EVAL-AD7142EB View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

EVAL-AD7142EB

Programmable Capacitance-to-Digital Converter with Environmental Compensation

Analog Devices 

AD7142

Σ-Δ

16

16-BIT

CDC

SLOW_FILTER_UPDATE_LVL

REGISTER 0x003

COMPARATOR 3

WORD0 – WORD3

PROXIMITY

STAGE_MAX_WORD0

STAGE_MAX_WORD1

STAGE_MAX_WORD2

STAGE_MAX_WORD3

BANK 3 REGISTERS

MAX LEVEL

DETECTION

LOGIC

STAGE_MAX_AVG

BANK 3 REGISTERS

STAGE_MAX_TEMP

BANK 3 REGISTERS

STAGE_HIGH_THRESHOLD

BANK 3 REGISTERS

STAGE_MIN_WORD0

STAGE_MIN_WORD1

STAGE_MIN_WORD2

STAGE_MIN_WORD3

BANK 3 REGISTERS

CONTROL

LOGIC

MIN LEVEL

DETECTION

LOGIC

SW

STAGE_MIN_AVG

BANK 3 REGISTER3

STAGE_MIN_TEMP

BANK 3 REGISTERS

STAGE_LOW_THRESHOLD

BANK 3 REGISTERS

FP_PROXIMITY_CNT

REGISTER 0x002

LP_PROXIMITY_CNT

REGISTER 0X002

STAGE_FF_WORD0

STAGE_FF_WORD1

STAGE_FF_WORD2

STAGE_FF_WORD3

STAGE_FF_WORD4

STAGE_FF_WORD5

STAGE_FF_WORD6

STAGE_FF_WORD7

COMPARATOR 1

WORD0 – WORD3

PROXIMITY 1

PROXIMITY_DETECTION_RATE

REGISTER 0x003

BANK 3 REGISTERS

PROXIMITY

PROXIMITY TIMING

CONTROL LOGIC

FP_PROXIMITY_RECAL

REGISTER 0x004

LP_PROXIMITY_RECAL

REGISTER 0X004

SW1

STAGE_SF_WORD0

STAGE_SF_WORD1

STAGE_SF_WORD2

STAGE_SF_WORD3

STAGE_SF_WORD4

STAGE_SF_WORD5

STAGE_SF_WORD6

STAGE_SF_WORD7

BANK 3 REGISTERS

7

Σ WORD(N)

N=0

8

STAGE_FF_AVG

BANK 3 REGISTERS

STAGE_SF_AMBIENT

BANK 3 REGISTERS

COMPARATOR 2

AVERAGE – AMBIENT

PROXIMITY_RECAL_LVL

REGISTER 0x003

STAGE_FF_WORDX

STAGE_SF_WORDX

SENSOR

CONTACT

AMBIENT VALUE

TIME

NOTES

1. SLOW FILTER EN IS SET AND SW1 IS CLOSED WHEN |WORD 0–WORD 3| EXCEEDS THE VALUE PROGRAMMED IN THE SLOW_FILTER_UPDATE_LVL REGISTER PROVIDING

PROXIMITY IS NOT SET.

2. PROXIMITY 1 IS SET WHEN |WORD 0–WORD 3| EXCEEDS THE VALUE PROGRAMMED IN THE PROXIMITY_DETECTION_RATE REGISTER.

3. PROXIMITY 2 IS SET WHEN |AVERAGE–AMBIENT| EXCEEDS THE VALUE PROGRAMMED IN THE PROXIMITY_RECAL_LVL REGISTER.

4. DESCRIPTION OF COMPARATOR FUNCTIONS:

COMPARATOR 1: USED TO DETECT WHEN A USER IS APPROACHING OR LEAVING A SENSOR.

COMPARATOR 2: USED TO DETECT WHEN A USER IS HOVERING OVER A SENSOR, OR APPROACHING A SENSOR VERY SLOWLY.

ALSO USED TO DETECT IF THE SENSOR AMBIENT LEVEL HAS CHANGED AS A RESULT OF THE USER INTERACTION.

FOR EXAMPLE, HUMIDITY OR DIRT LEFT BEHIND ON SENSOR.

COMPARATOR 3: USED TO ENABLE THE SLOW FILTER UPDATE RATE. THE SLOW FILTER IS UPDATED WHEN SLOW FILTER EN IS SET AND PROXIMITY IS NOT SET.

Figure 30. AD7142 Proximity Detection and Environmental Calibration

Rev. 0 | Page 21 of 68

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