IN OUT
GND
CIN
470 nF COUT
22 µF
VIN
6 V to 26 V VOUT
5 V to 20 V
ON/OFF ADJ R1
R2
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LM2941x 1-A Low Dropout Adjustable Regulator
1 Features 3 Description
The LM2941 positive voltage regulator features the
1• Operating VIN Range: 6 V to 26 V ability to source 1 A of output current with a typical
• Output Voltage Adjustable From 5 V to 20 V dropout voltage of 0.5 V and a maximum of 1 V over
• Dropout Voltage Typically 0.5 V at IOUT =1A the entire temperature range. Furthermore, a
quiescent current reduction circuit has been included
• Output Current in Excess of 1 A which reduces the ground pin current when the
• Trimmed Reference Voltage differential between the input voltage and the output
• Reverse Battery Protection voltage exceeds approximately 3 V. The quiescent
current with 1 A of output current and an input-output
• Internal Short-Circuit Current Limit differential of 5 V is therefore only 30 mA. Higher
• Mirror Image Insertion Protection quiescent currents only exist when the regulator is in
• P+Product Enhancement Tested the dropout mode (VIN −VOUT ≤3 V).
• TTL, CMOS Compatible ON/OFF Switch Designed also for vehicular applications, the LM2941
• WSON Space-Saving Package and all regulated circuitry are protected from reverse
battery installations or two-battery jumps. During line
2 Applications transients, such as load dump when the input voltage
can momentarily exceed the specified maximum
• Industrial operating voltage, the regulator will automatically shut
• Automotive down to protect both the internal circuits and the load.
Familiar regulator features such as short circuit and
thermal overload protection are also provided.
Device Information(1)
PART NUMBER PACKAGE BODY SIZE (NOM)
WSON (8) 4.00 mm x 4.00 mm
TO-263 (5) 10.16 mm x 8.42 mm
LM2941 TO-220 (5) 14.986 mm x 10.16 mm
TO-220 (5) 10.16 mm x 8.51 mm
TO-263 (5) 10.16 mm x 8.42 mm
LM2941C TO-220 (5) 14.986 mm x 10.16 mm
TO-220 (5) 10.16 mm x 8.51 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
1
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.
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Table of Contents
1 Features.................................................................. 18 Application and Implementation ........................ 12
8.1 Application Information............................................ 12
2 Applications ........................................................... 18.2 Typical Application.................................................. 12
3 Description............................................................. 19 Power Supply Recommendations...................... 14
4 Revision History..................................................... 210 Layout................................................................... 14
5 Pin Configuration and Functions......................... 310.1 Layout Guidelines ................................................. 14
6 Specifications......................................................... 410.2 Layout Example .................................................... 14
6.1 Absolute Maximum Ratings ...................................... 410.3 Power Dissipation ................................................. 16
6.2 ESD Ratings ............................................................ 410.4 Thermal Considerations........................................ 17
6.3 Recommended Operating Conditions....................... 411 Device and Documentation Support................. 18
6.4 Thermal Information.................................................. 511.1 Device Support .................................................... 18
6.5 Electrical Characteristics: LM2941T, LM2941S,
LM2941LD.................................................................. 511.2 Documentation Support ....................................... 18
6.6 Electrical Characteristics: LM2941CT, LM2941CS... 611.3 Related Links ........................................................ 18
6.7 Typical Characteristics.............................................. 711.4 Trademarks........................................................... 18
11.5 Electrostatic Discharge Caution............................ 18
7 Detailed Description............................................ 10 11.6 Glossary................................................................ 19
7.1 Overview................................................................. 10
7.2 Functional Block Diagram....................................... 10 12 Mechanical, Packaging, and Orderable
Information........................................................... 19
7.3 Feature Description................................................. 10
7.4 Device Functional Modes........................................ 11
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision H (December 2014) to Revision I Page
• Changed update pin names to TI nomenclature ................................................................................................................... 1
Changes from Revision G (April 2013) to Revision H Page
• Added Device Information and ESD Ratings tables, Feature Description section, Device Functional Modes,
Application and Implementation section, Power Supply Recommendations section, Layout section, Device and
Documentation Support section, and Mechanical, Packaging, and Orderable Information section; updated Thermal Info.. 1
Changes from Revision F (April 2013) to Revision G Page
• Changed layout of National Data Sheet to TI format ............................................................................................................. 1
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ON/OFF
GND
INPUT
N/C
ADJ
GND
N/C
OUTPUT
1
3
4
2
6
5
7
8
GND*
* TIE TO GND OR LEAVE FLOATING
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5 Pin Configuration and Functions
TO-220 (KC) Plastic Package
4 Pins
Top View
TO-263 (KTT) Surface-Mount Package
4 Pins
WSON (NGN)Surface Mount Package
8 Leads
Top View
Pin Functions
PIN TYPE DESCRIPTION
NAME KC KTT NGN
ADJ 1 1 8 I Sets output voltage
ON/OFF 2 2 1 I Enable/Disable control
GND 3 3 2, 7 — Ground
IN 4 4 3 I Input supply
Regulated output voltage. This pin requires an output capacitor to
OUT 5 5 5 O maintain stability. See the Detailed Design Procedure section for
output capacitor details.
