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Analog Devices Inc. LTC4126EV-ADJ#TRPBF
- Part No.:
- LTC4126EV-ADJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 12-VFQFN Exposed Pad
- Datasheet:
-
LTC4126EV-ADJ#TRPBF.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 12LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,466
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Product details
Overview
LTC4126EV-ADJ#TRPBF from Analog Devices is a wireless single-cell Li-Ion battery charger IC with integrated 1.2V multi-mode charge-pump DC/DC regulator, programmable 1–50mA charge current via external resistor, 4.2V charge voltage, and 3.0V battery disconnect threshold. It enables compact hearing aid power systems with simultaneous wireless charging and regulated low-noise supply.
For engineers reviewing the LTC4126EV-ADJ#TRPBF datasheet, LTC4126EV-ADJ#TRPBF pinout, LTC4126EV-ADJ#TRPBF application, or LTC4126EV-ADJ#TRPBF equivalent, key selection criteria include NTC-based temperature-qualified charging, dual-mode (50kHz/75kHz) switching to avoid audible noise, 12-lead 2mm × 2mm LQFN package with exposed GND pad, and differential undervoltage current limiting (DUVCL) for stable operation under variable coupling conditions.
Technical Context
The LTC4126EV-ADJ#TRPBF integrates three functional blocks: an AC rectifier with overvoltage limit (5.5V typical VCC high limit), a linear CC/CV Li-Ion charger with 6-hour safety timer and automatic recharge at 97.5% of VCHG, and a thermally optimized multi-mode charge-pump DC/DC regulator delivering 1.2V at up to 60mA output current.
Its DC/DC operates in three modes: regulated 3:1 step-down (VBAT > 3.6V), open-loop 3:1 (3.3V < VBAT ≤ 3.6V), and 2:1 step-down (VBAT ≤ 3.3V), with switching frequencies fixed at 50kHz or 75kHz depending on mode-ensuring no spectral energy falls within the 20Hz–20kHz audio band.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Charge Voltage | 4.2V ±21mV - precise termination point for standard Li-Ion cells, minimizing stress and maximizing cycle life. |
| Programmable Charge Current | 1mA to 50mA - set by single external resistor (RPROG = 100·1.1V/ICHG − 2.2kΩ), enabling fine-grained power budgeting for ultra-low-power wearables. |
| DC/DC Output Voltage | 1.2V ±40mV (typical) - tightly regulated rail for hearing aid ASICs, with load regulation maintained across 0–60mA output range. |
| Battery Disconnect Threshold | 3.0V ±70mV - prevents deep discharge damage by isolating battery from system loads below safe operating voltage. |
| NTC Temperature Monitoring | Voltage thresholds at 76.5% (cold) and 34.9% (hot) of VCC - enables safe charging between ~0°C and ~40°C without external ADC or microcontroller. |
| Switching Frequency | 50kHz or 75kHz - selected automatically per battery voltage; avoids audible noise and simplifies EMI filtering. |
| Package | 12-lead 2mm × 2mm × 0.74mm LQFN with exposed GND pad - supports high thermal conductivity and minimal PCB footprint for space-constrained implants and wearables. |
Pinout & Package
Thermally enhanced 12-lead LQFN (2mm × 2mm × 0.74mm) with exposed GND pad (Pin 13) requiring solder connection to PCB ground for electrical integrity and thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NTC (Pin 1) | Thermistor input | Monitors battery temperature via voltage divider; suspends charging if outside safe range (0°C–40°C typical), referenced to VCC. |
| EN (Pin 2) | Digital enable input | Active-high logic control (VIH ≥ 1.1V) for DC/DC; overrides PBEN when asserted; tie to BAT for always-on operation. |
| PBEN (Pin 3) | Pushbutton toggle input | Internal 4MΩ pull-up enables momentary-GND button control; ignored if EN is high. |
| PROG (Pin 4) | Charge current programming | Connects to GND via precision resistor to set ICHG from 1mA to 50mA; 1% tolerance recommended. |
| ACPR (Pin 5) | Input power availability indicator | CMOS output referenced to OUT; high when VCC–VBAT ≥ 80mV (typ), low when ≤27mV (typ); requires DC/DC enabled. |
| CHRG (Pin 6) | Open-drain charge status | Indicates state via pull-down current (300µA typ): slow blink (1.14Hz) = charging, fast blink (4.58Hz) = fault, pulled low = done, Hi-Z = no input power. |
| ACIN (Pin 7) | AC receive coil interface | Connects to parallel LC tank for wireless power reception; internal rectifier feeds VCC; short to GND if unused. |
| BAT (Pin 8) | Battery connection | Direct connection to single-cell Li-Ion anode; powers DC/DC and receives charge current; decouple with 1µF ceramic if DC/DC active during charge. |
