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Analog Devices Inc. LTC4009CUF#TRPBF
- Part No.:
- LTC4009CUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC4009CUF#TRPBF.pdf
- Description:
- IC BAT CHG MULT-CHEM 1-4CL 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,818
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Product details
Overview
LTC4009CUF#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous buck-mode constant-current/constant-voltage battery charger controller for multi-chemistry Li-ion/Li-polymer, lead-acid, and NiMH battery packs. It delivers ±0.5% output float voltage accuracy, 4% charge current accuracy, and programmable AC adapter input current limiting with 3% accuracy across 6V–28V input and 2V–28V output ranges. Designed for notebook computers and portable instrumentation, it supports external microcontroller-based charge termination and full-system power path management.
For engineers reviewing the LTC4009CUF#TRPBF datasheet, LTC4009CUF#TRPBF pinout, LTC4009CUF#TRPBF application, or LTC4009CUF#TRPBF equivalent, key selection criteria include its 550kHz quasi-constant-frequency PWM architecture (enabling ceramic capacitor use without audible noise), thermally enhanced 20-pin 4mm × 4mm QFN package, and dual-role PROG pin for both charge current programming and analog monitoring.
Technical Context
The LTC4009CUF#TRPBF implements current-mode PWM control with an internal 5V INTVDD regulator, synchronous gate drivers (TGATE/BGATE), and adaptive loop compensation via the ITH node. Its architecture separates input current limiting (CLP/CLN sensing) from battery voltage regulation (FBDIV/VFB or FVS0/FVS1), enabling independent optimization of adapter power utilization and battery safety margins.
Unlike integrated chargers, it provides no built-in termination logic - all end-of-charge decisions (e.g., C/10 detection, timer cutoff, temperature monitoring) must be handled externally. The CHRG open-drain output delivers three-state status (strong pull-down, 25µA weak pull-down, high-Z) to signal bulk charge, low-current charge, and input current limit conditions without requiring additional level-shifting circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Synchronous buck PWM controller - enables >90% efficiency at 2A with ceramic output capacitors and eliminates audible noise. |
| Switching Frequency | 550kHz typical - allows compact 6.8µH inductor and small input/output filter components. |
| Output Voltage Range | 2V to 28V - fully adjustable via external resistor divider on VFB (LTC4009) or pin-selectable 4.1V/4.2V per cell (LTC4009-1/-2). |
| Charge Current Accuracy | ±4% - determined by RPROG, RIN, and RSENSE matching; enables precise current setting without calibration. |
| Input Current Limit Accuracy | ±3% - set by CLP–CLN differential voltage; ensures adapter power is fully utilized without overloading. |
| Operating Temp Range | 0°C to 85°C - specified for commercial-grade C-temp variant (LTC4009CUF#TRPBF). |
| Package | 20-pin 4mm × 4mm × 0.75mm QFN with exposed thermal pad - achieves θJA = 37°C/W for high-power charging in space-constrained layouts. |
Pinout & Package
Thermally enhanced 20-pin plastic QFN (4mm × 4mm, 0.75mm height) with exposed GND pad (Pin 21) requiring PCB soldering for thermal and electrical integrity. Package meets JEDEC MO-220 standards and supports reflow assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLN (1) | Adapter current limit negative sense | Differential input referenced to CLP; sets 100mV threshold for input current limiting - must be filtered to reject switching noise. |
| CLP (2) | Adapter current limit positive sense & power | Primary power source for IC; senses adapter current and supplies internal circuits up to 28V. |
| DCIN (3) | DC input supply | Secondary power input (e.g., system rail); isolated from CLP by diode; bypassed with ≥0.1µF capacitor. |
| ICL (4) | Input current limit indicator | Open-drain active-low output signaling when charge current is reduced due to adapter current limit. |
| DCDIV (5) | AC adapter present comparator input | Resistor-divider input detecting adapter presence (1.2V threshold) and overvoltage (1.825V OVP). |
| SHDN (6) | Active-low shutdown control | Pulled down internally with 50kΩ; <300mV forces shutdown, reducing battery leakage to <1.5µA. |
| ACP (7) | AC adapter present indicator | Open-drain output active-low when adapter voltage exceeds DCDIV threshold - remains functional in all states. |
| CHRG (8) | Charge status indicator | Three-state open-drain output: strong pull-down (bulk), 25µA weak pull-down (C/10), high-Z (no charge). |
| FBDIV (9) | Battery feedback divider source | Open-drain PFET connecting BAT to external resistor divider - enables precise float voltage programming. |
| VFB (10) | Battery voltage feedback input | High-impedance input (±20nA bias) referenced to 1.2085V internal reference - sets output voltage via resistor ratio. |
| BAT (11) | Battery pack connection | Main battery terminal; voltage sensed for PWM control and overvoltage protection (106% of programmed VOUT). |
| ITH (12) | PWM current control & compensation | Error amplifier output controlling peak inductor current; external RC network sets loop stability and soft-start time. |
| PROG (13) | Charge current programming & monitor | Analog voltage proportional to actual charge current (11.67µA/mV); used for programming and real-time monitoring. |