NC — — 4, 6 — No internal connection. Connect to GND or leave open.
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6 Specifications
6.1 Absolute Maximum Ratings(1)(2)
MIN MAX UNIT
LM2941T, LM2941S, LM2941LD 60 V
Input voltage (Survival Voltage, ≤100 ms) LM2941CT, LM2941CS 45 V
Internal power dissipation (3) Internally Limited
Maximum junction temperature 150 °C
TO-220 (T), Wave, 10 s 260 °C
Soldering remperature(4) TO-263 (S), 30 s 235 °C
WSON-8 (LD), 30 s 235 °C
Storage temperature, Tstg −65 150 °C
(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 dissipation is a function of TJ(max), RθJA, and TA. The maximum allowable power dissipation at any ambient
temperature is PD= (TJ(max) −TA)/RθJA. If this dissipation is exceeded, the die temperature will rise above 150°C and the LM2941 will
go into thermal shutdown. If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper
area thermally connected to the package. The value RθJA for the WSON package is specifically dependent on PCB trace area, trace
material, and the number of layers and thermal vias. For improved thermal resistance and power dissipation for the WSON package,
refer to Application Note AN-1187 (SNOA401). It is recommended that 6 vias be placed under the center pad to improve thermal
performance.
(4) Refer to JEDEC J-STD-020C for surface mount device (SMD) package reflow profiles and conditions. Unless otherwise stated, the
temperature and time are for Sn-Pb (STD) only.
6.2 ESD Ratings VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions MIN MAX UNIT
LM2941T −40 125
LM2941CT 0 125
Temperatures LM2941S −40 125 °C
LM2941CS 0 125
LM2941LD −40 125
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6.4 Thermal Information LM2941LD LM2941S, LM2941T
WSON TO-263 TO-220
THERMAL METRIC(1)(2) UNIT
(NGN) (KTT) (KC)
8 PINS 5 PINS 5 PINS
RθJA Junction-to-ambient thermal resistance 40.5 41 32.1
RθJC(top) Junction-to-case (top) thermal resistance 26.2 43.2 25.6
RθJB Junction-to-board thermal resistance 17 22.9 18.3 °C/W
ψJT Junction-to-top characterization parameter 0.2 11.4 8.5
ψJB Junction-to-board characterization parameter 17.2 21.9 17.7
RθJC(bot) Junction-to-case (bottom) thermal resistance 3.2 0.9 0.7
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
(2) The maximum power dissipation is a function of TJ(max), RθJA, and TA. The maximum allowable power dissipation at any ambient
temperature is PD= (TJ(max) −TA)/RθJA. If this dissipation is exceeded, the die temperature will rise above 150°C and the LM2941 will
go into thermal shutdown. If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper
area thermally connected to the package. The value RθJA for the WSON package is specifically dependent on PCB trace area, trace
material, and the number of layers and thermal vias. For improved thermal resistance and power dissipation for the WSON package,
refer to Application Note AN-1187 (SNOA401). It is recommended that 6 vias be placed under the center pad to improve thermal
performance.
