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Analog Devices Inc. LTC4012IUF-2#PBF
- Part No.:
- LTC4012IUF-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC4012IUF-2#PBF.pdf
- Description:
- IC BAT CHG MULT-CHEM 1-4CL 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,167
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Product details
Overview
LTC4012IUF-2#PBF from Analog Devices (formerly Linear Technology) is a synchronous buck battery charger controller optimized for 4-cell Li-ion/polymer packs with 4.2V/cell output. It delivers ±0.5% float voltage accuracy, programmable charge current (±4% accuracy), and 550kHz quasi-constant-frequency PWM operation with no audible noise using ceramic capacitors. Designed for notebook computers and portable instruments, it integrates PowerPath™ ideal diode control, AC adapter input current limiting, and analog charge current monitoring via the PROG pin.
For engineers reviewing the LTC4012IUF-2#PBF datasheet, LTC4012IUF-2#PBF pinout, LTC4012IUF-2#PBF application, or LTC4012IUF-2#PBF equivalent, key selection considerations include its –40°C to 125°C industrial temperature grade, 20-pin 4mm × 4mm QFN package, pin-programmable 4.2V/cell output, INFET-controlled input power path, and absence of built-in charge termination requiring external MCU supervision.
Technical Context
The LTC4012IUF-2#PBF implements a current-mode synchronous buck topology with integrated gate drivers for external NMOS high-side (TGATE) and synchronous rectifier (BGATE) FETs. Its PWM operates at 550kHz nominal frequency with 20–633kHz range, supporting soft-start via ITH compensation and cycle-by-cycle peak current sensing referenced to CSP/CSN.
PowerPath™ control uses the INFET output to drive an external PMOS between DCIN and CLP, regulating forward voltage to ~25mV and blocking reverse current within 6µs when DCIN–CLP falls below –25mV. Charge voltage is set by FVS0/FVS1 pins: for LTC4012IUF-2#PBF, FVS1=5V and FVS0=0V selects 4.2V/cell (e.g., 16.8V for 4S), with ±0.8% accuracy over –40°C to 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 16.8V (4.2V × 4 cells), pin-programmed via FVS0/FVS1; enables direct compatibility with standard 4S Li-ion battery packs. |
| Charge Current Accuracy | ±4% over temperature; achieved via matched RIN resistors and PROG pin feedback, enabling precise current regulation without calibration. |
| Input Voltage Range | 6V to 28V on CLP pin; supports wide-range AC adapters and industrial DC inputs while maintaining regulation. |
| Switching Frequency | 550kHz typical; allows compact 6.8µH inductors and ceramic output capacitors without audible switching noise. |
| Operating Temperature | –40°C to 125°C junction; validated for industrial and extended-temperature embedded systems with full parameter guarantees. |
| Package | 20-pin 4mm × 4mm × 0.75mm QFN with exposed thermal pad; provides low θJA = 37°C/W for high-power charging in space-constrained layouts. |
| Float Voltage Accuracy | ±0.8% over full temperature range; ensures cell voltage remains within safe limits for long-term Li-ion reliability and cycle life. |
Pinout & Package
20-pin (4mm × 4mm) plastic QFN package with exposed GND paddle (Pin 21), requiring soldering to PCB thermal pad for electrical integrity and thermal performance (θJA = 37°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLN (1) | Adapter current limit negative sense | Senses voltage drop across RSENSE; threshold is 100mV below CLP to enable precise input current limiting without external op-amps. |
| CLP (2) | Adapter input supply & current limit reference | Primary input power rail (6–28V); supplies internal circuits and serves as reference for CLN, INFET, and DCIN comparators. |
| INFET (3) | PMOS gate driver for PowerPath™ ideal diode | Drives external PFET to maintain ~25mV forward drop; blocks reverse current in <6µs if DCIN–CLP < –25mV. |
| DCIN (4) | DC adapter voltage sense input | Monitors adapter presence relative to CLP; enables charger only when DCIN > CLP + 60mV and triggers ACP output. |
