Analog Devices Inc. LTC4054XES5-4.2#TRMPBF

Overview

LTC4054XES5-4.2#TRMPBF from Analog Devices (formerly Linear Technology) is a standalone linear Li-ion battery charger IC in a 5-lead TSOT-23 package, delivering up to 800mA programmable charge current with ±1% 4.2V float voltage accuracy and thermal regulation. It integrates internal P-MOSFET, requires no external sense resistor or blocking diode, and is optimized for USB-powered portable devices.

For engineers reviewing the LTC4054XES5-4.2#TRMPBF datasheet, LTC4054XES5-4.2#TRMPBF pinout, LTC4054XES5-4.2#TRMPBF application, or LTC4054XES5-4.2#TRMPBF equivalent, key selection criteria include trickle-charge disable status, thermal regulation onset at ~120°C, C/10 termination, PROG-pin-based current programming, and CHRG open-drain status signaling.

Technical Context

The LTC4054XES5-4.2#TRMPBF implements constant-current/constant-voltage charging with automatic transition between modes and thermal feedback limiting based on die temperature. Its internal P-channel MOSFET (RON ≈ 600mΩ) eliminates need for external blocking diode, while PROG pin serves dual role: programming charge current via external resistor and monitoring real-time current via VPROG = 1.0V in CC mode.

Unlike the LTC4054 variant, the 'X' suffix denotes absence of trickle-charge functionality-VBAT < 2.9V does not initiate low-current pre-charge. Charge termination uses filtered comparator monitoring PROG pin voltage falling below 100mV for >1ms, ensuring immunity to transient load noise.

Key Specifications

Pinout & Package

5-lead TSOT-23 package with exposed pad (not electrically connected); footprint optimized for thermal conduction to PCB copper. Pin 2 (GND) is primary thermal sink; recommended layout includes ≥2500mm² copper area and thermal vias.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear Li-ion charging applications.

Compared with MCP73831T-2ACI/OT, LTC4054XES5-4.2#TRMPBF delivers 60% higher current headroom and active thermal protection critical for compact enclosures; versus BQ24075RGTR, it offers smaller footprint and simpler analog interface at the cost of missing USB protocol features.

Availability

LTC4054XES5-4.2#TRMPBF is available at Aetrix Electronics and suitable for USB-powered wearables, Bluetooth audio devices, portable medical sensors, and smart remote controls requiring stable component supply across production lifecycles.

Supply support for LTC4054XES5-4.2#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 acquired Linear Technology in 2017 and maintains its high-performance analog IC portfolio, emphasizing precision, reliability, and application-specific optimization for demanding electronic systems.

The LTC4054X series belongs to Linear's dedicated battery management product line, designed specifically for space-constrained, USB-compliant portable electronics requiring minimal external components and robust thermal safety.

FAQ

What distinguishes LTC4054XES5-4.2#TRMPBF from the standard LTC4054ES5-4.2?

The LTC4054XES5-4.2#TRMPBF omits the trickle-charge function present in the LTC4054ES5-4.2. When battery voltage falls below 2.9V, the standard version initiates a low-current pre-charge; the 'X' variant skips this step and begins constant-current charging only when VBAT exceeds 2.9V. This simplifies charging logic for applications using healthy, regularly maintained cells.

How is charge current programmed on LTC4054XES5-4.2#TRMPBF?

Charge current is set by connecting a precision 1% resistor (RPROG) between the PROG pin and GND. The relationship is IBAT = 1000 × (VPROG / RPROG), where VPROG is regulated to 1.0V during constant-current mode. For example, RPROG = 1.25kΩ yields 800mA; RPROG = 2kΩ yields 500mA. The PROG pin voltage can be monitored at any time to infer real-time charge current.

Does LTC4054XES5-4.2#TRMPBF support automatic recharge, and how does it work?

Yes, LTC4054XES5-4.2#TRMPBF supports automatic recharge. After charge termination, it continuously monitors BAT voltage with a 2ms-filtered comparator. When VBAT drops to 4.05V (VFLOAT – 150mV), a new charge cycle initiates. This threshold corresponds to ~80–90% state-of-charge, ensuring the battery remains near full capacity without host MCU intervention.

What thermal considerations apply to LTC4054XES5-4.2#TRMPBF in high-ambient environments?

LTC4054XES5-4.2#TRMPBF activates thermal regulation when die temperature approaches 120°C, reducing charge current to maintain safe operation. With θJA = 125°C/W (typical 2-layer board), ambient temperature rise directly impacts deliverable current-for example, at 60°C ambient and 5V input, max current drops to ~320mA for a 3.75V battery. Layout with ≥2500mm² copper and thermal vias is essential for sustained 800mA performance.

Can LTC4054XES5-4.2#TRMPBF be used without a battery connected?

No-LTC4054XES5-4.2#TRMPBF requires a battery or equivalent capacitive load on the BAT pin for stable constant-voltage loop operation. Without a battery, the feedback loop becomes unstable and may oscillate or fail to regulate. If testing without a battery is necessary, a minimum 10µF low-ESR tantalum capacitor is recommended to emulate battery impedance and ensure regulation integrity.