LDC2112, LDC2114 Inductive Touch Solution for Low-Power HMI and Button Applicati datasheet

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LDC2112,LDC2114
SNOSD15B–DECEMBER2016–REVISEDAPRIL2017
LDC2112, LDC2114 Inductive Touch Solution for Low-Power HMI Button Applications
1 Features 3 Description
• LowPowerConsumption: Inductive sensing technology enables touch button
1 design for human machine interface (HMI) on a wide
– OneButton:6 µAat0.625SPS
variety of materials such as metal, glass, plastic, and
– TwoButtons:72 µAat20SPS wood, by measuring small deflections of conductive
• ConfigurableButtonScanRates: targets. The sensor for an inductive touch system is a
coil that can be implemented on a small PCB located
– 0.625SPSto80SPS
behindthepanelandprotectedfromtheenvironment.
• ForceLevelMeasurementofTouchButtons Inductive sensing solution is insensitive to humidity or
• IndependentChannelOperation: non-conductive contaminants such as oil and dirt. It is
able to automatically correct for any deformation in
– TwoChannelsforLDC2112
theconductivetargets.
– FourChannelsforLDC2114
The LDC2112/LDC2114 is a multi-channel low-noise
• IntegratedAlgorithms toEnable:
inductance to digital converter with integrated
– AdjustableForceThresholdperButton algorithms to implement inductive touch applications.
– EnvironmentalShiftCompensation The device employs an innovative LC resonator that
offers high rejection of noise and interference. The
– SimultaneousButtonPressDetection
LDC2112/LDC2114 can reliably detect material
• SupportsIndependentOperationwithoutMCU
deflectionsoflessthan200nm.
• RobustEMI Performance:
The LDC2112/LDC2114 includes an ultra-low power
– AllowsforCISPR22andCISPR24 mode intended for power on/off buttons in battery
Compliance poweredapplications.
• OperatingVoltageRange:1.8V ± 5%
The LDC2112/LDC2114 is available in a 16-pin
• TemperatureRange:–40°Cto+85°C DSBGA or TSSOP package. The 0.4 mm pitch
• Interface: DSBGA package has a very small 1.6 × 1.6 mm
nominal body size with a maximum height of 0.4 mm.
– I2C
The 0.65 mm pitch TSSOP package has a 5.0 × 4.4
– DedicatedLogicOutputperChannel mm nominal body size with a maximum height of 1.2
mm.
2 Applications
Touch Buttons and Force Level Measurements on DeviceInformation(1)
Different Materials, Including Metal, Plastic, and PARTNUMBER PACKAGE BODYSIZE(NOM)
Glassfor: LDC2112/LDC2114 DSBGA(16) 1.6mm×1.6mm
• ConsumerElectronics: LDC2112/LDC2114 TSSOP(16) 5.0mm×4.4mm
– Smartphones (1) For all available packages, see the orderable addendum at
theendofthedatasheet.
– Smart WatchesandOtherWearableDevices
– Smart Speakers SimplifiedSchematic
– Tablets/PCs
– VirtualRealityHeadsets LDC2114 VDD
OUT0
– SoundBars
IN0 Digital OUT1
• IndustrialApplications: Algorithm OUT2
OUT3
– Televisions
IN1
– HandheldDevices
Resonant Inductive INTB
IN2 Circuit Sensing Core Logic
– HomeAppliances Driver LPWRB
– HMIPanelsandKeypads
IN3
COM I2C SCL
SDA
GND
Copyright © 2016, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.
