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Analog Devices Inc. LTC4126EV#TRMPBF
- Part No.:
- LTC4126EV#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 12-VFQFN Exposed Pad
- Datasheet:
-
LTC4126EV#TRMPBF.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 12LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:495
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Product details
Overview
LTC4126EV#TRMPBF 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 applications.
For engineers reviewing the LTC4126EV#TRMPBF datasheet, LTC4126EV#TRMPBF pinout, LTC4126EV#TRMPBF application, or LTC4126EV#TRMPBF 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 at 3.0V, and precise thermal fault thresholds (VCOLD = 76.5% VCC, VHOT = 34.9% VCC).
Technical Context
The LTC4126EV#TRMPBF integrates three core subsystems: an AC rectifier with differential undervoltage lockout (DUVLO) and current limiting (DUVCL), a full-featured linear CC/CV 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 output up to 60mA in 3:1 mode or open-loop VBAT/3 in 3:1 unregulated mode.
Its operation is tightly coupled to battery voltage thresholds: VLOBAT1 (3.6V), VLOBAT2 (3.3V), and VDISCONNECT (3.0V) govern DC/DC mode transitions and system shutdown; switching frequency shifts between 50kHz (3:1 mode) and 75kHz (2:1 mode); and NTC monitoring uses dual comparators with 1.5% hysteresis referenced to VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Charge Current | Fixed 7.5mA - eliminates external current-setting resistor, simplifies layout for space-constrained hearing aids. |
| Charge Voltage | Selectable 4.2V or 4.35V via VSEL pin - supports standard and high-capacity Li-Ion cells without redesign. |
| DC/DC Output | Regulated 1.2V ±40mV (VBAT > 3.6V or < 3.3V) - powers low-voltage ASICs with minimal noise in audio band. |
| Battery Disconnect | 3.0V threshold (±70mV) - prevents deep discharge and preserves battery cycle life in wearables. |
| NTC Thresholds | VCOLD = 76.5% VCC (rising), VHOT = 34.9% VCC (falling), 1.5% hysteresis - enables safe 0°C–40°C charging per Li-Ion spec. |
| Switching Frequency | 50kHz (3:1 mode) or 75kHz (2:1 mode) - avoids audible noise (<20kHz) in hearing devices. |
| Package | 12-lead 2mm × 2mm × 0.74mm LQFN with exposed GND pad - thermally enhanced for high-density PCBs. |
Pinout & Package
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 input | Monitors battery temperature via voltage divider; suspends charging if outside 0°C–40°C range. |
| EN (2) | Digital enable input | Logic-high (>1.1V) forces DC/DC on; logic-low disables it, enabling pushbutton-only control. |
| PBEN (3) | Pushbutton toggle input | Internal 4MΩ pull-up enables momentary ground activation; ignored if EN is high. |
| 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 indicator | Open-drain CMOS output high when VCC–VBAT > 80mV; low when <27mV - signals usable wireless power. |
| CHRG (6) | Charge status output | Open-drain pin with 300µA pull-down: slow blink = charging, fast blink = fault, pulled low = done. |
| ACIN (7) | AC receive input | Connects to LC tank (coil + 68nF); internal rectifier converts wireless AC to VCC supply. |
| BAT (8) | Battery connection | Direct interface to single-cell Li-Ion; supplies both charger and DC/DC converter. |
| STAT2 (9), STAT1 (10) | Status logic outputs | CMOS outputs referenced to VOUT (1.2V); indicate charge state only when DC/DC is enabled. |
| VCC (11) | DC input supply | Accepts rectified ACIN or external DC; clamped at 5.5V max; powers internal circuitry when ACIN inactive. |
| OUT (12) | DC/DC regulated output | Delivers 1.2V to load; requires ≥2.2µF ceramic capacitor close to pin for stability. |
| GND (13) | Ground reference | Exposed thermal pad - must be soldered to PCB ground plane for θJA = 92°C/W and EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode charge-pump DC/DC | Automatically switches between regulated 3:1 (VBAT > 3.6V), open-loop VBAT/3 (3.3V < VBAT < 3.6V), and regulated 2:1 (VBAT < 3.3V) - maintains 1.2V output across full battery range. |
