Texas Instruments BQ24351DSGR

Overview

BQ24351DSGR from Texas Instruments is a highly integrated charger front-end protection IC for Li-ion battery systems, featuring input over-voltage (10.5 V threshold), over-current (1.2 A typ), and battery over-voltage (4.35 V) protection, with integrated P-FET and LDO-mode CHGIN output (6.38 V regulation). It serves as a safety-critical interface between AC/DC adapters and host charging controllers in portable electronics.

For engineers reviewing the BQ24351DSGR datasheet, BQ24351DSGR pinout, BQ24351DSGR application, or BQ24351DSGR equivalent, key selection considerations include its 2mm × 2mm WSON-8 package, soft-start/soft-stop transient suppression, thermal shutdown (150°C), and dual-role CHGIN output supporting both host power supply and gate-drive coordination in battery management systems.

Technical Context

The BQ24351DSGR implements a dual-FET protection architecture with Q1 (ACIN→OUT) and Q2 (ACIN→CHGIN), enabling independent current limiting and fault isolation. Its control logic integrates blanking timers (tBLK(CHGIN) = 10 ms), deglitch delays (tDGL(OVP) = 256 ms), and recovery timing (tREC(OCP) = 131 ms) to prevent false triggering during adapter plug-in transients or load steps.

It operates across three distinct modes: power-on reset (VUVLO = 1.95 V), LDO-regulated CHGIN output (VO(REG) = 6.38 V), and sleep mode (VSENTRY = 55 mV, VSEXIT = 90 mV), all coordinated via analog comparators and internal state machines without requiring external microcontroller intervention.

Key Specifications

Pinout & Package

Package: 2mm × 2mm, 8-pin WSON (DSG) with exposed thermal pad electrically connected to GND. Requires soldering of thermal pad to PCB ground plane using ≥4 thermal vias for thermal performance compliance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar charger front-end protection applications.

Compared with BQ24351DSGR, BQ24381DSGR offers programmability but lacks the critical 6.38 V LDO output, while TPS259211DRCT reduces integration-both require additional components to replicate BQ24351DSGR's complete protection + host power functionality.

Availability

BQ24351DSGR is available at Aetrix Electronics and suitable for smartphone charging front-ends, tablet battery protection modules, wearable power management, and industrial handheld terminals requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BQ24351DSGR 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 precision analog ICs and battery management solutions.

The BQ24351DSGR belongs to TI's bq243xx family of charger front-end protection ICs, designed specifically to replace discrete protection circuits in Li-ion-powered portable devices-emphasizing robustness against adapter surges, thermal resilience, and seamless integration with host-controlled charging architectures.

FAQ

What is the primary function of the BQ24351DSGR in a battery charging system?

The BQ24351DSGR acts as a safety-critical front-end protector between the AC/DC adapter and the battery charging circuit. It continuously monitors ACIN voltage, input current, and battery voltage to disable internal FETs during over-voltage (10.5 V), over-current (1.2 A), or battery over-voltage (4.35 V) events. The BQ24351DSGR also provides a regulated 6.38 V output (CHGIN) for host controller power, eliminating need for separate LDOs or diodes.

Does the BQ24351DSGR require external components to operate safely?

Yes-the BQ24351DSGR requires specific external components for safe operation: a ≥1 µF ceramic capacitor from ACIN to GND (CACIN), another ≥1 µF ceramic capacitor from CHGIN to GND (CCHGIN), and a 100–470 kΩ resistor (RBAT) between VBAT and battery pack+. These are mandated in TI SLUSA62A Section 9 to ensure proper surge suppression, LDO stability, and safe battery voltage sensing without exposing the battery to hazardous voltages during IC failure.

How does the BQ24351DSGR handle input voltage transients during AC adapter plug-in?

The BQ24351DSGR uses a combination of soft-start (10 ms blanking time), input OVP deglitch (256 ms), and soft-stop (gradual FET turn-off) to manage plug-in transients. During ACIN ramp-up, soft-start limits inrush current; if voltage exceeds 10.5 V, the device waits 256 ms before disabling outputs-rejecting brief spikes while responding to sustained over-voltage. Soft-stop prevents ringing-induced voltage spikes by ramping gate drive down over ~100 µs, as shown in TI SLUSA62A Figure 3.

Can the BQ24351DSGR be used without connecting the VBAT pin?

Yes-if battery over-voltage protection is not required, the VBAT pin must be connected directly to GND per TI SLUSA62A Pin Functions table. Leaving VBAT floating is prohibited. When tied to GND, the BVOVP function is disabled, and the device operates solely on ACIN and CHGIN monitoring. This configuration is valid for systems where battery voltage is managed externally or where single-cell Li-ion voltage is inherently constrained.

What thermal design guidance applies to the BQ24351DSGR's exposed thermal pad?

The BQ24351DSGR's exposed thermal pad must be soldered to a PCB copper pour connected to the GND net using ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart). TI specifies qJB = 15.4°C/W (junction-to-board) under JEDEC JESD51-8 conditions-achievable only with proper pad layout. Failure to connect the thermal pad results in >60°C higher junction temperature at 1 A load, risking premature thermal shutdown and reduced reliability.