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Analog Devices Inc. LTC4126EV#TRPBF
- Part No.:
- LTC4126EV#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 12-VFQFN Exposed Pad
- Datasheet:
-
LTC4126EV#TRPBF.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 12LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,495
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Product details
Overview
LTC4126EV#TRPBF from Analog Devices is a wireless single-cell Li-Ion battery charger IC with integrated 1.2V step-down charge-pump DC/DC regulator, fixed 7.5mA charge current, pin-selectable 4.2V/4.35V charge voltage, and NTC-based temperature-qualified charging - designed for ultra-low-power hearing aid ASIC power delivery.
For engineers reviewing the LTC4126EV#TRPBF datasheet, LTC4126EV#TRPBF pinout, LTC4126EV#TRPBF application, or LTC4126EV#TRPBF equivalent, this page delivers verified functional identity, validated 12-pin LQFN package mapping, confirmed multi-mode DC/DC operation (3:1/2:1), real-world battery disconnect threshold (3.0V), and precise thermal fault thresholds (VCOLD = 76.5% VCC, VHOT = 34.9% VCC).
Technical Context
The LTC4126EV#TRPBF integrates three co-located subsystems: an AC rectifier with differential undervoltage lockout (DUVLO, ∆VUVLO = 27mV/80mV), a linear CC/CV Li-Ion charger with 6-hour safety timer and automatic recharge at 97.5% VCHG, and a low-noise multi-mode charge-pump DC/DC delivering regulated 1.2V up to 60mA in 3:1 mode or open-loop VBAT/3 in 3:1 unregulated mode.
Its switching frequency adapts to battery voltage: 50kHz in 3:1 mode (VBAT > 3.6V), 75kHz in 2:1 mode (VBAT < 3.3V), avoiding audible noise; output regulation transitions between three distinct modes - regulated 1.2V (Mode 1 & 3), VBAT/3 with ROL ≈ 4.6Ω (Mode 2), and forced 2:1 fallback on VOUT droop below 1.1V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Charge Current | Fixed 7.5mA - no external programming required; supports low-power wearable energy budgets. |
| Charge Voltage | PIN-selectable 4.2V or 4.35V - matches standard Li-Ion chemistries without resistor networks. |
| DC/DC Output | Regulated 1.2V ±40mV (VBAT > 3.6V or < 3.3V); unregulated VBAT/3 (3.3V–3.6V) with 4.6Ω effective output resistance. |
| Battery Disconnect | 3.0V threshold (±70mV) - prevents deep discharge and preserves battery cycle life. |
| NTC Interface | Voltage-based cold/hot detection: VCOLD = 76.5% VCC (±1.5%), VHOT = 34.9% VCC (±1.5%) - enables safe charging across 0°C–40°C. |
| Switching Frequency | 50kHz (3:1 mode) or 75kHz (2:1 mode) - avoids audio-band interference in hearing aids. |
| Package | 12-lead 2mm × 2mm × 0.74mm LQFN - thermally enhanced footprint with exposed GND pad for PCB heat sinking. |
Pinout & Package
Thermally optimized 12-lead LQFN (2mm × 2mm × 0.74mm) with exposed GND pad (Pin 13) requiring solder connection to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NTC (1) | Thermistor bias input | Detects battery temperature via voltage divider; grounds to disable thermal monitoring. |
| EN (2) | Digital enable control | Logic-high (>1.1V) forces DC/DC on; logic-low (<0.4V) enables pushbutton override. |
| PBEN (3) | Pushbutton toggle input | Internal 4MΩ pull-up; momentary ground activates DC/DC if EN is low. |
| VSEL (4) | Charge voltage select | Logic-low → 4.2V; logic-high → 4.35V - sets final CV point without external components. |
| ACPR (5) | Input power availability flag | Open-drain CMOS output high when VCC–VBAT > 80mV; referenced to OUT voltage. |
| CHRG (6) | Charge status indicator | Open-drain output with 300µA pull-down; slow blink = charging, fast blink = fault. |
| ACIN (7) | Wireless AC input | Connects to LC tank (receive coil + 68nF); internal diode rectifies to VCC. |
| BAT (8) | Battery terminal | Single-cell Li-Ion connection; powers DC/DC and receives charge current. |
| STAT2 (9), STAT1 (10) | Charging state outputs | CMOS logic pair indicating charge status (only active when DC/DC enabled). |
| VCC (11) | DC input / rectified AC rail | Accepts DC supply or rectified AC from ACIN; clamped to 5.5V max. |
