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Analog Devices Inc. LTC4126EV-ADJ#TRMPBF
- Part No.:
- LTC4126EV-ADJ#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 12-VFQFN Exposed Pad
- Datasheet:
-
LTC4126EV-ADJ#TRMPBF.pdf
- Description:
- IC BATT CHG 1-50MA ADJ LI-ION
- Quantity:
- Payment:
- Shipping:
Inventory:425
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Product details
Overview
LTC4126EV-ADJ#TRMPBF from Analog Devices is a wireless single-cell Li-Ion battery charger IC with integrated 1.2V step-down multi-mode charge pump DC/DC regulator. It delivers programmable 1–50mA CC/CV charging, 4.2V termination voltage, and low-noise 50kHz/75kHz switching - all in a thermally enhanced 12-lead 2mm × 2mm LQFN package. Designed for hearing aids and ultra-low-power wearables, it supports NTC-based temperature-qualified charging and automatic recharge.
For engineers reviewing the LTC4126EV-ADJ#TRMPBF datasheet, LTC4126EV-ADJ#TRMPBF pinout, LTC4126EV-ADJ#TRMPBF application, or LTC4126EV-ADJ#TRMPBF equivalent, this page provides verified technical context, validated pin functions, real-world use cases in hearing aids and IoT wearables, and two confirmed alternative parts with documented functional differences.
Technical Context
The LTC4126EV-ADJ#TRMPBF integrates three core subsystems: an AC rectification and input power controller (accepting DC via VCC or AC via ACIN/LC tank), a linear CC/CV Li-Ion charger with 6-hour safety timer and DUVLO/DUVCL protection, and a proprietary multi-mode charge pump DC/DC regulator delivering regulated 1.2V output up to 60mA. Its operation spans three battery-voltage-dependent modes: 3:1 regulated (VBAT > 3.6V), 3:1 open-loop (3.3V < VBAT ≤ 3.6V), and 2:1 regulated (VBAT ≤ 3.3V).
Charge current is set by a single external resistor (RPROG) on PROG pin per RPROG = (110 V·Ω)/ICHG − 2.2kΩ; NTC monitoring uses dual comparators with VCOLD = 76.5% VCC (rising) and VHOT = 34.9% VCC (falling), each with 1.5% hysteresis. Status signaling occurs via open-drain CHRG (blink patterns), CMOS STAT1/STAT2, and ACPR - all referenced to OUT when DC/DC is enabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Charge Voltage | 4.2V ±21mV - precise termination for standard Li-Ion cells, preventing overcharge and ensuring cycle life. |
| Programmable Charge Current | 1mA to 50mA - set via external RPROG; enables optimization for battery capacity and thermal constraints in space-constrained devices. |
| DC/DC Output Voltage | 1.2V ±40mV (typ.) - tightly regulated rail for hearing aid ASICs, with mode-switching to maintain regulation down to 3.0V battery. |
| DC/DC Output Current | Up to 60mA - sufficient to power low-voltage analog/digital signal chains without external regulators. |
| Switching Frequency | 50kHz or 75kHz - selected automatically per operating mode to avoid audible noise in audio-sensitive applications. |
| Low Battery Disconnect | 3.0V ±70mV - disconnects load at safe cutoff threshold to prevent deep discharge and cell damage. |
| NTC Threshold Accuracy | VCOLD = 76.5% VCC ±1.5%, VHOT = 34.9% VCC ±1.5% - enables reliable 0°C–40°C charging qualification per Li-Ion manufacturer guidelines. |
Pinout & Package
Thermally enhanced 12-lead 2mm × 2mm × 0.74mm LQFN package with exposed GND pad (Pin 13) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NTC (1) | Thermistor bias input | Monitors battery temperature via voltage divider; suspends charging if outside 0°C–40°C safe range. |
| EN (2) | Digital enable input | Active-high logic control (VIH ≥ 1.1V) for DC/DC; overrides PBEN when asserted. |
| PBEN (3) | Pushbutton toggle input | Internal 4MΩ pull-up enables momentary-GND button control; ignored if EN is high. |
| PROG (4) | Charge current programming node | Accepts 0Ω–107kΩ resistor to set ICHG from 1mA to 50mA with ±25% tolerance. |
| ACPR (5) | Input power availability indicator | CMOS output high when VCC–VBAT > 80mV; low when <27mV - only valid when DC/DC is enabled. |
| CHRG (6) | Open-drain charge status | Indicates charging (slow blink), fault (fast blink), done (pulled low), or no power (Hi-Z). |
| ACIN (7) | AC receive coil interface | Connects to parallel LC tank for wireless power reception; internal rectifier feeds VCC. |
| BAT (8) | Battery connection | Direct Li-Ion anode connection; powers DC/DC and receives charge current; requires 1µF decoupling when DC/DC active. |
| STAT2 (9), STAT1 (10) | Charging state indicators | CMOS outputs encoding charge status (e.g., 00 = done, 01 = charging); referenced to OUT voltage. |
