Datasheet

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LM3420

www.ti.com

SNVS116D –MAY 1998–REVISED MAY 2013

LM3420-4.2, -8.2, -8.4, -12.6, -16.8 Lithium-Ion Battery Charge Controller

Check for Samples: LM3420

FEATURES

DESCRIPTION

The LM3420 series of controllers are monolithic

• Voltage Options for Charging 1, 2, 3 or 4 Cells

integrated circuits designed for charging and end-of-

• Tiny SOT-23-5 Package

charge control for Lithium-Ion rechargeable batteries.

• Precision (0.5%) End-of-Charge Control

The LM3420 is available in five fixed voltage versions

for one through four cell charger applications (4.2V,

• Drive Capability for External Power Stage

8.2V/8.4V, 12.6V and 16.8V respectively).

• Low Quiescent Current, 85 μA (Typ.)

Included in a very small package is an (internally

compensated) op amp, a bandgap reference, an NPN

APPLICATIONS

output transistor, and voltage setting resistors. The

• Lithium-Ion Battery Charging

amplifier's inverting input is externally accessible for

• Suitable for Linear and Switching Regulator

loop frequency compensation. The output is an open-

Charger Designs emitter NPN transistor capable of driving up to 15 mA

of output current into external circuitry.

A trimmed precision bandgap reference utilizes

temperature drift curvature correction for excellent

voltage stability over the operating temperature

range. Available with an initial tolerance of 0.5% for

the A grade version, and 1% for the standard version,

the LM3420 allows for precision end-of-charge control

for Lithium-Ion rechargeable batteries.

The LM3420 is available in a sub-miniature 5-lead

surface mount package thus allowing very compact

designs.

Typical Application and Functional Diagram

Figure 1. Typical Constant Current/Constant Voltage

Li-Ion Battery Charger

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2SIMPLE SWITCHER is a trademark of Texas Instruments.

3All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (27 pages)

