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Analog Devices Inc. LTC4125EUFD#TRPBF
- Part No.:
- LTC4125EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Management - Specialized
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC4125EUFD#TRPBF.pdf
- Description:
- 5W AUTORESONANT WIRELESS POWER T
- Quantity:
- Payment:
- Shipping:
Inventory:2,003
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Product details
Overview
LTC4125EUFD#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 5W AutoResonant wireless power transmitter IC that drives a full-bridge LC tank to deliver regulated power across an air gap. It features integrated 100mΩ MOSFETs, programmable input current limiting (0.785–0.815V threshold), NTC-based thermal monitoring, and multi-method foreign object detection. It operates in medical equipment, industrial handhelds, and military sensors requiring contactless charging with fault-safe operation.
For engineers reviewing the LTC4125EUFD#TRPBF datasheet, LTC4125EUFD#TRPBF pinout, LTC4125EUFD#TRPBF application, or LTC4125EUFD#TRPBF equivalent, key selection criteria include its 50kHz–250kHz AutoResonant frequency tracking, 3V–5.5V input range, 20-pin 4mm × 5mm QFN package, and dual-stage transmit power search with FB-based load detection.
Technical Context
The LTC4125EUFD#TRPBF implements a patent-pending AutoResonant control loop that dynamically locks switching frequency to the series LC tank's natural resonance-enabling maximum power transfer despite coil inductance drift or temperature variation. Its internal full-bridge driver uses pulse-width modulation with PTH1/PTH2 pins to scale output power in discrete steps.
It executes periodic Optimum Power Search cycles using CTS/CTD timing capacitors, monitoring FB voltage for abrupt tank voltage changes indicating receiver load satisfaction, while simultaneously checking IMON for overcurrent, NTC for overheating, FTH for frequency-based foreign object detection, and die temperature for thermal shutdown-ensuring fail-safe operation without external microcontroller intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 5.5V - powers both logic and high-current bridge sections via separate IN, IN1, IN2 pins. |
| Output Power Capability | Over 5W - delivered wirelessly to tuned receivers using full-bridge resonant drive topology. |
| Switching Frequency Range | 50kHz to 250kHz - AutoResonant adjustment ensures continuous lock to LC tank resonance. |
| Integrated Switch RDS(on) | 150mΩ per MOSFET - low conduction loss enables high efficiency at 5W output with minimal heatsinking. |
| Operating Junction Temp | –40°C to 125°C - specified for industrial and medical environments with thermal protection active above TJMAX. |
| Package | 20-lead 4mm × 5mm QFN - thermally enhanced with exposed pad tied to GND for PCB heat dissipation. |
| Input Current Limit Threshold | 1.175–1.225V at IMON - sets precise average input current limit independent of sense resistor tolerance. |
Pinout & Package
Package: 20-lead (4mm × 5mm) plastic QFN, 0.75mm profile, exposed thermal pad (Pin 21) required to be connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN, IN1, IN2 | Independent supply inputs | IN powers logic; IN1/IN2 separately power half-bridge legs-enables localized decoupling (1µF + 47µF recommended). |
| SW1, SW2 | Full-bridge center taps | Drive series LC tank between SW1–SW2; SW1–GND supports half-bridge mode with reduced max power. |
| FB | Resonance feedback input | Monitors rectified peak tank voltage to detect receiver load presence and optimize transmit power stepwise. |
| IMON | Current monitor output | Sources current proportional to input sense voltage; 0.80V threshold triggers search pause, 1.20V triggers immediate shutdown. |
| NTC, FTH, DTH | Fault detection inputs | NTC monitors thermistor for overtemperature/foreign metal; FTH sets max resonant frequency for conductive object detection. |
| CTS, CTD | Search timing capacitors | CTS sets power search settling time (1–20ms); CTD sets delay between search intervals (≥1s typical). |
| STAT | Open-drain status output | Pulls low during valid power delivery; high-impedance during fault or no-receiver condition-drives LED indicator directly. |
