STMicroelectronics EVAL6924U

Overview

EVAL6924U from STMicroelectronics is an evaluation board for the L6924U monolithic Li-Ion/Li-Polymer battery charger IC. It implements dual-input (USB or AC adapter) charging with programmable 4.2 V ±1% regulation, linear or quasi-pulse operation modes, integrated power MOSFET and thermal protection, and supports full functional validation of charge current programming (up to 1 A), end-of-charge detection, NTC/PTC temperature monitoring, and status output interfacing in a VFQFPN16 package. Designed for compact portable electronics development.

For engineers reviewing the EVAL6924U datasheet, EVAL6924U pinout, EVAL6924U application, or EVAL6924U equivalent, this board enables rapid verification of L6924U-based charging systems - including USB/AC input priority management, thermal foldback behavior, pre-charge/fast-charge/CV phase transitions, gas gauge functionality via IEND, and host MCU interface using ST1/ST2 status outputs.

Technical Context

The EVAL6924U board implements the complete reference design for the L6924U IC, supporting both linear and quasi-pulse charging modes. It provides external resistor networks for programming IAC (up to 1 A), IUSB (500 mA high-power / 100 mA low-power), TMAXCH (via TPRG capacitor), IENDTH (termination current), and TH (NTC/PTC thermistor divider), with dedicated test points for VIN, VOUT, VOSNS, and all critical pins.

It integrates all required passive components per ST's recommended layout: input/output capacitors optimized for ESR and ripple handling, thermal vias under the VFQFPN16 footprint, and LED indicators driven by ST1/ST2 open-collector outputs. The board supports real-time monitoring of charging current via the IEND pin's proportional voltage (gas gauge function) and validates battery presence detection through VOSNS/VOUT differential sensing.

Key Specifications

Availability

EVAL6924U is available at Aetrix Electronics and suitable for GPS devices, digital still cameras, USB-powered portable audio players, and standalone battery chargers requiring stable component supply, fast prototyping cycles, and production-ready reference validation.

Supply support for EVAL6924U 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer applications.

The EVAL6924U belongs to ST's Battery Management Evaluation Kit product line, engineered to accelerate time-to-prototype for portable Li-Ion charging systems requiring dual-input flexibility, thermal safety compliance, and minimal PCB footprint.

FAQ

Does EVAL6924U support both USB and AC adapter inputs simultaneously?

No - the EVAL6924U board implements the L6924U's MODE pin logic to select either USB (MODE = HIGH) or AC adapter (MODE = LOW) as the active input source. Input priority is not automatic; it requires external control of the MODE signal. The board includes jumpers to configure this selection statically during testing.

Can I modify the fast-charge current on EVAL6924U without soldering?

Yes - the board provides 0603 footprints and test points for the IAC (AC mode) and IUSB (USB mode) current-setting resistors, allowing quick value changes with surface-mount resistors or zero-ohm links. Resistor values are labeled per ST's 7% accuracy spec (e.g., 12 kΩ for ~1 A, 24 kΩ for ~500 mA).

Is the NTC thermistor interface on EVAL6924U pre-configured for common battery packs?

The board includes a 10 kΩ NTC footprint and adjustable voltage divider (R1/R2) to match standard 10 kΩ @ 25 °C NTCs with B25/85 = 3950 K. Hot/cold thresholds are set via TH pin voltage (10–15% and 40–60% of 1.8 V VREF), validated against ST's recommended thermistor curves in AN4217.

Does EVAL6924U include battery presence detection circuitry?

Yes - the board implements the L6924U's battery absence detection using separate VOUT (power path) and VOSNS (sense path) connections. A small sink current is forced through VOUT; if VOSNS fails to track VOUT within tolerance, the IC enters standby - verified on board via LED status and oscilloscope monitoring of VOSNS waveform.