Si12T & Si14T — Low-Power Capacitive Touch ICs for Smart Locks

Si12T (12-ch) and Si14T (14-ch) are ultra-low-power capacitive touch sensors with touch-pause detection designed for smart locks that combine card swipe (NFC/RFID) and touch keypad.

Key Feature: Seamless Card + Touch Coexistence

In ACD (Auto Card Detect) mode:

• Si522A (RFID reader) controls Si12T/Si14T via SCT pin

• 1 µs before emitting LF field → SCT high → touch sensing paused

• 1 µs after field → SCT low → touch instantly resumes

Total field emission only 15 µs — completely imperceptible to users, zero false triggers between card reading and touch.

Highlights

• Si12T: Pin-to-pin & functional replacement for ADS TSM12 (no changes needed)

• Si14T: Adds 2 extra channels → up to 14 keys

• Both support multi-chip synchronization

• Ultra-low power, high noise immunity

Applications

• Smart door locks (fingerprint + card + touch keypad)

• Touch panels & keypads

• Membrane switches

• Mobile devices

Perfect drop-in solution for hybrid card+touch smart locks — reliable, responsive, and zero interference.