| PTH1, PTH2, PTHM | Pulse width control inputs | Set SW1/SW2 on-time proportionality and minimum pulse width (1/32 of LC period when shorted to GND). |
Key Features
| Feature | Design Value |
|---|---|
| AutoResonant frequency tracking | Maintains exact LC tank resonance continuously-no manual tuning needed despite component drift or coupling variation. |
| Optimum Power Search algorithm | Performs linear PWM ramp with FB voltage slope detection to find minimum sufficient transmit power-maximizing system efficiency. |
| Dual-stage input current protection | 0.80V threshold pauses search; 1.20V threshold forces immediate shutdown-prevents sustained overload under fault conditions. |
| Multi-sensor foreign object detection | Combines FTH (frequency shift), NTC (thermal rise), and die temperature sensing to reliably halt power on metal intrusion or overheating. |
| Thermally optimized QFN package | Exposed pad (Pin 21) must connect to GND plane-reduces θJA to 43°C/W for stable 5W operation without external heatsink. |
Applications
| Medical Implant Chargers | Military Sensor Beacons |
|---|---|
Use Scenario: Wireless charging of sealed implantable devices (e.g., neurostimulators) through human tissue with variable coupling. IC Role / Device Role / Timing Role: Primary-side resonant power controller that adapts frequency and power in real time to maintain safe, efficient energy transfer across shifting coil alignment. Use Value: Eliminates connectors and hermetic feedthroughs; AutoResonant tracking compensates for tissue-induced inductance shifts; NTC input prevents tissue heating. | Use Scenario: Battery recharging of ruggedized battlefield sensors deployed in extreme ambient temperatures. IC Role / Device Role / Timing Role: Autonomous wireless transmitter enabling maintenance-free operation in inaccessible locations with no physical access for cable replacement. Use Value: –40°C to 125°C operation ensures reliability in desert/cold-weather deployments; foreign object detection prevents arcing near metallic debris. |
| Industrial Handheld Scanners | Hermetically Sealed Equipment |
Use Scenario: In-field recharging of explosion-proof barcode scanners used in chemical plants where spark-free operation is mandatory. IC Role / Device Role / Timing Role: Isolated power source eliminating battery compartment seals and mechanical wear from repeated connector mating. Use Value: No exposed contacts reduces ignition risk; 5W output enables fast recharge; CTD-programmed long search delays minimize RF emissions during idle periods. | Use Scenario: Powering sensors inside vacuum chambers or radiation-shielded enclosures where wiring penetrations compromise integrity. IC Role / Device Role / Timing Role: Fully self-contained resonant driver mounted externally, transferring power through non-conductive chamber walls. Use Value: Hermetic and electrical isolation maintained; AutoResonant compensation handles wall-induced parasitic capacitance shifts; FB feedback ensures consistent power delivery despite barrier losses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wireless power transmitter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ51222RGER | TI part uses proprietary Qi-compliant protocol; requires external MCU for power negotiation; lower max output (2.5W). | Designed for consumer electronics (earbuds, wearables); lacks NTC input and multi-threshold current limiting. | Choose BQ51222RGER only if Qi certification and bidirectional communication are required-not for industrial/military standalone transmitters. |
| MP-A21-0001 | Microchip reference design module; integrates MCU, gate drivers, and coil; fixed 5W output; no programmable search timing. | Turnkey solution with pre-certified EMI; larger footprint (25mm × 25mm); no PTH/NTC/FTH pin-level configurability. | Choose MP-A21-0001 for rapid prototyping where layout and firmware are constrained-but not when custom fault response or thermal adaptation is needed. |
Compared with BQ51222RGER and MP-A21-0001, the LTC4125EUFD#TRPBF provides direct analog control of resonant frequency, pulse width, and multiple independent fault thresholds-enabling deterministic, microcontroller-free operation in safety-critical industrial and medical systems where real-time adaptability and failure-mode transparency are essential.