| 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 temperature qualification | Two independent comparators monitor VCOLD (76.5% VCC) and VHOT (34.9% VCC) with 1.5% hysteresis - pauses charging and safety timer during thermal faults. |
| Low-battery disconnect | Hard disconnect at 3.0V (±70mV) with hysteresis - eliminates parasitic drain and protects cell longevity in always-on wearables. |
| Wireless-ready AC input stage | ACIN pin accepts resonant LC tank (coil + 68nF); internal rectifier and overvoltage clamp (5.5V) enable direct coil interface without external diodes. |
Applications
| Hearing Aids | Wireless Headsets |
|---|---|
Use Scenario: Miniaturized in-ear device powered by 30–50mAh Li-Ion cell, charged wirelessly via magnetic induction pad. IC Role / Device Role / Timing Role: LTC4126EV#TRMPBF serves as combined wireless charger and 1.2V system power rail generator, replacing discrete rectifier + LDO + charger. Use Value: Eliminates need for USB port or battery replacement; 2mm × 2mm footprint enables sub-1cm³ form factor; 50kHz/75kHz switching avoids audio-band interference. |
Use Scenario: Compact Bluetooth earbud with sealed housing, requiring maintenance-free charging and stable low-noise power for RF/analog front-end. IC Role / Device Role / Timing Role: LTC4126EV#TRMPBF provides battery management and clean 1.2V supply synchronized to wireless charging events. Use Value: Integrated DUVCL prevents intermittent charging during pocket/charging-pad misalignment; NTC monitoring ensures safe charging during extended wear. |
| IoT Wearables | Low-Power Medical Sensors |
Use Scenario: Skin-contact patch sensor with 20–40mAh battery, recharged daily via bedside induction pad. IC Role / Device Role / Timing Role: LTC4126EV#TRMPBF manages battery health (recharge at 97.5% VCHG, 6h timer, thermal pause) while powering ultra-low-IQ MCU and BLE radio. Use Value: 4µA BAT quiescent current (DC/DC off) extends shelf life; 3.0V disconnect prevents capacity loss from storage discharge. |
Use Scenario: Disposable diagnostic patch with embedded biosensor, requiring reliable single-cell Li-Ion charging and precision analog supply. IC Role / Device Role / Timing Role: LTC4126EV#TRMPBF acts as safety-critical power manager - enforcing temperature limits, voltage thresholds, and charge termination per medical standards. Use Value: VCOLD/VHOT thresholds traceable to VCC eliminate external references; CHRG pin provides unambiguous fault signaling (fast blink = thermal/bad battery). |
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 buck charger; no built-in DC/DC regulator; requires external LDO for 1.2V rail. | Targets higher-power wearables (≥100mAh); lacks NTC temperature qualification and low-VBAT disconnect. | Choose BQ51013BRGER only if >100mA charging and external regulation are acceptable; LTC4126EV#TRMPBF is superior for sub-10mA, ultra-small, thermally constrained designs. |
| MAX77734EWA+T | PMIC with wireless charging receiver, 1.2V LDO (200mA), and fuel gauge; larger 2.5mm × 2.5mm WLP package; no DUVCL or NTC integration. | Designed for smartwatches with display and connectivity; higher IQ and complexity unsuitable for hearing aids. | Select MAX77734EWA+T for feature-rich systems needing fuel gauging and multiple rails; LTC4126EV#TRMPBF offers lower size, lower IQ, and purpose-built thermal/wireless safety. |
Compared with BQ51013BRGER and MAX77734EWA+T, the LTC4126EV#TRMPBF uniquely combines ultra-low 7.5mA charging, integrated 1.2V charge-pump DC/DC, NTC qualification, and 2mm × 2mm footprint - making it the only viable solution for Class I hearing aids and sub-50mAh medical wearables requiring certified thermal safety and zero audible noise.
