Texas Instruments BQ25887RGET

Overview

BQ25887RGET from Texas Instruments is a 2-cell (2s) Li-ion battery charger IC with integrated boost-mode switching, I²C control, and active cell balancing. It delivers up to 2-A charge current at 93.4% efficiency (5-V input, 7.6-V battery), supports 3.9–6.2-V USB-compatible input, and integrates 16-bit ADC for real-time monitoring of bus/battery voltage/current, cell voltages, temperature, and die temperature - used in compact portable electronics requiring precise dual-cell management.

For engineers reviewing the BQ25887RGET datasheet, BQ25887RGET pinout, BQ25887RGET application, or BQ25887RGET equivalent, this page provides verified technical context, validated pin functions, confirmed cell-balancing operation, exact thermal regulation thresholds (T_REG = 120°C, T_SHUT = 150°C), and I²C-configurable charge parameters including ±0.5% V_CELL regulation accuracy and 100–2200-mA I_CHG range.

Technical Context

The BQ25887RGET implements a synchronous boost converter architecture operating at 1.35–1.65 MHz to step up USB input (3.9–6.2 V) to charge two series Li-ion cells (up to 8.4 V). Its integrated cell balancing uses dual MOSFETs (QCBH/QCBL) with programmable start/stop voltage differentials (80–190 mV / 30–100 mV) and up to 400 mA balancing current, triggered only when both cells exceed 3.7 V and ΔV exceeds qualification threshold.

It features Input Current Optimizer (ICO) that dynamically adjusts V_INDPM up to 5.5 V to maximize power without overloading adapters, plus a 16-bit ADC with selectable resolution (10–15 bits) and conversion times from 3 ms (fastest) to 24 ms (highest resolution), supporting simultaneous measurement of V_BUS, I_BUS, V_BAT, I_BAT, V_MID, TS, and die temperature.

Key Specifications

Pinout & Package

Package: VQFN-24 (RGE), 4.00 mm × 4.00 mm, 0.5-mm pitch, exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2s Li-ion boost charger applications.

Compared with BQ25887RGET, BQ25886RGET removes balancing and adds power path for system load support, while BQ25883RGET retains I²C but omits balancing and high-resolution ADC - making BQ25887RGET the only option with integrated balancing, JEITA thermal zones, and 16-bit multi-channel monitoring in this family.

Availability

BQ25887RGET is available at Aetrix Electronics and suitable for electronic toys, VR headsets, IP network cameras, and drone payload control systems requiring stable component supply, long-term lifecycle support, and production-ready I²C-configurable battery management.

Supply support for BQ25887RGET 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 technologies with decades of battery-charger IP development.

The BQ25887RGET belongs to TI's BQ25xxx boost-mode charger product line, engineered specifically for USB-powered 2s Li-ion applications demanding high integration, precision regulation, and autonomous cell balancing without external FETs or controllers.

FAQ

What is the maximum supported input current for BQ25887RGET?

The BQ25887RGET supports input current limits from 500 mA to 3.3 A with 100-mA resolution, set either via the ILIM pin (analog) or I²C registers. At 3.3-A setting, it fully utilizes high-current USB adapters while maintaining ±7.5% regulation accuracy across temperature. The BQ25887RGET also features Input Current Optimizer (ICO) to prevent adapter overload by dynamically adjusting input voltage limit up to 5.5 V.

Does BQ25887RGET support JEITA-compliant charging profiles?

Yes, the BQ25887RGET implements full JEITA thermistor-based charging control with five temperature zones (0–10°C, 10–45°C, 45–60°C, and cutoffs at <0°C and >60°C), configured via TS pin voltage thresholds referenced to REGN. It automatically reduces charge current to I_CHG/2 below 10°C and above 45°C, and suspends charging entirely outside 0–60°C - all without host intervention. This behavior is confirmed in the BQ25887RGET datasheet Section 7.5 (JEITA Thermistor Comparator).

How does cell balancing work on BQ25887RGET, and what are its activation conditions?

The BQ25887RGET performs automatic cell balancing using integrated high-side (QCBH) and low-side (QCBL) MOSFETs, delivering up to 400 mA balancing current. Activation requires three simultaneous conditions: both cells ≥3.7 V, cell voltage difference ≥80 mV (programmable up to 190 mV), and qualification mode enabled. Balancing stops when ΔV falls below 30–100 mV (also programmable). These thresholds and timing are hardware-controlled and do not require I²C polling - a key design feature of the BQ25887RGET.

What is the function of the MID pin on BQ25887RGET, and why is a series resistor required?

The MID pin on BQ25887RGET measures the voltage at the interconnect between the two series Li-ion cells, enabling bottom-cell voltage monitoring and cell balancing control. A mandatory 300-Ω series resistor must be placed between the physical battery midpoint and the MID pin to protect against reverse polarity connection of the bottom cell - a failure mode that could otherwise damage the IC. This resistor is explicitly required in the BQ25887RGET datasheet Pin Functions table and is part of the safety design for 2s configurations.

Can BQ25887RGET operate without I²C communication enabled?

Yes, the BQ25887RGET operates autonomously without I²C: default register settings enable full charging, cell balancing, JEITA thermal control, and safety timers. I²C is optional for configuration (e.g., custom V_REG, I_CHG, V_INDPM) and real-time monitoring (ADC reads, fault status). The CD pin allows hardware disablement while preserving I²C/ADC access, and STAT/PG/INT pins provide essential status without host interaction - confirming BQ25887RGET's robustness as a standalone solution.