LDC2112,LDC2114
SNOSD15B–DECEMBER2016–REVISEDAPRIL2017 www.ti.com
Table of Contents
1 Features.................................................................. 1 7.5 RegisterMaps.........................................................15
2 Applications........................................................... 1 8 ApplicationandImplementation........................ 28
3 Description............................................................. 1 8.1 ApplicationInformation............................................28
4 RevisionHistory..................................................... 2 8.2 TypicalApplication..................................................38
5 PinConfigurationandFunctions......................... 3 9 PowerSupplyRecommendations...................... 40
6 Specifications......................................................... 5 10 Layout................................................................... 40
6.1 AbsoluteMaximumRatings......................................5 10.1 LayoutGuidelines.................................................40
6.2 ESDRatings..............................................................5 10.2 LayoutExample....................................................40
6.3 RecommendedOperatingConditions.......................5 10.3 DSBGALightSensitivity ......................................41
6.4 ThermalInformation..................................................5 11 DeviceandDocumentationSupport................. 42
6.5 ElectricalCharacteristics...........................................6 11.1 DocumentationSupport .......................................42
6.6 DigitalInterface.........................................................7 11.2 RelatedLinks........................................................42
6.7 I2CInterface..............................................................7 11.3 ReceivingNotificationofDocumentationUpdates42
6.8 TypicalCharacteristics..............................................8 11.4 CommunityResources..........................................42
7 DetailedDescription............................................ 10 11.5 Trademarks...........................................................42
7.1 Overview.................................................................10 11.6 ElectrostaticDischargeCaution............................42
7.2 FunctionalBlockDiagram.......................................10 11.7 ExportControlNotice...........................................42
7.3 FeatureDescription.................................................11 11.8 Glossary................................................................43
7.4 DeviceFunctionalModes........................................15 12 Mechanical,Packaging,andOrderable
Information........................................................... 43
4 Revision History
ChangesfromRevisionA(January2017)toRevisionB Page
• ChangedunitofDataset-uptimefromµstons(typo) ......................................................................................................... 7
• ChangedMulti-ChannelandSingle-ChannelOperation...................................................................................................... 11
• AddedLDC2112toRegisterEN–Address0x0CTable...................................................................................................... 19
ChangesfromOriginal(December2016)toRevisionA Page
• ChangedAdvanceInformationtoProductionDataRelease.................................................................................................. 1
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5 Pin Configuration and Functions
LDC2112
16-PinDSBGA LDC2112
TopView(BumpsDown) 16-PinTSSOP
TopView
1 2 3 4
COM 1 16 SCL
A NC IN1 IN0 GND GND 2 15 OUT0
LPWRB 3 14 SDA
VDD 4 13 OUT1
B NC INTB ADDR NC LDC2112
INTB 5 12 NC
NC 6 11 ADDR
LPW
C VDD SDA OUT1
RB NC 7 10 GND
IN1 8 9 IN0
D GND COM SCL OUT0
PinFunctions -LDC2112
PIN
I/O(1) DESCRIPTION
NAME DSBGANO. TSSOPNO.
VDD C1 4 P Powersupply
D1 2
GND G Ground(2)
A4 10
Interruptoutput
INTB B2 5 O
PolaritycanbeconfiguredinRegister0x11.
Normal/LowPowerModeselect
LPWRB C2 3 I
SetLPWRBtoV forNormalPowerModeorgroundforLowPowerMode.
DD
CommonreturncurrentpathforallLCresonatorsensors
COM D2 1 A AcapacitorshouldbeconnectedfromthispintoGND.RefertoSettingCOM
PinCapacitor.
IN0 A3 9 A Channel0LCsensorinput
IN1 A2 8 A Channel1LCsensorinput
Channel0logicoutput
OUT0 D4 15 O
PolaritycanbeconfiguredinRegister0x1C.
Channel1logicoutput
OUT1 C4 13 O
PolaritycanbeconfiguredinRegister0x1C.
I2Caddress
ADDR B3 11 I WhenADDR=Ground,I2Caddress=0x2A.WhenADDR=V ,I2Caddress=
DD
0x2B.
SCL D3 16 I I2Cclock
SDA C3 14 I/O I2Cdata
A1 7
Noconnect
NC B1 6 —
Leavethemfloating.
B4 12
(1) I=Input,O=Output,P=Power,G=Ground,A=Analog
(2) BothpinsshouldbeconnectedtothesystemgroundonthePCB.
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LDC2114
16-PinDSBGA LDC2114
TopView(BumpsDown) 16-PinTSSOP
1 2 3 4 TopView
COM 1 16 SCL
A IN2 IN1 IN0 GND
GND 2 15 OUT0
LPWRB 3 14 SDA
B IN3 INTB OUT3 OUT2 VDD 4 13 OUT1
LDC2114
INTB 5 12 OUT2
C VDD LPW SDA OUT1 IN3 6 11 OUT3
RB
IN2 7 10 GND
IN1 8 9 IN0
D GND COM SCL OUT0
PinFunctions -LDC2114
PIN
I/O(1) DESCRIPTION
NAME DSBGANO. TSSOPNO.
VDD C1 4 P Powersupply
D1 2
GND G Ground(2)
A4 10
Interruptoutput
INTB B2 5 O
PolaritycanbeconfiguredinRegister0x11.