| VCC (11) | Rectified DC supply input | Accepts rectified ACIN or external DC; clamped to 5.5V max; powers internal circuitry and charger. |
| OUT (12) | Regulated DC/DC output | Delivers 1.2V to system load; requires ≥2.2µF ceramic capacitor for stability and transient response. |
| GND (13) | Ground reference & thermal pad | Exposed pad must be soldered to PCB ground plane for thermal dissipation (θJA = 92°C/W) and noise reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode charge pump DC/DC | Three battery-voltage-triggered modes (3:1 regulated, 3:1 open-loop, 2:1 regulated) sustain 1.2V output across full 3.0–4.25V Li-Ion range. |
| Differential undervoltage current limiting (DUVCL) | Gradually reduces charge current as VCC–VBAT drops from 154mV to 116mV - prevents oscillatory charging under weak coupling. |
| Integrated NTC temperature qualification | Dual-threshold comparator (VCOLD/VHOT) with hysteresis ensures safe charging only within 0°C–40°C, pausing timer during faults. |
| Wireless + wired input flexibility | Accepts power via ACIN (wireless LC tank) or direct VCC connection - enables hybrid charging architectures and fallback operation. |
| Ultra-low quiescent current | 4µA BAT quiescent current (DC/DC off) and 37µA VCC quiescent (DC/DC on, no load) extend shelf life in hearing aids and wearables. |
Applications
| Hearing Aid Power Management | Wireless Charging Earbuds |
|---|---|
Use Scenario: Compact in-ear hearing aids requiring maintenance-free wireless charging and ultra-low-noise 1.2V supply for analog front-end ASICs. IC Role / Device Role / Timing Role: Primary battery charger and system power regulator - manages Li-Ion charge profile while generating clean, ripple-free 1.2V rail. Use Value: Eliminates physical connectors; 50kHz/75kHz switching avoids audible interference; 3.0V disconnect preserves battery health during storage. |
Use Scenario: True wireless stereo (TWS) earbuds with case-based wireless charging and individual battery management per earpiece. IC Role / Device Role / Timing Role: Receiver-side wireless charging IC with integrated DC/DC - handles coil-coupled power conversion and regulates voltage for Bluetooth SoC. Use Value: Reduces BOM count by combining charger + regulator; DUVCL maintains stable charging despite variable coil alignment; NTC prevents overheating in sealed enclosures. |
| IoT Wearable Sensors | Medical Patch Monitors |
Use Scenario: Skin-adhesive biosensors powered by small Li-Ion cells, recharged wirelessly through clothing or docking cradles. IC Role / Device Role / Timing Role: Low-power wireless charging interface and regulated supply generator - enables maintenance-free operation for multi-week deployments. Use Value: 1–50mA programmable charge current matches micro-capacity batteries; 6-hour safety timer prevents overcharge in unattended use. |
Use Scenario: Disposable or reusable ECG/temperature patches requiring clinical-grade battery safety and long shelf life. IC Role / Device Role / Timing Role: Safety-certifiable charging controller with temperature qualification and low-battery disconnect - ensures compliance with medical device standards. Use Value: NTC thresholds aligned with ISO 14971 risk management; 3.0V disconnect prevents cell venting; 4µA quiescent current extends shelf life beyond 12 months. |
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 | Single-chip Qi-compliant receiver with integrated 5V buck; no programmable charge current or NTC support; requires external 1.2V LDO for low-voltage loads. | Targets Qi-standard chargers; lacks native 1.2V output and temperature-qualified charging - unsuitable for hearing aids or medical patches. | Select only for Qi ecosystem compatibility where 5V system rail suffices and temperature monitoring is handled externally. |
| LTC4125EUD#PBF | Transmitter-side wireless power controller (not receiver); no battery charging or DC/DC regulation; drives external transmit coil with adaptive frequency tuning. | Used on charging base/cradle side; cannot replace LTC4126EV-ADJ#TRMPBF in end-device - serves complementary role in full system. | Choose only as companion part in complete wireless charging solution; not a functional substitute for receiver-side charging. |
Compared with BQ51013BRGER and LTC4125EUD#PBF, the LTC4126EV-ADJ#TRMPBF uniquely integrates wireless reception, programmable Li-Ion charging, NTC safety, and a dedicated 1.2V low-noise regulator - making it the sole option for space-constrained, audio-sensitive, and medically regulated applications requiring all four functions in one die.
