Analog Devices Inc. LTC4001EUF-1#PBF

Overview

LTC4001EUF-1#PBF from Analog Devices (formerly Linear Technology) is a 2A synchronous buck Li-ion battery charger IC designed for 5V wall adapters. It integrates P- and N-channel MOSFETs, current sense, and ±1% 4.1V float voltage regulation in a single 16-pin QFN package. Its low power dissipation enables compact integration into handheld devices operating above 60°C where extended battery life and thermal safety are critical.

For engineers reviewing the LTC4001EUF-1#PBF datasheet, LTC4001EUF-1#PBF pinout, LTC4001EUF-1#PBF application, or LTC4001EUF-1#PBF equivalent, key selection considerations include its 4.1V fixed float voltage for high-temperature battery longevity, programmable 2A charge current via PROG pin resistor, integrated short-circuit and overtemperature protection, and Kelvin-sense BATSENS/GNDSENS architecture for accurate voltage regulation at the cell terminals.

Technical Context

The LTC4001EUF-1#PBF implements a constant-current/constant-voltage charging algorithm using a 1.5MHz synchronous buck converter with internal 127mΩ P-MOSFET and 121mΩ N-MOSFET. It employs dual-loop control: a current error amplifier regulates charge current via the PROG pin (1.213V reference), while a float voltage error amplifier maintains 4.1V regulation referenced to BATSENS/GNDSENS.

Thermal management includes automatic shutdown when junction temperature exceeds ~160°C, and temperature-qualified charging via NTC thermistor monitoring with cold/hot thresholds set by VINSENSE-derived voltage dividers. Charge termination is configurable via TIMER capacitor (time-based), IDET threshold (current-based), or external EN control.

Key Specifications

Pinout & Package

Package: 16-lead (4mm × 4mm) plastic QFN with exposed thermal pad (Pin 17 = GND). Requires soldering of exposed pad to PCB ground plane for rated thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGER and MP2617GQZ, the LTC4001EUF-1#PBF uniquely delivers 4.1V float voltage with ±0.5% accuracy, Kelvin-sense regulation, and analog-programmable 2A charging-all in a thermally optimized QFN without MCU dependency-making it optimal for high-reliability, high-temp portable equipment.

Availability

LTC4001EUF-1#PBF is available at Aetrix Electronics and suitable for smartphones, digital cameras, charging docks, and handheld computers requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to +85°C.

Supply support for LTC4001EUF-1#PBF 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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LTC4001 family was designed specifically for space-constrained, thermally demanding portable Li-ion charging applications where reliability, integration, and high-temperature battery longevity are paramount.

FAQ

What is the primary function of the LTC4001EUF-1#PBF in a battery charging system?

The LTC4001EUF-1#PBF serves as a complete 2A synchronous buck Li-ion battery charger IC. It manages constant-current and constant-voltage charging, regulates a precise 4.1V float voltage, detects end-of-charge via IDET threshold, provides automatic recharge, and implements comprehensive protection including short-circuit, overtemperature, and NTC-based thermal qualification. The LTC4001EUF-1#PBF integrates all necessary power switches, sense elements, and control logic-eliminating external MOSFETs, sense resistors, and blocking diodes.

Why does the LTC4001EUF-1#PBF use a 4.1V float voltage instead of the more common 4.2V?

The LTC4001EUF-1#PBF uses a fixed 4.1V float voltage to improve long-term battery capacity retention and safety in applications operating or stored above ~60°C. This reduced voltage trades off initial capacity for significantly slower electrolyte decomposition and reduced mechanical stress in prismatic and polymer cells-minimizing swelling and avoiding open CID in cylindrical cells. The LTC4001EUF-1#PBF's ±0.5% accuracy ensures consistent performance across temperature and unit variance.

How is charge current programmed on the LTC4001EUF-1#PBF?

Charge current on the LTC4001EUF-1#PBF is programmed via an external resistor (RPROG) connected between the PROG pin (Pin 12) and GNDSENS (Pin 4). The PROG pin maintains a 1.213V reference, so IBAT ≈ 1.110kΩ / RPROG. For example, a 549Ω resistor sets 2A charge current. The LTC4001EUF-1#PBF also supports DAC-based current programming via the same PROG pin, enabling dynamic adjustment in MCU-controlled systems.

What role do the BATSENS and GNDSENS pins play in the LTC4001EUF-1#PBF?

The BATSENS (Pin 16) and GNDSENS (Pin 4) pins provide a Kelvin-sense connection to the battery terminals, enabling the LTC4001EUF-1#PBF to regulate voltage precisely at the cell itself-not at the IC's output. BATSENS connects to the battery's positive terminal and references the internal 4.1V divider, while GNDSENS connects to the battery's negative terminal and serves as the ground reference for both the float voltage and charge current loops. This eliminates errors from PCB trace resistance, ensuring accurate CC/CV transitions and reliable end-of-charge detection. The LTC4001EUF-1#PBF relies on this pair for all critical voltage measurements.

Can the LTC4001EUF-1#PBF operate without an NTC thermistor?

Yes, the LTC4001EUF-1#PBF can operate without an NTC thermistor. To disable temperature qualification, connect the NTC pin (Pin 11) directly to GNDSENS (Pin 4). This forces the internal comparators inactive and allows uninterrupted charging regardless of battery temperature. However, omitting NTC monitoring removes critical safety protection against lithium plating at low temperatures (<0°C) and thermal runaway at high temperatures (>50°C). The LTC4001EUF-1#PBF retains all other protections-including overvoltage, short-circuit, and overtemperature shutdown-even with NTC disabled.