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Analog Devices Inc. LTC4085EDE#PBF
- Part No.:
- LTC4085EDE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LTC4085EDE#PBF.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:428
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Product details
Overview
LTC4085EDE#PBF from Analog Devices (formerly Linear Technology) is a USB power manager and single-cell Li-ion battery charger IC with integrated ideal diode controller and PowerPath™ architecture. It regulates input current (up to 500 mA high-power / 100 mA low-power mode), delivers precise 4.2 V ±0.8% float voltage, and dynamically balances load current and charge current to stay within USB-compliant limits - used in portable USB-powered devices such as MP3 players and digital cameras.
For engineers reviewing the LTC4085EDE#PBF datasheet, LTC4085EDE#PBF pinout, LTC4085EDE#PBF application, or LTC4085EDE#PBF equivalent, key selection criteria include its dual-mode input current limiting (HPWR-selectable), NTC-based temperature-qualified charging, programmable charge current up to 1.2 A via PROG resistor, and seamless source arbitration between USB, wall adapter, and battery.
Technical Context
The LTC4085EDE#PBF implements a constant-current/constant-voltage linear charging algorithm with thermal feedback and C/10 end-of-charge detection. Its PowerPath architecture uses analog control loops to enforce real-time compliance with programmed input current limits (ICL = 1000 V / RCLPROG) while automatically reducing IBAT when ILOAD increases - ensuring total input current never exceeds the limit.
It integrates an internal 215 mΩ ideal diode (BAT→OUT) with optional external PFET gate drive (GATE pin), plus independent comparators for WALL adapter detection (4.25 V rising threshold), NTC thermistor monitoring (0.74×VNTC cold / 0.29×VNTC hot), and suspend mode (SUSP > 1.2 V). All logic inputs feature 2 μA internal pull-downs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.35 V to 5.5 V - supports standard USB VBUS (5 V ±10%) and wall adapter inputs without external regulation. |
| Float Voltage Accuracy | 4.2 V ±0.8% - tight regulation enables safe, full-capacity charging of single-cell Li-ion batteries without overvoltage risk. |
| Max Charge Current | 1.2 A - programmable via external PROG resistor (e.g., 100 kΩ → 500 mA); limited by thermal regulation at junction temperatures ≥105°C. |
| Input Current Limit | Selectable 100% or 20% of programmed value (e.g., 500 mA / 100 mA) via HPWR pin - ensures strict USB 2.0 compliance in both active and suspend modes. |
| Ideal Diode RON | 215 mΩ (internal) - minimizes voltage drop (VFWD ≈ 55 mV @ 600 mA) during battery-to-load power delivery, preserving system runtime. |
| NTC Interface | Dedicated NTC and VNTC pins with cold/hot fault thresholds - enables JEITA-compliant charging profiles by disabling charge outside 0°C–50°C range. |
| Operating Temp | –40°C to +85°C - specified performance across industrial temperature range; junction limit 110°C with θJA = 40°C/W. |
Pinout & Package
The LTC4085EDE#PBF is housed in a 14-lead, 4 mm × 3 mm × 0.75 mm low-profile DFN package with exposed pad (Pin 15) that must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (1) | USB VBUS Input | Primary input supply; current-limited path to OUT; accepts 4.35–5.5 V; protected by UVLO (3.6 V rising). |
| OUT (2) | System Power Output | Delivers regulated power to load from IN or BAT; requires ≥4.7 μF bypass capacitor; powers internal circuitry when IN is absent. |
| CLPROG (3) | Input Current Limit Set | Resistor-to-ground sets ICL = 1000 V / RCLPROG; also provides real-time IIN monitor voltage (VCLPROG = IIN × RCLPROG / 1000). |
| HPWR (4) | High-Power Mode Select | Logic input: >1.2 V → 100% ICL; <0.4 V → 20% ICL; internal 2 μA pull-down ensures default low-power mode at startup. |
| SUSP (5) | USB Suspend Control | Active-high input: >1.2 V disables IN→OUT path, reduces IIN to ≤100 μA, but preserves BAT→OUT ideal diode and charging functions. |
| TIMER (6) | Charge Timer Capacitor | Capacitor-to-ground sets total charge time: tTIMER = CTIMER × RPROG × 3 h / (0.1 μF × 100 kΩ); shorting to GND disables charging. |
| WALL (7) | Wall Adapter Detect Input | Comparator input: >4.25 V rising triggers wall adapter presence, disables IN→OUT path, and pulls ACPR low. |
| NTC (8) | Thermistor Sense Input | Monitors battery temperature via NTC divider; disables charging if voltage <0.29×VNTC (hot) or >0.74×VNTC (cold). |
| VNTC (9) | NTC Bias Reference | 4.4–4.85 V output; supplies bias current to NTC network; used with equal-value resistor to set thermistor midpoint. |
| ACPR (10) | Wall Adapter Present Output | Open-drain active-low flag; indicates WALL comparator assertion; disabled if all supplies (IN/OUT/BAT) are below UVLO. |
| CHRG (11) | Charge Status Indicator | Open-drain output: pulled low during charging; high-impedance when charge terminates (C/10 detected) or supplies removed. |
| PROG (12) | Battery Charge Current Set | Resistor-to-ground programs ICHG = 50,000 V / RPROG (e.g., 100 kΩ → 500 mA); PROG pin voltage held at 1.0 V ±2%. |
