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AS3932

Datasheet - Detailed Descr i p ti on

8 Detailed Description

The AS3932 is a three-dimensional low power low-frequency wake-up receiver. The AS3932 is capable to detect the presence of an inductive

coupled carrier and extract the envelope of the On-Off-Keying (OOK) modulated carrier. In case the carrier is Manchester coded the clock is

recovered from the transmitted signal and the data can be correlated with a programmed pattern. If the detected pattern corresponds to the

stored one a wake-up signal (IRQ) is risen up. The pattern correlation can be bypassed in which case the wake-up detection is based only on the

frequency detection.

The AS3932 is made up by three independent receiving channels, one envelop detector, one data correlator, 8 programmable registers with the

main logic and a real time clock.

The digital logic can be accessed by an SPI. The real time clock can be based on a crystal oscillator or on an internal RC one. If the internal RC

oscillator is used, a calibration procedure can be performed to improve its accuracy.

Figure 10. Block Diagram of LF Wake-up Receiver AS3932

Wake-up

Main Logic

Envelope Detector /

Data Slicer

Correlator

I/V

Bias

Xtal RTC

Xin

RC RTC

SPI

Channel

Amplifier 1

Channel

Amplifier 2

Channel

Amplifier 3

RSSI

RSSI

RSSI

Data

Data

Data

IRQ

Xout

GND

VCC

LF1P

LF2P

LF3P

SCL

SDI

SDO

LFN

DAT

CS

Channel

Selector

Freq. OK

Freq. OK

Freq. OK

AS3932