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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 LM3420-4.2, -8.2, -8.4, -12.6, -16.8 Lithium-Ion Battery Charge Controller Check for Samples: LM3420 FEATURES DESCRIPTION • • • • • The LM3420 series of controllers are monolithic integrated circuits designed for charging and end-ofcharge control for Lithium-Ion rechargeable batteries. The LM3420 is available in five fixed voltage versions for one through four cell charger applications (4.2V, 8.2V/8.4V, 12.6V and 16.8V respectively).
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com Figure 2. LM3420 Functional Diagram Connection Diagrams 5-Lead Small Outline Package Top View Actual Size *No internal connection, but should be soldered to PC board for best heat transfer. Figure 3. SOT-23 Package See Package DBV0005A Figure 4. SOT-23 Package See Package DBV0005A These devices have limited built-in ESD protection.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 OPERATING RATINGS (1) (2) Ambient Temperature Range −40°C ≤ TA ≤ +85°C Junction Temperature Range −40°C ≤ TJ ≤ +125°C Output Current (1) (2) 15 mA Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not ensure specific performance limits.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com LM3420-8.2 ELECTRICAL CHARACTERISTICS Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V(IN) = VREG, VOUT = 1.5V. Symbol Parameter VREG Conditions IOUT = 1 mA Typical (1) Iq Quiescent Current IOUT = 1 mA IOUT = 1 mA Transconductance ΔIOUT/ΔVREG VOUT = 6V 1 mA ≤ IOUT ≤ 15 mA 1V ≤ VOUT ≤ VREG − 1.2V (−1.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 LM3420-8.4 ELECTRICAL CHARACTERISTICS Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V(IN) = VREG, VOUT = 1.5V. Symbol Parameter VREG Conditions IOUT = 1 mA Typical (1) Iq Quiescent Current IOUT = 1 mA IOUT = 1 mA Transconductance ΔIOUT/ΔVREG VOUT = 6V 1 mA ≤ IOUT ≤ 15 mA 1V ≤ VOUT ≤ VREG − 1.2V (−1.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com LM3420-12.6 ELECTRICAL CHARACTERISTICS Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V(IN) = VREG, VOUT = 1.5V. Symbol Parameter VREG Conditions IOUT = 1 mA Typical (1) Iq Quiescent Current IOUT = 1 mA IOUT = 1 mA Transconductance ΔIOUT/ΔVREG VOUT = 10V 1 mA ≤ IOUT ≤ 15 mA 1V ≤ VOUT ≤ VREG − 1.2V (−1.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 LM3420-16.8 ELECTRICAL CHARACTERISTICS Specifications with standard type face are for TJ = 25°C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V(IN) = VREG, VOUT = 1.5V. Symbol Parameter VREG Conditions IOUT = 1 mA Typical (1) Iq Quiescent Current IOUT = 1 mA IOUT = 1 mA Transconductance ΔIOUT/ΔVREG VOUT = 15V 1 mA ≤ IOUT ≤ 15 mA 1V ≤ VOUT ≤ VREG − 1.2V (−1.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS 8 4.2V Bode Plot Response Time for 4.2V Version Figure 5. Figure 6. Response Time for 4.2V Version 8.2V and 8.4V Bode Plot Figure 7. Figure 8. Response Time for 8.2V, 8.4V Versions Response Time for 8.2V, 8.4V Versions Figure 9. Figure 10.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) 12.6V Bode Plot Response Time for 12.6V Version Figure 11. Figure 12. Response Time for 12.6V Version 16.8V Bode Plot Figure 13. Figure 14. Response Time for 16.8V Version Response Time for 16.8V Version Figure 15. Figure 16.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 10 Regulation Voltage vs Output Voltage and Load Resistance Circuit Used for Bode Plots Figure 17. Figure 18. Circuit Used for Response Time Regulation Voltage vs Output Voltage and Load Resistance Figure 19. Figure 20. Quiescent Current Internal Feedback Resistor (Rf) Tempco Figure 21. Figure 22.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Regulation Voltage vs Output Voltage and Load Resistance Normalized Temperature Drift Figure 23. Figure 24. Output Saturation Voltage (VSAT) Regulation Voltage vs Output Voltage and Load Resistance Figure 25. Figure 26. PRODUCT DESCRIPTION The LM3420 is a shunt regulator specifically designed to be the reference and control section in an overall feedback loop of a Lithium-Ion battery charger.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com where • • • • Rf ≈ 75 kΩ for the 4.2V part Rf ≈ 181 kΩ for the 8.4V part Rf ≈ 287 kΩ for the 12.6V part Rf ≈ 392 kΩ for the 16.8V part (1) The resistor (Rf) in the formula is an internal resistor located on the die. Since this resistor value will affect the phase margin, the worst case maximum and minimum values are important when analyzing closed loop stability.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 Figure 28. Normalized Temperature Drift with Output Externally Trimmed Decreasing VREG Figure 29. Increasing VREG Figure 30. Changing VREG Formulas for selecting trim resistor values are shown below, based on the percent of increase (%incr) or percent of decrease (%decr) of the output voltage from the nominal voltage. For LM3420-4.2 Rincrease = 22x105/%incr Rdecrease = (53x105/%decr) − 75x103 (2) (3) For LM3420-8.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION The LM3420 regulator/driver provides the reference and feedback drive functions for a Lithium-Ion battery charger. It can be used in many different charger configurations using both linear and switching topologies to provide the precision needed for charging Lithium-Ion batteries safely and efficiently. Output voltage tolerances better than 0.5% are possible without using trim pots or precision resistors.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 As the battery charges, its voltage begins to rise, and is sensed at the IN pin of the LM3420. Once the battery voltage reaches 8.4V, the LM3420 begins to regulate and starts sourcing current to the base of Q2. Transistor Q2 begins controlling the ADJ. pin of the LM317 which begins to regulate the voltage across the battery and the constant voltage portion of the charging cycle starts.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com Figure 33. High Efficiency Switching Regulator Constant Current/Constant Voltage 2-Cell Charger Figure 34. Low Dropout Constant Current/Constant Voltage Li-Ion Battery Charger A switching regulator, constant-current, constant-voltage two-cell Li-Ion battery charging circuit is shown in Figure 33. This circuit provides much better efficiency, especially over a wide input voltage range than the linear topologies. For a 1A charger an LM2575-ADJ.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 Once the battery voltage reaches 8.4V, the LM3420 takes over and begins to control the feedback pin of the LM2575-ADJ. The LM3420 now regulates the voltage across the battery, and the charger becomes a constantvoltage charger. Loop compensation network R6 and C3 ensure stable operation of the charger circuit under both constant-current and constant-voltage conditions.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com Figure 36. (Fast) Pulsed Constant Current 2-Cell Charger A rapid charge Lithium-Ion battery charging circuit is shown in Figure 36. This configuration uses a switching regulator to deliver the charging current in a series of constant current pulses. At the beginning of the charge cycle (constant-current mode), this circuit performs identically to the previous LM2575 charger by charging the battery at a constant current of 1A.
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LM3420 www.ti.com SNVS116D – MAY 1998 – REVISED MAY 2013 Figure 37. MOSFET Low Dropout Charger Figure 37 shows a low dropout constant voltage charger using a MOSFET as the pass element, but this circuit does not include current limiting. This circuit uses Q3 and a Schottky diode to isolate the battery from the charging circuitry when the input voltage is removed, to prevent the battery from discharging. Q2 should be a high current (0.2Ω) FET, while Q3 can be a low current (2Ω) device.
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LM3420 SNVS116D – MAY 1998 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision C (May 2013) to Revision D • 20 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LM3420AM5-8.4 NRND SOT-23 DBV 5 1000 TBD Call TI Call TI -40 to 125 D03A LM3420AM5-8.4/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 D03A LM3420M5X-8.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 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.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) LM3420AM5-8.4 SOT-23 DBV 5 1000 178.0 8.4 LM3420AM5-8.4/NOPB SOT-23 DBV 5 1000 178.0 LM3420M5X-8.4/NOPB SOT-23 DBV 5 3000 178.0 3.2 3.2 1.4 4.0 8.0 Q3 8.4 3.2 3.2 1.4 4.0 8.0 Q3 8.4 3.2 3.2 1.4 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3420AM5-8.4 SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3420AM5-8.4/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3420M5X-8.4/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.
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