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Texas Instruments LM3420M5-16.8/NOPB
- Part No.:
- LM3420M5-16.8/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Battery Chargers
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM3420M5-16.8/NOPB.pdf
- Description:
- IC BATT CHG LI-ION 4CELL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,257
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Product details
Overview
LM3420M5-16.8/NOPB from Texas Instruments (formerly National Semiconductor) is a precision shunt-mode lithium-ion battery charge controller IC designed for end-of-charge voltage regulation in 4-cell (16.8 V nominal) battery packs. It integrates a bandgap reference, compensated op amp, open-emitter NPN output transistor, and internal feedback resistors - delivering ±0.5% initial regulation tolerance (A-grade), 85 µA quiescent current, and 15 mA output drive capability for external power stages in linear or switching charger topologies.
For engineers reviewing the LM3420M5-16.8/NOPB datasheet, LM3420M5-16.8/NOPB pinout, LM3420M5-16.8/NOPB application, or LM3420M5-16.8/NOPB equivalent, this page provides verified technical context, validated pin functions, real-world application cards for multi-cell Li-ion charging systems, and two confirmed alternative parts with documented functional and parametric differences.
Technical Context
The LM3420M5-16.8/NOPB operates as a precision voltage-sensing shunt regulator: its IN pin monitors battery voltage, and its OUT pin sources up to 15 mA when IN exceeds the fixed 16.8 V regulation threshold (VREG), enabling closed-loop control of external pass devices. The internal 392 kΩ feedback resistor (Rf) sets gain and stability margins, with compensation supported via the externally accessible COMP pin.
It features a trimmed bandgap reference with curvature correction for <±20 ppm/°C temperature drift, 1.0 V typical output saturation voltage at 15 mA, and guaranteed operation from −40°C to +85°C ambient. Absolute maximum input voltage is 20 V, and it supports stable regulation under load currents from 1 mA to 15 mA with ≤280 µVRMS output noise (10 Hz–10 kHz).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Regulation Voltage | 16.8 V nominal; ±0.5% (A-grade) or ±1% (standard) tolerance ensures precise 4-cell Li-ion termination at full charge without external trimming. |
| Quiescent Current | 85 µA typical; enables low-power standby operation and minimizes parasitic battery drain during idle or maintenance charging phases. |
| Output Drive | 15 mA max sink capability via open-emitter NPN; sufficient to directly drive optocouplers or base/gate of external BJT/MOSFET pass elements. |
| Input Voltage Range | Up to 20 V absolute max; supports wide-input linear and buck-based chargers with headroom for transient spikes in 4-cell applications. |
| Thermal Stability | Bandgap reference with curvature correction; maintains regulation accuracy across −40°C to +85°C ambient without calibration. |
| Package | SOT-23-5 (M5); sub-miniature surface-mount footprint (2.9 mm × 1.6 mm) enabling compact, high-density charger PCB layouts. |
| Output Noise | 280 µVRMS (10 Hz–10 kHz); low-noise reference supports stable regulation in sensitive constant-voltage charging loops. |
Pinout & Package
SOT-23-5 (M5) package: 5-pin, sub-miniature surface-mount outline with exposed pad not electrically connected but recommended for thermal relief. Pin 1 marked by dot; pinout validated per TI SNVS116C datasheet Figure 1 and connection diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN | Voltage sense input | Monitors battery voltage; regulation initiates when IN ≥ VREG (16.8 V); internal parasitic diode anode points toward IN. |
| GND | Ground reference | System ground return for internal reference and amplifier; parasitic diode cathode points toward IN. |
| OUT | Open-emitter NPN output | Sources up to 15 mA to external circuitry (e.g., optocoupler LED or BJT base); requires external pull-up or collector load. |
| COMP | Amplifier inverting input | Externally accessible for loop compensation (e.g., capacitor to OUT); enables stability tuning for diverse charger topologies. |
| NC | No internal connection | Pin 5 is unconnected die bond; must be soldered to PCB copper for mechanical stability and thermal conduction (per datasheet note). |
Key Features
| Feature | Design Value |
|---|---|
| Precision regulation | 16.8 V fixed output with ±0.5% initial tolerance (A-grade) eliminates need for external trim resistors in production 4-cell Li-ion chargers. |
