SNVS116E May   1998  – December 2014 LM3420

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 LM3420 Electrical Characteristics
    6. 6.6 LM3420A Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Test Circuits
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Compensation
      2. 8.3.2 VREG External Voltage Trim
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation as Control Section
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application: Constant Current/Constant Voltage Li-Ion Battery Charger
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Compensation Capacitor
      3. 9.2.3 Application Curve
      4. 9.2.4 Other Application Circuits
        1. 9.2.4.1 Low Dropout Constant Current/Constant Voltage 2-Cell Charger
        2. 9.2.4.2 High-Efficiency Switching Regulator Constant Current/Constant Voltage 2-Cell Charger
        3. 9.2.4.3 Low Dropout Constant Current/Constant Voltage Li-Ion Battery Charger
        4. 9.2.4.4 High-Efficiency Switching Charger With High Side Current Sensing
        5. 9.2.4.5 Fast-Pulsed Constant Current 2-Cell Charger
        6. 9.2.4.6 MOSFET Low Dropout Charger
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Trademarks
    2. 12.2 Electrostatic Discharge Caution
    3. 12.3 Glossary
  13. 13Mechanical, 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)(2)
MIN MAX UNIT
Input voltage VIN 20 V
Output current 20 mA
Junction temperature 150 °C
Lead temperature Vapor phase (60 seconds) 215
Infrared (15 seconds) 220
Power dissipation (TA = 25°C)(3) 300 mV
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 must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), RθJA (junction-to-ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax − TA)/RθJA or the number given in the Absolute Maximum Ratings, whichever is lower. The typical thermal resistance (RθJA) when soldered to a printed circuit board is approximately 181.2°C/W for the DBV0005A package.

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)(1)(2)
MIN NOM MAX UNIT
Ambient temperature −40 85 °C
Junction temperature −40 125
Output current 15 mA
(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 power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), RθJA (junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax − TA)/RθJA or the number given in the Absolute Maximum Ratings, whichever is lower. The typical thermal resistance (RθJA) when soldered to a printed circuit board is approximately 181.2°C/W for the DBV0005A package.

6.4 Thermal Information

THERMAL METRIC(1) LM3420 UNIT
SOT-23 (DBV)
5 PINS
RθJA Junction-to-ambient thermal resistance 181.2  °C/W
RθJC(top) Junction-to-case (top) thermal resistance 91.2
RθJB Junction-to-board thermal resistance 38.2
ψJT Junction-to-top characterization parameter 5.3
ψJB Junction-to-board characterization parameter 37.7
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 LM3420 Electrical Characteristics

Unless otherwise specified, specifications apply over full operating temperature range and VIN = VREG, VOUT = 1.5 V.
PARAMETER TEST CONDITIONS MIN(2)   TYP(1) MAX(2) UNIT
VREG Regulation voltage IOUT = 1 mA, TJ = 25°C 8.316 8.4 8.484 V
IOUT = 1 mA 8.232 8.4 8.568
Regulation voltage tolerance IOUT = 1 mA, TJ = 25°C –1% 1%
IOUT = 1 mA –2% 2%
IQ Quiescent current IOUT = 1 mA, TJ = 25°C 85 125 μA
IOUT = 1 mA 85 150
Gm Transconductance
ΔIOUT/ΔVREG		 20 μA ≤ IOUT ≤ 1 mA, VOUT = 6 V
TJ = 25°C		 1 3.3 mA/mV
20 μA ≤ IOUT ≤ 1 mA, VOUT = 6 V 0.50 3.3
1 mA ≤ IOUT ≤ 15 mA, VOUT = 6 V 2.5 6
1 mA ≤ IOUT ≤ 15 mA, VOUT = 6 V 1.4 6
AV Voltage gain
ΔVOUT/ΔVREG		 1 V ≤ VOUT ≤ VREG − 1.2V, RL = 470 Ω(3)
TJ = 25°C		 450 1000 V/V
1 V ≤ VOUT ≤ VREG − 1.3 V, RL = 470 Ω 200 1000
1 V ≤ VOUT ≤ VREG − 1.2 V, RL = 5 kΩ(3)
TJ = 25°C		 1000 3500 V/V
1 V ≤ VOUT ≤ VREG − 1.3 V, RL = 5 kΩ 700 3500
VSAT Output saturation(4) VIN = VREG + 100 mV
TJ = 25°C		 1 1.2 V
VIN = VREG + 100 mV 1 1.3
IL Output leakage current VIN = VREG − 100 mV, VOUT = 0 V
TJ = 25°C		 0.1 0.5 μA
VIN = VREG − 100 mV, VOUT = 0 V 0.1 1
Rf Internal feedback resistor(5) TJ = 25°C 135 181 227 kΩ
En Output noise voltage IOUT = 1 mA, 10 Hz ≤ f ≤ 10 kHz 140 μVRMS
(1) Typical numbers are at 25°C and represent the most likely parametric norm.
(2) Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate Averaging Outgoing Quality Level (AOQL).
(3) Actual test is done using equivalent current sink instead of a resistor load.
(4) VSAT = V(IN) − VOUT, when the voltage at the IN pin is forced 100 mV above the nominal regulating voltage (VREG).
(5) See Application and Implementation and Typical Characteristics sections for information on this resistor.

