Analog Devices Inc. LTC4050EMS-4.2#TRPBF

Overview

LTC4050EMS-4.2#TRPBF 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. It is used in portable electronics requiring safe, autonomous Li-Ion charging without microcontroller intervention.

For engineers reviewing the LTC4050EMS-4.2#TRPBF datasheet, LTC4050EMS-4.2#TRPBF pinout, LTC4050EMS-4.2#TRPBF application, or LTC4050EMS-4.2#TRPBF equivalent, key selection criteria include its 10-pin MSOP package, C/10 end-of-charge detection, 5µA sleep-mode battery drain, thermistor interface implementation, and compatibility with external P-channel MOSFET or high-gain PNP pass transistors.

Technical Context

The LTC4050EMS-4.2#TRPBF implements a precision analog control loop using an internal 2.47V reference, current amplifier, and voltage amplifier to regulate both charge current (via RPROG/RSENSE feedback) and float voltage (via BAT pin resistor divider). Its thermistor interface uses dual comparators with hysteresis to monitor NTC resistance thresholds (RHOT ≈ 4.1kΩ, RCOLD ≈ 28.5kΩ) corresponding to 50°C and 0°C.

Charge termination combines time-based control (externally programmable via TIMER pin capacitor, tTIMER = CTIMER × 3h / 0.1µF) and C/10 current detection. Recharge is triggered automatically when battery voltage drops below 3.98V after full charge, and insertion of a discharged battery (<3.98V) resets the timer and initiates a new cycle.

Key Specifications

Pinout & Package

The LTC4050EMS-4.2#TRPBF is housed in a 10-pin plastic MSOP package with exposed thermal pad (MS package per LTC DWG #05-08-1661), optimized for thermal dissipation in linear charging applications.

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#TRPBF, LTC4053EDD-4.2#TRPBF adds USB-native support at the cost of higher pin count and complexity, while LTC1731ES8-4.2#TRPBF trades recharge autonomy and ACPR indication for smaller footprint and reduced feature set - choice depends on input source requirements and system-level charge management architecture.

Availability

LTC4050EMS-4.2#TRPBF is available at Aetrix Electronics and suitable for cellular phones, handheld computers, charging docks, and medical handheld devices requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC4050EMS-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 semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs for precision instrumentation, industrial, automotive, and communications markets.

The LTC4050EMS-4.2#TRPBF belongs to Linear's legacy battery management product line, designed specifically for autonomous, low-component-count linear charging of single-cell Li-Ion batteries in portable consumer and medical electronics.

FAQ

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

The LTC4050EMS-4.2#TRPBF 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, ensuring reliable Li-Ion cell termination without overvoltage stress.

How does the LTC4050EMS-4.2#TRPBF implement thermistor-based temperature protection?

The LTC4050EMS-4.2#TRPBF uses its NTC pin to bias a 10kΩ NTC thermistor (e.g., Dale NTHS-1206N02) against internal resistive dividers. It detects cold faults when thermistor resistance exceeds ~28.5kΩ (≈0°C) and hot faults when resistance falls below ~4.1kΩ (≈50°C), suspending charge and freezing the timer until temperature returns to the valid window.

Can the LTC4050EMS-4.2#TRPBF be used with a PNP transistor instead of a P-channel MOSFET?

Yes, the LTC4050EMS-4.2#TRPBF supports PNP pass transistors via its DRV pin, but requires a high-gain Darlington device (e.g., ZTX749) due to the current amplifier's low gain (~0.6µA/mV). A 1000pF capacitor from DRV to VCC is mandatory for stability, and charge current error increases with lower transistor β - MOSFET use is preferred for accuracy.

What happens when the input supply is removed from the LTC4050EMS-4.2#TRPBF?

When the input supply is removed, the LTC4050EMS-4.2#TRPBF automatically enters sleep mode, reducing battery drain current to 5µA (max). In this state, the internal resistor divider at the BAT pin disconnects, DRV pulls high to disable the pass element, and CHRG and ACPR go high-impedance - preserving battery capacity during standby.

Does the LTC4050EMS-4.2#TRPBF support automatic recharge after self-discharge?

Yes, the LTC4050EMS-4.2#TRPBF monitors battery voltage continuously and initiates a new charge cycle automatically when VBAT drops below 3.98V (for 4.2V cells), even while the battery remains connected. This ensures the cell stays at full capacity without external intervention or microcontroller polling.