Texas Instruments BQ24120RHLTG4

Overview

BQ24120RHLTG4 from Texas Instruments is a single-chip switched-mode Li-ion/Li-polymer charge-management IC supporting 1- or 2-cell battery packs, delivering up to 2-A fast-charge current with ±10% current regulation accuracy, 4.2-V fixed output voltage, and 1.1-MHz synchronous PWM operation. It integrates power FETs, high-side current sensing, thermal shutdown, and battery temperature monitoring for portable medical devices and industrial handheld equipment.

For engineers reviewing the BQ24120RHLTG4 datasheet, BQ24120RHLTG4 pinout, BQ24120RHLTG4 application, or BQ24120RHLTG4 equivalent, key selection criteria include its VQFN-20 package, programmable precharge/termination via ISET1/ISET2, dual STAT outputs for host processor interface, and integrated EMI-reduction features enabling FCC-B compliance without external filters.

Technical Context

The BQ24120RHLTG4 implements a fixed-frequency (1.1 MHz), voltage-mode synchronous buck controller with feed-forward compensation and 0%–100% duty cycle capability. Its internal PMOS/NMOS power stage eliminates bootstrap capacitor requirements and supports high-side current sensing via the SNS pin with ±10% regulation accuracy over temperature.

Charge sequencing includes preconditioning (15–200 mA), constant-current fast charge (150–2000 mA), and constant-voltage regulation (4.2 V ±0.5%), with termination based on programmable minimum current detection and a safety timer (25–572 minutes). Battery temperature qualification uses VTSB-biased NTC monitoring with LTF/HTF/TCO thresholds and 20–40 ms deglitch timing.

Key Specifications

Pinout & Package

VQFN-20 package (3.5 mm × 4.5 mm) with exposed thermal pad electrically connected to VSS; requires PCB star-ground connection between VSS and PGND via thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-ion charge-management applications.

Compared with BQ24120RHLTG4, BQ24123RHLTG4 adds voltage flexibility at the cost of pin count and external component dependency, while BQ24125RHLTG4 trades simplicity for external feedback precision-making BQ24120RHLTG4 the most integrated, lowest-component solution for fixed 4.2-V single-cell charging.

Availability

BQ24120RHLTG4 is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld scanners, and emergency communication radios requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for BQ24120RHLTG4 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 and embedded processing technologies, with decades of expertise in power management ICs for battery-powered systems.

The bqSWITCHER™ product line, including BQ24120RHLTG4, was designed specifically for high-efficiency, low-EMI Li-ion/Li-polymer charging in space-constrained portable equipment-emphasizing integration, thermal robustness, and regulatory compliance.

FAQ

What is the maximum input voltage rating for BQ24120RHLTG4?

The BQ24120RHLTG4 has a 20-V absolute maximum rating on IN and OUT pins, with recommended operating input voltage from 4.35 V to 16.0 V. Exceeding 20 V risks permanent damage, and switching noise spikes must remain within this limit through proper PCB layout and input capacitance.

How does BQ24120RHLTG4 handle battery temperature monitoring?

The BQ24120RHLTG4 monitors battery temperature via the TS pin using an NTC thermistor divider biased by the VTSB output (3.15 V ±10%). It enforces three thresholds: LTF/HTF for charge initiation and LTF/TCO during charging, with 20–40 ms deglitch to prevent false suspend events.

Can BQ24120RHLTG4 support both 1-cell and 2-cell Li-ion batteries?

Yes, BQ24120RHLTG4 supports both configurations: it delivers fixed 4.2-V output for 1-cell operation and can be configured for 8.4-V output in 2-cell mode using the CELLs pin-though BQ24120RHLTG4's default is 4.2 V, and 2-cell use requires external resistor pull-up per datasheet Section 6.

What is the purpose of the TTC pin on BQ24120RHLTG4?

The TTC pin on BQ24120RHLTG4 accepts an external capacitor to ground to program the safety charge timer (25–572 minutes). When pulled low, it disables both timer and current-termination detection-enabling continuous charging for applications requiring indefinite float or maintenance modes.

Does BQ24120RHLTG4 require external MOSFETs for operation?

No, BQ24120RHLTG4 integrates synchronous PMOS and NMOS power FETs capable of 2-A continuous output current. No external switches are needed, simplifying design and reducing footprint-only external passive components (inductor, capacitors, sense resistor, and optional NTC) are required.