Analog Devices Inc. LT3650IDD-8.2#TRPBF

Overview

LT3650IDD-8.2#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 2-cell Li-Ion/Polymer battery charger IC with integrated 2A switch, 8.2V float voltage, 9V–32V input range, and programmable C/10 or timer-based charge termination. It delivers up to 2A constant-current charging, features NTC temperature monitoring, bad-battery detection, and auto-recharge at 97.5% float voltage - used in 12V–24V automotive cradle chargers and industrial handheld instruments.

For engineers reviewing the LT3650IDD-8.2#TRPBF datasheet, LT3650IDD-8.2#TRPBF pinout, LT3650IDD-8.2#TRPBF application, or LT3650IDD-8.2#TRPBF equivalent, key selection considerations include its 8.2V fixed float voltage, 12-pin DFN (3mm × 3mm) package with exposed thermal pad, ±0.5% float voltage accuracy, 5% charge current accuracy, and compatibility with system-level input current limiting via CLP pin.

Technical Context

The LT3650IDD-8.2#TRPBF implements average current mode control with a fixed 1MHz switching frequency, using an internal 2A N-channel MOSFET switch driven by a bootstrapped BOOST rail. Its voltage error amplifier integrates BAT-to-float error to generate ITH, which sets average charge current via SENSE-BAT sensing.

It supports dual termination modes: C/10 detection (ITH = 0.1V) or programmable timer (CTIMER = 0.68µF → 3-hour full cycle), with preconditioning below 5.65V and auto-restart when BAT drops 2.5% below 8.2V. The RNG/SS pin enables dynamic charge current scaling and soft-start via 50µA current source.

Key Specifications

Pinout & Package

LT3650IDD-8.2#TRPBF is housed in a 12-lead (3mm × 3mm) plastic DFN package with exposed thermal pad (Pin 13 = GND), rated for –40°C to +85°C operation. The low-profile (0.75mm) package supports high-density PCB layouts and efficient thermal dissipation when soldered to ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3650EDD-8.2#TRPBF, the LT3650IDD-8.2#TRPBF guarantees full specification compliance at –40°C, making it essential for automotive and industrial environments; versus BQ24610RTWR, it eliminates external FETs and NTC interface circuitry while delivering tighter float voltage accuracy and integrated safety timers.

Availability

LT3650IDD-8.2#TRPBF is available at Aetrix Electronics and suitable for 12V–24V automotive cradle chargers, industrial handheld instruments, and desktop docking stations requiring stable component supply, long-term lifecycle assurance, and guaranteed –40°C to +85°C operation.

Supply support for LT3650IDD-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, automotive, and industrial markets.

The LT3650 product line delivers monolithic, high-voltage Li-ion chargers optimized for 2-cell stacks in space-constrained, thermally demanding applications - designed specifically for automotive, industrial, and portable equipment where reliability and integration are critical.

FAQ

What is the exact float voltage of the LT3650IDD-8.2#TRPBF?

The LT3650IDD-8.2#TRPBF has a fixed nominal float voltage of 8.2V, with a guaranteed accuracy of ±0.5% (8.16V to 8.24V) over the full –40°C to +85°C operating temperature range. This corresponds to 4.10V per cell for safe, full-capacity charging of two-series Li-ion or Li-polymer batteries, and is factory-trimmed - no external resistor network is required to set this value.

Does the LT3650IDD-8.2#TRPBF support automatic recharge after battery voltage drop?

Yes, the LT3650IDD-8.2#TRPBF automatically restarts charging when the battery voltage at the BAT pin falls 2.5% below its 8.2V float voltage - i.e., at 7.99V. This behavior occurs only after a full charge cycle has terminated and the device is in standby mode (85µA quiescent current). The auto-recharge function remains active regardless of whether termination was triggered by C/10 detection or the internal timer.

How is charge current programmed on the LT3650IDD-8.2#TRPBF?

Maximum charge current on the LT3650IDD-8.2#TRPBF is set by an external sense resistor (RSENSE) between SENSE and BAT pins, where RSENSE = 0.1V / ICHG(MAX). For example, a 0.05Ω resistor programs 2A. Additionally, the RNG/SS pin provides dynamic scaling: applying a voltage (0–1V) sourced by a 50µA current sets ICHG(MAX) proportionally - e.g., 0.5V yields 50% of full-scale current.

What package type and thermal characteristics does the LT3650IDD-8.2#TRPBF use?

The LT3650IDD-8.2#TRPBF uses a 12-lead (3mm × 3mm) plastic DFN package with an exposed thermal pad (Pin 13 = GND). Its thermal resistance is θJA = 43°C/W and θJC = 3°C/W. To ensure reliable operation at 2A, the exposed pad must be soldered to a minimum 100mm² copper area connected to the PCB ground plane, enabling efficient heat dissipation in compact industrial and automotive layouts.

Can the LT3650IDD-8.2#TRPBF operate with input voltages below 11.5V?

The LT3650IDD-8.2#TRPBF requires either VIN ≥ 11.5V *or* (VBOOST – VSW) > 2V to start up. Below 11.5V, startup is possible only if the BOOST–SW differential exceeds 2V - typically achieved by pre-charging the BOOST capacitor from the battery or an auxiliary source before VIN ramp-up. Once running, the IC operates down to 9V, but undervoltage lockout (UVLO) resets at 8.7V with 0.2V hysteresis.