6.5 Electrical Characteristics: LM2941T, LM2941S, LM2941LD
5 V ≤VOUT ≤20 V, VIN = VOUT + 5 V, COUT = 22 μF, unless otherwise specified. MIN (minimum) and MAX (maximum)
specifications in apply over the full Operating Temperature Range (unless otherwise specified) and typical values apply at TJ
= 25°C. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
5 mA ≤IOUT ≤1 A(1) 1.211 1.275 1.339
Reference voltage V
5 mA ≤IOUT ≤1 A(1), TJ= 25°C 1.237 1.275 1.313
Line regulation VOUT + 2 V ≤VIN ≤26 V, IOUT = 5 mA 4 10 mV/V
Load regulation 50 mA ≤IOUT ≤1 A 7 10 mV/V
Output impedance 100 mADC and 20 mArms, ƒOUT = 120 Hz 7 mΩ/V
VOUT + 2 V ≤VIN < 26 V, IOUT = 5 mA 10 20 mA
VOUT + 2 V ≤VIN < 26 V, IOUT = 5 mA, TJ=10 15
25°C
Quiescent current VIN = VOUT + 5 V, IOUT = 1 A 30 60 mA
VIN = VOUT + 5 V, IOUT = 1 A, TJ= 25°C 30 45
RMS output noise, % of VOUT 10 Hz to 100 kHz, IOUT = 5 mA 0.003%
ƒOUT = 120 Hz, 1 Vrms, IL= 100 mA 0.005 0.04
Ripple rejection %/V
ƒOUT = 120 Hz, 1 Vrms, IL= 100 mA, TJ= 25°C 0.005 0.02
Long-term stability 0.4 %/1000 Hr
IOUT = 1 A 0.5 1 V
Dropout voltage IOUT = 1 A, TJ= 25°C 0.5 0.8
IOUT = 100 mA 110 200 mV
Short-circuit current VIN max = 26 V(2) 1.6 1.9 A
VOUT max 1 V above nominal VOUT 75
Maximum line transient 60 V
ROUT = 100 Ω, t ≤100 ms
Maximum operational input 26 31 VDC
voltage
Reverse polarity ROUT = 100 Ω, VOUT ≥ −0.6 V −15 −30
DC input voltage V
Reverse polarity t≤100 ms, ROUT = 100 Ω −50 −75
transient input voltage
(1) The output voltage range is 5 V to 20 V and is determined by the two external resistors, R1 and R2. See Figure 18.
(2) Output current capability will decrease with increasing temperature, but will not go below 1 A at the maximum specified temperatures.
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Electrical Characteristics: LM2941T, LM2941S, LM2941LD (continued)
5 V ≤VOUT ≤20 V, VIN = VOUT + 5 V, COUT = 22 μF, unless otherwise specified. MIN (minimum) and MAX (maximum)
specifications in apply over the full Operating Temperature Range (unless otherwise specified) and typical values apply at TJ
= 25°C. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ON/OFF threshold IOUT ≤1 A 1.30 0.80
voltage ON V
ON/OFF threshold IOUT ≤1 A 2 1.3
voltage OFF VON/OFF = 2 V, IOUT ≤1 A 50 300
ON/OFF threshold μA
current VON/OFF = 2 V, IOUT ≤1 A, TJ= 25°C 50 100
6.6 Electrical Characteristics: LM2941CT, LM2941CS
5 V ≤VOUT ≤20 V, VIN = VOUT + 5 V, COUT = 22 μF, unless otherwise specified. MIN (minimum) and MAX (maximum)
specifications in apply over the full Operating Temperature Range (unless otherwise specified) and typical values apply at TJ
= 25°C. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
5 mA ≤IOUT ≤1 A(1) 1.211 1.275 1.339
Reference voltage V
5 mA ≤IOUT ≤1 A(1), TJ= 25°C 1.237 1.275 1.313
VOUT + 2 V ≤VIN ≤26 V, IOUT = 5 mA, TJ=
Line regulation 4 10 mV/V
25°C
Load regulation 50 mA ≤IOUT ≤1 A, TJ= 25°C 7 10 mV/V
Output impedance 100 mADC and 20 mArms, ƒOUT = 120 Hz 7 mΩ/V
VOUT + 2 V ≤VIN < 26 V, IOUT = 5 mA, TJ=10 15 mA
25°C
Quiescent current VIN = VOUT + 5 V, IOUT = 1 A 30 60 mA
VIN = VOUT + 5 V, IOUT = 1 A, TJ= 25°C 30 45
10 Hz to 100 kHz 0.003%
RMS output noise, % of VOUT IOUT = 5 mA
Ripple rejection ƒOUT = 120Hz, 1 Vrms, IL= 100 mA, TJ= 25°C 0.005 0.02 %/V
Long-term stability 0.4 %/1000 Hr
IOUT = 1A 0.5 1 V
Dropout voltage IOUT = 1A, TJ= 25°C 0.5 0.8
IOUT = 100 mA 110 200 mV
Short-circuit current VIN max = 26 V(2), TJ= 25°C 1.6 1.9 A
VOUT max 1 V above nominal VOUT, ROUT = 100 55
Maximum line transient 45 V
Ω, t ≤100 ms, , TJ= 25°C
Maximum operational input TJ= 25°C 26 31 VDC
voltage
Reverse polarity ROUT = 100 Ω, VOUT ≥ −0.6 V, TJ= 25°C −15 −30
DC input voltage V
Reverse polarity t≤100 ms, ROUT = 100 Ω, TJ= 25°C −45 −55
transient input voltage
ON/OFF threshold IOUT ≤1 A, TJ= 25°C 1.3 0.8
voltage ON V
ON/OFF threshold IOUT ≤1 A, TJ= 25°C 2 1.3
voltage OFF
ON/OFF threshold VON/OFF = 2 V, IOUT ≤1 A, TJ= 25°C 50 100 μA
current
(1) The output voltage range is 5 V to 20 V and is determined by the two external resistors, R1 and R2. See Typical Application.
