Asset Publisher

AS3442 - Power & Communication Interface

Accessory charging & communication for smart earbuds


  • Show battery level of charging box on phone
  • Automatically pair TWS with phone when opening charging case
  • Accessory firmware updates


  • Simultaneous battery charging & communication with only two pins
  • Reduced number of mechanical connections to accessory
  • Enables smaller footprint with enhanced communication capabilities
  • Less influence on accessory design
  • No Bluetooth component required in charging cradle

Product parameters

Interface I2C
Package WL-CSP16
Size [mm] 2.25 x 2.25 x 0.6

General description

Bluetooth earphones are gaining popularity and mobile charging for these devices is mandatory. Both, earphones and charger cradle, are equipped with electronics and sensors, but the connection between the charging case and the earphones is typically limited to two wires – ground and power. Without enhancing the capabilities of the two wires only power transfer for charging the battery is possible.

The AS3442/47 allows to extend the functionality of the two wire connection to enable charging and simultaneous communication to the earpiece. The MCU inside the charger cradle can request data from the earphone while the charging process is on-going and vice versa. In order to operate the system two chips per side are necessary. The master device (AS3442), which is typically located in the charger cradle, and a client device (AS3447), which is located in the accessory. The master device features an I2C interface typically connected to a MCU inside the charger cradle to initiate the single wire connection to the client device. Furthermore it enables readout of AS3442 register and I2C sensors which are connected to the AS3442 I2C master interface. An interrupt signal line is available to detect status changes on GPIOs or if communication is interrupted. The client device features besides the I2C master interface up to 5 GPIOs which can be controlled via the host MCU. An interrupt input pin is available whose status signal is also transferred to host MCU accordingly.

Not Recommended for New Designs
ams-OSRAM AG is discontinuing production of this device. Final lifetime buy order must be placed by June 30, 2021. Please contact your local sales representative for further information.

This product suits for the following applications:

  • Smart Earbuds


Title Category Headline Buy
AS3442 Evaluation Board Application Board Accessory Power & Communication Interface

Environmental documents

Type Description Language
RoHS Certificate RoHS Certificate AS3442 English


Type Description Language
EoL Notification AS1xxx, AS25xx, AS3xxx, AS73211, AS89020, SL900A, TMD4704 (issued 2020-Dec) English

Other information

Type Description Language
Factsheet Accessory charging and communication for smart earbuds with POW:COM English
Asset Publisher

Related products