P9242-R Datasheet

© 2018 Integrated Device Technology, Inc

16

January 16, 2018

7.3 Enable Pin – EN

The P9242-R can be disabled by applying a logic HIGH to the EN pin. When the voltage on the EN pin is pulled high, operation is suspended

and the P9242-R is placed in the low-current Shut Down Mode. If pulled low, the P9242-R is active.

7.4 Buzzer – BUZR Pin

An optional AC-type ceramic buzzer can be connected between the BUZR pin to GND through a current limiting resistor. A short 4kHz “chirp”

sound will indicate when the object is detected. Do not connect this pin if the buzzer function is not desired.

7.5 Voltage Demodulation – VDEM1 Pin

In order to increase the communication reliability in any load condition, the P9242-R has integrated two demodulation schemes, one based on

coil current information and the other based on coil voltage modulation. The voltage mode envelope detector is implemented using a discrete

solution as depicted on Figure 14. This simple implementation achieves the envelope detector function low-pass filter as well as the DC filter

function.

Figure 14. Voltage Mode Envelope Detector

D1

R1

R2

C1

R3

C2

C3

Packet

Decoder

To Registers

P9242-R

VDEM1

7.6 Current Demodulation – IDEMI

The current-mode detector takes the modulation information from the current sense resistor, which carries the coil current modulation

information in addition to the averaged input current. There is an additional discrete low-pass filter and DC filter between the ISNS_OUT and

IDEMI pins. The packet decoder block is shared between the voltage-mode and current-mode detectors. The packet decoder selects either

voltage-mode or current-mode signals depending upon which produces the best demodulated signal.

Figure 15. Current Mode Envelope Detector

VIN

Vbridge

Packet

Decoder

To Registers

20mΩ

P9242-R

R1

C1

C2

C3