(2) Output current capability will decrease with increasing temperature, but will not go below 1 A at the maximum specified temperatures.
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6.7 Typical Characteristics
Figure 2. Dropout Voltage vs. Temperature
Figure 1. Dropout Voltage
Figure 3. Output Voltage Figure 4. Quiescent Current vs. Temperature
Figure 5. Quiescent Current Figure 6. Quiescent Current
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Typical Characteristics (continued)
Figure 8. Load Transient Response
Figure 7. Line Transient Response
Figure 9. Ripple Rejection Figure 10. Output Impedance
Figure 11. Low Voltage Behavior Figure 12. Low Voltage Behavior
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Typical Characteristics (continued)
Figure 14. Output at Voltage Extremes
Figure 13. Output Capacitor ESR
Figure 15. Output at Voltage Extremes Figure 16. Peak Output Current
Figure 17. Maximum Power Dissipation (TO-220)
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7 Detailed Description
7.1 Overview
The LM2941 positive voltage regulator features the ability to source 1 A of output current with a dropout voltage
of typically 0.5 V and a maximum of 1 V over the entire temperature range. Furthermore, a quiescent current
reduction circuit has been included which reduces the ground current when the differential between the input
voltage and the output voltage exceeds approximately 3 V. The quiescent current with 1 A of output current and
an input-output differential of 5 V is therefore only 30 mA. Higher quiescent currents only exist when the regulator
is in the dropout mode (VIN – VOUT ≤3 V).
7.2 Functional Block Diagram
7.3 Feature Description
7.3.1 Short-Circuit Current Limit
The internal current limit circuit is used to protect the LDO against high-load current faults or shorting events. The
LDO is not designed to operate in a steady-state current limit. During a current-limit event, the LDO sources
constant current. Therefore, the output voltage falls when load impedance decreases. Note also that if a current
limit occurs and the resulting output voltage is low, excessive power may be dissipated across the LDO, resulting
a thermal shutdown of the output.
7.3.2 Overvoltage Shutdown (OVSD)
Input voltage greater than typically 30 V will cause the LM2941 output to be disabled. When operating with the
input voltage greater than the maximum recommended input voltage of 26 V, the device performance is not
ensured. Continuous operation with the input voltage greater than the maximum recommended input voltage is
discouraged.
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Feature Description (continued)
7.3.3 Thermal Shutdown (TSD)
The LM2941 contains the thermal shutdown circuitry to turn off the output when excessive heat is dissipated in
the LDO. The internal protection circuitry of the LM2941 is designed to protect against thermal overload
conditions. The TSD circuitry is not intended to replace proper heat sinking. Continuously running the device into
thermal shutdown degrades its reliability as the junction temperature will be exceeding the absolute maximum
junction temperature rating.
7.3.4 Thermal Overload Protection
The LM2941 incorporates a linear form of thermal protection that limits the junction temperature (TJ) to typically
155°C.
Should the LM2941 see a fault condition that results in excessive power dissipation and the junction temperature
approaches 155°C, the device will respond by reducing the output current (which reduces the power dissipation)
to hold the junction temperature at 155°C.
Thermal Overload protection is not an ensured operating condition. Operating at, or near to, the thermal overload
condition for any extended period of time is not encouraged, or recommended, as this may shorten the lifetime of
the device.
7.4 Device Functional Modes
7.4.1 Operation With ON/OFF Control
The ON/OFF pin has no internal pull-up or pull-down to establish a default condition and, as a result, this pin
must be terminated externally, either actively or passively. The ON/OFF pin requires a low level to enable the
output, and a high level to disable the output. To ensure reliable operation, the ON/OFF pin voltage must rise
above the maximum ON/OFF(OFF) voltage threshold (2 V) to disable the output, and must fall below the
minimum ON/OFF(ON) voltage threshold (0.8 V) to enable the output. If the ON/OFF function is not needed this
pin can be connected directly to Ground. If the ON/OFF pin is being pulled to a high state through a series
resistor, an allowance must be made for the ON/OFF pin current that will cause a voltage drop across the pull-up
resistor
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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
Figure 18 shows the typical application circuit for the LM2941. The output capacitor, COUT, must have a
capacitance value of at least 22 µF with an equivalent series resistance (ESR) of at least 100 mΩ, but no more
than 1 Ω. The minimum capacitance value and the ESR requirements apply across the entire expected operating
ambient temperature range.
