0 96 52

6 1 0 66 47

7 0 0.2 115 64

8 0 0.4 98 70

9 0 0.6 89 63

10 0 0.8 82 57

11 0 1 79 57

12 0.066 0.066 125 89

13 0.175 0.175 93 72

LMS8117A

www.ti.com

SNOS487F –MAY 2004–REVISED DECEMBER 2016

Product Folder Links: LMS8117A

Thermal Considerations (continued)

Table 1. RθJA Different Heat Sink Area (continued)

LAYOUT COPPER AREA (in2) THERMAL RESISTANCE: RθJA (°C/W)

TOP SIDE(1) BOTTOM SIDE SOT-223 T0-252

14 0.284 0.284 83 61

15 0.392 0.392 75 55

16 0.5 0.5 70 53

Figure 29. Top View of the Thermal Test Pattern in Actual Scale

LMS8117A

SNOS487F –MAY 2004–REVISED DECEMBER 2016

www.ti.com

Product Folder Links: LMS8117A

Figure 30. Bottom View of the Thermal Test Pattern in Actual Scale

LMS8117A

www.ti.com

SNOS487F –MAY 2004–REVISED DECEMBER 2016

Product Folder Links: LMS8117A

11 Device and Documentation Support

11.1 Documentation Support

11.1.1 Related Documentation

For related documentation see the following:

AN–1028 Maximum Power Enhancement Techniques for Power Packages (SNVA036)

11.2 Receiving Notification of Documentation Updates

To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper

right corner, click on Alert me to register and receive a weekly digest of any product information that has

changed. For change details, review the revision history included in any revised document.

11.3 Community Resources

The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective

contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of

Use.

TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration

among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help

solve problems with fellow engineers.

Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and

contact information for technical support.

11.4 Trademarks

E2E is a trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

11.5 Electrostatic Discharge Caution

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with

appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more

susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

11.6 Glossary

SLYZ022 —TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.

12 Mechanical, Packaging, and Orderable Information

The following pages include mechanical, packaging, and orderable information. This information is the most

current data available for the designated devices. This data is subject to change without notice and revision of

this document. For browser-based versions of this data sheet, refer to the left-hand navigation.

PACKAGE OPTION ADDENDUM

www.ti.com 6-Feb-2020

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LMS8117ADT-3.3/NOPB ACTIVE TO-252 NDP 3 75 Green (RoHS

& no Sb/Br) SN Level-2-260C-1 YEAR 0 to 125 LMS8117

ADT-3.3

LMS8117ADT-ADJ/NOPB ACTIVE TO-252 NDP 3 75 Green (RoHS

& no Sb/Br) SN Level-2-260C-1 YEAR 0 to 125 LMS8117

ADT-ADJ

LMS8117ADTX-3.3/NOPB ACTIVE TO-252 NDP 3 2500 Green (RoHS

& no Sb/Br) SN Level-2-260C-1 YEAR 0 to 125 LMS8117

ADT-3.3

LMS8117ADTX-ADJ/NOPB ACTIVE TO-252 NDP 3 2500 Green (RoHS

& no Sb/Br) SN Level-2-260C-1 YEAR 0 to 125 LMS8117

ADT-ADJ

LMS8117AMP-1.8/NOPB ACTIVE SOT-223 DCY 4 1000 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM 0 to 125 LS00

LMS8117AMP-3.3/NOPB ACTIVE SOT-223 DCY 4 1000 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM 0 to 125 LS01

LMS8117AMP-ADJ/NOPB ACTIVE SOT-223 DCY 4 1000 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM 0 to 125 LS0A

LMS8117AMPX-1.8/NOPB ACTIVE SOT-223 DCY 4 2000 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM 0 to 125 LS00

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance

do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may

reference these types of products as "Pb-Free".

RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.

Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based

flame retardants must also meet the <=1000ppm threshold requirement.

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

PACKAGE OPTION ADDENDUM

www.ti.com 6-Feb-2020

Addendum-Page 2

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

MECHANICAL DATA

MPDS094A – APRIL 2001 – REVISED JUNE 2002

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

DCY (R-PDSO-G4) PLASTIC SMALL-OUTLINE

4202506/B 06/2002

6,30 (0.248)

6,70 (0.264)

2,90 (0.114)

3,10 (0.122)

6,70 (0.264)

7,30 (0.287) 3,70 (0.146)

3,30 (0.130)

0,02 (0.0008)

0,10 (0.0040)

1,50 (0.059)

1,70 (0.067)

0,23 (0.009)

0,35 (0.014)

1 2 3

0,66 (0.026)

0,84 (0.033)

1,80 (0.071) MAX

Seating Plane

0°–10°

Gauge Plane

0,75 (0.030) MIN

0,25 (0.010)

0,08 (0.003)

0,10 (0.004) M

2,30 (0.091)

4,60 (0.181) M

0,10 (0.004)

NOTES: A. All linear dimensions are in millimeters (inches).

B. This drawing is subject to change without notice.

C. Body dimensions do not include mold flash or protrusion.

D. Falls within JEDEC TO-261 Variation AA.

www.ti.com

PACKAGE OUTLINE

10.42

9.40

6.73

6.35

6.22

5.97 1.27

0.88

5.46

4.96

2.285

4.57

1.02

0.64

3X 0.88

0.64

2.55 MAX

0.88

0.46

1.14

0.89

0.60

0.46

0.17

0.51 MIN

4.32 MIN

(2.345)

(2.5)

TO-252 - 2.55 mm max heightNDP0003B

TRANSISTOR OUTLINE

4219870/A 03/2018

NOTES:

1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing

per ASME Y14.5M.

2. This drawing is subject to change without notice.

3. Reference JEDEC registration TO-252.

0.25 C A B

TOP & BOTTOM

PKG

OPTIONAL

SEATING PLANE

SCALE 1.500

www.ti.com

EXAMPLE BOARD LAYOUT

0.07 MAX

ALL AROUND 0.07 MIN

ALL AROUND

(4.57)

2X (1.3) 2X (2.15) (5.7)

(5.5)

(2.285)(4.38)

(R0.05) TYP

TO-252 - 2.55 mm max heightNDP0003B

TRANSISTOR OUTLINE

4219870/A 03/2018

NOTES: (continued)

4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature numbers

SLMA002(www.ti.com/lit/slm002) and SLMA004 (www.ti.com/lit/slma004).

5. Vias are optional depending on application, refer to device data sheet. It is recommended that vias under paste be filled, plugged or tented.

LAND PATTERN EXAMPLE

EXPOSED METAL SHOWN

SCALE: 8X

SYMM

PKG

SEE SOLDER MASK

DETAIL

EXPOSED

METAL

METAL EDGE

SOLDER MASK

OPENING

NON SOLDER MASK

DEFINED

(PREFERRED) SOLDER MASK DETAIL

EXPOSED

METAL

METAL UNDER

SOLDER MASK

OPENING

SOLDER MASK DEFINED

www.ti.com

EXAMPLE STENCIL DESIGN

2X (2.15)

2X (1.3)

(4.57)

(4.38)

(1.32) TYP

(1.35) TYP

(0.26) (R0.05) TYP

16X (1.12)

16X (1.15)

TO-252 - 2.55 mm max heightNDP0003B

TRANSISTOR OUTLINE

4219870/A 03/2018

NOTES: (continued)

6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate

design recommendations.

7. Board assembly site may have different recommendations for stencil design.

PKG

SOLDER PASTE EXAMPLE

BASED ON 0.125 MM THICK STENCIL

SCALE: 8X

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