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Analog Devices Inc. LTC4009IUF#PBF
- Part No.:
- LTC4009IUF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC4009IUF#PBF.pdf
- Description:
- IC BAT CHG MULT-CHEM 1-4CL 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,120
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Product details
Overview
LTC4009IUF#PBF from Analog Devices (formerly Linear Technology) is a synchronous step-down battery charger controller for multi-chemistry batteries. It delivers ±0.5% float voltage accuracy, 4% charge current accuracy, and programmable 6V–28V input/2V–28V output ranges. Its 550kHz quasi-constant-frequency PWM architecture eliminates audible noise with ceramic capacitors and supports external microcontroller-based charge termination in notebook computers and portable instruments.
For engineers reviewing the LTC4009IUF#PBF datasheet, LTC4009IUF#PBF pinout, LTC4009IUF#PBF application, or LTC4009IUF#PBF equivalent, key selection criteria include its I-grade (–40°C to 125°C) thermal rating, 20-pin 4mm × 4mm QFN package with exposed GND pad, AC adapter input current limiting with ICL status indication, and dual-mode CHRG output for C/10 detection and charging state monitoring.
Technical Context
The LTC4009IUF#PBF implements current-mode PWM control using an internal error amplifier that compares PROG-derived average charge current and VFB-sensed battery voltage against 1.2085V reference. Its ITH node sets cycle-by-cycle peak inductor current, while CLP/CLN inputs enable precise adapter input current regulation via external sense resistor.
Unlike integrated chargers, it provides no built-in termination logic-charge algorithm management is fully delegated to an external MCU via PROG voltage monitoring, CHRG/ICL/ACP status outputs, and FBDIV-controlled feedback path. The device operates in nonsynchronous mode below ~25% of max programmed current to prevent boost during input-limited operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temp Range | –40°C to 125°C (I-grade), enabling use in industrial and automotive-adjacent portable systems |
| Switching Frequency | 467–633 kHz (typ 550 kHz), allowing compact 6.8µH inductors and ceramic bulk capacitors without audible noise |
| Float Voltage Accuracy | ±0.5% (LTC4009 variant), supporting precision Li-ion, Li-polymer, or custom chemistry voltage setpoints |
| Charge Current Accuracy | ±4% (C-grade), ±5% (I-grade), determined by RPROG, RIN, and RSENSE matching |
| Input Current Limit Acc. | ±3%, set by external RIN on CLP/CLN, with active-low ICL output signaling limit activation |
| Voltage Input Range | 6V to 28V DCIN, compatible with 12V/19V/24V AC adapters and wide-range industrial supplies |
| Output Voltage Range | 2V to 28V, programmable via external FBDIV–VFB resistor divider (not pin-strapped) |
Pinout & Package
Thermally enhanced 20-pin 4mm × 4mm × 0.75mm plastic QFN (UF package) with exposed GND pad (Pin 21) requiring PCB soldering for thermal and electrical integrity (θJA = 37°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLN (1) | Current limit sense negative | Reference for adapter input current sensing; threshold is CLP – 100mV; must be filtered to reject switching noise |
| CLP (2) | Current limit sense positive / power rail | Primary input power source for IC; also used with CLN to set input current limit; 6V–28V operating range |
| DCIN (3) | DC input supply | Secondary input rail, typically diode-isolated from CLP; powers IC when CLP is absent; 6V–28V range |
| ICL (4) | Input current limit indicator | Open-drain output pulled low when charge current is reduced due to adapter current limiting |
| DCDIV (5) | AC adapter present detection | Comparator input for detecting adequate DC input; threshold set by resistor divider from DCIN; enables ACP output |
| SHDN (6) | Active-low shutdown control | Pulled below 300mV to force shutdown; includes 50kΩ internal pull-down; disables all gate drivers and INTVDD |
| ACP (7) | AC adapter present indicator | Open-drain output pulled low when DCDIV threshold is exceeded; active in all operational states including shutdown |
| CHRG (8) | Charge status indicator | Three-state open-drain output: strong pull-down (bulk charge), 25µA weak pull-down (C/10), high-Z (termination or fault) |
| FBDIV (9) | Battery feedback divider source | Open-drain PFET connecting BAT to feedback network during charge; enables precise VFB referencing to battery potential |
| VFB (10) | Battery voltage feedback input | High-impedance input referenced to 1.2085V internal bandgap; sets float voltage via external resistor divider from FBDIV |
| BAT (11) | Battery pack connection | Main battery terminal; used for voltage sensing, current sensing (CSP/CSN), and FBDIV switching; GND-referenced up to 28V |
| ITH (12) | PWM control voltage node | Error amplifier output controlling peak inductor current; external RC network sets loop compensation and soft-start behavior |