Availability
LTC4125EUFD#TRPBF is available at Aetrix Electronics and suitable for medical equipment, industrial handhelds, and military sensors requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LTC4125EUFD#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 its high-performance analog IC portfolio with rigorous automotive and industrial qualification standards.
The LTC4125EUFD#TRPBF belongs to Linear's wireless power controller product line, designed specifically for robust, self-contained resonant transmitters in harsh environments where reliability, fault resilience, and analog configurability outweigh protocol compliance needs.
FAQ
What is the primary function of the LTC4125EUFD#TRPBF in a wireless power system?
The LTC4125EUFD#TRPBF serves as a fully autonomous wireless power transmitter controller. It drives a full-bridge LC tank at its exact resonant frequency using AutoResonant technology, performs periodic Optimum Power Search to match receiver load demand, and enforces multiple hardware-based fault protections-including foreign object detection via FTH, NTC, and die temperature monitoring-without requiring external microcontroller supervision.
How does the LTC4125EUFD#TRPBF achieve AutoResonant frequency tracking?
The LTC4125EUFD#TRPBF continuously monitors current and voltage phase relationships at SW1 and SW2 to detect zero-crossing points in the LC tank. It dynamically adjusts its switching frequency cycle-by-cycle to maintain in-phase drive-ensuring operation precisely at the tank's natural resonant frequency (fn = 1/(2π√LC)) regardless of temperature drift, coil aging, or coupling variation. This eliminates manual tuning and sustains peak efficiency across operating conditions.
What are the critical external components required for basic operation of the LTC4125EUFD#TRPBF?
Essential external components for the LTC4125EUFD#TRPBF include: a series LC tank (LTX and CTX) connected between SW1 and SW2; bypass capacitors (1µF on IN, 47µF each on IN1/IN2); timing capacitors on CTS (1–20ms search settling) and CTD (≥1s inter-search delay); a resistor divider on FB to sense tank voltage; and optional resistors on FTH, NTC, and PTHM for threshold programming. The exposed thermal pad (Pin 21) must be soldered to a GND plane.
Can the LTC4125EUFD#TRPBF operate without the FB feedback pin connected?
Yes-the LTC4125EUFD#TRPBF can operate without FB connected, but auto load detection is disabled. In this configuration, it delivers fixed power based solely on PTH1/PTH2 settings and performs only frequency- and current-based fault checks. The STAT pin remains functional for power-delivery indication, but the device cannot adapt transmit power to receiver load requirements-reducing system efficiency and increasing risk of overheating under light-load conditions.
What is the role of the IMON pin in the LTC4125EUFD#TRPBF, and how is it configured?
The IMON pin on the LTC4125EUFD#TRPBF sources a current proportional to the voltage across the input current sense resistor (RIS). With an external gain resistor (RIMON), it generates a voltage representing average input current. A rising IMON voltage of 0.80V pauses the power search; 1.20V triggers immediate shutdown. To configure, connect RIS between VIN and IS–, tie IS+ to VIN via RIN, and place RIMON between IMON and GND-with optional capacitor for filtering.
LTC4125EUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- Wireless Power Transmitter
- Current - Supply:
- 1mA
- Voltage - Supply:
- 3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x5)
LTC4125EUFD#TRPBF FAQ
1.How can I place an order for LTC4125EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4125EUFD#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 LTC4125EUFD#TRPBF reliable?
The price and inventory of LTC4125EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4125EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC4125EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4125EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4125EUFD#TRPBF?
LTC4125EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4125EUFD#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 LTC4125EUFD#TRPBF?
For technical support, including LTC4125EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4125EUFD#TRPBF requirements.
6.How does Aetrix verify that LTC4125EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC4125EUFD#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 LTC4125EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC4125EUFD#TRPBF?
All LTC4125EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4125EUFD#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 LTC4125EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC4125EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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