Analog Devices Inc. LTC4069EDC-4.4#TRPBF

Overview

LTC4069EDC-4.4 from Analog Devices (formerly Linear Technology) is a standalone linear lithium-ion battery charger IC with integrated P-channel MOSFET, 4.4V float voltage, 750mA programmable charge current, ±0.6% float voltage accuracy, and NTC thermistor input for temperature-qualified charging. It operates directly from USB power (4.5V–5.5V) in portable electronics requiring compact, thermally robust, safety-compliant charging.

For engineers reviewing the LTC4069EDC-4.4 datasheet, LTC4069EDC-4.4 pinout, LTC4069EDC-4.4 application, or LTC4069EDC-4.4 equivalent, key selection considerations include C/10 charge termination detection, thermal regulation at ~115°C, automatic recharge threshold (ΔVRECHRG = 100mV), shutdown current <20μA, and 2mm × 2mm DFN-6 package with exposed pad grounding.

Technical Context

The LTC4069EDC-4.4 implements a three-loop control architecture-constant-current (CA), constant-voltage (VA), and constant-temperature (TA)-with priority-based diode steering to ensure safe, adaptive charging. Its internal P-channel MOSFET eliminates external blocking diodes and sense resistors, while PROG pin servoing to 1.0V enables precise current programming via single resistor (e.g., 2kΩ → 500mA).

Thermal feedback actively reduces charge current when die temperature approaches 115°C, enabling reliable operation under high ambient or high-power conditions without derating. The CHRG open-drain output provides three-state status indication: strong pull-down during active charge, high-impedance at C/10 or timer end, and 2Hz pulsing (25% or 75% duty) for NTC fault or defective battery detection.

Key Specifications

Pinout & Package

The LTC4069EDC-4.4 is housed in a 6-lead, 2mm × 2mm plastic DFN package with an exposed thermal pad (Pin 7) that must be soldered to PCB ground for electrical integrity and rated thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24075RGER and MAX1555ESA+, the LTC4069EDC-4.4 uniquely supports 4.4V Li-ion cells, integrates NTC monitoring with hysteresis, and provides active thermal regulation-making it the only choice for high-density, temperature-critical, 4.4V battery applications.

Availability

LTC4069EDC-4.4 is available at Aetrix Electronics and suitable for wireless PDAs, cellular phones, and portable medical sensors requiring stable component supply, JEITA-compliant charging, and compact 2mm × 2mm DFN integration.

Supply support for LTC4069EDC-4.4 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 and maintains its high-performance analog and power management portfolio.

The LTC4069EDC-4.4 belongs to Linear's precision battery charger IC family, designed specifically for space-constrained, USB-powered portable devices needing accurate 4.4V Li-ion charging with integrated safety features.

FAQ

What is the exact float voltage and accuracy of the LTC4069EDC-4.4?

The LTC4069EDC-4.4 has a preset float voltage of 4.4V with ±0.6% accuracy over 0°C to 85°C. This is achieved via an internal precision resistor divider on the BAT pin, eliminating external components. At 25°C, typical VFLOAT is 4.400V; min/max values are 4.375V and 4.425V across temperature and process variation. This specification is confirmed in the Electrical Characteristics table of the official datasheet.

How does the LTC4069EDC-4.4 implement thermal regulation, and what is the trip point?

The LTC4069EDC-4.4 uses an internal transconductance amplifier (TA loop) to regulate junction temperature to approximately 115°C. When die temperature approaches this threshold, the TA loop actively reduces charge current to maintain thermal equilibrium. This occurs without external components and is independent of ambient temperature sensing. The trip point is fixed and not user-adjustable; it is verified in Typical Performance Characteristics Figure G09 (Power FET On-Resistance vs Temperature).

Can the LTC4069EDC-4.4 be used with batteries requiring 4.2V float voltage?

No-the LTC4069EDC-4.4 is factory-trimmed for 4.4V float voltage and cannot be adjusted to 4.2V. Its internal resistor divider is laser-trimmed during production and has no external adjustment pins or registers. For 4.2V applications, consider alternatives like the LTC4054-4.2 or BQ24075RGER. Using LTC4069EDC-4.4 with 4.2V cells risks overcharging and violates battery manufacturer specifications.

What is the function of the CHRG pin, and how do its three states map to operational conditions?

The CHRG pin on the LTC4069EDC-4.4 is an open-drain output with three distinct states: (1) Strong pull-down (<105mV at 5mA) during active charging; (2) High-impedance when charge current drops to C/10, timer expires, or PROG is floated; (3) 2Hz pulsing (25% duty for NTC fault, 75% for defective battery). These states are defined in the PIN FUNCTIONS section and validated in Figure 2 (State Diagram) of the datasheet.

Is the exposed pad (Pin 7) of the LTC4069EDC-4.4 electrically connected, and what is its role?

Yes-the exposed pad (Pin 7) of the LTC4069EDC-4.4 is internally connected to GND and must be soldered to the PCB ground plane. It serves dual purposes: (1) Electrical return path for internal GND currents, and (2) Primary thermal conduction path-failure to solder it results in θJA degrading from 60°C/W to >120°C/W, risking thermal shutdown or reliability failure. This requirement is explicitly stated in the ORDER INFORMATION and ABSOLUTE MAXIMUM RATINGS sections.