Analog Devices Inc. LT3650EMSE-8.2#TRPBF

Overview

LT3650EMSE-8.2#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 2-cell Li-Ion/Polymer battery charger IC with integrated 2A switch, operating from 9V to 32V input and delivering 8.2V float voltage. It features programmable C/10 or timer-based charge termination, NTC temperature monitoring, and bad-battery detection - used in 12V–24V industrial handhelds and automotive cradle chargers.

For engineers reviewing the LT3650EMSE-8.2#TRPBF datasheet, LT3650EMSE-8.2#TRPBF pinout, LT3650EMSE-8.2#TRPBF application, or LT3650EMSE-8.2#TRPBF equivalent, key selection criteria include input voltage range (9–32V), 8.2V float accuracy (±0.04V), 2A max charge current, 1MHz fixed-frequency average current mode control, and MSOP-12 thermal performance (θ_JA = 43°C/W).

Technical Context

The LT3650EMSE-8.2#TRPBF implements average current mode step-down regulation with a bootstrapped 2A internal switch, enabling high-efficiency charging across wide VIN (9–32V) while maintaining precise 8.2V float voltage (±0.5%). Its dual termination modes-C/10 detection (7.5–12.5mV sense threshold) and user-programmable timer (3-hour typical via 0.68µF capacitor)-support robust battery management in safety-critical systems.

It integrates preconditioning (5.65V threshold), auto-recharge at 97.5% float voltage, and binary-coded open-collector status outputs (CHRG/FAULT). The RNG/SS pin enables dynamic charge current adjustment and soft-start, while CLP provides system-level input current limiting by servoing charge current against external supply load.

Key Specifications

Pinout & Package

LT3650EMSE-8.2#TRPBF is housed in a 12-lead plastic MSOP package (3mm × 4.4mm, 0.65mm pitch) with exposed thermal pad (Pin 13 = GND). The package supports 43°C/W junction-to-ambient thermal resistance and requires soldering of the exposed pad to PCB ground for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-cell Li-ion charger applications.

Compared with LT3650EMSE-8.2#TRPBF, the LT3650EMSE-8.4#TRPBF offers identical functionality at a higher float voltage for newer 2S chemistries, while the MP2617GQ-Z sacrifices critical safety and system-integration features to reduce BOM count - making LT3650EMSE-8.2#TRPBF the preferred choice for industrial and automotive designs requiring robustness and configurability.

Availability

LT3650EMSE-8.2#TRPBF is available at Aetrix Electronics and suitable for industrial handheld instruments, 12V–24V automotive cradle chargers, and desktop cradle chargers requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LT3650EMSE-8.2#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial, and automotive markets.

The LT3650 product line delivers monolithic, high-input-voltage Li-ion chargers optimized for 12V–32V systems where space, thermal performance, and functional safety are critical - targeting portable industrial, automotive, and medical battery-powered equipment.

FAQ

What is the exact float voltage of the LT3650EMSE-8.2#TRPBF?

The LT3650EMSE-8.2#TRPBF has a nominal float voltage of 8.2V, specified as 8.16V (min) to 8.24V (max) over temperature and line conditions - corresponding to ±0.04V absolute accuracy (0.5% of 8.2V). This value is factory-trimmed and does not require external calibration. The LT3650EMSE-8.2#TRPBF achieves this precision using an internal bandgap reference and laser-trimmed resistive divider, ensuring reliable 2-cell Li-ion termination without external feedback components.

Does the LT3650EMSE-8.2#TRPBF support automatic recharge, and at what threshold?

Yes, the LT3650EMSE-8.2#TRPBF supports automatic recharge when the battery voltage drops to 97.5% of its float voltage - i.e., 7.995V (8.2V × 0.975). This behavior is hard-coded and non-adjustable. Upon crossing this threshold, the IC exits standby mode and initiates a new CC/CV cycle. The LT3650EMSE-8.2#TRPBF maintains 85µA standby current until recharge triggers, minimizing self-discharge impact on the connected battery pack.

Can the LT3650EMSE-8.2#TRPBF be used without the NTC thermistor?

Yes, the LT3650EMSE-8.2#TRPBF operates fully without the NTC thermistor: leave the NTC pin unconnected to disable temperature monitoring. The IC will still perform preconditioning, CC/CV charging, termination, and auto-recharge. However, thermal fault protection is forfeited - a critical consideration for applications subject to ambient extremes or high-power operation. The LT3650EMSE-8.2#TRPBF's NTC function remains enabled only when thermistor impedance to ground is <250kΩ; open-circuit satisfies this condition.

What is the maximum allowable input voltage for the LT3650EMSE-8.2#TRPBF?

The absolute maximum input voltage for the LT3650EMSE-8.2#TRPBF is 40V, per its Absolute Maximum Ratings table. Continuous operation is rated from 9V to 32V, with a minimum start-up voltage of 11.5V (or V_BOOST–V_SW > 2V). Exceeding 32V during normal operation risks violating the recommended operating conditions, though transient spikes up to 40V are tolerated briefly without damage - provided layout minimizes inductive kickback and input capacitance adequately absorbs energy.

How is charge current programmed on the LT3650EMSE-8.2#TRPBF?

Charge current is programmed via an external sense resistor (R_SENSE) between SENSE and BAT pins, where R_SENSE = 0.1V / I_CHG(MAX). For example, a 50mΩ resistor sets 2A max current. The LT3650EMSE-8.2#TRPBF also allows dynamic adjustment using the RNG/SS pin: sourcing 50µA into a resistor (e.g., 20kΩ → 1V) scales I_CHG(MAX) linearly. The LT3650EMSE-8.2#TRPBF guarantees ±5% charge current accuracy across temperature and line variations.