Analog Devices Inc. LTC4069EDC-4.4#TRMPBF

Overview

LTC4069EDC-4.4 from Analog Devices (formerly Linear Technology) is a standalone linear lithium-ion battery charger IC designed for single-cell 4.4V float applications. It delivers up to 750mA constant-current/constant-voltage charging, integrates an internal P-channel MOSFET and thermal regulation, and operates within USB power specifications (3.75V–5.5V input). Its 2mm × 2mm DFN-6 package with exposed pad enables compact portable designs such as wireless PDAs and cellular phones.

For engineers reviewing the LTC4069EDC-4.4 datasheet, LTC4069EDC-4.4 pinout, LTC4069EDC-4.4 application, or LTC4069EDC-4.4 equivalent, key selection criteria include its 4.4V ±0.6% float voltage accuracy, C/10 charge termination detection, NTC thermistor-based temperature qualification, programmable charge current (via PROG pin resistor), and thermal feedback limiting to ~115°C junction temperature.

Technical Context

The LTC4069EDC-4.4 implements a three-loop control architecture-constant-current (CA), constant-voltage (VA), and constant-temperature (TA)-with priority logic ensuring safe mode transitions. The CA loop regulates PROG pin voltage to 1.00V ±20mV during fast charge; VA maintains BAT at 4.4V via internal R1/R2 divider; TA activates when die temperature approaches 115°C, reducing charge current without halting operation.

It features automatic trickle charge below 2.9V battery voltage, timer-based termination (4.5 hrs typical), recharge threshold at ~4.3V, and dual-fault CHRG pin signaling: 2Hz/75% duty cycle for defective batteries, 2Hz/25% duty cycle for NTC over/under-temperature events. Undervoltage charge limiting (ΔVUVCL1 ≈220mV) prevents excessive input droop during high-current draw.

Key Specifications

Pinout & Package

The LTC4069EDC-4.4 is housed in a 6-lead, 2mm × 2mm × 0.75mm low-profile plastic DFN package with exposed pad (Pin 7), which must be soldered to PCB ground for electrical integrity and thermal performance (θ_JA = 60°C/W).

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 high-capacity Li-ion cells, integrates NTC monitoring and thermal foldback, and achieves <1μA battery drain in shutdown-making it optimal for space-constrained, safety-critical, and high-energy-density applications.

Availability

LTC4069EDC-4.4 is available at Aetrix Electronics and suitable for wireless PDAs, cellular phones, portable medical sensors, and USB-powered IoT endpoints requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

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, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies.

The LTC4069EDC-4.4 belongs to ADI's Linear Technology battery management product line, engineered specifically for compact, USB-compliant, high-accuracy Li-ion charging in portable consumer and industrial devices.

FAQ

What is the exact float voltage of the LTC4069EDC-4.4 and how accurate is it?

The LTC4069EDC-4.4 has a preset float voltage of 4.4V with ±0.6% accuracy over temperature (0°C to 85°C). This specification is guaranteed by internal precision resistor divider R1/R2 and applies under load conditions (IBAT = 2mA). The value is fixed-not user-adjustable-and optimized for high-energy-density Li-ion cells rated for 4.4V termination. This accuracy ensures safe, full-capacity charging without overvoltage stress.

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) that monitors die temperature and begins reducing charge current when junction temperature approaches ~115°C. This constant-temperature mode operates alongside CC/CV control and prevents thermal runaway without halting charging. The threshold is fixed and not user-configurable; thermal foldback is fully autonomous and requires no external components or firmware interaction.

Can the LTC4069EDC-4.4 be used with standard USB ports, and what input voltage range does it support?

Yes, the LTC4069EDC-4.4 is explicitly designed to operate directly from USB power sources. It accepts an input voltage range of 3.75V to 5.5V, includes undervoltage lockout (UVLO) at 3.6V (rising), and features ΔVUVCL1 undervoltage charge limiting (~220mV) to maintain stability across variable USB cable impedances. Its 750mA max current and low quiescent draw make it compliant with USB 2.0/3.0 power delivery constraints.

What NTC thermistor configuration is required for the LTC4069EDC-4.4, and how does it respond to temperature faults?

The LTC4069EDC-4.4 requires a 100kΩ NTC thermistor (e.g., Vishay NTHS0603N01N1003J) connected between NTC pin and GND, plus a 100kΩ 1% resistor (RNOM) from NTC pin to VCC. Charging suspends if NTC pin voltage falls below 0.35×VCC (hot fault) or rises above 0.76×VCC (cold fault); CHRG pin then pulses at 2Hz with 25% duty cycle. Each threshold includes ~3°C hysteresis to prevent oscillation.

How is charge current programmed on the LTC4069EDC-4.4, and what is the accuracy?

Charge current is programmed by connecting a precision resistor (RPROG) from PROG pin to GND. Current = 1000 × V_PROG/R_PROG, where V_PROG is servoed to 1.00V ±20mV during constant-current mode. With a 2kΩ 1% resistor, nominal current is 500mA ±5%. Accuracy is maintained across temperature and line voltage; RPROG values from 1.33kΩ (750mA) to 10kΩ (100mA) are supported.