Standard 4-Touch Keys BS814A-2 + HT48R002 Characteristics Touch Keys : BS814A-2 8-pin SOP + HT48R002 Operating voltage : 2.2V ~ 5.5V Low standby current Auto-calibration Reliable touch key detections High power supply rejection Standby and normal operating power modes Maximum key on duration time detection Power supply voltage drop rejection function 4 touch inputs 2 wire serial interface Data Output : NMOS with internal pull high resistor Clock Input : with internal pull-high resistor Sensitivity adjustment using an external capacitor Minimal number of external components 10-pin MSOP Applications Consumer Products, Home Appliances, Industrial Control, Health Care Products, etc. Application Circuit VDD LED D1 LED D2 LED D3 LED D4 VDD C1 10UF P1 R1 4.7K U1 4 3 2 1 CN1 C2 0.1UF VDD GND DATA CLOCK 1 2 3 4 5 VDD PA6 PA5 PA7/RES PA4 R2 4.7K R3 4.7K R4 4.7K 10 9 8 7 6 VSS PA0 PA1/TMR PA2/INT PA3 HT48R002_1OMSOP HT48R002_10MSOP JP1 KEY1 1 2 3 4 CT1 (0-25)PF GND VDD DATA CLOCK U1 VDD KEY2 1 2 3 CT3 (0-25)PF KEY4 VDD VDD KEY2 KEY1 VSS GND KEY3 KEY2 DATA OUT1 KEY4 OUT3 CLOCK OUT2 8 VDD 7 GND 5 DATA 5 CLOCK CT2 (0-25)PF KEY3 KEY1 KEY0 CS4 (0-25)PF 4 BS814A-2 8SOP 8SOP BS814A-2 C1 104 BAT1 CR2032