Availability
LTC4126EV#TRMPBF is available at Aetrix Electronics and suitable for hearing aids, wireless headsets, IoT wearables, and low-power medical sensors requiring stable component supply, RoHS-compliant packaging, and guaranteed tape-and-reel delivery in 500-unit mini-reels.
Supply support for LTC4126EV#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, industrial automation, and healthcare markets.
The LTC4126EV#TRMPBF belongs to Analog Devices' Power Management group, specifically engineered for ultra-low-power, size-constrained wireless charging applications where thermal safety, acoustic silence, and battery longevity are non-negotiable design requirements.
FAQ
What is the exact charge current and voltage configuration of the LTC4126EV#TRMPBF?
The LTC4126EV#TRMPBF delivers a fixed 7.5mA constant-current charge with pin-selectable constant-voltage termination: 4.2V when VSEL = 0V, or 4.35V when VSEL = 5V. These values are factory-trimmed and do not require external resistors or calibration. The LTC4126EV#TRMPBF also enforces automatic recharge at 97.5% of the selected VCHG and terminates after 6 hours regardless of state of charge.
How does the LTC4126EV#TRMPBF handle low battery conditions during DC/DC operation?
The LTC4126EV#TRMPBF implements three-tiered battery monitoring: VLOBAT1 (3.6V), VLOBAT2 (3.3V), and VDISCONNECT (3.0V). When VBAT falls below 3.6V, the DC/DC shifts from regulated 3:1 to open-loop VBAT/3 mode; below 3.3V, it enters regulated 2:1 mode; and below 3.0V, it disconnects the battery entirely from all loads. This ensures continuous 1.2V output down to 3.3V and prevents deep discharge damage - a critical feature for the LTC4126EV#TRMPBF in hearing aids.
Can the LTC4126EV#TRMPBF operate without wireless power input?
Yes, the LTC4126EV#TRMPBF supports dual-input operation: it can be powered either wirelessly via ACIN (with external LC tank) or directly via DC applied to the VCC pin. When using DC input, ACIN must be grounded. In both cases, the LTC4126EV#TRMPBF performs identical battery charging and DC/DC regulation functions - enabling flexible design for products that may transition from wired to wireless charging or require fallback power paths.
What is the role of the ACPR pin on the LTC4126EV#TRMPBF and how is it used?
The ACPR pin on the LTC4126EV#TRMPBF is a digital CMOS output indicating sufficient input power availability: it goes high when VCC–VBAT exceeds 80mV (typical) and low when it drops below 27mV (typical). Its high level is referenced to OUT (1.2V), so it is only active when the DC/DC converter is enabled. The ACPR pin allows host microcontrollers to detect valid wireless coupling before initiating system wake-up - a key function for power-gated architectures using the LTC4126EV#TRMPBF.
Does the LTC4126EV#TRMPBF include protection against unsafe battery temperatures?
Yes, the LTC4126EV#TRMPBF integrates dedicated NTC-based temperature qualification: it monitors battery temperature via the NTC pin using two independent comparators - one for cold (VCOLD rising threshold = 76.5% VCC) and one for hot (VHOT falling threshold = 34.9% VCC), each with 1.5% hysteresis. If temperature moves outside the safe range, the LTC4126EV#TRMPBF immediately suspends charging and signals the fault via fast-blinking CHRG and STAT pins - meeting medical-grade thermal safety requirements.
LTC4126EV#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:
- 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#TRMPBF FAQ
1.How can I place an order for LTC4126EV#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4126EV#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#TRMPBF reliable?
The price and inventory of LTC4126EV#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#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC4126EV#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4126EV#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4126EV#TRMPBF?
LTC4126EV#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4126EV#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#TRMPBF?
For technical support, including LTC4126EV#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4126EV#TRMPBF requirements.
6.How does Aetrix verify that LTC4126EV#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC4126EV#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#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC4126EV#TRMPBF?
All LTC4126EV#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4126EV#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#TRMPBF part is unused and in its original packaging.
Return procedure for LTC4126EV#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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