8.2 Typical Application
Note: Using 1 kΩfor R1 will ensure that the bias current error from the adjust pin will be negligible. Do not bypass R1
or R2. This will lead to instabilities.
*Required if regulator is located far from power supply filter.
** COUT must be at least 22 μF to maintain stability. May be increased without bound to maintain regulation during
transients. Locate as close as possible to the regulator. This capacitor must be rated over the same operating
temperature range as the regulator and the ESR is critical.
Figure 18. 5-V to 20-V Adjustable Regulator
8.2.1 Design Requirements
DESIGN PARAMETER EXAMPLE VALUE
Input voltage range 10 V to 26 V
Output voltage 15 V
Output current range 5 mA to 1 A
Input capacitor value 0.47 µF
Output capacitor value 22 µF minimum
Output capacitor ESR range 100 mΩto 1 Ω
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8.2.2 Detailed Design Procedure
8.2.2.1 Output Capacitor
A tantalum capacitor with a minimum capacitance value of 22 μF, and ESR in the range of 0.01 Ωto 5 Ω, is
required at the output pin for loop stability. It must be located less than 1 cm from the device. There is no
limitation on any additional capacitance.
Alternately, a high quality X5R/X7R 22 μF ceramic capacitor may be used for the output capacitor only if an
appropriate value of series resistance is added to simulate the ESR requirement. The ceramic capacitor selection
must include an appropriate voltage de-rating of the capacitance value due to the applied output voltage. The
series resistor (for ESR simulation) should be in the range of 0.1 Ωto 1 Ω.
8.2.2.2 Setting the Output Voltage
The output voltage range is 5 V to 20 V and is set by the two external resistors, R1 and R2. See the Figure 18.
The output voltage is given by the formula:
VOUT = VREF × ((R1 + R2) / R1)
where
• VREF is typically 1.275 V (1)
Using 1 kΩfor R1 will ensure that the bias current error of the adjust pin will be negligible. Using a R1 value
higher than 10 kΩmay cause the output voltage to shift across temperature due to variations in the adjust pin
bias current.
Calculating the upper resistor (R2) value of the pair when the lower resistor (R1) value is known is accomplished
with the following formula:
R2 = R1 × ((VOUT / VREF) – 1) (2)
The resistors used for R1 and R2 should be high quality, tight tolerance, and with matching temperature
coefficients. It is important to remember that, although the value of VREF is ensured, the final value of VOUT is not.
The use of low quality resistors for R1 and R2 can easily produce a VOUT value that is unacceptable.
8.2.3 Application Curves
Figure 19. Low Voltage Behavior Figure 20. Output at Voltage Extremes
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9 Power Supply Recommendations
The device is designed to operate from an input voltage supply range between VOUT + 1 V up to a maximum of
26 V. This input supply must be well regulated and free of spurious noise. To ensure that the LM2941 output
voltage is well regulated, the input supply should be at least VOUT + 2 V.
10 Layout
10.1 Layout Guidelines
The dynamic performance of the LM2941 is dependent on the layout of the PCB. PCB layout practices that are
adequate for typical LDOs may degrade the PSRR, noise, or transient performance of the LM2941. Best
performance is achieved by placing CIN and COUT on the same side of the PCB as the LM2941, and as close as
is practical to the package. The ground connections for CIN and COUT should be back to the LM2941 ground pin
using as wide and short of a copper trace as is practical.
10.2 Layout Example
Figure 21. LM2941 WSON Package Typical Layout
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Layout Example (continued)
Figure 22. LM2941 TO-220 Package Typical Layout
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Layout Example (continued)
Figure 23. LM2941 TO-263 Package Typical Layout
10.3 Power Dissipation
Consideration should be given to the maximum power dissipation (PD(MAX)) which is limited by the maximum
operating junction temperature (TJ(MAX)) of 125°C, the maximum operating ambient temperature (TA(MAX)) of the
application, and the thermal resistance (RθJA) of the package. Under all possible conditions, the junction
temperature (TJ) must be within the range specified in the Operating Ratings. The total power dissipation of the
device is given by:
PD= ( (VIN −VOUT) x IOUT) + (VIN x IGND) (3)
where IGND is the operating ground pin current of the device (specified under Electrical Characteristics: LM2941T,
LM2941S, LM2941LD and Electrical Characteristics: LM2941CT, LM2941CS).