| ACP (5) | Active-low AC present indicator | Open-drain output pulled low when DCIN > BAT + 500mV; signals host MCU that valid adapter is connected. |
| SHDN (6) | Active-low shutdown control | Pulled below 300mV to force shutdown; draws <10µA from battery in shutdown, maximizing standby time. |
| CHRG (7) | Active-low charge status indicator | Three-state output: strong pull-down during bulk charge, 25µA weak pull-down at C/10, high-Z near end-of-charge. |
| ICL (8) | Active-low input current limit indicator | Pulled low when charge current is reduced due to AC adapter current limiting; enables dynamic power budgeting. |
| FVS0 (9) | Battery voltage select LSB | Logic input (GND/INTVDD) selecting 4.2V/cell for LTC4012IUF-2#PBF; paired with FVS1 to configure 1S–4S pack voltage. |
| FVS1 (10) | Battery voltage select MSB | Logic input (GND/INTVDD) selecting 4.2V/cell for LTC4012IUF-2#PBF; defines exact float voltage without external resistor dividers. |
| BAT (11) | Battery pack voltage feedback reference | Direct connection to battery terminal; used by internal error amplifier to regulate VFB at 1.2085V during constant-voltage phase. |
| ITH (12) | PWM current control & loop compensation node | Voltage-controlled current source setting peak inductor current; external RC network sets loop bandwidth and stability. |
| PROG (13) | Charge current programming & monitoring | Voltage output linearly proportional to charge current (e.g., 1.2V = 1A); enables real-time current readback and precision programming. |
| CSN (14) | Current sense negative input | Connects to low-side of RSENSE; senses voltage drop across sense resistor with common-mode range up to BAT + 200mV. |
| CSP (15) | Current sense positive input | Connects to high-side of RSENSE; differential input with 125mV max VCS-MAX per cycle for accurate current limiting. |
| BGATE (16) | Synchronous rectifier NMOS gate driver | Drives low-side FET in buck converter; reduces conduction losses vs. diode rectification, improving efficiency >95% at 2A. |
| INTVDD (17) | Internal 5V regulator output | Provides regulated 5V (±1%) for gate drivers; shuts down in SHDN mode; can power external logic if current ≤20mA. |
| SW (18) | Buck switch node | High dv/dt node connecting to inductor; requires tight layout with minimal trace length to reduce EMI and switching losses. |
| TGATE (19) | High-side NMOS gate driver | Drives buck converter's top-side FET; bootstrap supply via BOOST pin enables high-side NMOS use without floating supply. |
| BOOST (20) | TGATE bootstrap capacitor return | Connects to bootstrap capacitor between SW and INTVDD; sustains TGATE drive voltage during high-side FET conduction. |
| GND (21) | Ground reference & thermal pad | Exposed paddle must be soldered to PCB ground plane; provides primary thermal path and low-impedance reference for all analog circuits. |
Key Features
| Feature | Design Value |
|---|---|
| Pin-programmable 4.2V/cell output | Eliminates external resistor divider for 4S Li-ion packs; FVS0/FVS1 pins directly select 16.8V float voltage with ±0.8% accuracy. |
| PowerPath™ ideal diode control | INFET output regulates forward voltage to ~25mV and blocks reverse current in <6µs, enabling seamless switchover between adapter and battery. |
| 550kHz synchronous buck PWM | Enables use of small 6.8µH inductors and ceramic capacitors without audible noise, reducing solution size and BOM cost. |
| Analog charge current monitor | PROG pin outputs voltage linearly proportional to charge current (e.g., 1.2V = 1A), allowing real-time current measurement without ADC. |
| AC adapter input current limiting | CLP/CLN inputs set precise input current limit (e.g., 2A) independent of battery voltage, preventing adapter overload during simultaneous system operation. |
| –40°C to 125°C guaranteed operation | Full electrical specifications validated across industrial temperature range, supporting ruggedized portable and backup systems. |