Normal/LowPowerModeselect
LPWRB C2 3 I
SetLPWRBtoV forNormalPowerModeorgroundforLowPowerMode.
DD
CommonreturncurrentpathforallLCresonatorsensors
COM D2 1 A AcapacitorshouldbeconnectedfromthispintoGND.RefertoSettingCOMPin
Capacitor.
IN0 A3 9 A Channel0LCsensorinput
IN1 A2 8 A Channel1LCsensorinput
IN2 A1 7 A Channel2LCsensorinput
IN3 B1 6 A Channel3LCsensorinput
Channel0logicoutput
OUT0 D4 15 O
PolaritycanbeconfiguredinRegister0x1C.
Channel1logicoutput
OUT1 C4 13 O
PolaritycanbeconfiguredinRegister0x1C.
Channel2logicoutput
OUT2 B4 12 O
PolaritycanbeconfiguredinRegister0x1C.
Channel3logicoutput
OUT3 B3 11 O
PolaritycanbeconfiguredinRegister0x1C.
SCL D3 16 I I2Cclock
I2Cdata
SDA C3 14 I/O I2Caddress=0x2A.
(1) I=Input,O=Output,P=Power,G=Ground,A=Analog
(2) BothpinsshouldbeconnectedtothesystemgroundonthePCB.
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6 Specifications
6.1 Absolute Maximum Ratings
Overoperatingtemperaturerangeunlessotherwisenoted.(1)
MIN MAX UNIT
V Supplyvoltage 2.2 V
DD
VoltageonSCL,SDA –0.3 3.6 V
V
I Voltageonanyotherpin –0.3 2.2(2) V
T Junctiontemperature –40 85 ℃
J
T Storagetemperature –65 125 °C
STG
(1) StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratings
only,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommended
OperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.
(2) Maximumvoltageacrossanytwopins(notincludingSCLorSDA)isV +0.3V.
DD
6.2 ESD Ratings
VALUE UNIT
Humanbodymodel(HBM),perANSI/ESDA/JEDECJS-001(1) ±1000
Electrostatic
V(ESD) discharge CCh1a0r1g(e2)ddevicemodel(CDM),perJEDECspecificationJESD22- ±250 V
(1) JEDECdocumentJEP155statesthat500-VHBMallowssafemanufacturingwithastandardESDcontrolprocess.
(2) JEDECdocumentJEP157statesthat250-VCDMallowssafemanufacturingwithastandardESDcontrolprocess.
6.3 Recommended Operating Conditions
Overoperatingtemperaturerangeunlessotherwisenoted.
MIN NOM MAX UNIT
V Supplyvoltage 1.71 1.89 V
DD
T Junctiontemperature –40 85 °C
J
6.4 Thermal Information
LDC2112/LDC2114
THERMALMETRIC(1) DSBGA TSSOP UNIT
16PINS 16PINS
R Junction-to-ambientthermalresistance 81.8 105.1 °C/W
θJA
R Junction-to-case(top)thermalresistance 0.4 40.3 °C/W
θJC(top)
R Junction-to-boardthermalresistance 18.2 50.2 °C/W
θJB
Ψ Junction-to-topcharacterizationparameter 0.3 3.6 °C/W
JT
Junction-to-boardcharacterization
Ψ 18 49.6 °C/W
JB parameter
(1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheSemiconductorandICPackageThermalMetricsapplication
report.
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6.5 Electrical Characteristics
Overoperatingtemperaturerangeunlessotherwisenoted.V =1.8V,T =25°C.
DD J
PARAMETER TESTCONDITIONS MIN TYP MAX UNIT
POWER
V Supplyvoltage 1.71 1.8 1.89 V
DD
4channels,40SPSperchannel,
Normalpowermodesupplycurrent
IDDNP (4channels)(1)(2)(3) 1mssamplingwindowperchannel, 0.49 mA
LPWRB=V
DD
2channels,40SPSperchannel,
Normalpowermodesupplycurrent
IDDNP (2channels)(1)(2) 1mssamplingwindowperchannel, 0.26 mA
LPWRB=V
DD
1channel,1.25SPSperchannel,
Lowpowermodesupply
IDDLP current(1)(2) 1mssamplingwindowperchannel, 9 µA
LPWRB=Ground
I Standbysupplycurrent Nobuttonactive(EN=0x00) 5 7 µA
DDSB
SENSOR
RegistersSENSORn_CONFIG:RPn=0
ISENSOR,MAX Sensormaximumcurrentdrive (4) 2.5 mA
Sensorminimumparallelresonant
R 350 Ω
P,MIN impedance
Sensormaximumparallelresonant
R 10 kΩ
P,MAX impedance
f Sensorresonantfrequency 1 30 MHz
SENSOR
Q Sensorminimumqualityfactor 5
SENSOR,MIN
Q Sensormaximumqualityfactor 30
SENSOR,MAX
Sensoroscillationpeak-to-peak MeasuredontheINn(4)pinswith
V 0.9 V
SENSOR,PP voltage referencetoCOM.