| PROG (13) | Charge current programming/monitoring | Sets max charge current via RPROG; provides linear voltage proportional to actual charge current (11.67 µA/mV) |
| CSN (14) | Current sense negative input | Connects to low-side of RSENSE via RIN; common-mode range extends 50mV below BAT |
| CSP (15) | Current sense positive input | Connects to high-side of RSENSE via RIN; common-mode range extends 200mV above BAT |
| BGATE (16) | Synchronous rectifier gate driver | Drives external NMOS for low-loss bottom switch; rail-to-rail swing from GND to INTVDD |
| INTVDD (17) | Internal 5V regulator output | 5.0V ±1% regulated supply (4.85–5.15V); powers gate drivers; shuts down in SHDN; max 20mA load |
| SW (18) | Switch node | Connection point between external inductor and both NFETs; critical for layout; voltage swings from GND to CLP |
| TGATE (19) | Top-side NFET gate driver | Drives external NMOS high-side switch; bootstrapped from BOOST; swing up to CLP + 5V |
| BOOST (20) | Bootstrap capacitor return | Return node for bootstrap capacitor connected between SW and INTVDD; enables TGATE high-side drive |
| GND (21) | Exposed thermal pad | Single-point ground for reference circuits and thermal dissipation; must be soldered to PCB copper area |
Key Features
| Feature | Design Value |
|---|---|
| No-audible-noise PWM | Quasi-constant 550kHz frequency prevents ceramic capacitor piezoelectric squeal in portable applications |
| External charge termination | No internal timer or voltage cutoff-full algorithm control delegated to MCU via PROG voltage and CHRG states |
| Adapter input current limiting | Programmable CLP/CLN threshold with ICL status flag enables dynamic charge rate adjustment under fixed-power adapters |
| Linear charge current monitor | PROG pin delivers 11.67 µA/mV analog voltage directly proportional to instantaneous charge current |
| Three-level CHRG output | Distinguishes bulk charge (strong sink), C/10 condition (25µA weak sink), and termination/fault (high-Z) without external logic |
| Micropower shutdown | 215µA DCIN shutdown current and <1.5µA BAT leakage preserve battery life during long standby |
Applications
| Notebook Computers | Portable Instruments |
|---|---|
Use Scenario: Dual-input (AC adapter + battery) power management in ultrabooks with Li-ion 3S/4S packs and system load sharing. IC Role / Device Role / Timing Role: Synchronous buck controller regulating charge current and voltage under MCU supervision; manages adapter priority and input current capping. Use Value: Enables 95%+ efficiency at 2A charge current with ceramic output caps, eliminating coil whine and reducing thermal footprint vs. linear solutions. | Use Scenario: Field-deployable handheld test equipment requiring reliable charging across varying input sources (12V vehicle, 24V bench, USB-PD). IC Role / Device Role / Timing Role: Multi-chemistry charger controller supporting Li-ion, NiMH, and lead-acid via software-configured voltage/current profiles. Use Value: Wide 6V–28V input range and programmable 2V–28V output eliminate need for separate charger ICs per battery type. |
| Battery Backup Systems | Industrial Portable Terminals |
Use Scenario: Uninterruptible power supply for edge gateway devices with 24V LiFePO4 backup battery and 12–28V DC input. IC Role / Device Role / Timing Role: Primary charger controller interfacing with system MCU to implement temperature-compensated CC/CV and low-current trickle modes. Use Value: ±0.5% voltage accuracy and ±4% current accuracy ensure cell-level consistency across 4-series packs over –40°C to 125°C ambient. | Use Scenario: Ruggedized warehouse scanners with hot-swappable Li-ion batteries and 12V vehicle charging interface. IC Role / Device Role / Timing Role: Adapter current-limited charger preventing brownout during simultaneous system operation and battery recharge. Use Value: ICL output signals input current limit event to host MCU, enabling real-time load shedding or display alerts before adapter overload. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery charger controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC4015IUFD#PBF | Integrated 4A synchronous buck with I2C interface, Coulomb counting, and built-in termination algorithms | Replaces MCU-based control with autonomous charging; requires I2C host and different layout | Select when full autonomous charge management is preferred over external MCU control |
| BQ24725ARGER | Texas Instruments part with SMBus interface, 5V–28V input, but only ±1% voltage accuracy and no analog PROG monitoring | Designed for server/enterprise battery systems; lacks C/10 analog flag and three-state CHRG output | Select for SMBus-based systems needing standardized communication, not analog monitoring or fine-grained status |
Compared with LTC4015IUFD#PBF and BQ24725ARGER, the LTC4009IUF#PBF offers superior analog monitoring fidelity (11.67 µA/mV PROG scaling, ±0.5% VFB) and flexible MCU-directed termination, but requires more external components and firmware development effort.