Applications
| Notebook Computers | Portable Instruments |
|---|---|
|
Use Scenario: Charging 4-cell Li-ion battery packs in ultrabooks with simultaneous system operation from AC adapter. IC Role / Device Role / Timing Role: Synchronous buck controller managing charge current/voltage, PowerPath™ enabling seamless AC/battery switchover, and input current limiting to avoid adapter overload. Use Value: Delivers 95%+ efficiency at 2A, eliminates audible noise with ceramic caps, and maintains ±0.8% voltage accuracy across –40°C to 125°C for reliable battery longevity. |
Use Scenario: Recharging handheld multimeters and oscilloscopes with 4S Li-ion packs in field-deployed environments. IC Role / Device Role / Timing Role: Battery charger controller providing programmable C/10 detection, analog current monitoring via PROG, and robust thermal performance in compact enclosures. Use Value: Enables precise charge current control (±4%), low-battery trickle charge via PROG pin circuitry, and shutdown current <10µA for multi-week standby. |
| Battery Backup Systems | Industrial Portable Terminals |
|
Use Scenario: Maintaining 4S Li-ion backup power for PoE-powered access points during grid outages. IC Role / Device Role / Timing Role: High-efficiency charger with INFET-driven ideal diode ensuring zero reverse leakage, and ACP/CHRG indicators for remote status monitoring. Use Value: Achieves <1µA BAT leakage in shutdown, supports 28V input for wide-range PoE injectors, and provides C/10 end-of-charge signal for MCU-controlled termination. |
Use Scenario: Powering warehouse scanners and RFID readers with hot-swappable 4S Li-ion batteries in cold-storage facilities. IC Role / Device Role / Timing Role: Industrial-grade charger controller operating reliably at –40°C, with FVS0/FVS1 pin configuration eliminating external voltage-setting components. Use Value: Guarantees ±0.8% float voltage accuracy at low temperature, supports 6–28V input for vehicle-mounted DC sources, and integrates ICL status for dynamic load management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery charger controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC4012IUF-1#PBF | Pin-programmed for 4.1V/cell (16.4V for 4S) instead of 4.2V/cell; identical package, pinout, and temperature grade. | Targeted at Li-ion chemistries requiring lower float voltage for enhanced cycle life or safety margin. | Select LTC4012IUF-1#PBF when battery specification mandates 4.1V/cell; otherwise LTC4012IUF-2#PBF is optimal for standard 4S packs. |
| BQ24725ARHBT | TI part with integrated MOSFET drivers but no PowerPath™ ideal diode; requires external PFET for input OR-ing and lacks INFET output. | Designed for server/industrial chargers with separate power path ICs; lacks single-chip AC/battery switchover capability. | Choose BQ24725ARHBT only if existing design uses discrete ideal diode control and prioritizes TI ecosystem support over integrated PowerPath™. |
Compared with LTC4012IUF-1#PBF, the LTC4012IUF-2#PBF provides higher 4.2V/cell output for maximum energy density in standard 4S Li-ion packs, while BQ24725ARHBT requires additional external components to replicate INFET-based PowerPath™ functionality and offers no direct pin-compatible replacement.
Availability
LTC4012IUF-2#PBF is available at Aetrix Electronics and suitable for notebook computers, portable instruments, and battery backup systems requiring stable component supply across industrial temperature ranges and long product lifecycles.
Supply support for LTC4012IUF-2#PBF 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
Analog Devices (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and consumer markets.
The LTC4012 family was designed as a flexible, high-efficiency battery charger controller platform for multi-cell Li-ion/polymer systems, emphasizing precision voltage/current regulation, integrated PowerPath™ management, and industrial-grade reliability.