C Sensorinputpincapacitance 17 pF
IN
CONVERTER
Minimumnormalpowermodescan
SRNP,MIN rate(5) LPWRB=VDD 7 10 13 SPS
Maximumnormalpowermodescan
SRNP,MAX rate(5) LPWRB=VDD 56 80 104 SPS
Minimumlowpowermodescan
SRLP,MIN rate(5) LPWRB=Ground 0.438 0.625 0.813 SPS
Maximumlowpowermodescan
SRLP,MAX rate(5) LPWRB=Ground 3.5 5 6.5 SPS
Resolution Datacodewidth 12 Bits
(1) Sensorconfiguration:L =0.85µH,C =58pF,Q =11,R =0.7kΩ.
SENSOR SENSOR SENSOR P
(2) I2Ccommunicationandpull-upresistorscurrentisnotincluded.
(3) Four-channelsupplycurrentisapplicabletoLDC2114only.
(4) Theitalicnisthechannelindex,i.e.,n=0or1forLDC2112;n=0,1,2,or3forLDC2114.
(5) Fortypicaldistributionofthescanrates,refertoFigure9.
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6.6 Digital Interface
Overoperatingtemperaturerangeunlessotherwisenoted.V =1.8V,T =25°C.Pins:LPWRB,INTB,OUT0,OUT1,
DD J
OUT2,OUT3,andADDR.
PARAMETER TESTCONDITIONS MIN TYP MAX UNIT
VOLTAGELEVELS
V Inputhighvoltage 0.8×V V
IH DD
V Inputlowvoltage 0.2×V V
IL DD
V Outputhighvoltage I =400µA 0.8×V V
OH SOURCE DD
V Outputlowvoltage I =400µA 0.2×V V
OL SINK DD
I Digitalinputleakagecurrent –500 500 nA
L
6.7 I2C Interface
MIN TYP MAX UNIT
VOLTAGELEVELS
V Inputhighvoltage 0.7×V V
IH DD
V Inputlowvoltage 0.3×V V
IL DD
V Outputlowvoltage 3mAsinkcurrent 0.2×V V
OL DD
HYS Hysteresis(1) 0.05×V V
DD
I2CTIMINGCHARACTERISTICS
f Clockfrequency 400 kHz
SCL
t Clocklowtime 1.3 µs
LOW
t Clockhightime 0.6 µs
HIGH
Afterthisperiod,thefirst
t HoldtimerepeatedSTARTcondition 0.6 µs
HD;STA clockpulseisgenerated.
Set-uptimeforarepeatedSTART
t 0.6 µs
SU;STA condition
t Dataholdtime 0 µs
HD;DAT
t Dataset-uptime 100 ns
SU;DAT
t Set-uptimeforSTOPcondition 0.6 µs
SU;STO
BusfreetimebetweenaSTOPand
t 1.3 µs
BUF STARTcondition
t Datavalidtime 0.9 µs
VD;DAT
t Datavalidacknowledgetime 0.9 µs
VD;ACK
Pulsewidthofspikesthatmustbe
tSP suppressedbytheinputfilter(1) 50 ns
(1) Thisparameterisspecifiedbydesignand/orcharacterizationandisnottestedinproduction.
SDA
tf tLOW tHD;STA tr tBUF
tr tf tSP
SCL
tHD;STA tSU;STA tSU;STO
tHIGH
tHD;DAT tSU;DAT
START REPEATED STOP START
START
Figure1. I2CTimingDiagram
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6.8 Typical Characteristics
Overrecommendedoperatingconditionsunlessspecifiedotherwise.V =1.8V,T =25°C.
