AT42QT1012_10 ATMEL [ATMEL Corporation], AT42QT1012_10 Datasheet
AT42QT1012_10
Related parts for AT42QT1012_10
AT42QT1012_10 Summary of contents
Page 1
Features • Number of Keys: – One, toggle mode (touch-on/touch-off), plus programmable auto-off delay and external cancel – Configurable as either a single key or a proximity sensor • Technology: – Patented spread-spectrum charge-transfer (direct mode) • Key outline sizes: ...
Page 2
Pinout and Schematic 1.1 Pinout Configurations 1.1.1 6-pin SOT23-6 1.1.2 8-pin UDFN/USON AT42QT1012 2 OUT 1 6 TIME VSS 2 5 VDD SNSK 3 4 SNS Pin SNS SNSK 1 N VDD QT1012 N/C ...
Page 3
Pin Descriptions Table 1-1. Pin Listing 6-Pin 8-Pin Name Type 1 5 OUT Vss 3 1 SNSK I SNS I Vdd 6 6 TIME – 2 N/C – 3 N/C 1. I/O ...
Page 4
UDFN/USON Figure 1-2. SENSE ELECTRODE Re Figure 1-1 on page 3 • Cs capacitor (Cs) – see • Sample resistor (Rs) – see • Voltage levels – see • Output polarity selection resistor (Rop) – see • Rm ...
Page 5
Overview of the AT42QT1012 2.1 Introduction The AT42QT1012 (QT1012 single key device featuring a touch on/touch off (toggle) output with a programmable auto switch-off capability. The QT1012 is a digital burst mode charge-transfer (QT controls. It includes ...
Page 6
A series resistor, Rs, should be placed in line with SNSK to the electrode to suppress electrostatic discharge (ESD) and electromagnetic compatibility (EMC) effects. Figure 2-1. 2.4 Sensitivity 2.4.1 Introduction The sensitivity on the QT1012 is a function of things ...
Page 7
Operation Specifics 3.1 Acquisition Modes 3.1.1 Introduction The OUT pin of the QT1012 can be configured to be active high or active low. • If active high then: – “on” is high – “off” is low • If active ...
Page 8
Detect Threshold The device detects a touch when the signal has crossed a threshold level. The threshold level is fixed at 10 counts. 3.3 Detect Integrator It is desirable to suppress detections generated by electrical noise or from quick ...
Page 9
Figure 3-3. The QT1012's drift compensation is asymmetric; the reference level drift-compensates in one direction faster than it does in the other. Specifically, it compensates faster for decreasing signals than for increasing signals. Increasing signals should not be compensated for ...
Page 10
Output Polarity Selection The output (OUT pin) of the QT1012 can be configured to have an active high or active low output by means of the output configuration resistor Rop. The resistor is connected between the output and either ...
Page 11
Output Drive The OUT pin can sink or source mA. When a large value of Cs (>20 nF) is used the OUT current should be limited to < prevent gain-shifting side effects, which happen ...
Page 12
Figure 3-6. Table 3-2. Vt Vss Vdd OUT Table 3-3. Vt Vss Vdd OUT Table 3-4. Vm Vss Vdd 3.11.3 Auto Off – User-programmed Delay If a user-programmed delay is required network (resistor and capacitor) can be used ...
Page 13
Figure 3-7. 3.11.4 Configuring the User-programmed Auto-off Delay The QT1012 can be configured to give auto-off delays ranging from minutes to hours by means of a simple RC network and the delay multiplier input. With the delay multiplier set at ...
Page 14
Figure 3- The charts in high or active low output. Example using the formula to calculate Rt and Ct Requirements: • Active high output (Vop connected to VSS) • Auto-off delay nominal 45 ...
Page 15
Figure 3-9. 3500 3000 2500 2000 1500 1000 500 0 0 4000 3500 3000 2500 2000 1500 1000 500 0 0 9543D–AT42–08/10 Auto-off Delay, Active High Output Vm = Vss (delay multiplier = x1) 5V Active High Ct = 100nF ...
Page 16
Figure 3-10. Auto-off Delay, Active Low Output 4000 3500 3000 Ct = 100nF 2500 2000 1500 1000 500 0 0 3500 3000 Ct = 100nF 2500 2000 1500 1000 500 0 0 Example using a chart to calculate Rt and ...
Page 17
Auto Off – Overriding the Auto Off Delay In normal operation the QT1012 output is turned off automatically after the auto-off delay. In some applications it may be useful to extend the auto-off delay (“sustain” function switch ...
Page 18
Figure 3-12. Override Pulse (Delay Multiplier x24) Figure 3-13 Figure 3-13. Overriding Auto Off AT42QT1012 18 SENSE ELECTRODE VDD 5 RS VDD 3 SNSK CS 4 SNS Rm VSS 2 VDD Vm VSS Tp shows override pulses being applied to ...
Page 19
Examples of Typical Applications Figure 3-14. Application 1 ELECTRODE Figure 3-15. Application 2 9543D–AT42–08/10 Active low, driving PNP transistor, auto off time 375s 9000s = 2.5 hours 100nF Rm 1M SENSE VDD RS 3 SNSK CS ...
Page 20
Circuit Guidelines 4.1 More Information Refer to Application Note QTAN0002, Secrets of a Successful QTouch™ Design and the Touch Sensors Design Guide (both downloadable from the Atmel construction and design methods. 4.2 Sample Capacitor Cs is the charge sensing ...
Page 21
Electrode trace routing: Keep the electrode trace (and the electrode itself) away from other signal, power, and ground traces including over or next to ground planes. Adjacent switching signals can induce noise onto the sensing signal; any adjacent trace or ...
Page 22
Specifications 5.1 Absolute Maximum Specifications Operating temperature Storage temperature V DD Max continuous pin current, any control or drive pin Short circuit duration to Vss, any pin Short circuit duration to Vdd, any pin Voltage forced onto any pin ...
Page 23
Signal Processing Vdd = 3. recommended range, unless otherwise noted Description Threshold differential Hysteresis Consensus filter length 5.5 DC Specifications Vdd = 3.0V 4.7 nF ...
Page 24
Mechanical Dimensions 5.6.1 6-pin SOT23 Pin # Top View 0. View B Notes: 1. This package is compliant with JEDEC specification MO-178 Variation AB 2. Dimension D ...
Page 25
UDFN/USON Pin TOP VIEW C0 BOTTOM VIEW Note: 1. ALL DIMENSIONS ARE IN mm. ANGLES IN DEGREES. 2. COPLANARITY APPLIES TO THE ...
Page 26
Part Marking 5.7.1 AT42QT1012– 6-pin SOT23-6 Pin 1 ID 5.7.2 AT42QT1012– 8-pin UDFN/USON Abbreviated Part Number: 1012 AT42QT Class code (H = Industrial, green NiPdAu) Pin 1 ID 5.8 Part Number Part Number AT42QT1012-TSHR AT42QT1012-MAH 5.9 Moisture Sensitivity Level ...
Page 27
Associated Documents • Application Note – QTAN0002, Secrets of a Successful QTouch™ Design • User Guide – Touch Sensors Design Guide Revision History Revision No. Revision A – August 2009 Revision B – September 2009 Revision C – May 2010 ...
Page 28
Headquarters Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Disclaimer: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to ...