Analog Devices Inc. LTC4050EMS-4.2#PBF

Overview

LTC4050EMS-4.2#PBF from Analog Devices (formerly Linear Technology) is a standalone linear lithium-ion battery charger IC for single-cell 4.2V systems, featuring ±1% float voltage accuracy, programmable charge current up to 500mA, thermistor-based temperature supervision (0°C–50°C), and automatic trickle/constant-current/constant-voltage charging sequence control. It is used in portable electronics requiring safe, autonomous Li-Ion charging without microcontroller intervention.

For engineers reviewing the LTC4050EMS-4.2#PBF datasheet, LTC4050EMS-4.2#PBF pinout, LTC4050EMS-4.2#PBF application, or LTC4050EMS-4.2#PBF equivalent, key selection considerations include its 10-pin MSOP package, C/10 end-of-charge detection, PROG-pin-programmable current, NTC interface thresholds (RHOT ≈ 4.1kΩ, RCOLD ≈ 28.5kΩ), and sleep-mode battery drain of only 5µA.

Technical Context

The LTC4050EMS-4.2#PBF implements a precision analog control loop using an internal 2.47V reference, current amplifier, and voltage amplifier to regulate both charge current (via external RPROG and RSENSE) and final float voltage (4.2V ±1%). Its thermistor interface uses dual comparators with built-in hysteresis to suspend charging outside 0°C–50°C by disabling the current amplifier and freezing the timer.

Charge termination is configurable via external TIMER capacitor (tTIMER = CTIMER × 3h / 0.1µF) or C/10 detection (10% of programmed IBAT). Recharge triggers automatically when battery voltage drops below 3.98V after full charge, and insertion of a discharged cell (<3.98V) resets the timer and initiates a new cycle.

Key Specifications

Pinout & Package

Package: 10-pin MSOP (3mm × 3mm, 0.5mm pitch), RoHS-compliant, surface-mount.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar lithium-ion linear charger applications.

Compared with LTC4050EMS-4.2#PBF, LTC4053EDD-4.2#PBF adds USB interface logic at the expense of pin compatibility and higher integration complexity, while LTC1731ES8-4.2#PBF reduces feature set (no ACPR, no PROG shutdown) to achieve smaller footprint and lower cost - neither is pin-compatible, but both serve overlapping Li-Ion charging roles.

Availability

LTC4050EMS-4.2#PBF is available at Aetrix Electronics and suitable for portable medical monitors, handheld barcode scanners, wireless headphone charging docks, and smart wearable fitness trackers requiring stable component supply and long-lifecycle support.

Supply support for LTC4050EMS-4.2#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 and maintains its high-performance analog IC portfolio, emphasizing precision, reliability, and automotive/industrial qualification.

The LTC4050EMS-4.2#PBF belongs to Linear's standalone battery management IC family, designed specifically for autonomous, firmware-free Li-Ion charging in space-constrained portable electronics with stringent safety and accuracy requirements.

FAQ

What is the exact float voltage accuracy of the LTC4050EMS-4.2#PBF?

The LTC4050EMS-4.2#PBF provides a regulated float voltage of 4.2V with ±1% accuracy over the full operating temperature range (–40°C to 85°C) and input voltage range (5V ≤ VCC ≤ 10V). This specification is guaranteed by design and confirmed in the Electrical Characteristics table under "Regulated Output (Float) Voltage" for the LTC4050-4.2 variant.

How does the LTC4050EMS-4.2#PBF handle battery temperature monitoring?

The LTC4050EMS-4.2#PBF uses its NTC pin to interface with a 10kΩ NTC thermistor (e.g., Dale NTHS-1206N02) to enforce a 0°C to 50°C charging window. Internal comparators detect RHOT ≈ 4.1kΩ (hot fault) and RCOLD ≈ 28.5kΩ (cold fault), suspending charge current and freezing the timer until temperature returns to range - no external ADC or firmware is required.

Can the LTC4050EMS-4.2#PBF automatically restart charging after battery voltage drops?

Yes. The LTC4050EMS-4.2#PBF automatically initiates a new charge cycle when the battery voltage falls below 3.98V after full charge - a feature called automatic recharge. This occurs without external intervention and applies whether the drop results from self-discharge or system load, ensuring the battery remains topped off during standby.

What is the minimum battery voltage that triggers trickle charging in the LTC4050EMS-4.2#PBF?

The LTC4050EMS-4.2#PBF begins trickle charging when the sensed battery voltage (at the BAT pin) is below 2.49V, with a typical threshold of 2.49V and tolerance of 2.41V to 2.58V. Trickle current is set to 10% of the programmed full-scale charge current and continues until the cell voltage exceeds this threshold.

Does the LTC4050EMS-4.2#PBF support shutdown via the PROG pin?

Yes. The LTC4050EMS-4.2#PBF can be forced into shutdown by floating the PROG pin. An internal 2.3µA current source pulls the pin voltage above the 3.6V shutdown threshold, disabling the DRV output, resetting the timer, and disconnecting the internal battery divider - reducing quiescent current to 5µA in sleep mode.