Availability
LTC4009IUF#PBF is available at Aetrix Electronics and suitable for notebook computers, portable instruments, and battery backup systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC4009IUF#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 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC4009IUF#PBF belongs to Linear's precision battery charger controller family, designed for high-efficiency, externally managed charging of multi-cell Li-ion, Li-polymer, and other chemistries in space- and thermally-constrained portable systems.
FAQ
What is the operating temperature range specified for the LTC4009IUF#PBF?
The LTC4009IUF#PBF is rated for –40°C to 125°C junction temperature (I-grade), validated across the full range for parameters including ±0.5% float voltage accuracy and ±5% charge current accuracy. This makes the LTC4009IUF#PBF suitable for industrial portable equipment and automotive-adjacent applications where ambient temperatures exceed commercial-grade limits.
How does the LTC4009IUF#PBF implement input current limiting without a dedicated current-sense amplifier?
The LTC4009IUF#PBF uses differential sensing across CLP and CLN pins with a fixed 100mV threshold to detect when adapter input current exceeds the value set by the external RIN resistor. When triggered, it reduces charge current via the ITH node and asserts the open-drain ICL output low-no separate current-sense amplifier is required because the function is integrated into the CLP/CLN comparator structure.
Can the LTC4009IUF#PBF be used to charge lithium iron phosphate (LiFePO4) batteries?
Yes-the LTC4009IUF#PBF supports any battery chemistry via external programming. For LiFePO4, configure the FBDIV–VFB resistor divider to set a 3.6V/cell float voltage (e.g., 14.4V for 4S), and adjust RPROG/RSENSE for appropriate CC current. Its lack of fixed termination logic allows full customization of charge profile stages including constant-voltage hold and taper cutoff.
What is the purpose of the FBDIV pin on the LTC4009IUF#PBF, and how does it differ from the LTC4009-1/LTC4009-2 variants?
FBDIV on the LTC4009IUF#PBF is an open-drain PFET that connects the battery (BAT) to the feedback divider network during charging, ensuring VFB is referenced to true battery potential-not system ground. This eliminates errors from PCB trace resistance. In contrast, LTC4009-1/LTC4009-2 replace FBDIV and VFB with digital FVS0/FVS1 pins for fixed 4.1V/cell or 4.2V/cell selection-no external divider needed.
Does the LTC4009IUF#PBF require external MOSFETs, and what are the gate drive specifications?
Yes-the LTC4009IUF#PBF is a controller-only IC requiring external high-side (TGATE) and synchronous rectifier (BGATE) NMOS FETs. TGATE drives up to CLP + 5V with 60–110ns rise/fall times; BGATE swings rail-to-rail from GND to INTVDD (4.85–5.15V). Both outputs support standard logic-level FETs and require proper gate resistors and bootstrap components for reliable switching.
LTC4009IUF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- 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, Reverse Current
- 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)
LTC4009IUF#PBF FAQ
1.How can I place an order for LTC4009IUF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4009IUF#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 LTC4009IUF#PBF reliable?
The price and inventory of LTC4009IUF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4009IUF#PBF is usually 5 days.
3.What payment methods are accepted for LTC4009IUF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4009IUF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4009IUF#PBF?
LTC4009IUF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4009IUF#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 LTC4009IUF#PBF?
For technical support, including LTC4009IUF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4009IUF#PBF requirements.
6.How does Aetrix verify that LTC4009IUF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4009IUF#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 LTC4009IUF#PBF meets industry standards.
7.What is the process for return or replacement of LTC4009IUF#PBF?
All LTC4009IUF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4009IUF#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 LTC4009IUF#PBF part is unused and in its original packaging.
Return procedure for LTC4009IUF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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