The maximum allowable junction temperature rise (ΔTJ) depends on the maximum expected ambient
temperature (TA(MAX)) of the application, and the maximum allowable junction temperature (TJ(MAX)):
ΔTJ= TJ(MAX) −TA(MAX) (4)
The maximum allowable value for junction to ambient Thermal Resistance, RθJA, required to keep the junction
temperature, TJ, from exceeding maximum allowed can be calculated using the formula:
RθJA =ΔTJ/ PD(MAX) (5)
The maximum allowable power dissipation, PD(MAX), required allowed for a specific ambient temperature can be
calculated using the formula:
PD(MAX) =ΔTJ/ RθJA (6)
Additional information for thermal performance of surface mount packages can be found in AN-1520: A Guide to
Board Layout for Best Thermal Resistance for Exposed Packages (SNVA183), AN-1187: Leadless Leadframe
Package (LLP) (SNOA401), and AN-2020: Thermal Design By Insight, Not Hindsight (SNVA419).
16 Submit Documentation Feedback Copyright © 1999–2015, Texas Instruments Incorporated
Product Folder Links: LM2941 LM2941C
LM2941
,
LM2941C
www.ti.com
SNVS770I –JUNE 1999–REVISED JANUARY 2015
10.4 Thermal Considerations
10.4.1 TO-263 Mounting
The thermal dissipation of the TO-263 package is directly related to the printed circuit board construction and the
amount of additional copper area connected to the TAB.
The TAB on the bottom of the TO-263 package is connected to the die substrate via a conductive die attach
adhesive, and to device pin 3. As such, it is strongly recommend that the TAB area be connected to copper area
directly under the TAB that is extended into the ground plane via multiple thermal vias. Alternately, but not
recommended, the TAB may be left floating (i.e. no direct electrical connection). The TAB must not be connected
to any potential other than ground.
10.4.2 WSON Mounting
The NGN (Pullback) 8-Lead WSON package requires specific mounting techniques which are detailed in
Application Note 1187: Leadless Leadframe Package (LLP) (SNOA401). Referring to the section PCB Design
Recommendations in AN-1187, it should be noted that the pad style which should be used with the WSON
package is the NSMD (non-solder mask defined) type.
The thermal dissipation of the WSON package is directly related to the printed circuit board construction and the
amount of additional copper area connected to the DAP.
The DAP (exposed pad) on the bottom of the WSON package is connected to the die substrate via a conductive
die attach adhesive, and to device pin 2 and pin 7. As such, it is strongly recommend that the DAP area be
connected copper area directly under the DAP that is extended into the ground plane via multiple thermal vias.
Alternately, but not recommended, the DAP area may be left floating (i.e. no direct electrical connection). The
DAP area must not be connected to any potential other than ground.
Copyright © 1999–2015, Texas Instruments Incorporated Submit Documentation Feedback 17
Product Folder Links: LM2941 LM2941C
LM2941
,
LM2941C
SNVS770I –JUNE 1999–REVISED JANUARY 2015
www.ti.com
11 Device and Documentation Support
11.1 Device Support
11.1.1 Definition of Terms
Dropout Voltage The input-voltage differential at which the circuit ceases to regulate against further reduction in
input voltage. Measured when the output voltage has dropped 100 mV from the nominal value
obtained at (VOUT + 5 V) input, dropout voltage is dependent upon load current and junction
temperature.
Input-Output Differential The voltage difference between the unregulated input voltage and the regulated
output voltage for which the regulator will operate.
Input Voltage The DC voltage applied to the input terminals with respect to ground.
Line Regulation The change in output voltage for a change in the input voltage. The measurement is made
under conditions of low dissipation or by using pulse techniques such that the average chip
temperature is not significantly affected.
Load Regulation The change in output voltage for a change in load current at constant chip temperature.
Long Term Stability Output voltage stability under accelerated life-test conditions after 1000 hours with
maximum rated voltage and junction temperature.
Output Noise Voltage The rms AC voltage at the output, with constant load and no input ripple, measured over
a specified frequency range.
Quiescent Current That part of the positive input current that does not contribute to the positive load current.
The regulator ground lead current.
Ripple Rejection The ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage.
Temperature Stability of VOUT The percentage change in output voltage for a thermal variation from room
temperature to either temperature extreme.
11.2 Documentation Support
11.2.1 Related Documentation
•AN-1520: A Guide to Board Layout for Best Thermal Resistance for Exposed Packages (SNVA183)
•AN-1187: Leadless Leadframe Package (LLP) (SNOA401)
•AN-2020: Thermal Design By Insight, Not Hindsight (SNVA419)
11.3 Related Links
Table 1 below lists quick access links. Categories include technical documents, support and community
resources, tools and software, and quick access to sample or buy.