| GATE (13) | External PFET Gate Driver | Drives gate of external P-channel MOSFET (source=OUT, drain=BAT) to reduce ideal diode impedance; must remain high-impedance when unused. |
| BAT (14) | Battery Connection | Connects to single-cell Li-ion anode; serves as charge sink (CC/CV) and discharge source (ideal diode); internal 4.2 V reference applied via precision divider. |
| Exposed Pad (15) | Ground Thermal Pad | Electrically and thermally connected to GND; mandatory PCB soldering required for thermal dissipation and signal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Load-Dependent Charging | Automatically scales IBAT downward as ILOAD rises - guarantees sum (ILOAD + IBAT) never exceeds programmed ICL, eliminating USB bus overcurrent faults. |
| PowerPath™ Source Arbitration | Seamlessly transitions between USB, wall adapter, and battery without output droop - prioritizes external sources first, then engages BAT→OUT ideal diode only when needed. |
| Integrated Ideal Diode Control | Combines 215 mΩ internal PFET with GATE pin for external PFET - reduces forward voltage drop to ~55 mV @ 600 mA, minimizing battery energy loss during backup operation. |
| JEITA-Compliant Temperature Management | Uses dedicated NTC/VNTC interface with cold/hot fault thresholds and hysteresis - suspends charging outside 0°C–50°C, preventing lithium plating or thermal runaway. |
| Programmable Safety Timers | Independent TIMER capacitor sets total charge duration; recharging triggered when VBAT drops 100 mV below float voltage - prevents over-discharge and extends cycle life. |
Applications
| USB-Powered Portable Audio | Digital Camera Power Management |
|---|---|
Use Scenario: MP3 player draws variable load current (50–400 mA) while charging its 3.7 V Li-ion cell from USB port. IC Role / Device Role / Timing Role: LTC4085EDE#PBF acts as USB current limiter, battery charger, and seamless power switch - managing IN→OUT, OUT→BAT, and BAT→OUT paths in real time. Use Value: Ensures USB compliance (≤500 mA draw), prevents battery overvoltage (4.2 V ±0.8%), and maintains uninterrupted audio playback during USB disconnect via ideal diode. | Use Scenario: Compact digital camera operates from USB bus during file transfer and charges battery from wall adapter when docked. IC Role / Device Role / Timing Role: LTC4085EDE#PBF detects WALL presence (via WALL pin), disables USB path, and enables simultaneous load powering + battery charging from 5 V wall input. Use Value: Eliminates need for separate wall adapter detection circuitry; allows fast charging (up to 1.2 A) while powering camera electronics - no manual power-source switching required. |
| USB-C Accessory with Battery Backup | Industrial Handheld Scanner |
Use Scenario: USB-C dongle with built-in Li-ion battery powers itself and attached peripherals; must operate from USB, wall adapter, or battery alone. IC Role / Device Role / Timing Role: LTC4085EDE#PBF serves as PowerPath controller - arbitrating three input sources and providing C/10-terminated charging with NTC monitoring. Use Value: Delivers uninterrupted operation across all power scenarios; NTC input ensures safe charging in varying ambient conditions (e.g., warehouse cold storage). | Use Scenario: Rugged handheld scanner used in logistics environments experiences frequent USB connect/disconnect cycles and must maintain uptime during battery-only operation. IC Role / Device Role / Timing Role: LTC4085EDE#PBF manages transient loads (laser, imager, radio) using 4.7 μF OUT capacitor and 215 mΩ ideal diode - suppressing voltage droop during peak current bursts. Use Value: Prevents system brownouts during barcode scanning; internal soft-start (5 mA/μs) eliminates inrush stress on USB host port. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar USB power management and Li-ion charging applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ24075RGTR | Fixed 500 mA charge current; no HPWR-selectable input limit; lacks WALL input and ACPR output; no NTC interface. | Best suited for cost-sensitive USB-only applications without wall adapter support or temperature qualification. | Choose BQ24075RGTR only if wall adapter detection and JEITA compliance are unnecessary - it omits critical LTC4085EDE#PBF features like dual-input arbitration and thermal safety. |
| MAX1555ESA+ | Fixed 100 mA/500 mA input limit (no resistor programming); no ideal diode gate drive; no TIMER pin for charge timeout; no NTC input. | Targeted at simple USB-charged devices where battery runtime extension via ideal diode is not required. | Select MAX1555ESA+ only for basic USB charging without PowerPath flexibility - it cannot replicate LTC4085EDE#PBF's dynamic load/charge balancing or external PFET optimization. |
Compared with BQ24075RGTR and MAX1555ESA+, the LTC4085EDE#PBF uniquely combines programmable input current limiting, wall adapter detection with automatic path disable, NTC-based temperature qualification, and external ideal diode control - making it the only option among the three capable of robust, multi-source, thermally safe USB-battery systems.
