Texas Instruments BQ24038RHLRG4

Overview

BQ24038RHLRG4 from Texas Instruments is a single-chip Li-ion/Li-polymer battery charge and system power-path management IC with integrated DPPM, 4.2 V/4.36 V selectable charge voltage, 3.3-V LDO output, and autonomous AC/USB source selection. It delivers up to 2-A total current, supports power supplement mode, and operates in –40°C to +125°C ambient for portable power systems.

For engineers reviewing the BQ24038RHLRG4 datasheet, BQ24038RHLRG4 pinout, BQ24038RHLRG4 application, or BQ24038RHLRG4 equivalent, this device is selected for space-constrained USB/AC-powered portable devices requiring simultaneous system power delivery and battery charging with thermal regulation, dynamic input current limiting, and precise voltage-based charge termination.

Technical Context

The BQ24038RHLRG4 implements dual-input power-path architecture with independent P-FETs (Q1 for AC, Q3 for USB, Q2 for battery), enabling seamless source handoff and battery supplement mode. Its DPPM circuit monitors OUT voltage via the DPPM pin and scales regulation using a 1.15× scale factor to maintain system stability under peak load.

Charge control is configured via ISET1 (fast-charge current), ISET2 (USB current limit: 100 mA/500 mA), and VBSEL (4.2 V or 4.36 V charge voltage). Thermal regulation activates at 115°C (Q2) and shutdown occurs at 155°C (Q1/Q3), with deglitch timing of 22.5 ms across all fault comparators.

Key Specifications

Pinout & Package

Package: 20-pin VQFN (RHL), 4.50 mm × 3.50 mm, exposed thermal pad connected to VSS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery charge and power-path management applications.

Compared with BQ24038RHLRG4, BQ24032ARHLR lacks voltage selectability and offers lower OUT regulation, while BQ24075RHLR omits DPPM and LDO but adds USB data-line support - making BQ24038RHLRG4 optimal for designs needing programmable charge voltage, regulated system rail, and autonomous load balancing.

Availability

BQ24038RHLRG4 is available at Aetrix Electronics and suitable for smartphone power management, portable medical monitors, digital camera charging systems, and industrial handheld scanners requiring stable component supply across production lifecycles.

Supply support for BQ24038RHLRG4 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 over 50 years of innovation in energy-efficient electronics.

The bqTINY™ III series-including BQ24038RHLRG4-is designed for space-constrained portable applications requiring integrated Li-ion charging, dynamic power-path control, and autonomous multi-source power management without external FETs or controllers.

FAQ

What is the function of the VBSEL pin on the BQ24038RHLRG4?

The VBSEL pin on the BQ24038RHLRG4 selects the battery charge termination voltage: logic LOW configures 4.2 V, and logic HIGH configures 4.36 V. This allows field-programmable adaptation to different Li-ion cell specifications without changing hardware. The BQ24038RHLRG4 uses this pin to enable precise voltage-based charge termination aligned with cell manufacturer recommendations and safety margins.

How does the BQ24038RHLRG4 handle simultaneous USB and AC input connection?

The BQ24038RHLRG4 uses the PSEL pin to prioritize one input as primary (AC if HIGH, USB if LOW); the non-prioritized source remains available as backup. When both are present, only the primary source powers the system and charges the battery. The BQ24038RHLRG4 does not parallel inputs - it selects autonomously, ensuring predictable power routing and preventing backfeed or contention.

Does the BQ24038RHLRG4 support battery supplement mode, and how is it triggered?

Yes, the BQ24038RHLRG4 supports battery supplement mode: when system load exceeds input current capability (e.g., USB at 500 mA), the IC draws additional current from the battery to maintain OUT voltage above the DPPM threshold. Entry occurs when V_OUT ≤ V_BAT – 60 mV; exit when V_OUT ≥ V_BAT – 20 mV. This behavior is inherent to the BQ24038RHLRG4's DPPM architecture and requires no external control.

What is the purpose of the DPPM pin on the BQ24038RHLRG4, and how is it configured?

The DPPM pin on the BQ24038RHLRG4 sets the minimum system output voltage threshold before charge current reduction begins. A resistor from DPPM to GND programs a 2.6–5 V reference, which is scaled by 1.15× to determine actual regulation voltage. This configuration allows designers to tune system stability under varying load profiles. The BQ24038RHLRG4 relies on this pin to prevent brownouts without requiring host intervention.

Can the BQ24038RHLRG4 operate without an external timer resistor, and what happens if TMR is tied to LDO?

Yes - tying the TMR pin to the LDO output (3.3 V) disables the fast-charge safety timer and charge termination functions, allowing continuous charging until manually halted. This configuration is documented in the BQ24038RHLRG4 datasheet as a valid operational mode for applications requiring indefinite float charging. The BQ24038RHLRG4 enters this state when TMR is held at 3.3 V, overriding external resistor timing.