| STAT2 (Pin 9), STAT1 (Pin 10) | Charging status logic outputs | CMOS outputs referenced to OUT; encode charge/fault states jointly with ACPR; inactive if DC/DC disabled. |
| VCC (Pin 11) | Rectified input supply | Output of internal AC rectifier (from ACIN) or DC input node; clamped to 5.5V max; powers internal circuitry and charger. |
| OUT (Pin 12) | DC/DC regulated output | Delivers 1.2V to load; requires ≥2.2µF low-ESR ceramic capacitor placed adjacent to pin for stability and transient response. |
| GND (Pin 13) | Ground reference & thermal pad | Exposed copper pad on package underside; must be soldered to PCB ground plane for electrical return and thermal dissipation (θJA = 92°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode charge-pump DC/DC | Three operating modes (3:1 regulated, 3:1 open-loop, 2:1) maintain 1.2V output across full battery range (3.0V–4.25V) while optimizing efficiency and noise. |
| Differential undervoltage current limiting (DUVCL) | Gradually reduces charge current as VCC–VBAT drops from 154mV to 116mV-prevents oscillatory charging under weak magnetic coupling in wireless systems. |
| Temperature-qualified charging | Integrated NTC comparators with 1.5% hysteresis eliminate need for external temperature sensing circuitry or firmware intervention. |
| Low-noise 50kHz/75kHz switching | Fixed-frequency operation avoids audio-band interference critical for hearing aid signal chains and sensitive analog front-ends. |
| Ultra-low quiescent current | 4µA BAT quiescent current (DC/DC off, VBAT = 4.25V) extends shelf life and runtime in intermittently powered wearables. |
Applications
| Hearing Aid Power System | Wireless Charging Earbud | |
|---|---|---|
Use Scenario: Compact in-ear device requiring simultaneous wireless charging and ultra-low-noise 1.2V supply for audio DSP and RF transceiver. IC Role / Device Role / Timing Role: Dual-role IC providing CC/CV Li-Ion charging and regulated step-down conversion, eliminating need for separate charger + LDO. Use Value: Enables sub-10mm form factor with 60mA DC/DC output, 3.0V disconnect protection, and NTC-based thermal safety-no external supervision required. |
Use Scenario: True wireless stereo (TWS) earbud case with integrated wireless transmitter and earbud receiver using resonant coupling. IC Role / Device Role / Timing Role: Receiver-side power management IC handling AC rectification, battery charging, and system rail generation from same coil. Use Value: DUVCL ensures stable charging despite variable coil alignment; 50kHz/75kHz switching avoids interference with Bluetooth audio transmission. |
|
| IoT Medical Sensor Patch | Low-Power Wearable Tracker | |
Use Scenario: Disposable skin-adhered patch monitoring vital signs for 7+ days, recharged wirelessly via bedside pad. IC Role / Device Role / Timing Role: Primary power IC managing energy harvesting from wireless field, battery health, and regulated supply for sensor hub. Use Value: 1mA minimum charge current enables trickle replenishment from low-power transmitters; 6-hour safety timer prevents overcharge in unattended use. |
Use Scenario: Fitness tracker with coin-cell-sized Li-Ion battery and daily wireless charging via cradle. | IC Role / Device Role / Timing Role: Integrated charger + DC/DC eliminates discrete regulators and reduces BOM count by two components. Use Value: 2mm × 2mm LQFN package saves >30% board area vs. traditional charger + LDO solution; pushbutton control (PBEN) enables user-initiated power-on. |
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-boost DC/DC; no programmable charge current; fixed 4.2V charge voltage; larger 3mm × 3mm QFN package. | Designed for Qi-standard consumer electronics; lacks NTC input and low-noise 1.2V rail; unsuitable for hearing aids due to higher EMI and voltage mismatch. | Select only if Qi compliance and 5V system rail are mandatory; not drop-in for 1.2V ASIC supply or medical-grade thermal safety. |
| MAX77751EWA+T | High-efficiency buck-boost charger with I²C interface, 1.8V–5.5V output; requires external MCU for configuration; no integrated NTC comparator; 16-pin WLP package. | Targeted at smartphones/tablets with host-controlled power management; adds software complexity and PCB area vs. LTC4126EV-ADJ#TRPBF's autonomous operation. | Choose when dynamic output voltage adjustment or telemetry logging is needed; avoid when autonomous, ultra-compact, or low-EMI operation is primary. |
Compared with BQ51013BRGER and MAX77751EWA+T, the LTC4126EV-ADJ#TRPBF uniquely combines autonomous NTC-based thermal safety, ultra-low-noise 1.2V DC/DC output, and DUVCL for robust wireless charging in miniaturized medical devices-without requiring host MCU or Qi infrastructure.