Availability
LTC4085EDE#PBF is available at Aetrix Electronics and suitable for portable USB devices, battery-backed industrial scanners, and digital imaging equipment requiring stable component supply and long-term lifecycle support.
Supply support for LTC4085EDE#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.
The LTC4085EDE#PBF belongs to Linear's PowerPath™ family - designed specifically for USB-powered portable electronics needing intelligent source arbitration, precise Li-ion charging, and seamless battery backup without external FETs or discrete diodes.
FAQ
What is the maximum battery charge current supported by the LTC4085EDE#PBF?
The LTC4085EDE#PBF supports a maximum battery charge current of 1.2 A, programmable via the PROG pin resistor (e.g., RPROG = 42 kΩ yields ~1.2 A). However, actual delivered current is reduced under thermal regulation above 105°C junction temperature or when load current consumes available input current budget - ensuring ILOAD + IBAT never exceeds the programmed input limit.
How does the LTC4085EDE#PBF handle USB suspend mode compliance?
When SUSP pin voltage exceeds 1.2 V, the LTC4085EDE#PBF disables the IN→OUT power path and reduces input supply current to ≤100 μA - meeting USB 2.0 suspend specification. Crucially, the BAT→OUT ideal diode and battery charging functions remain fully operational, allowing continuous device operation and charging even during USB suspend.
Can the LTC4085EDE#PBF charge a battery while powering a load from a wall adapter?
Yes. When a wall adapter is detected via the WALL pin (>4.25 V), the LTC4085EDE#PBF disables the IN→OUT path and allows the wall adapter (connected to OUT) to simultaneously power the load and charge the battery through the OUT→BAT path - enabling true "power-through" charging without requiring separate wall adapter circuitry.
What is the purpose of the CLPROG pin on the LTC4085EDE#PBF?
The CLPROG pin on the LTC4085EDE#PBF serves two critical functions: (1) it sets the input current limit (ICL = 1000 V / RCLPROG) via an external resistor to ground, and (2) its voltage (VCLPROG) provides a real-time analog monitor of actual input current (IIN = VCLPROG × 1000 / RCLPROG), enabling system-level current measurement without additional sense components.
Does the LTC4085EDE#PBF require external components for basic operation?
Yes - minimal external components are required: a PROG resistor (for charge current), a CLPROG resistor (for input current limit), a TIMER capacitor (for charge timeout), a 4.7 μF capacitor on OUT, and a 0.1 μF capacitor on IN. Optional components include NTC thermistor network, external PFET for ideal diode enhancement, and wall adapter detection circuitry - all detailed in the LTC4085EDE#PBF datasheet application schematics.
LTC4085EDE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PowerPath™
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 1
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- 1.5A
- Battery Pack Voltage:
- 4.2V
- Voltage - Supply (Max):
- 5.5V
- Interface:
- USB
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-DFN (4x3)
LTC4085EDE#PBF FAQ
1.How can I place an order for LTC4085EDE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4085EDE#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 LTC4085EDE#PBF reliable?
The price and inventory of LTC4085EDE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4085EDE#PBF is usually 5 days.
3.What payment methods are accepted for LTC4085EDE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4085EDE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4085EDE#PBF?
LTC4085EDE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4085EDE#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 LTC4085EDE#PBF?
For technical support, including LTC4085EDE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4085EDE#PBF requirements.
6.How does Aetrix verify that LTC4085EDE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4085EDE#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 LTC4085EDE#PBF meets industry standards.
7.What is the process for return or replacement of LTC4085EDE#PBF?
All LTC4085EDE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4085EDE#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 LTC4085EDE#PBF part is unused and in its original packaging.
Return procedure for LTC4085EDE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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