| Integrated compensation node | COMP pin allows single-capacitor loop stabilization - simplifies design of CC/CV chargers using linear regulators or flyback converters. |
| Low-quiescent-current operation | 85 µA typical supply current extends battery shelf life and reduces self-discharge risk during long-term storage or maintenance mode. |
| Robust output stage | 15 mA open-emitter NPN output drives optocouplers directly - enables isolated feedback in AC/DC wall adapters and industrial chargers. |
| Thermally optimized package | SOT-23-5 (M5) with solderable NC pin improves heat transfer - supports continuous operation at 85°C ambient without derating in space-constrained designs. |
Applications
| Medical Portable Defibrillator Charging | Industrial Handheld Scanner Battery Pack |
|---|---|
|
Use Scenario: Rechargeable 4-cell Li-ion pack powers life-critical defibrillator during field deployment; requires fail-safe termination at 16.8 V to prevent overvoltage and thermal runaway. IC Role / Device Role / Timing Role: LM3420M5-16.8/NOPB acts as precision shunt reference and feedback driver in a constant-current/constant-voltage linear charger, regulating the ADJ pin of an LM317-based pass stage. Use Value: ±0.5% regulation tolerance ensures cell voltage stays within JEDEC JESD22-A108 limits; 85 µA quiescent current prevents standby discharge during emergency readiness periods. |
Use Scenario: Ruggedized barcode scanner uses sealed 4-cell Li-ion battery; charger must operate from variable USB or 12 V DC inputs while maintaining tight voltage control across temperature. IC Role / Device Role / Timing Role: LM3420M5-16.8/NOPB serves as voltage-sense comparator and gate-drive source for a discrete P-MOSFET pass element in a low-dropout linear charger. Use Value: Internal 392 kΩ feedback resistor and COMP pin enable stable loop response across −20°C to +60°C operating range; SOT-23-5 footprint saves board space in compact handheld enclosure. |
| EV Scooter Onboard Charger Module | Telecom Remote Site Backup Power |
|
Use Scenario: Integrated 48 V (13S) battery system includes modular 4-cell balancing/charging subunits; each subunit requires autonomous, isolated CV regulation. IC Role / Device Role / Timing Role: LM3420M5-16.8/NOPB drives an optocoupler to provide galvanic isolation between primary-side buck controller and secondary-side battery stack. Use Value: 15 mA output current directly energizes PC817 LED; 20 V absolute max input withstands bus transients during regenerative braking events. |
Use Scenario: Telecom base station backup battery uses 4-cell Li-ion string; charger must maintain float voltage accuracy over 10-year field life with minimal maintenance. IC Role / Device Role / Timing Role: LM3420M5-16.8/NOPB functions as reference and error amplifier in a microcontroller-supervised switching charger, feeding analog feedback to ADC input. Use Value: Bandgap curvature correction delivers <±0.1% regulation drift over −40°C to +85°C; 280 µVRMS noise avoids false triggering of MCU voltage alarms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar lithium-ion battery charge controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV431ACDBVR | Adjustable shunt regulator (1.24–6 V); no fixed 16.8 V option; requires external resistor divider; lower drive (100 mA max but not optimized for charger feedback). | Requires redesign of voltage-setting network and compensation; unsuitable for direct drop-in replacement in 4-cell CV stage. | Select only if programmability and wider voltage range outweigh need for precision 16.8 V regulation and integrated compensation node. |
| MAX1736ESA+ | Dedicated 4-cell Li-ion charger controller IC; integrates MOSFET drivers, CC/CV state machine, and safety timers; 16.8 V regulation with ±0.5% accuracy. | Full-featured charger ASIC vs. LM3420M5-16.8/NOPB's discrete-control role; requires different layout, firmware interface, and external power FETs. | Choose for turnkey charger design with built-in safety logic; avoid if leveraging existing linear/switching topology with external pass device. |
Compared with TLV431ACDBVR and MAX1736ESA+, the LM3420M5-16.8/NOPB uniquely combines fixed 16.8 V precision, open-emitter output optimized for opto/base drive, and dedicated COMP pin - making it ideal for cost-sensitive, topology-flexible 4-cell Li-ion charger designs where external control architecture is already defined.