Availability
LTC4126EV-ADJ#TRPBF 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 long-term availability.
Supply support for LTC4126EV-ADJ#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC4126EV-ADJ#TRPBF belongs to Analog Devices' Power by Linear™ wireless charging product line, designed specifically for ultra-low-power, size-constrained wearable and implantable medical devices requiring autonomous, thermally safe, and EMI-optimized power management.
FAQ
What is the function of the PROG pin on the LTC4126EV-ADJ#TRPBF?
The PROG pin on the LTC4126EV-ADJ#TRPBF sets the battery charge current via an external resistor connected to GND. Using the formula RPROG = (100 × 1.1V)/ICHG − 2.2kΩ, designers can precisely program ICHG from 1mA to 50mA. For example, a 12.4kΩ resistor yields ~7.5mA charge current. The LTC4126EV-ADJ#TRPBF uses this pin to configure its linear CC/CV charger without requiring digital interface or trimming.
How does the LTC4126EV-ADJ#TRPBF handle low-input-power conditions during wireless charging?
The LTC4126EV-ADJ#TRPBF employs Differential Undervoltage Current Limiting (DUVCL) to gracefully scale charge current as VCC–VBAT drops from 154mV to 116mV-avoiding abrupt shutdowns common with basic DUVLO circuits. This prevents oscillatory charging under weak magnetic coupling. When current falls below 40% of programmed value, the CHRG pin blinks fast (4.58Hz) to indicate DUVCL activation. The LTC4126EV-ADJ#TRPBF maintains system stability without external intervention.
Can the LTC4126EV-ADJ#TRPBF operate without wireless power input?
Yes-the LTC4126EV-ADJ#TRPBF supports dual power sources. When ACIN is grounded, a DC voltage (2.7V–5.5V) applied directly to the VCC pin powers both the charger and internal circuitry. The IC functions identically: charging proceeds at programmed current, DC/DC delivers 1.2V, and all protections (NTC, DUVCL, safety timer) remain fully active. This flexibility allows the same LTC4126EV-ADJ#TRPBF design to serve wired and wireless charging variants.
What is the purpose of the exposed pad (Pin 13) on the LTC4126EV-ADJ#TRPBF package?
The exposed pad (Pin 13) on the LTC4126EV-ADJ#TRPBF is a dedicated GND connection that must be soldered to the PCB ground plane. It serves two critical roles: (1) providing low-impedance electrical return for internal currents, and (2) dissipating heat-enabling θJA = 92°C/W. Omitting this connection risks thermal shutdown, voltage regulation drift, and reduced reliability. The LTC4126EV-ADJ#TRPBF datasheet explicitly requires soldering this pad for guaranteed operation across –20°C to 85°C.
How does the LTC4126EV-ADJ#TRPBF indicate charging status and faults?
The LTC4126EV-ADJ#TRPBF provides status through three complementary interfaces: (1) CHRG pin (open-drain) blinks slowly (1.14Hz) during charging, fast (4.58Hz) for faults (NTC, bad battery, DUVCL), pulls low when done, or floats with no input; (2) ACPR goes high when VCC–VBAT ≥ 80mV; (3) STAT1/STAT2 encode states jointly (e.g., 0/1 = charging) when DC/DC is enabled. All indicators are implemented autonomously within the LTC4126EV-ADJ#TRPBF-no firmware required.
LTC4126EV-ADJ#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:
- 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#TRPBF FAQ
1.How can I place an order for LTC4126EV-ADJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4126EV-ADJ#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-ADJ#TRPBF reliable?
The price and inventory of LTC4126EV-ADJ#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-ADJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC4126EV-ADJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4126EV-ADJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4126EV-ADJ#TRPBF?
LTC4126EV-ADJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4126EV-ADJ#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-ADJ#TRPBF?
For technical support, including LTC4126EV-ADJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4126EV-ADJ#TRPBF requirements.
6.How does Aetrix verify that LTC4126EV-ADJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC4126EV-ADJ#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-ADJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC4126EV-ADJ#TRPBF?
All LTC4126EV-ADJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4126EV-ADJ#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-ADJ#TRPBF part is unused and in its original packaging.
Return procedure for LTC4126EV-ADJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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