FAQ
What battery chemistries does the LTC4012IUF-2#PBF support?
The LTC4012IUF-2#PBF supports any rechargeable battery chemistry including Li-ion, Li-polymer, NiMH, and lead-acid. Its architecture lacks built-in termination, requiring external MCU supervision for full charge algorithms. For Li-ion, it delivers precise 4.2V/cell output with ±0.8% accuracy across –40°C to 125°C, making LTC4012IUF-2#PBF ideal for 4S packs where voltage tolerance directly impacts safety and cycle life.
How does the LTC4012IUF-2#PBF implement PowerPath™ control?
The LTC4012IUF-2#PBF uses its INFET pin to drive an external PMOS transistor between DCIN and CLP, regulating forward voltage to ~25mV during charging. If DCIN drops below CLP, INFET turns off the PFET within 6µs when DCIN–CLP falls below –25mV to block reverse current. This enables seamless switchover between adapter and battery without external diodes or controllers, a core function of LTC4012IUF-2#PBF in portable systems.
What is the purpose of the FVS0 and FVS1 pins on the LTC4012IUF-2#PBF?
FVS0 (Pin 9) and FVS1 (Pin 10) are digital inputs that configure the LTC4012IUF-2#PBF's output voltage for 1–4 series Li-ion cells. For LTC4012IUF-2#PBF, FVS1 = 5V and FVS0 = 0V selects 4.2V/cell (e.g., 16.8V for 4S). This eliminates external resistor dividers, simplifying layout and improving accuracy versus analog programming methods used in the base LTC4012 variant.
Can the LTC4012IUF-2#PBF operate without an external microcontroller?
No - the LTC4012IUF-2#PBF is a controller, not a complete charger IC. It lacks built-in charge termination, state machine, or safety timers. An external MCU must monitor CHRG, ICL, and PROG outputs, manage preconditioning/trickle charge, and terminate charging at C/10 or timeout. The LTC4012IUF-2#PBF provides the precision analog regulation and PowerPath™ foundation, but full algorithm execution requires host supervision.
What is the maximum charge current achievable with the LTC4012IUF-2#PBF?
The LTC4012IUF-2#PBF supports charge currents up to 3A depending on external component selection (RSENSE, RIN, RPROG) and thermal design. At 2A, typical efficiency exceeds 95% with 6.8µH inductor and ceramic capacitors. The PROG pin provides linear current monitoring (e.g., 1.2V = 1A), and CSP/CSN inputs support peak current sensing up to 195mV per cycle, defining the practical upper limit for stable operation in the LTC4012IUF-2#PBF design.
LTC4012IUF-2#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PowerPath™
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Battery Chemistry:
- Multi-Chemistry
- Number of Cells:
- 1 ~ 4
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- -
- Fault Protection:
- Over Voltage
- Charge Current - Max:
- -
- Battery Pack Voltage:
- 16.8V
- Voltage - Supply (Max):
- 28V
- Interface:
- -
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LTC4012IUF-2#PBF FAQ
1.How can I place an order for LTC4012IUF-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4012IUF-2#PBF 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 LTC4012IUF-2#PBF reliable?
The price and inventory of LTC4012IUF-2#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4012IUF-2#PBF is usually 5 days.
3.What payment methods are accepted for LTC4012IUF-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4012IUF-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4012IUF-2#PBF?
LTC4012IUF-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4012IUF-2#PBF 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 LTC4012IUF-2#PBF?
For technical support, including LTC4012IUF-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4012IUF-2#PBF requirements.
6.How does Aetrix verify that LTC4012IUF-2#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4012IUF-2#PBF 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 LTC4012IUF-2#PBF meets industry standards.
7.What is the process for return or replacement of LTC4012IUF-2#PBF?
All LTC4012IUF-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4012IUF-2#PBF, 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 LTC4012IUF-2#PBF part is unused and in its original packaging.
Return procedure for LTC4012IUF-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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