Analog Devices Inc. LT3650EMSE-8.2#PBF

Overview

LT3650EMSE-8.2#PBF from Analog Devices (formerly Linear Technology) is a monolithic 2-cell Li-Ion/Polymer battery charger IC with 9V–32V input range, 8.2V float voltage, and up to 2A programmable charge current. It integrates a 1MHz average-current-mode buck regulator, internal safety timer (typically 3 hours), C/10 termination detection, and NTC-based temperature monitoring. It is used in industrial handheld instruments and 12V–24V automotive charging systems.

For engineers reviewing the LT3650EMSE-8.2#PBF datasheet, LT3650EMSE-8.2#PBF pinout, LT3650EMSE-8.2#PBF application, or LT3650EMSE-8.2#PBF equivalent, key selection factors include its 8.2V fixed float voltage, MSOP-12 package with exposed thermal pad, ±0.5% float voltage accuracy, 5% charge current accuracy, and dual termination options (C/10 or timer-based).

Technical Context

The LT3650EMSE-8.2#PBF employs average current mode control with a 1MHz fixed-frequency buck architecture, using an integrated 2.5A switch and bootstrapped BOOST drive for high efficiency. Its voltage error amplifier (V-EA) and current error amplifier (C-EA) jointly regulate both constant-current (CC) and constant-voltage (CV) phases via BAT and SENSE feedback paths.

It implements dual termination logic: C/10 detection triggers at ITH = 0.1V (corresponding to 10% of programmed IMAX), while the internal timer uses a capacitor on TIMER pin (e.g., 0.68µF → 3-hour timeout). Precondition mode activates below 5.65V BAT, reducing charge current to 15% of IMAX until threshold is crossed.

Key Specifications

Pinout & Package

LT3650EMSE-8.2#PBF is housed in a 12-lead plastic MSOP package (3mm × 3mm, 0.75mm height) with exposed thermal pad (Pin 13) that must be soldered 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 LTC4000EMS#PBF and BQ24610RGER, the LT3650EMSE-8.2#PBF offers integrated switching, fixed 8.2V float matched to common 2S Li-ion cells, and autonomous safety features (precondition, bad-battery detection, NTC monitoring) - reducing design effort and component count for dedicated 2-cell applications.

Availability

LT3650EMSE-8.2#PBF is available at Aetrix Electronics and suitable for industrial handheld instruments, 12V–24V automotive charging systems, and desktop cradle chargers requiring stable component supply, long lifecycle support, and guaranteed lead-free compliance.

Supply support for LT3650EMSE-8.2#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) designs precision analog, mixed-signal, and power management ICs for high-reliability industrial, automotive, and communications applications.

The LT3650 product line delivers complete, high-voltage monolithic Li-ion chargers optimized for 12V/24V input systems - targeting space-constrained, thermally demanding applications where integration, safety, and minimal external components are critical.

FAQ

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

The LT3650EMSE-8.2#PBF has a factory-trimmed nominal float voltage of 8.2V, with guaranteed accuracy of ±0.5% (8.16V to 8.24V) over temperature and line. This value is fixed and cannot be adjusted externally - it is distinct from the LT3650-8.4 variant, which targets 8.4V. The 8.2V setting is optimized for 2-cell Li-ion batteries requiring 4.10V per cell.

Does the LT3650EMSE-8.2#PBF support automatic preconditioning for deeply discharged batteries?

Yes, the LT3650EMSE-8.2#PBF automatically enters precondition mode when the BAT pin voltage falls below 5.65V. In this mode, it delivers 15% of the programmed maximum charge current (set by RSENSE) until the battery reaches the precondition threshold. This protects weak or over-discharged cells from damage due to excessive initial current, and is fully autonomous - no host intervention required.

Can the LT3650EMSE-8.2#PBF be used with a 12V input supply?

Yes, the LT3650EMSE-8.2#PBF operates reliably from 12V input - its 9V–32V input range and 11.5V minimum start-up voltage are fully compatible with nominal 12V systems (e.g., automotive or industrial rails). Input transient tolerance up to 40V absolute maximum further ensures robustness against load-dump spikes commonly seen in vehicle environments.

How is charge termination configured on the LT3650EMSE-8.2#PBF?

Charge termination on the LT3650EMSE-8.2#PBF is configurable via two independent methods: C/10 detection (default when TIMER pin is grounded) or internal timer (enabled by connecting a capacitor to TIMER pin). With timer enabled, charging continues beyond C/10 to "top off" the battery until the programmed timeout (e.g., 3 hours with 0.68µF), after which the LT3650EMSE-8.2#PBF enters standby.

What thermal management provisions does the LT3650EMSE-8.2#PBF include?

The LT3650EMSE-8.2#PBF features an exposed thermal pad (Pin 13, SGND) that must be soldered to the PCB ground plane to achieve its specified θJA of 43°C/W. It also includes thermal foldback - IMAX reduces progressively above 100°C junction temperature - and NTC-based temperature monitoring that suspends charging if battery temperature exceeds safe limits (0°C–40°C).