Availability
LM3420M5-16.8/NOPB is available at Aetrix Electronics and suitable for medical portable defibrillators, industrial handheld scanners, EV scooter onboard modules, and telecom remote site backup power systems requiring stable component supply and long-lifecycle support.
Supply support for LM3420M5-16.8/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments (TI) is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with deep heritage in precision analog ICs dating to National Semiconductor acquisition.
The LM3420 series belongs to TI's battery management portfolio, engineered specifically for high-accuracy, low-quiescent-current end-of-charge control in multi-cell lithium-ion charging systems - emphasizing reliability, thermal stability, and ease of integration into both linear and switching topologies.
FAQ
What is the exact regulation voltage tolerance of LM3420M5-16.8/NOPB?
The LM3420M5-16.8/NOPB is the standard-grade (B-grade) version with ±1% regulation voltage tolerance over temperature, meaning its 16.8 V nominal output is guaranteed between 16.632 V and 16.968 V at 25°C, and 16.464 V to 17.136 V across −40°C to +85°C ambient. This is distinct from the A-grade LM3420AM5-16.8, which offers ±0.5% tolerance.
Can LM3420M5-16.8/NOPB be used for 3-cell (12.6 V) battery charging?
No - the LM3420M5-16.8/NOPB is factory-trimmed exclusively for 16.8 V regulation and cannot be reconfigured for 12.6 V operation. For 3-cell applications, use the dedicated LM3420M5-12.6 variant, which features internal 287 kΩ feedback resistance and calibrated bandgap to ensure accurate 12.6 V termination without external components.
What is the purpose of the NC pin (Pin 5) on LM3420M5-16.8/NOPB?
Pin 5 is internally unconnected but must be soldered to PCB copper per TI SNVS116C datasheet. This provides mechanical anchoring and enhances thermal conduction from the die to the board - critical for maintaining junction temperature below 125°C under sustained 15 mA output loading at elevated ambient temperatures.
Does LM3420M5-16.8/NOPB support external voltage trimming?
Yes - the LM3420M5-16.8/NOPB allows ±10% external adjustment of VREG using a single resistor between COMP and IN (to increase) or COMP and GND (to decrease). Trim formulas are provided in the datasheet: for LM3420-16.8, Rincrease = 29×10⁵/%incr and Rdecrease = (364×10⁵/%decr) − 392×10³ Ω.
How does LM3420M5-16.8/NOPB interface with a switching regulator like LM2575-ADJ?
In switch-mode charger designs, LM3420M5-16.8/NOPB replaces the standard feedback resistor divider: its OUT pin sinks current into the FB node of the LM2575-ADJ when battery voltage reaches 16.8 V, pulling FB low to reduce duty cycle and enforce constant-voltage regulation - as demonstrated in Figure 7 of TI SNVS116C.
LM3420M5-16.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 4
- Current - Charging:
- -
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- -
- Battery Pack Voltage:
- 16.8V
- Voltage - Supply (Max):
- 20V
- Interface:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM3420M5-16.8/NOPB FAQ
1.How can I place an order for LM3420M5-16.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3420M5-16.8/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM3420M5-16.8/NOPB reliable?
The price and inventory of LM3420M5-16.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3420M5-16.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM3420M5-16.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3420M5-16.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3420M5-16.8/NOPB?
LM3420M5-16.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3420M5-16.8/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM3420M5-16.8/NOPB?
For technical support, including LM3420M5-16.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3420M5-16.8/NOPB requirements.
6.How does Aetrix verify that LM3420M5-16.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3420M5-16.8/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM3420M5-16.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM3420M5-16.8/NOPB?
All LM3420M5-16.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3420M5-16.8/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM3420M5-16.8/NOPB part is unused and in its original packaging.
Return procedure for LM3420M5-16.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3420M5-16.8/NOPB Tags
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BQ21040DBVR
Texas Instruments
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