Analog Devices Inc. LTC4054XES5-4.2#TRPBF

Overview

LTC4054XES5-4.2#TRPBF from Analog Devices (formerly Linear Technology) is a standalone linear Li-ion battery charger IC with thermal regulation in 5-lead TSOT-23 package. It delivers up to 800mA programmable charge current, features ±1% 4.2V float voltage accuracy, C/10 termination, and automatic recharge - designed for USB-powered portable devices requiring compact, low-component-count charging solutions.

For engineers reviewing the LTC4054XES5-4.2#TRPBF datasheet, LTC4054XES5-4.2#TRPBF pinout, LTC4054XES5-4.2#TRPBF application, or LTC4054XES5-4.2#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal regulation behavior, exact package mapping to TSOT-23, and two rigorously cross-checked alternative parts for single-cell Li-ion charging systems.

Technical Context

The LTC4054XES5-4.2#TRPBF implements constant-current/constant-voltage (CC/CV) charging with internal P-channel MOSFET and no external sense resistor or blocking diode required. Its thermal feedback loop activates at ~120°C junction temperature to reduce charge current and prevent overheating.

Unlike the standard LTC4054, the 'X' variant omits trickle charge functionality (no 2.9V threshold activation), simplifying operation for batteries pre-conditioned above 2.9V. Charge termination uses a filtered comparator monitoring PROG pin voltage falling below 100mV for ≥1ms, ensuring immunity to transient load noise.

Key Specifications

Pinout & Package

Package: 5-lead ThinSOT™ (TSOT-23), 0.95mm maximum height, lead pitch 0.95mm, exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP73831T-2DCI/OT, LTC4054XES5-4.2#TRPBF offers superior thermal adaptability for dense layouts; compared with BQ24075RGTR, it provides identical core charging functionality in a smaller, lower-cost package without USB protocol overhead.

Availability

LTC4054XES5-4.2#TRPBF is available at Aetrix Electronics and suitable for USB-powered portable devices, Bluetooth wearables, charging docks, and medical sensor patches requiring stable component supply across production lifecycles.

Supply support for LTC4054XES5-4.2#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LTC4054X series belongs to Linear's precision battery management product line, engineered specifically for space-constrained, thermally sensitive USB-charged Li-ion applications where minimal external components and guaranteed safety margins are mandatory.

FAQ

What is the key functional difference between LTC4054XES5-4.2#TRPBF and LTC4054ES5-4.2#TRPBF?

The LTC4054XES5-4.2#TRPBF omits the trickle charge feature present in the standard LTC4054ES5-4.2#TRPBF. Specifically, it does not activate charging when battery voltage falls below 2.9V - instead, it waits until BAT exceeds 2.9V before entering constant-current mode. This simplifies operation for batteries that remain above the trickle threshold during normal use, reducing unnecessary low-current stress on aging cells. The LTC4054XES5-4.2#TRPBF retains all other functions: 4.2V ±1% regulation, thermal feedback, C/10 termination, automatic recharge at 4.05V, and PROG pin programmability.

Does LTC4054XES5-4.2#TRPBF require an external blocking diode?

No, LTC4054XES5-4.2#TRPBF does not require an external blocking diode. Its internal P-channel MOSFET architecture prevents reverse current flow from the battery to the input supply (VCC), eliminating both the forward voltage drop and power loss associated with discrete diodes. This design also removes the need for an external current-sense resistor, further reducing component count and PCB area. The absence of these components is explicitly confirmed in the official datasheet's "No MOSFET, Sense Resistor or Blocking Diode Required" feature list and functional block diagram.

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

Charge current on LTC4054XES5-4.2#TRPBF is programmed using a single external resistor (R_PROG) connected between the PROG pin (Pin 5) and ground. The relationship is defined as I_BAT = 1000 × (V_PROG / R_PROG), where V_PROG is held at 1.0V during constant-current mode. For example, a 1.25kΩ 1% resistor sets I_BAT ≈ 800mA. The PROG pin also serves as a real-time current monitor: measuring its voltage allows calculation of instantaneous battery current without additional circuitry. This dual function is intrinsic to the LTC4054XES5-4.2#TRPBF's architecture and is validated in the Electrical Characteristics table and Operation section of the datasheet.

What thermal protection mechanism does LTC4054XES5-4.2#TRPBF implement?

LTC4054XES5-4.2#TRPBF implements junction-temperature-based thermal regulation, activating when die temperature approaches ~120°C. Unlike simple thermal shutdown, this feature dynamically reduces charge current to maintain safe operating temperature - preserving charging functionality while preventing damage. The regulation point is fixed and not user-adjustable; its effectiveness depends on PCB thermal design (θ_JA ranges from 80°C/W to 150°C/W based on copper area). This behavior is confirmed in the Thermal Considerations section, Typical Performance Characteristics (Figure G21), and Absolute Maximum Ratings table, where T_JMAX = 125°C and thermal limiting onset is specified at ~120°C.

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

LTC4054XES5-4.2#TRPBF can be powered without a battery, but output stability requires an external capacitor on the BAT pin. The datasheet states that the constant-voltage feedback loop is stable only when a battery is present; with no battery, a ≥1µF ceramic capacitor (with optional 1Ω series resistor for low-ESR types) is required to prevent oscillation and excessive ripple. Operating without either battery or capacitor risks unstable regulation and potential damage to downstream circuitry. This requirement is explicitly documented in the "Stability Considerations" section and supported by application circuit recommendations in Figure 2 and related text.