6.6 LM3420A Electrical Characteristics

Unless otherwise specified, specifications apply over full operating temperature range and VIN = VREG, VOUT = 1.5 V.
PARAMETER TEST CONDITIONS MIN(2)   TYP(1) MAX(2) UNIT
VREG Regulation voltage IOUT = 1 mA, TJ = 25°C 8.358 8.4 8.442 V
IOUT = 1 mA 8.316 8.4 8.484
Regulation voltage tolerance IOUT = 1 mA, TJ = 25°C –0.5% 0.5%
IOUT = 1 mA –1% 1%
IQ Quiescent current IOUT = 1 mA, TJ = 25°C 85 110 μA
IOUT = 1 mA 85 115
Gm Transconductance
ΔIOUT/ΔVREG		 20 μA ≤ IOUT ≤ 1 mA, VOUT = 6 V
TJ = 25°C		 1.3 3.3 mA/mV
20 μA ≤ IOUT ≤ 1 mA, VOUT = 6 V 0.75 3.3
1 mA ≤ IOUT ≤ 15 mA, VOUT = 6 V 3 6
1 mA ≤ IOUT ≤ 15 mA, VOUT = 6 V 1.5 6
AV Voltage gain
ΔVOUT/ΔVREG		 1 V ≤ VOUT ≤ VREG − 1.2 V, RL = 470 Ω(3)
TJ = 25°C		 550 1000 V/V
1 V ≤ VOUT ≤ VREG − 1.3 V, RL = 470 Ω 250 1000
1 V ≤ VOUT ≤ VREG − 1.2 V, RL = 5 kΩ(3)
TJ = 25°C		 1500 3500 V/V
1 V ≤ VOUT ≤ VREG − 1.3 V, RL = 5 kΩ 900 3500
VSAT Output saturation(4) VIN = VREG + 100 mV
TJ = 25°C		 1 1.2 V
VIN = VREG + 100 mV 1 1.3
IL Output leakage current VIN = VREG − 100 mV, VOUT = 0 V
TJ = 25°C		 0.1 0.5 μA
VIN = VREG − 100 mV, VOUT = 0 V 0.1 1
Rf Internal feedback resistor(5) TJ = 25°C 135 181 227 kΩ
En Output noise voltage IOUT = 1 mA, 10 Hz ≤ f ≤ 10 kHz 140 μVRMS
(1) Typical numbers are at 25°C and represent the most likely parametric norm.
(2) Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlation using Statistical Quality Control (SQC) methods. The limits are used to calculate Averaging Outgoing Quality Level (AOQL).
(3) Actual test is done using equivalent current sink instead of a resistor load.
(4) VSAT = VIN − VOUT, when the voltage at the IN pin is forced 100 mV above the nominal regulating voltage (VREG).
(5) See Application and Implementation and Typical Characteristics sections for information on this resistor.

6.7 Typical Characteristics

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Figure 1. Bode Plot
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Figure 3. Response Time
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Figure 5. Internal Feedback Resistor (Rf) Tempco
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Figure 7. Output Saturation Voltage (VSAT)
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Figure 2. Response Time
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Figure 4. Quiescent Current
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Figure 6. Normalized Temperature Drift