Table 1. Related Links
TECHNICAL TOOLS & SUPPORT &
PARTS PRODUCT FOLDER SAMPLE & BUY DOCUMENTS SOFTWARE COMMUNITY
LM2941 Click here Click here Click here Click here Click here
LM2941C Click here Click here Click here Click here Click here
11.4 Trademarks
All trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
18 Submit Documentation Feedback Copyright © 1999–2015, Texas Instruments Incorporated
Product Folder Links: LM2941 LM2941C
LM2941
,
LM2941C
www.ti.com
SNVS770I –JUNE 1999–REVISED JANUARY 2015
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.
Copyright © 1999–2015, Texas Instruments Incorporated Submit Documentation Feedback 19
Product Folder Links: LM2941 LM2941C
PACKAGE OPTION ADDENDUM
www.ti.com 9-Jun-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
LM2941CS NRND DDPAK/
TO-263 KTT 5 45 TBD Call TI Call TI 0 to 125 LM2941CS
P+
LM2941CS/NOPB ACTIVE DDPAK/
TO-263 KTT 5 45 Green (RoHS
& no Sb/Br) SN Level-3-245C-168 HR 0 to 125 LM2941CS
P+
LM2941CSX/NOPB ACTIVE DDPAK/
TO-263 KTT 5 500 Green (RoHS
& no Sb/Br) SN Level-3-245C-168 HR 0 to 125 LM2941CS
P+
LM2941CT NRND TO-220 KC 5 45 TBD Call TI Call TI 0 to 125 LM2941CT
P+
LM2941CT/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS
& no Sb/Br) SN Level-1-NA-UNLIM LM2941CT
P+
LM2941CT/LF04 ACTIVE TO-220 NEB 5 45 Green (RoHS
& no Sb/Br) SN Level-1-NA-UNLIM LM2941CT
P+
LM2941CT/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS
& no Sb/Br) SN Level-1-NA-UNLIM 0 to 125 LM2941CT
P+
LM2941LD NRND WSON NGN 8 1000 TBD Call TI Call TI -40 to 125 L2941LD
LM2941LD/NOPB ACTIVE WSON NGN 8 1000 Green (RoHS
& no Sb/Br) NIPDAU | SN Level-3-260C-168 HR -40 to 125 L2941LD
LM2941LDX/NOPB ACTIVE WSON NGN 8 4500 Green (RoHS
& no Sb/Br) NIPDAU | SN Level-3-260C-168 HR -40 to 125 L2941LD
LM2941S NRND DDPAK/
TO-263 KTT 5 45 TBD Call TI Call TI -40 to 125 LM2941S
P+
LM2941S/NOPB ACTIVE DDPAK/
TO-263 KTT 5 45 Green (RoHS
& no Sb/Br) SN Level-3-245C-168 HR -40 to 125 LM2941S
P+
LM2941SX NRND DDPAK/
TO-263 KTT 5 500 TBD Call TI Call TI -40 to 125 LM2941S
P+
LM2941SX/NOPB ACTIVE DDPAK/
TO-263 KTT 5 500 Green (RoHS
& no Sb/Br) SN Level-3-245C-168 HR -40 to 125 LM2941S
P+
LM2941T NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2941T
P+
LM2941T/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS
& no Sb/Br) SN Level-1-NA-UNLIM LM2941T
P+
LM2941T/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS
& no Sb/Br) SN Level-1-NA-UNLIM -40 to 125 LM2941T
P+
PACKAGE OPTION ADDENDUM
www.ti.com 9-Jun-2020
Addendum-Page 2
(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.