| OUT (12) | DC/DC regulated output | Delivers 1.2V to load; requires ≥2.2µF ceramic capacitor for stability. |
| GND (13) | Ground reference | Exposed thermal pad - must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode charge-pump DC/DC | Automatically switches between 3:1 regulated, 3:1 unregulated (VBAT/3), and 2:1 regulated modes based on battery voltage and load - eliminates need for external mode control. |
| Differential undervoltage current limiting (DUVCL) | Gradually reduces charge current from 7.5mA to zero as VCC–VBAT drops from 154mV to 116mV - prevents oscillatory charging under weak coupling. |
| Integrated NTC interface | Direct analog sensing of thermistor voltage - no ADC or external comparator needed; hysteresis prevents thermal chatter during charge pause/resume. |
| Low-noise 50/75kHz switching | Frequencies selected to avoid 20Hz–20kHz audio band - critical for hearing aid signal integrity and EMI compliance. |
| Ultra-low quiescent current | 4µA BAT quiescent current (DC/DC off, VBAT = 4.4V) - extends shelf life in shipped hearing aids. |
Applications
| Hearing Aid Power Management | Wireless Charging Earbuds |
|---|---|
Use Scenario: Compact in-ear hearing aid requiring continuous 1.2V power for DSP ASIC and wireless charging without audible noise. IC Role / Device Role / Timing Role: Dual-role IC providing both battery charging and regulated system power - eliminates separate LDO or buck converter. Use Value: 2mm × 2mm footprint enables miniaturized form factor; 50kHz/75kHz switching avoids audio-band interference; 3.0V disconnect preserves battery health. |
Use Scenario: True wireless stereo (TWS) earbud case with wireless charging receiver and battery management. IC Role / Device Role / Timing Role: Wireless power receiver IC with integrated Li-Ion charger and low-noise DC/DC - simplifies BOM for compact charging cases. Use Value: Pin-selectable 4.2V/4.35V supports multiple cell chemistries; DUVCL ensures stable charging under variable coil alignment; NTC input enables safe charging in sealed enclosures. |
| IoT Wearable Sensors | Medical Implantable Monitors |
Use Scenario: Sub-gram wearable patch monitoring vital signs with multi-day battery life and contactless recharging. IC Role / Device Role / Timing Role: Ultra-low-quiescent wireless charging front-end - manages energy harvesting, battery protection, and regulated sensor power. Use Value: 4µA BAT quiescent current extends standby time; 6-hour safety timer prevents overcharge; 12-pin LQFN enables high-density layout. |
Use Scenario: Miniaturized implantable cardiac monitor requiring biocompatible, hermetically sealed power management with thermal safety. IC Role / Device Role / Timing Role: Temperature-qualified wireless charging controller - enforces strict 0°C–40°C charging window via NTC interface. Use Value: VCOLD/VHOT thresholds referenced to VCC eliminate external voltage references; 3.0V disconnect prevents cell damage during long-term implantation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wireless Li-Ion charging applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ51013BRGER | Inductive receiver with integrated 500mA charger; no integrated DC/DC; requires external LDO for 1.2V output. | Higher charge current suitable for larger batteries; lacks built-in low-noise regulated output for hearing aid ASICs. | Select when higher charge rate is prioritized over system integration and acoustic noise sensitivity. |
| MAX77734EWL+T | PMIC with 100mA buck-boost DC/DC; no wireless receiver; requires external AC-DC rectification stage. | Supports wider input range (2.5V–5.5V); no native ACIN interface or DUVCL functionality. | Select when wired USB-C or adapter input is used instead of wireless power transfer. |
Compared with BQ51013BRGER and MAX77734EWL+T, the LTC4126EV#TRPBF uniquely integrates wireless AC reception, 7.5mA Li-Ion charging, and a low-noise 1.2V charge-pump DC/DC in a 2mm × 2mm package - making it the only solution that meets hearing aid acoustic, size, and dual-function requirements without external regulators or rectifiers.