| CSN (14) | Current sense negative input | Low-side current sense input; operates within (BAT – 50mV) to (BAT + 200mV) range - requires matched RIN resistor. |
| CSP (15) | Current sense positive input | High-side current sense input; paired with CSN to measure RSENSE voltage drop with ±125mV max offset. |
| BGATE (16) | Synchronous rectifier gate driver | 5V CMOS output driving NMOS bottom FET; improves efficiency by replacing Schottky diode in buck stage. |
| INTVDD (17) | Internal 5V regulator output | Stable 5V supply (±1%) for gate drivers; short-circuit protected (50–130mA); shuts down during SHDN. |
| SW (18) | Switch node | Connection point between external inductor and power FETs; critical for EMI and layout - requires tight copper pour and minimal trace length. |
| TGATE (19) | Top FET gate driver | Bootstrapped NMOS gate driver (GND to CLN+5V); drives external high-side switch with 60–110ns rise/fall times. |
| BOOST (20) | Bootstrap supply input | Return node for bootstrap capacitor; voltage range (INTVDD–1V) to (CLN+5V) - requires low-ESR ceramic capacitor. |
| GND (21) | Ground / Exposed Pad | Single-point reference for internal bandgap and error amplifiers; must be soldered to large PCB ground plane for thermal and noise performance. |
Key Features
| Feature | Design Value |
|---|---|
| No audible noise operation | Quasi-constant 550kHz PWM frequency prevents sub-audible modulation - enables use of low-ESR ceramic bulk capacitors instead of electrolytics. |
| Programmable input current limit | External RIN sets adapter current limit independently of battery charge current - maximizes power delivery under fixed AC adapter constraints. |
| Three-state CHRG output | Integrates bulk charge, C/10 detection, and input current limit status into one pin - reduces MCU GPIO count and eliminates external logic. |
| Analog charge current monitor | PROG pin provides linear 11.67µA/mV output proportional to actual charge current - enables real-time telemetry without ADC oversampling. |
| Micropower shutdown | Reduces total battery leakage to <1.5µA while preserving state - extends standby time in portable instruments and backup systems. |
Applications
| Notebook Computer Power Management | Portable Test Instrumentation |
|---|---|
Use Scenario: Dual-input (AC adapter + battery) power system in ultraportable laptops requiring seamless transition between sources and precise Li-ion charge control. IC Role / Device Role / Timing Role: Primary battery charge controller managing CC/CV profile, input current limiting, and system power path arbitration via external MCU. Use Value: Enables 92% peak efficiency at 2A with 6.8µH inductor and ceramic caps - reducing thermal load and board area vs. discrete solutions. |
Use Scenario: Handheld multimeter or oscilloscope with rechargeable Li-ion pack and long battery life requirements. IC Role / Device Role / Timing Role: High-accuracy charger controller interfacing with on-board MCU for custom charge algorithms including temperature-compensated termination. Use Value: ±0.5% float voltage accuracy and ±4% current accuracy ensure cell longevity and capacity retention over 500+ cycles. |
| Battery Backup Systems | Industrial Portable Equipment |
Use Scenario: UPS or telecom backup unit using 2S/3S Li-ion packs with strict input power budgeting during grid failure. IC Role / Device Role / Timing Role: Adaptive charger that dynamically scales charge current based on available AC adapter power while maintaining system load priority. Use Value: Programmable input current limit (via CLP/CLN) prevents brownouts during simultaneous system operation and battery recharge. |
Use Scenario: Ruggedized handheld HMI or data logger operating in variable ambient temperatures with field-replaceable batteries. IC Role / Device Role / Timing Role: Flexible chemistry-agnostic charger supporting Li-ion, LiFePO₄, or sealed lead-acid via external MCU configuration. Use Value: Wide 2V–28V output range and external termination logic allow safe charging of diverse chemistries without hardware redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery charger controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2617GR-Z | Integrated 3A buck charger with built-in MOSFETs; fixed 4.2V output; no input current limiting or PROG monitoring. | Targeted at cost-sensitive, single-cell Li-ion applications where external FETs and flexibility are unnecessary. | Select MP2617GR-Z only if board space is critical and programmability is not required - LTC4009CUF#TRPBF retains design flexibility for multi-cell and multi-chemistry support. |
| BQ24725ARGER | TI's SMBus-compatible 3-phase synchronous buck controller; supports up to 20V input; includes digital telemetry registers but lacks analog PROG monitoring. | Designed for server/enterprise battery systems with PMBus host communication and thermal foldback. | Choose BQ24725ARGER for SMBus-managed rack-mounted systems; LTC4009CUF#TRPBF suits standalone MCU-controlled portable designs needing analog simplicity and low component count. |
Compared with MP2617GR-Z and BQ24725ARGER, the LTC4009CUF#TRPBF offers superior analog monitoring fidelity (PROG pin), wider output voltage range (2V–28V), and true independent input current limiting - making it optimal for portable equipment where MCU integration, efficiency, and chemistry flexibility are prioritized over digital bus control or monolithic integration.