(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.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
LM2941CSX/NOPB DDPAK/
TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2
LM2941LD WSON NGN 8 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1
LM2941LD/NOPB WSON NGN 8 1000 180.0 12.4 4.3 4.3 1.1 8.0 12.0 Q1
LM2941LDX/NOPB WSON NGN 8 4500 330.0 12.4 4.3 4.3 1.1 8.0 12.0 Q1
LM2941SX DDPAK/
TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2
LM2941SX/NOPB DDPAK/
TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2
PACKAGE MATERIALS INFORMATION
www.ti.com 29-Sep-2019
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
LM2941CSX/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0
LM2941LD WSON NGN 8 1000 210.0 185.0 35.0
LM2941LD/NOPB WSON NGN 8 1000 195.0 200.0 45.0
LM2941LDX/NOPB WSON NGN 8 4500 370.0 355.0 55.0
LM2941SX DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0
LM2941SX/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0
PACKAGE MATERIALS INFORMATION
www.ti.com 29-Sep-2019
Pack Materials-Page 2
www.ti.com
PACKAGE OUTLINE
C
B
9.25
7.67
6.86
5.69
3.05
2.54
14.73
12.29
5X 1.02
0.64
4X 1.7
8.89
6.86
12.88
10.08
(6.275)
4.83
4.06 1.40
1.14
3.05
2.03
0.61
0.30
-3.963.71
6.8
2X (R1)
OPTIONAL
16.51
MAX
A
10.67
9.65
(4.25)
4215009/A 01/2017
TO-220 - 16.51 mm max heightKC0005A
TO-220
NOTES:
1. All controlling linear dimensions are in inches. Dimensions in brackets are in millimeters. Any dimension in brackets or parenthesis are for
reference only. Dimensioning and tolerancing per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. Shape may vary per different assembly sites.
0.25 C A B
PIN 1 ID
(OPTIONAL)
15
OPTIONAL
CHAMFER
SCALE 0.850
NOTE 3
15
AAAA
www.ti.com
EXAMPLE BOARD LAYOUT
0.07 MAX
ALL AROUND
0.07 MAX
ALL AROUND (1.45)
(2)
(R0.05) TYP
4X (1.45)
4X (2)
5X ( 1.2) (1.7) TYP
(6.8)
FULL R
TYP
TO-220 - 16.51 mm max heightKC0005A
TO-220
4215009/A 01/2017
LAND PATTERN
NON-SOLDER MASK DEFINED
SCALE:12X
PKG
PKG
METAL
TYP
SOLDER MASK
OPENING, TYP
15
MECHANICAL DATA
NDH0005D
www.ti.com
MECHANICAL DATA
KTT0005B
www.ti.com
BOTTOM SIDE OF PACKAGE
TS5B (Rev D)
MECHANICAL DATA
NEB0005F
www.ti.com
www.ti.com
PACKAGE OUTLINE
C
8X 0.35
0.25
2X
2.4
0.8 MAX
(0.25)
(0.25) (0.2)
(0.15)
0.05
0.00
8X 0.6
0.4
3 0.05
2.2 0.05
6X 0.8
A4.1
3.9 B
4.1
3.9
(0.2) TYP
WSON - 0.8 mm max heightNGN0008A
PLASTIC SMALL OUTLINE - NO LEAD
4214794/A 11/2019
PIN 1 INDEX AREA
SEATING PLANE
0.08 C
1
45
8
PIN 1 ID 0.1 C A B
0.05 C
THERMAL PAD
EXPOSED SYMM
SYMM
9
DETAIL A
SEE
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. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
SCALE 3.000
PIN 1 ID DETAIL A
PIN 1 ID
www.ti.com
EXAMPLE BOARD LAYOUT
0.07 MIN
ALL AROUND
0.07 MAX
ALL AROUND
8X (0.3)
(3)
(3.3)
6X (0.8)
(2.2)
( 0.2) VIA
TYP (0.85)
(1.25)
8X (0.5)
(R0.05) TYP
WSON - 0.8 mm max heightNGN0008A
PLASTIC SMALL OUTLINE - NO LEAD
4214794/A 11/2019
SYMM
1
45
8
LAND PATTERN EXAMPLE
EXPOSED METAL SHOWN
SCALE:15X
SYMM 9
NOTES: (continued)
4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature
number SLUA271 (www.ti.com/lit/slua271).
5. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown
on this view. It is recommended that vias under paste be filled, plugged or tented.
SOLDER MASK
OPENING
SOLDER MASK
METAL UNDER
SOLDER MASK
DEFINED
EXPOSED
METAL
METAL
SOLDER MASK
OPENING
SOLDER MASK DETAILS
NON SOLDER MASK
DEFINED
(PREFERRED)
EXPOSED
METAL
www.ti.com
EXAMPLE STENCIL DESIGN
(R0.05) TYP
0.59
4X (1.31)
8X (0.3)
8X (0.5)
4X (0.98)
(3.3)
(0.755)
6X (0.8)
WSON - 0.8 mm max heightNGN0008A
PLASTIC SMALL OUTLINE - NO LEAD
4214794/A 11/2019
NOTES: (continued)
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
SOLDER PASTE EXAMPLE
BASED ON 0.125 mm THICK STENCIL
EXPOSED PAD 9:
78% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE
SCALE:20X
SYMM
1
45
8
METAL
TYP
SYMM 9
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