Analog Devices Inc. LTC4156EUFD#TRPBF

Overview

LTC4156EUFD#TRPBF 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. It manages power distribution from USB and wall adapter inputs to a single-cell LiFePO₄ battery and system load, delivering up to 15W with switching efficiency >95% at 3.3V battery and 2A load, VFLOAT programmable to 3.45–3.80V, and integrated USB On-The-Go 5V back-powering. It is used in portable medical devices requiring seamless input priority switchover and low-battery instant-on capability.

For engineers reviewing the LTC4156EUFD#TRPBF datasheet, LTC4156EUFD#TRPBF pinout, LTC4156EUFD#TRPBF application, or LTC4156EUFD#TRPBF equivalent, key selection criteria include dual-input overvoltage protection thresholds (6.0V), I²C-adjustable charge current (up to 2.55A), JEITA-compliant NTC thermistor ADC, and 28-pin 4mm × 5mm QFN package with exposed thermal pad.

Technical Context

The LTC4156EUFD#TRPBF integrates a synchronous step-down switching charger with 2.25MHz fixed-frequency PWM control, monolithic high-side/low-side MOSFET drivers (R_PMOS = 90mΩ, R_NMOS = 80mΩ), and dual-input priority multiplexer with independent OVP (6.0V rising threshold) and UVLO (4.25V falling threshold). Its PowerPath architecture enables simultaneous battery charging and system powering without brownout during input transitions.

I²C interface supports full configuration of charge parameters-including float voltage (four settings), safety timer (0.25–4h), recharge threshold (96.6–98.4% of VFLOAT), and USB OTG output current limit (1.4A)-with real-time status reporting (VBUS/VOUT/BAT currents, fault flags, NTC ADC codes). The device implements JEITA temperature-dependent charge control via integrated 7-bit NTC ADC with kOFFSET = 0.113 V/V and kHIGH = 0.895 V/V.

Key Specifications

Pinout & Package

The LTC4156EUFD#TRPBF is housed in a 28-lead, 4mm × 5mm × 0.75mm plastic QFN package with exposed thermal pad (Pin 29 = GND). The package supports high-power dissipation and requires PCB thermal relief design per Linear/LT AN132.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24650RGER and MAX77751EWJ+T, the LTC4156EUFD#TRPBF uniquely integrates LiFePO₄-specific float voltage settings, hardware-based dual-input priority, and calibrated JEITA ADC-reducing firmware overhead and external component count in medical and industrial battery systems.

Availability

LTC4156EUFD#TRPBF is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld scanners, and emergency backup power units requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.

Supply support for LTC4156EUFD#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LTC4156EUFD#TRPBF belongs to Linear's PowerPath™ family of battery management ICs, designed specifically for high-reliability portable equipment requiring seamless dual-input power arbitration, LiFePO₄-optimized charging, and USB OTG functionality.

FAQ

What is the maximum supported battery charge current for the LTC4156EUFD#TRPBF?

The LTC4156EUFD#TRPBF supports a maximum regulated battery charge current of 2.55A in 100% mode with RPROG = 340Ω. This is achieved using its internal current-sense amplifier (RCHG = 40mΩ) and programmable gain; actual delivered current depends on thermal design and input voltage. The LTC4156EUFD#TRPBF also supports 15 discrete I²C-adjustable charge current levels from 290mA to 2.55A.

Does the LTC4156EUFD#TRPBF support LiFePO₄ battery chemistry natively?

Yes, the LTC4156EUFD#TRPBF is explicitly designed for LiFePO₄ batteries. It provides four factory-trimmed float voltage settings (3.45V, 3.55V, 3.60V, 3.80V) optimized for LiFePO₄ cell characteristics, along with recharge thresholds referenced to VFLOAT and safety timers aligned with LiFePO₄ charge profiles. The LTC4156EUFD#TRPBF datasheet confirms this in both the title and Applications section.

How does the dual-input priority multiplexer work on the LTC4156EUFD#TRPBF?

The LTC4156EUFD#TRPBF implements hardware-based priority: WALLSNS input takes precedence over USBSNS. When voltage is detected on WALLSNS, it activates WALLGT to drive external N-MOSFETs and disables USBGT. Only if WALLSNS is inactive does USBSNS activate USBGT. This priority is fixed in silicon-no I²C command required-and ensures deterministic failover without firmware involvement. The LTC4156EUFD#TRPBF also supports programmable priority override via I²C.

Can the LTC4156EUFD#TRPBF deliver power back to a USB port (OTG mode)?

Yes, the LTC4156EUFD#TRPBF supports USB On-The-Go power delivery. When the ID pin is pulled low and LOCKOUT_ID_PIN is cleared via I²C, the device enters reverse PowerPath mode, using its internal switch to deliver regulated 4.75–5.25V at up to 1.4A from the battery to the VBUS pin. No external boost converter or diodes are needed-the LTC4156EUFD#TRPBF integrates all necessary circuitry.

What thermal management is required for the LTC4156EUFD#TRPBF in 3.5A charging applications?

The LTC4156EUFD#TRPBF has θ_JA = 43°C/W and requires its exposed pad (Pin 29) to be soldered to a minimum 200mm² PCB copper area tied to GND for reliable 3.5A operation. At 3.5A charge current and 5V input, power dissipation exceeds 1.2W; insufficient thermal relief causes junction temperature to exceed 125°C. The LTC4156EUFD#TRPBF datasheet mandates thermal pad soldering and recommends thermal vias under the pad per AN132 guidelines.