Availability
LTC4009CUF#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and battery backup systems requiring stable component supply, long-term manufacturability, and guaranteed commercial-temperature performance.
Supply support for LTC4009CUF#TRPBF 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 LTC4009CUF#TRPBF belongs to Linear's precision battery management IC family, designed specifically for high-efficiency, flexible, microcontroller-coordinated charging of multi-cell Li-ion, Li-polymer, and alternative chemistries in portable and industrial applications.
FAQ
What is the primary function of the PROG pin on the LTC4009CUF#TRPBF?
The PROG pin on the LTC4009CUF#TRPBF serves a dual role: it programs maximum charge current via an external resistor to ground, and simultaneously provides an analog voltage output (11.67µA/mV) linearly proportional to actual charge current. This enables both precise current setting and real-time monitoring without additional sensing circuitry - a key differentiator of the LTC4009CUF#TRPBF versus simpler chargers.
Does the LTC4009CUF#TRPBF support lithium iron phosphate (LiFePO₄) battery charging?
Yes, the LTC4009CUF#TRPBF supports LiFePO₄ charging through its fully adjustable 2V–28V output voltage range. Unlike fixed-voltage chargers, it requires external MCU control for proper termination (e.g., constant-voltage hold at 3.6V/cell and current taper), but its precision ±0.5% voltage regulation and wide input compatibility make it well-suited for LiFePO₄ in industrial portable equipment.
How does the LTC4009CUF#TRPBF handle input current limiting when powering both system load and battery?
The LTC4009CUF#TRPBF reduces charge current to maintain the programmed adapter input current limit (set by CLP–CLN differential), ensuring system load remains powered. When system load current approaches or exceeds the limit, the BOOST capacitor may discharge, temporarily halting PWM until load drops to ~85% of the limit - a behavior documented in the LTC4009CUF#TRPBF datasheet's Applications Information section.
What is the purpose of the FBDIV pin on the LTC4009CUF#TRPBF?
The FBDIV pin on the LTC4009CUF#TRPBF is an open-drain PFET output that connects the battery (BAT) to the external resistor divider network. It enables accurate float voltage programming by placing the divider reference directly at the battery terminal - eliminating errors from PCB trace resistance and ensuring ±0.5% regulation accuracy at the battery terminals, not just at the IC pins.
Can the LTC4009CUF#TRPBF be used without an external microcontroller?
The LTC4009CUF#TRPBF can operate in basic CC/CV mode without an MCU, but it lacks built-in charge termination logic (e.g., timer cutoff, temperature monitoring, or C/10 detection). For safe, compliant battery charging, an external controller is required to interpret CHRG/ICL/ACP signals and execute full charge algorithms - making the LTC4009CUF#TRPBF a building-block controller, not a standalone solution.
LTC4009CUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LTC4009CUF#TRPBF FAQ
1.How can I place an order for LTC4009CUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4009CUF#TRPBF 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 LTC4009CUF#TRPBF reliable?
The price and inventory of LTC4009CUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4009CUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC4009CUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4009CUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4009CUF#TRPBF?
LTC4009CUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4009CUF#TRPBF 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 LTC4009CUF#TRPBF?
For technical support, including LTC4009CUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4009CUF#TRPBF requirements.
6.How does Aetrix verify that LTC4009CUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC4009CUF#TRPBF 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 LTC4009CUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC4009CUF#TRPBF?
All LTC4009CUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4009CUF#TRPBF, 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 LTC4009CUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC4009CUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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