Analog Devices Inc. LTC4156IUFD#PBF

Overview

LTC4156IUFD#PBF from Analog Devices (formerly Linear Technology) is a dual-input I²C-controlled power manager and 3.5A LiFePO₄ battery charger with PowerPath™ instant-on operation, USB OTG support, and integrated overvoltage protection. It manages power distribution from USB and wall adapter inputs to a single-cell LiFePO₄ battery and system load, delivering up to 15W with ≥95% switching efficiency at 3A output and supporting four programmable float voltages (3.45V–3.8V). It is used in portable medical devices requiring reliable backup power and thermal-constrained charging.

For engineers reviewing the LTC4156IUFD#PBF datasheet, LTC4156IUFD#PBF pinout, LTC4156IUFD#PBF application, or LTC4156IUFD#PBF equivalent, key selection considerations include its I²C-adjustable charge current (up to 3.5A), dual-input priority multiplexing, NTC-based JEITA temperature profiling, USB On-The-Go 5V back-powering capability, and 28-pin 4mm × 5mm QFN package with exposed thermal pad.

Technical Context

The LTC4156IUFD#PBF integrates a synchronous step-down switching charger with programmable current limit (via CLPROG1/CLPROG2), a dual-input priority multiplexer with overvoltage lockout (6.0V threshold), and an I²C-controlled PowerPath™ regulator that enables instant-on operation even with deeply discharged batteries. Its internal 2.25MHz oscillator drives low-R_DS(on) MOSFETs (R_PMOS = 90mΩ, R_NMOS = 80mΩ) and supports dynamic input current allocation between VOUT and battery charging.

It features a dedicated thermistor ADC (NTC/NTCBIAS) for JEITA-compliant charge termination, configurable safety timers (0.25–4 hours), and dual-mode USB OTG: when ID pin is pulled low and LOCKOUT_ID_PIN is cleared, it delivers up to 1.4A at 5V from battery to VBUS without external components. All critical status flags-including bad battery, recharge threshold, and short-circuit fault-are reported via IRQ and readable over I²C.

Key Specifications

Pinout & Package

The LTC4156IUFD#PBF is housed in a 28-lead, 4mm × 5mm × 0.75mm plastic QFN package with exposed thermal pad (Pin 29 = GND), optimized for high-power density and thermal dissipation in portable systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-input power management and LiFePO₄ charging applications.

Compared with BQ24650RGER and MAX77757EWA+T, the LTC4156IUFD#PBF uniquely combines dual-input priority arbitration, LiFePO₄-specific charging algorithms, and USB OTG in one QFN package-eliminating six external components and reducing layout complexity for portable medical and industrial backup systems.

Availability

LTC4156IUFD#PBF is available at Aetrix Electronics and suitable for portable medical devices, portable industrial instruments, and backup power systems requiring stable component supply, extended temperature operation (–40°C to +125°C), and long-term obsolescence management.

Supply support for LTC4156IUFD#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial automation, and healthcare markets.

The LTC4156IUFD#PBF belongs to Linear's PowerPath™ family of intelligent battery chargers and power managers, designed specifically for space-constrained, thermally sensitive portable equipment requiring robust dual-input power handling and chemistry-optimized charging.

FAQ

What is the maximum supported charge current for the LTC4156IUFD#PBF?

The LTC4156IUFD#PBF supports a maximum regulated charge current of 3.5A when configured in 100% mode with R_PROG = 340Ω. This value is confirmed in the Electrical Characteristics table (ICHARGE(MAX) = 3.44–3.70A) and enables rapid charging of large-capacity LiFePO₄ cells in portable medical and industrial applications.

Does the LTC4156IUFD#PBF support USB On-The-Go functionality?

Yes, the LTC4156IUFD#PBF supports USB On-The-Go: when the ID pin is pulled low and the LOCKOUT_ID_PIN bit is cleared via I²C, it delivers up to 1.4A at 5V from the battery to the VBUS pin. This capability is implemented entirely internally-no external boost converter or level-shifting components are required for compliant USB host operation.

How does the LTC4156IUFD#PBF handle input priority between USB and wall adapter sources?

The LTC4156IUFD#PBF uses hardware-based priority: WALLSNS input takes precedence over USBSNS. When both are active, only WALLGT is driven to enable the wall adapter path. Priority can be overridden via I²C commands to force USBSNS selection or enable simultaneous sourcing, providing flexible power routing control for diverse system architectures.

What LiFePO₄-specific features does the LTC4156IUFD#PBF include?

The LTC4156IUFD#PBF includes four factory-trimmed float voltage settings (3.45V, 3.55V, 3.60V, 3.80V) optimized for LiFePO₄ cathode chemistry, JEITA-compliant NTC-based temperature profiling, C/10–C/50 charge termination thresholds, and low-voltage recharge (96.6–98.4% of VFLOAT) - all directly configurable via I²C without external resistors or firmware intervention.

What package type and thermal characteristics apply to the LTC4156IUFD#PBF?

The LTC4156IUFD#PBF uses a 28-lead 4mm × 5mm × 0.75mm plastic QFN package with exposed thermal pad (Pin 29 = GND). Its thermal resistance is θ_JA = 43°C/W, and it is rated for –40°C to +125°C junction temperature - enabling reliable operation in thermally demanding portable medical enclosures and industrial handhelds without forced airflow.