Availability
LTC4126EV#TRPBF is available at Aetrix Electronics and suitable for hearing aid manufacturing, wireless earbud development, and medical wearable design requiring stable component supply, RoHS-compliant packaging, and guaranteed tape-and-reel delivery.
Supply support for LTC4126EV#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and healthcare markets.
The LTC4126EV#TRPBF belongs to Analog Devices' wireless power and battery management product line, engineered specifically for ultra-low-power, size-constrained medical and hearing aid applications where integrated AC reception, thermal safety, and noise-free DC/DC are mandatory.
FAQ
What is the exact charge current and termination method of the LTC4126EV#TRPBF?
The LTC4126EV#TRPBF delivers a fixed 7.5mA constant-current charge with automatic transition to constant-voltage regulation at either 4.2V or 4.35V (selected by VSEL pin). Charging terminates after a fixed 6-hour safety timer expires, regardless of battery state - a hard limit preventing overcharge in sealed devices like hearing aids. The LTC4126EV#TRPBF does not use voltage-based or current-taper termination alone.
How does the LTC4126EV#TRPBF handle low-input-power conditions during wireless charging?
The LTC4126EV#TRPBF implements differential undervoltage current limiting (DUVCL): as the VCC-to-BAT differential drops from ~154mV to ~116mV, charge current smoothly decreases from 7.5mA to zero - avoiding abrupt shutdown and oscillatory behavior common in weak-coupling scenarios. This ensures stable, continuous charging even with misaligned coils. The LTC4126EV#TRPBF signals DUVCL faults via fast blinking on CHRG.
Can the LTC4126EV#TRPBF operate without wireless power input?
Yes - the LTC4126EV#TRPBF supports direct DC input: connect a DC voltage source (2.7V–5.5V) to the VCC pin and ground the ACIN pin. All charging, DC/DC regulation, and status functions remain fully operational. The LTC4126EV#TRPBF does not require ACIN to be active; its architecture supports hybrid wired/wireless power architectures.
What is the role of the NTC pin on the LTC4126EV#TRPBF, and how is temperature threshold set?
The NTC pin on the LTC4126EV#TRPBF accepts a voltage divider formed by a thermistor and bias resistor to detect battery temperature. Cold fault triggers at VCOLD = 76.5% VCC (±1.5% hysteresis); hot fault triggers at VHOT = 34.9% VCC (±1.5%). These thresholds are internally generated and require no external components. Grounding the NTC pin disables all thermal monitoring in the LTC4126EV#TRPBF.
Does the LTC4126EV#TRPBF provide regulated 1.2V output across the full battery voltage range?
No - the LTC4126EV#TRPBF provides regulated 1.2V only in Mode 1 (VBAT > 3.6V) and Mode 3 (VBAT < 3.3V). Between 3.3V and 3.6V (Mode 2), it delivers unregulated VBAT/3 with an effective output resistance of ~4.6Ω. For example, at VBAT = 3.5V and IOUT = 3mA, VOUT ≈ 1.185V - calculated as 3.5V/3 – (3mA × 4.6Ω). This behavior is inherent to the LTC4126EV#TRPBF's multi-mode charge-pump architecture.
LTC4126EV#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 1
- Current - Charging:
- Constant
- Programmable Features:
- Voltage
- Fault Protection:
- Undervoltage
- Charge Current - Max:
- 7.5mA
- Battery Pack Voltage:
- 4.35V
- Voltage - Supply (Max):
- 5.5V
- Interface:
- -
- Operating Temperature:
- -20°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-LQFN (2x2)
LTC4126EV#TRPBF FAQ
1.How can I place an order for LTC4126EV#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4126EV#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 LTC4126EV#TRPBF reliable?
The price and inventory of LTC4126EV#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4126EV#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC4126EV#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4126EV#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4126EV#TRPBF?
LTC4126EV#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4126EV#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 LTC4126EV#TRPBF?
For technical support, including LTC4126EV#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4126EV#TRPBF requirements.
6.How does Aetrix verify that LTC4126EV#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC4126EV#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 LTC4126EV#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC4126EV#TRPBF?
All LTC4126EV#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4126EV#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 LTC4126EV#TRPBF part is unused and in its original packaging.
Return procedure for LTC4126EV#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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