Texas Instruments BQ24311DSGT

Overview

BQ24311DSGT from Texas Instruments is a Li-ion battery front-end protection IC that provides integrated input overvoltage (<1 µs response), user-programmable input overcurrent (50–300 mA range), and battery overvoltage (4.35 V) protection. It features an internal 30 V-rated pass FET, thermal shutdown at 140–150 °C, and active-low open-drain FAULT signaling for mobile phone charging circuits.

For engineers reviewing the BQ24311DSGT datasheet, BQ24311DSGT pinout, BQ24311DSGT application, or BQ24311DSGT equivalent, this page delivers verified functional specifications, WSON-8 package layout guidance, real-world fault recovery timing (tON(OVP) = 8 ms, tREC(OCP) = 64 ms), and design-critical resistor programming relationships (e.g., IOCP ≈ 25 / RILIM).

Technical Context

The BQ24311DSGT implements independent analog monitoring loops for VIN, IIN, and VBAT - each with dedicated comparators, deglitch timers (tDGL(PGOOD) = 8 ms, tDGL(BOVP) = 176 µs), and hysteresis (VHYS-OVP = 20–110 mV, VHYS-BOVP = 200–320 mV). Its internal power FET Q1 is controlled via charge-pump gate drive to enable soft-start and soft-stop behavior during OVP/OCP/BOVP events.

Operation requires no external clock or microcontroller: CE enables/disables the device with internal pulldown, FAULT reports faults asynchronously as open-drain low, and ILIM sets current limit via external resistor (83.3–500 kΩ), while VBAT senses battery voltage through optional RBAT divider (100–470 kΩ) for safety isolation.

Key Specifications

Pinout & Package

Package: WSON-8 (2.00 mm × 2.00 mm) with exposed thermal pad connected internally to VSS. Requires PCB copper pad + thermal vias for thermal management per TI layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ24312DSGT and TPS259211DSGR, the BQ24311DSGT uniquely combines input OVP/OCP with battery overvoltage monitoring in a single 2-mm WSON package - enabling compact, standards-compliant Li-ion protection where space, cost, and triple-fault coverage are critical.

Availability

BQ24311DSGT is available at Aetrix Electronics and suitable for smartphone charging protection, USB-powered portable audio, MP3 player battery safety, and low-power handheld diagnostic tools requiring stable component supply and long-term lifecycle support.

Supply support for BQ24311DSGT 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 management IP.

The BQ24311DSGT belongs to TI's battery front-end protection product line, designed specifically to safeguard Li-ion cells against adapter faults, overcurrent, and overvoltage in space-constrained portable electronics.

FAQ

What is the maximum input voltage the BQ24311DSGT can withstand without damage?

The BQ24311DSGT has an absolute maximum input voltage rating of 30 V at the IN pin relative to VSS. This rating ensures survivability during transient overvoltage events such as adapter plug-in spikes or cable inductance-induced ringing. However, its overvoltage protection activates at 5.85 V typical, turning off the internal FET well before reaching the 30 V stress limit. Always use ≥1 µF ceramic capacitor at IN to suppress transients and maintain reliability of the BQ24311DSGT.

How do I set the input overcurrent threshold for the BQ24311DSGT?

The BQ24311DSGT input overcurrent threshold is set using an external resistor (RILIM) connected between the ILIM pin and VSS. The relationship is approximately IOCP (A) = 25 / RILIM (kΩ), supporting 50–300 mA range with RILIM values from 500 kΩ to 83.3 kΩ. For example, a 200 kΩ resistor yields ~125 mA trip point. Ensure RILIM is placed close to the IC and use 1% tolerance metal film for accuracy. The BQ24311DSGT datasheet Figure 4 confirms this correlation across temperature.

Does the BQ24311DSGT provide protection during reverse current flow (OUT to IN)?

The BQ24311DSGT supports reverse current flow from OUT to IN when powering accessories (e.g., Bluetooth headset from phone), but provides no overcurrent protection in that direction. If VOUT exceeds V(UVLO) + 0.7 V, the internal FET turns on to conduct reverse current up to 0.5 A - same as forward rating. However, OCP, OVP, BOVP, and thermal shutdown functions remain active only for forward (IN→OUT) operation. Reverse conduction is intended for accessory power, not fault protection, so system-level safeguards are still required.

What is the purpose of the VBAT pin on the BQ24311DSGT, and how should it be connected?

The VBAT pin on the BQ24311DSGT senses battery voltage for overvoltage protection (trip at 4.35 V). To prevent hazardous 30-V IN-side faults from appearing directly on the battery, TI mandates connection through a resistor (RBAT = 100–470 kΩ) rather than direct tie. A 100-kΩ RBAT limits fault current to ~246 µA while adding only ~1 mV error to the BOVP threshold - negligible versus the ±50 mV spec. Leaving VBAT unconnected or tying directly to battery violates safety requirements and voids BQ24311DSGT protection integrity.

How does the FAULT pin on the BQ24311DSGT behave during different fault conditions?

The FAULT pin on the BQ24311DSGT is an active-low open-drain output that goes low during any of four conditions: input overvoltage (>5.85 V), input overcurrent (persistent >IOCP), battery overvoltage (>4.35 V), or die temperature exceeding 140–150 °C. It remains high-impedance during normal operation or when CE is high. External pull-up (e.g., 47 kΩ to 3.3 V) is required. Each fault condition also increments a non-volatile counter; 15 consecutive events lock out the FET until power cycle or CE toggle - a key safety feature of the BQ24311DSGT.