Texas Instruments BQ25120F3AYFPT

Overview

BQ25120F3AYFPT from Texas Instruments is a highly integrated battery charge management IC for wearable and IoT devices, combining a 300-mA buck regulator (1.8-V default), 700-nA quiescent current with buck enabled, configurable 100-mA LDO or load switch, 0.5% accurate 3.6–4.65-V battery voltage regulation, and I²C-programmable charge parameters. It enables ultra-low-power operation in smart watches and health monitors.

For engineers reviewing the BQ25120F3AYFPT datasheet, BQ25120F3AYFPT pinout, BQ25120F3AYFPT application, or BQ25120F3AYFPT equivalent, key selection considerations include its 2.5-mm × 2.5-mm DSBGA package, <50-nA Ship Mode IQ, power-path management, TS thermistor monitoring, and I²C-configurable termination current down to 500 µA.

Technical Context

The BQ25120F3AYFPT integrates a DCS-Control™ buck converter optimized for light-load efficiency down to 10-µA, a linear charger supporting precharge/constant-current/constant-voltage Li-ion profiles, and power-path management enabling simultaneous system power and battery charging. Its dedicated TS input monitors NTC-based battery temperature with programmable hot/cool/cold thresholds.

It implements push-button wake/reset with three independent timers (tWAKE1, tWAKE2, tRESET), ship-mode entry via CD pin with <50-nA battery drain, and voltage-based battery monitoring reporting 60–100% SOC in 2% increments. All critical parameters-including VBATREG, ICHARGE, ITERM, and VIN(DPM)-are configurable via I²C or external resistors.

Key Specifications

Pinout & Package

Package: 25-pin DSBGA (YFP), 2.50 mm × 2.50 mm body size, 0.4-mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ25120F3AYFPT, BQ25120A offers load-switch priority and watchdog capability but sacrifices LDO convenience and higher VBATREG; BQ25121A provides 2.5-V SYS output at the cost of reduced battery voltage headroom and no LDO option-making BQ25120F3AYFPT optimal for 1.8-V wearables requiring maximum runtime and simplified power architecture.

Availability

BQ25120F3AYFPT is available at Aetrix Electronics and suitable for smart watches, fitness trackers, and medical wearables requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for production programs.

Supply support for BQ25120F3AYFPT 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 delivering analog and embedded processing solutions with emphasis on power management, signal chain, and connectivity technologies.

The BQ25120F3AYFPT belongs to TI's ultra-low-power battery management portfolio designed specifically for space- and energy-constrained wearables and IoT endpoints where sub-1-µA quiescent current and minimal external component count are mandatory.

FAQ

What is the minimum battery voltage supported by the BQ25120F3AYFPT?

The BQ25120F3AYFPT supports battery undervoltage lockout (BUVLO) programmable from 2.2 V to 3.0 V, with default set at 2.5 V. Below this threshold, the device disables charging and system power to protect the Li-ion cell from deep discharge damage. The BQ25120F3AYFPT uses a 150-mV hysteresis to prevent oscillation near the cutoff point.

How does the BQ25120F3AYFPT achieve <50-nA Ship Mode current?

The BQ25120F3AYFPT achieves <50-nA Ship Mode by disabling all internal circuitry except a minimal bias network and disconnecting PMID from BAT via internal FETs. Entry is triggered by driving the CD pin high while VIN is absent; the device then discharges PMID through a 20-kΩ internal resistor and enters ultra-low-leakage state. The BQ25120F3AYFPT maintains this state until MR is asserted or VIN is reapplied.

Can the BQ25120F3AYFPT charge a battery while powering the system from the same input source?

Yes, the BQ25120F3AYFPT implements true power-path management that allows simultaneous charging and system operation from a single IN source. When VIN is present, the device supplies SYS directly from VIN (with ~170-mV dropout) while diverting excess current to charge the battery. The BQ25120F3AYFPT automatically transitions to battery-only mode if VIN is removed, ensuring uninterrupted system operation.

What is the function of the TS pin on the BQ25120F3AYFPT?

The TS pin on the BQ25120F3AYFPT monitors battery temperature using an NTC thermistor connected in a resistor divider from VIN to GND. The BQ25120F3AYFPT compares TS voltage against programmable VHOT, VCOOL, VCOLD, and TSOFF thresholds to suspend charging outside safe thermal limits. Fault conditions are reported via I²C registers and can trigger INT pulses, ensuring compliance with Li-ion safety standards.

Is the BQ25120F3AYFPT pin-compatible with other devices in the BQ2512x family?

No, the BQ25120F3AYFPT is not pin-compatible with other BQ2512x variants such as BQ25120A or BQ25121A due to differences in default configurations and functional pin assignments-for example, LSCTRL behavior and PG functionality differ across variants. While sharing the same 25-pin DSBGA package, the BQ25120F3AYFPT requires unique layout and firmware initialization to match its specific LDO-default, watchdog-disabled, and 4.35-V VBATREG configuration.