Analog Devices Inc. LTC4120EUD-4.2#TRPBF

Overview

LTC4120EUD-4.2#TRPBF from Analog Devices is a fixed 4.2V float voltage wireless power receiver and synchronous buck battery charger IC, delivering up to 400mA charge current with ±1% feedback voltage accuracy and Dynamic Harmonization Control (DHC) for efficient air-gap charging across variable coupling distances. It integrates low-voltage preconditioning, NTC temperature qualification, timer-based termination, and auto-recharge - enabling sealed, rotating, or sanitary medical and industrial devices.

For engineers reviewing the LTC4120EUD-4.2#TRPBF datasheet, LTC4120EUD-4.2#TRPBF pinout, LTC4120EUD-4.2#TRPBF application, or LTC4120EUD-4.2#TRPBF equivalent, key selection considerations include its 4.2V fixed float voltage, 16-pin 3mm × 3mm QFN package, DHC input regulation at 14V, ±5% charge current accuracy, and compatibility with Li-Ion/Polymer batteries in harsh or isolated environments.

Technical Context

The LTC4120EUD-4.2#TRPBF implements a synchronous buck topology with integrated high-side and low-side MOSFETs (R_DS(ON) = 0.8Ω / 0.5Ω), programmable switching frequency (750kHz or 1.5MHz via FREQ pin), and precise current sensing through CHGSNS–BAT internal 300mΩ sense resistor. Its DHC architecture dynamically modulates resonant tank impedance by controlling pin 6 to regulate received input voltage without microprocessor intervention.

It features dedicated BATSNS pin (Pin 10) for direct battery voltage monitoring, eliminating external feedback dividers, and supports thermally qualified charging via NTC bias network referenced to INTVCC. The device enters sleep mode after charge termination and auto-restarts when battery voltage drops 2.2% below float voltage - all within –40°C to 125°C junction temperature range.

Key Specifications

Pinout & Package

Package: 16-lead (3mm × 3mm × 0.75mm) plastic QFN with exposed thermal pad (Pin 17 = GND). Requires soldering of exposed pad to PCB ground plane for θ_JA = 54°C/W thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wireless battery charging applications.

Compared with LTC4120EUD-4.2#TRPBF, LTC4125IDDB#TRPBF serves a complementary transmitter role and cannot perform battery charging, while BQ51013BRGER offers Qi standardization but sacrifices DHC-based coupling adaptability and wide-input resilience - making LTC4120EUD-4.2#TRPBF uniquely suited for custom, high-gap, industrial wireless charging systems.

Availability

LTC4120EUD-4.2#TRPBF is available at Aetrix Electronics and suitable for handheld medical instruments, industrial wireless sensors, and sanitary food processing equipment requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LTC4120EUD-4.2#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 medical electronics markets.

The LTC4120 product line delivers contactless battery charging solutions for sealed, rotating, or hygienic environments - designed specifically to replace mechanical connectors with robust, maintenance-free wireless power interfaces.

FAQ

What is the primary function of the DHC pin on the LTC4120EUD-4.2#TRPBF?

The DHC (Dynamic Harmonization Control) pin on the LTC4120EUD-4.2#TRPBF regulates input voltage by modulating the resonant frequency of the receiver tank when input voltage falls below 14V. It connects to a Schottky diode and capacitor network to dynamically adjust coupling efficiency - enabling stable charging across variable air gaps (0.4–1.8cm) without transmitter-side feedback. This function is essential for maintaining consistent power delivery in mechanically misaligned or moving systems.

How does the LTC4120EUD-4.2#TRPBF differ from the standard LTC4120 in terms of voltage regulation?

The LTC4120EUD-4.2#TRPBF uses a fixed 4.2V float voltage sensed directly at the BATSNS pin, eliminating the need for external feedback resistors. In contrast, the standard LTC4120 employs a programmable FB pin with adjustable 3.5–11V float range via resistive divider. This makes the LTC4120EUD-4.2#TRPBF simpler to implement for single-cell Li-Ion applications but less flexible for multi-cell or alternative chemistries.

Can the LTC4120EUD-4.2#TRPBF operate without an NTC thermistor?

Yes - the LTC4120EUD-4.2#TRPBF can operate without an NTC thermistor by tying the NTC pin to GND, which disables temperature qualification. However, doing so bypasses critical safety protection: the device will no longer pause charging during over-temperature or under-temperature conditions. For medical or industrial applications where battery thermal safety is mandated, NTC integration remains strongly recommended.

What is the minimum and maximum charge current supported by the LTC4120EUD-4.2#TRPBF?

The LTC4120EUD-4.2#TRPBF supports a programmable charge current range of 50mA to 400mA, set by a single 1% resistor connected between PROG (Pin 13) and GND. A 24.3kΩ resistor yields ~50mA, while a 3.01kΩ resistor yields ~400mA. The device guarantees ±5% accuracy across –40°C to 125°C, with typical performance within ±3% at 25°C.

Does the LTC4120EUD-4.2#TRPBF require external MOSFETs for buck conversion?

No - the LTC4120EUD-4.2#TRPBF integrates synchronous high-side and low-side MOSFETs with R_DS(ON) of 0.8Ω and 0.5Ω respectively. It drives an external inductor (e.g., 33µH) between SW and CHGSNS, and requires only passive components (capacitors, resistor, diode for DHC) for full operation - reducing BOM count and layout complexity versus controller-only solutions.