SNVS114G May   1999  – February 2015 LM3940

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Output Voltage Accuracy
      2. 7.3.2 Short-Circuit Protection
      3. 7.3.3 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation with VIN = 5 V
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 External Capacitors
          1. 8.2.2.1.1 Minimum Capacitance
          2. 8.2.2.1.2 ESR Limits
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Heatsinking
      1. 10.3.1 Heatsinking TO-220 Package Parts
      2. 10.3.2 Heatsinking DDPAK/TO-263 and SOT-223 Package Parts
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
Power dissipation(2) Internally Limited
Input supply voltage –0.3 7.5 V
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) The maximum allowable power dissipation is a function of the maximum junction temperature, TJ, the junction-to-ambient thermal resistance, RθJA, and the ambient temperature, TA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. The value of RθJA (for devices in still air with no heatsink) is 23.3°C/W for the TO-220 package, 40.9°C/W for the DDPAK/TO-263 package, and 59.3°C/W for the SOT-223 package. The effective value of RθJA can be reduced by using a heatsink (see Heatsinking for specific information on heatsinking).

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
Junction temperature, TJ –40 125 °C
Input supply voltage, VIN 4.5 5.5 V

6.4 Thermal Information

THERMAL METRIC(1) LM3940 UNIT
SOT-223 (DCY) TO-263 (KTT) TO-220 (NDE)
4 PINS 3 PINS 3 PINS
RθJA Junction-to-ambient thermal resistance, High-K 59.3 40.9 23.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 38.9 43.5 16.1 °C/W
RθJB Junction-to-board thermal resistance 8.1 23.5 4.8 °C/W
ψJT Junction-to-top characterization parameter 1.7 10.3 2.7 °C/W
ψJB Junction-to-board characterization parameter 8.0 22.5 4.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance n/a 0.8 1.1 °C/W
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Over operating free-air temperature range, VIN = 5 V, IOUT = 1 A, COUT = 33 μF (unless otherwise noted). Limits apply for TJ = 25°C, unless otherwise specified in the Test Conditions column.(1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VOUT Output voltage 5 mA ≤ IOUT ≤ 1 A, TJ = 25°C 3.20 3.3 3.40 V
5 mA ≤ IOUT ≤ 1 A,
–40°C ≤ TJ ≤ 125°C		 3.13 3.47
LM3940 1208025.gif
 Line regulation IOUT = 5 mA
4.5 V ≤ VIN ≤ 5.5 V		 20 40 mV
LM3940 1208026.gif
 Load regulation 50 mA ≤ IOUT ≤ 1 A, TJ = 25°C 35 50
50 mA ≤ IOUT ≤ 1 A
–40°C ≤ TJ ≤ 125°C		 35 80
ZOUT Output impedance IOUT (DC) = 100 mA
IOUT (AC) = 20 mA (rms)
ƒ = 120 Hz		 35 mΩ
IQ Quiescent current 4.5 V ≤ VIN ≤ 5.5 V, IOUT = 5 mA, TJ = 25°C 10 15 mA
4.5 V ≤ VIN ≤ 5.5 V, IOUT = 5 mA
–40°C ≤ TJ ≤ 125°C		 10 20
VIN = 5 V, IOUT = 1 A, TJ = 25°C 110 200
VIN = 5 V, IOUT = 1 A
–40°C ≤ TJ ≤ 125°C		 110 250
en Output noise voltage ƒBW = 10 Hz – 100 kHz
IOUT = 5 mA		 150 μV(rms)
VDO Dropout voltage(2) IOUT = 1 A, TJ = 25°C 0.5 0.8 V
IOUT = 1 A
–40°C ≤ TJ ≤ 125°C		 0.5 1
IOUT = 100 mA, TJ = 25°C 110 150 mV
IOUT = 100 mA
–40°C ≤ TJ ≤ 125°C		 110 200
IOUT(SC) Short-circuit current RL = 0 1.2 1.7 A
(1) All limits specified for TJ = 25°C are 100% tested and are used to calculate Outgoing Quality Levels. All limits at temperature extremes are verified via correlation using standard Statistical Quality Control (SQC) methods.
(2) Dropout voltage is defined as the input-output differential voltage where the regulator output drops to a value that is 100 mV below the value that is measured at VIN = 5 V.

6.6 Typical Characteristics

At TJ=25°C, unless otherwise noted.
LM3940 1208013.png Figure 1. Dropout Voltage
LM3940 1208015.png Figure 3. Output Voltage vs. Temperature
LM3940 1208017.png Figure 5. Quiescent Current vs. VIN
LM3940 1208021.png Figure 7. Ripple Rejection
LM3940 1208024.png Figure 9. Peak Output Current
LM3940 1208014.png Figure 2. Dropout Voltage vs. Temperature
LM3940 1208016.png Figure 4. Quiescent Current vs. Temperature
LM3940 1208018.png Figure 6. Quiescent Current vs. Load
LM3940 1208023.png Figure 8. Output Impedance
LM3940 1208022.png Figure 10. Low Voltage Behavior