DD J
Onechannelenabledwithabuttonsamplingwindowof1msunlessspecifiedotherwise.
1600 800
10 SPS 10 SPS
1400 20 SPS 700 20 SPS
A) 40 SPS A) 40 SPS
P 1200 80 SPS P 600 80 SPS
nt ( nt (
e e
urr 1000 urr 500
C C
ply 800 ply 400
p p
u u
S 600 S 300
e e
g g
a a
er 400 er 200
v v
A A
200 100
0 0
0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10
Sensor RP (k:) D001 Sensor RP (k:) D011
Figure2.SupplyCurrentvsSensorR forNormalPower Figure3.SupplyCurrentvsSensorR forNormalPower
P P
Mode.SensorFrequency=3.6MHz.FourChannels Mode.SensorFrequency=3.6MHz.TwoChannelsEnabled.
Enabled.
30 160
0.625 SPS VDD = 1.71 V
1.25 SPS 150 VDD = 1.8 V
A) 25 2.5 SPS A) VDD = 1.89 V
P 5 SPS P 140
ent ( 20 ent (
urr urr 130
C C
ply 15 ply 120
p p
u u
S S 110
e 10 e
g g
a a
er er 100
v v
A 5 A
90
0 80
0 1 2 3 4 5 6 7 8 9 10 -40 -20 0 20 40 60 80 100
Sensor RP (k:) D002 Temperature (qC) D003
Figure4.SupplyCurrentvsSensorR forLowPowerMode. Figure5.SupplyCurrentvsTemperature.SensorR =650
P P
SensorFrequency=3.6MHz. Ω,ScanRate=40SPS.
160 9
VDD = 1.71 V
150 VDD = 1.8 V
A) 8 VDD = 1.89 V
P 140
urrent ( 130 nt (A)P 7
C e
ply 120 Curr 6
e Sup 110 ndby 5
g a
era 100 St
v
A 4
90 -40qC 0qC 85qC
-25qC 25qC
80 3
1.7 1.75 1.8 1.85 1.9 -40 -20 0 20 40 60 80 100
VDD (V) D004 Temperature (qC) D005
Figure6.SupplyCurrentvsV .SensorR =650Ω,Scan Figure7.StandbyCurrentvsTemperature
DD P
Rate=40SPS.
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Typical Characteristics (continued)
Onechannelenabledwithabuttonsamplingwindowof1msunlessspecifiedotherwise.
9 450
400
8
350
A)
P 7 300
dby Current ( 6 Occurrences 220500
n 5 150
a
St
100
4
-40qC 0qC 85°C 50
-25qC 25qC
3 0
1.7 1.75 1.8 1.85 1.9 -12-11-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4
VDD (V) D006 Percentage Offset ((cid:8)) D007
Figure8.StandbyCurrentvsV Figure9.ScanRateDistributionat30°C
DD
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7 Detailed Description
7.1 Overview
The LDC2112/LDC2114 is a multi-channel, low-noise, high-resolution inductance to digital converter (LDC)
optimized for inductive touch applications. Button presses form micro-deflections in the conductive targets which
cause frequency shifts in the resonant sensors. The LDC2112/LDC2114 can measure such frequency shifts and
determine when button presses have occurred. With adjustable sensitivity per input channel, the
LDC2112/LDC2114 can reliably operate with a wide range of physical button structures and materials. The high
resolution measurement enables the implementation of force level buttons. The LDC2112/LDC2114 incorporates
customizablepost-processingalgorithmsforenhancedrobustness.
The LDC2112/LDC2114 can operate in an ultra-low power mode for optimal battery life, or can be toggled into a
higher scan rate for more responsive button press detection for game play or other low latency applications. The
LDC2112/LDC2114isoperationalfrom–40°Cto+85°Cwitha1.8V± 5%power supplyvoltage.
The LDC2112/LDC2114 is configured through 400 kHz I2C. Button presses can be reported through the I2C
interface or with configurable polarity dedicated push-pull outputs. Besides the LC resonant sensors, the only
external components necessary for operation are supply bypassing capacitors and a COM pin capacitor to
ground.
7.2 Functional Block Diagram
VDD
LDC2112
OUT0
Digital
Algorithm
IN0 OUT1
Resonant Inductive Logic INTB
Circuit Sensing Core LPWRB
Driver
IN1
COM ADDR
I2C SCL
SDA
GND
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Figure10. BlockDiagramofLDC2112
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