Analog Devices Inc. LTC4065LXEDC-4.1#TRPBF

Overview

LTC4065LXEDC-4.1#TRPBF from Analog Devices is a standalone linear lithium-ion battery charger IC designed for single-cell 4.1V float applications in space-constrained portable devices. It delivers up to 250mA constant-current/constant-voltage charging with ±0.6% float voltage accuracy, thermal regulation at ~115°C, and <1µA battery drain in shutdown - enabling reliable USB-powered charging in wristwatches, Bluetooth headsets, and coin-cell–based sensors.

For engineers reviewing the LTC4065LXEDC-4.1#TRPBF datasheet, LTC4065LXEDC-4.1#TRPBF pinout, LTC4065LXEDC-4.1#TRPBF application, or LTC4065LXEDC-4.1#TRPBF equivalent, key selection criteria include its 4.1V fixed float voltage (optimized for high-temperature or backup use), absence of trickle charge (LTC4065LX variant), 2×2mm DFN-6 package with exposed pad, and C/10 charge termination detection via open-drain CHRG pin.

Technical Context

The LTC4065LXEDC-4.1#TRPBF implements a three-loop control architecture: constant-current (PROG pin servo'd to 1.0V), constant-voltage (4.1V float set by internal resistor divider R1/R2), and constant-temperature (TA amplifier limiting junction temperature to ~115°C). Its internal P-channel power FET eliminates need for external blocking diode or sense resistor.

Unlike the LTC4065L-4.1 variant, this LTC4065LX-4.1 version omits low-battery trickle charge - it applies full programmed current immediately when V_BAT < 2.9V. Charge termination relies solely on C/10 detection and a 4.5-hour internal timer, with automatic recharge triggered when V_BAT drops ≥100mV below 4.1V.

Key Specifications

Pinout & Package

Package: 6-lead (2mm × 2mm) plastic DFN with exposed thermal pad (Pin 7 = GND). Exposed pad must be soldered to PCB ground plane for rated θ_JA = 60°C/W and safe thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1555 and BQ24040, the LTC4065LXEDC-4.1#TRPBF offers the smallest footprint and unique 4.1V float for thermal resilience, but lacks USB enumeration and system-power delivery - making it optimal for size- and temperature-critical single-function charging.

Availability

LTC4065LXEDC-4.1#TRPBF is available at Aetrix Electronics and suitable for wearable health sensors, USB-powered Bluetooth earbuds, and industrial backup power modules requiring stable component supply, long-lifecycle support, and guaranteed 4.1V float voltage accuracy.

Supply support for LTC4065LXEDC-4.1#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. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and communications infrastructure.

The LTC4065LX series belongs to Analog Devices' dedicated battery management IC portfolio, engineered specifically for ultra-compact, thermally constrained portable electronics where reliability, low quiescent current, and precise voltage regulation are critical.

FAQ

What is the exact float voltage of the LTC4065LXEDC-4.1#TRPBF and how is it trimmed?

The LTC4065LXEDC-4.1#TRPBF has a factory-trimmed constant-voltage float of 4.1V ±0.6% (4.058V to 4.142V) across –40°C to 85°C. This value is set by an internal laser-trimmed resistor divider (R1/R2) and does not require external components. The 4.1V specification is exclusive to the -4.1 suffix variants and is documented in the Electrical Characteristics table on page 3 of the Rev. D datasheet.

Does the LTC4065LXEDC-4.1#TRPBF support trickle charge for deeply discharged batteries?

No, the LTC4065LXEDC-4.1#TRPBF explicitly disables trickle charge - unlike the LTC4065L-4.1 variant. When V_BAT < 2.9V, it applies the full programmed charge current immediately. This behavior is confirmed in the Features list ("Available Without Trickle Charge") and Operation section (footnote 7 and Figure 2), which states "LTC4065LX/LTC4065LX-4.1 ONLY; no trickle charge."

How is charge current programmed on the LTC4065LXEDC-4.1#TRPBF and what is the minimum supported value?

Charge current is set by a single 1% resistor (R_PROG) from PROG (Pin 6) to GND, using I_BAT = 205 × (1V / R_PROG). For the LTC4065LXEDC-4.1#TRPBF, the minimum supported current is 8mA (requiring R_PROG = 25.6kΩ), and maximum is 250mA (R_PROG = 820Ω), as specified in the "LTC4065 Options" table on page 3 of the datasheet.

What thermal protection mechanism does the LTC4065LXEDC-4.1#TRPBF use and at what temperature does it activate?

The LTC4065LXEDC-4.1#TRPBF employs a constant-temperature feedback loop (TA amplifier) that begins reducing charge current when junction temperature approaches ~115°C. This is not a hard shutdown but a dynamic current foldback to maintain T_J ≈ 115°C, allowing safe operation under high ambient or high-power-dissipation conditions without external thermal sensors or PCB layout changes.

Can the LTC4065LXEDC-4.1#TRPBF be used with a 3.3V input supply?

No - the LTC4065LXEDC-4.1#TRPBF requires V_CC ≥ 3.75V for guaranteed operation (Absolute Maximum Ratings, page 2). At 3.3V, the device remains in undervoltage lockout (UVLO) and delivers zero charge current. Minimum functional input is 3.75V; typical USB 5V or wall adapter 4.5–5.5V supplies are recommended.