Availability
LTC4126EV-ADJ#TRMPBF is available at Aetrix Electronics and suitable for hearing aid manufacturing, wireless earbud production, and medical wearable development requiring stable component supply, RoHS-compliant packaging, and guaranteed -20°C to 85°C operational performance.
Supply support for LTC4126EV-ADJ#TRMPBF 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.
The LTC4126 product line was designed specifically for ultra-low-power wireless charging in hearing aids and medical wearables - emphasizing minimal external components, integrated safety features, and sub-audible switching noise.
FAQ
What is the exact package type and footprint of the LTC4126EV-ADJ#TRMPBF?
The LTC4126EV-ADJ#TRMPBF uses a 12-lead LQFN package measuring 2mm × 2mm × 0.74mm with an exposed GND pad (Pin 13). Its footprint matches standard 2mm × 2mm QFN layouts but has a slightly reduced height (0.74mm vs. typical 0.75mm) and requires soldering the exposed pad to PCB ground for thermal and electrical performance.
How is charge current programmed on the LTC4126EV-ADJ#TRMPBF?
Charge current on the LTC4126EV-ADJ#TRMPBF is set by an external resistor (RPROG) connected between PROG (Pin 4) and GND, using the formula RPROG = (110 V·Ω)/ICHG − 2.2kΩ. For example, 12.4kΩ yields ~7.5mA; 0Ω gives maximum 50mA. RPROG must be 1% tolerance and fall within 0Ω–107kΩ.
Does the LTC4126EV-ADJ#TRMPBF support both wireless and wired charging inputs?
Yes - the LTC4126EV-ADJ#TRMPBF accepts power either wirelessly via ACIN (connected to an LC tank) or directly via VCC (DC input). When using VCC, ACIN must be grounded. This dual-input capability allows flexible system architecture, including hybrid charging solutions and wired fallback modes.
What happens to the DC/DC output when the battery voltage drops below 3.3V?
When VBAT falls below 3.3V, the LTC4126EV-ADJ#TRMPBF automatically switches its DC/DC regulator to 2:1 step-down mode, maintaining a regulated 1.2V output up to 60mA. Below 3.0V, the IC disconnects the battery from all loads to prevent deep discharge - ensuring safe operation across the full Li-Ion voltage range.
Can the LTC4126EV-ADJ#TRMPBF operate without an NTC thermistor?
Yes - grounding the NTC pin (Pin 1) disables all temperature monitoring functionality. The LTC4126EV-ADJ#TRMPBF will then perform standard CC/CV charging without pausing for thermal faults. However, this bypasses critical safety protection required for medical or high-reliability applications per Li-Ion manufacturer guidelines.
LTC4126EV-ADJ#TRMPBF 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:
- Current, Timer
- Fault Protection:
- Undervoltage
- Charge Current - Max:
- 50mA
- Battery Pack Voltage:
- 4.2V
- 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-ADJ#TRMPBF FAQ
1.How can I place an order for LTC4126EV-ADJ#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4126EV-ADJ#TRMPBF 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-ADJ#TRMPBF reliable?
The price and inventory of LTC4126EV-ADJ#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4126EV-ADJ#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC4126EV-ADJ#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4126EV-ADJ#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4126EV-ADJ#TRMPBF?
LTC4126EV-ADJ#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4126EV-ADJ#TRMPBF 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-ADJ#TRMPBF?
For technical support, including LTC4126EV-ADJ#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4126EV-ADJ#TRMPBF requirements.
6.How does Aetrix verify that LTC4126EV-ADJ#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC4126EV-ADJ#TRMPBF 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-ADJ#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC4126EV-ADJ#TRMPBF?
All LTC4126EV-ADJ#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4126EV-ADJ#TRMPBF, 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-ADJ#TRMPBF part is unused and in its original packaging.
Return procedure for LTC4126EV-ADJ#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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