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  • The STS3921 and STS3922 products are a family of advanced analog front-ends with ST’s unique boostedNFC technology. They are ideal for applications that require the card emulation functionality, but are environmentally challenged or have limited space for the antenna. This solution allows for a simpler design than the conventional NFC controller-based architecture, and occupies a board footprint around one-third smaller.

    The boostedNFC technology from ST overcomes the main difficulties seen in these applications when using passive load modulation through generating a tag response with active transmission. This allows for tag-to-reader communication at coupling factors that are one order of magnitude lower than conventional methods. When compared to passive NFC implementations, boostedNFC increases the usable operating volume by up to 900%. The consumer’s experience during contactless transactions is easy, quick, and completely reliable, whether for payments in shops, ticketing in metro/urban mass transit infrastructures, or access control.
    boostedNFC products are compliant with the ISO 14443 and FeliCa™ protocols. An onboard EEPROM allows optimal operational settings to be selected and programmed by the customer.
    The STS3921 is provided in 20-bump wafer-length Chip-scale package (WLCSP20) whereas the STS3922 are delivered as bare dice.
    In order to meet environmental requirements, ST offers this device in different grades of ECOPACK®packages, depending on their level of environmental compliance. ECOPACK®specifications, grade definitions and product status are available at: www.st.com. ECOPACK®is an ST trademark.

    Key Features

    • Supply voltage range from 2.7 V to 3.6 V
    • Operating temperature: -25 °C to 85 °C
    • Extended read range in card emulation mode with antennas below 100 mm2
      • boostedNFC technology, based on active load modulation
      • Internal timing defined by VCO locked to reader frequency
      • Delay compensation and synchronization to ensure transmission in phase with reader field
      • Adjustable initial phase
      • Low-impedance output driver
      • Automatic output power control to avoid communication holes
    • Automatic antenna tuning (STS3922 only)
    • High degree of Interoperability
      • Automatic power control
      • Automatic gain control
    • EMVCo™, ISO/IEC 14443, JIS (X) 6319-4 compliance for full interoperability with existing payment and ticketing infrastructure.Card emulation supporting:
      • ISO/IEC 14443 Type A 106 kbps
      • ISO/IEC 14443 Type B 106 kbps
      • FeliCa™ 212 kbps
    • Interface to dual-interface microcontroller to boost card emulation performance
      • Contactless or NFC-WI interface to SE
      • Power supply switch for SE
    • Low power consumption
      • Low power in Wakeup mode
      • Mechanism to power the SE at field detection
    • Simple system integration
      • SPI interface and on-chip EEPROM for operating option settings
    • Delivery forms:
      • STS3922 delivered as bare dice
      • STS3921 in small footprint, with low overall cost of ownership: wafer-level chip-scale package (WLCSP)

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STS3922 No availability of distributors reported, please contact our sales office
EAR99 NEC Not Applicable SAWN WAFER F 8 - -


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Not Applicable



Operating Temperature (°C)





(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors