Texas Instruments BQ25618YFFT

Overview

BQ25618YFFT from Texas Instruments is a highly integrated I²C-controlled 1-cell Li-ion/Li-polymer battery charger IC with synchronous buck topology, 1.5A fast charge capability, 20mA ±10mA termination current, and integrated 1A boost converter delivering 4.6V–5.15V on PMID. It enables compact wearable charging cases (e.g., TWS earbud cases) with NVDC power path, JEITA-compliant thermal regulation, and ultra-low 7µA Ship mode leakage.

For engineers reviewing the BQ25618YFFT datasheet, BQ25618YFFT pinout, BQ25618YFFT application, or BQ25618YFFT equivalent, this page delivers verified technical context for space-constrained, low-quiescent-power wearable power management - including precise termination accuracy, dual-mode (charge/boost) operation, input voltage/current regulation, and WCSP package constraints.

Technical Context

The BQ25618YFFT implements a 1.5MHz synchronous buck charger with integrated high-side and low-side FETs (RON_HSFET = 55mΩ, RON_LSFET = 60mΩ), BATFET (19.5mΩ), and reverse-blocking FET (35mΩ), enabling >94.5% efficiency at 1A charge and 94% at 1A boost. Its NVDC architecture maintains SYS ≥3.5V even with zero or deeply discharged battery, supporting instant-on system behavior.

It features autonomous three-phase charging (pre-conditioning, constant-current, constant-voltage), programmable JEITA temperature thresholds via TS pin, and dual-role I²C interface for real-time configuration of VREG (±0.5% accuracy), ICHG (±5%), IINDPM (100mA–3.2A), and VINDPM (3.9V–5.4V). Thermal regulation activates at 110°C; shutdown occurs at 150°C.

Key Specifications

Pinout & Package

Package: 30-ball, 2.0mm × 2.4mm WCSP (YFF), 0.4mm pitch, bottom-side thermal pad connected to GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery charge management applications.

Compared with BQ25618YFFT, BQ25619RTWR offers better thermal performance but requires PCB redesign due to incompatible 24-pin WQFN footprint, while MP2662GQZ reduces system cost and size but sacrifices boost capability, thermal profiling, and fault-protection signaling - making BQ25618YFFT optimal for space-constrained, dual-mode wearable charging.

Availability

BQ25618YFFT is available at Aetrix Electronics and suitable for True Wireless Stereo (TWS) charging cases, smartwatch power modules, hearing aid rechargeable cases, and compact wireless headphone docks requiring stable component supply, long-term lifecycle support, and guaranteed authentic TI sourcing.

Supply support for BQ25618YFFT 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in battery charging solutions for portable electronics.

The BQ25618YFFT belongs to TI's BQ256xx family of highly integrated single-cell Li-ion chargers designed specifically for ultra-compact, low-leakage wearable and hearable applications - prioritizing minimal footprint, JEITA compliance, and dual charge/boost operation.

FAQ

What is the maximum supported battery voltage for BQ25618YFFT?

The BQ25618YFFT supports a typical charge voltage regulation range of 3.5V to 4.52V, with programmable 10mV steps. Its absolute maximum BAT pin voltage is 7V, and it provides ±0.5% accuracy at standard setpoints like 4.2V, 4.35V, and 4.45V. This makes BQ25618YFFT compatible with standard 1-cell Li-ion and Li-polymer batteries used in wearables, including those requiring higher-voltage chemistries up to 4.52V.

Does BQ25618YFFT support automatic transition between charge and boost modes?

Yes, BQ25618YFFT integrates autonomous mode switching logic that transitions between buck charging and boost operation based on system demand and input conditions. When VBUS is absent and SYS load exceeds battery sustain capability, it enters boost mode; when VBUS is applied and battery is below recharge threshold, it resumes charging - all without host intervention. The PMID_GOOD pin provides status feedback for external load control during these transitions.

What is the purpose of the BATSNS pin on BQ25618YFFT?

The BATSNS pin on BQ25618YFFT provides remote battery voltage sensing to compensate for PCB trace resistance between the IC and battery terminals. By measuring directly at the battery pack anode, BQ25618YFFT achieves ±0.5% charge voltage regulation accuracy - critical for maximizing runtime and ensuring safety in space-constrained wearables. If open or shorted, BQ25618YFFT defaults to BAT pin regulation and sets BATSNS_STAT flag.

How does BQ25618YFFT manage thermal regulation during high-current charging?

BQ25618YFFT initiates thermal regulation at 110°C junction temperature, progressively reducing charge current to maintain TJ ≤110°C. If temperature continues rising, it triggers thermal shutdown at 150°C (rising) with hysteresis down to 130°C (falling). Its 58.8°C/W θJA (YFF package) and integrated low-RDS(on) FETs (e.g., 19.5mΩ BATFET) minimize self-heating - enabling sustained 1.5A charging in thermally optimized layouts with proper copper pour under the thermal pad.

Can BQ25618YFFT operate without an I²C host controller?

Yes, BQ25618YFFT supports fully autonomous charging without I²C: it detects battery voltage, executes pre-conditioning → constant-current → constant-voltage phases, terminates at programmed ITERM, and reinitiates charge upon voltage drop below VRECHG. I²C is optional for advanced configuration - such as JEITA profile tuning, VINDPM tracking, or dynamic IINDPM adjustment - but not required for basic operation of BQ25618YFFT.