qt320 Quantum Research Group, qt320 Datasheet
qt320
Available stocks
Related parts for qt320
qt320 Summary of contents
Page 1
... No external switches, opamps, or other analog components aside from Cs are usually required. The Quantum-pioneered HeartBeat™ signal is also included, allowing a host controller to monitor the health of the QT320 continuously if desired; this feature can be disabled via the cloning process. ...
Page 2
... Only two low-cost, non-critical capacitors are required for operation. A unique aspect of the QT320 is the ability of the designer to ‘clone’ a wide range of user-defined setups into the part’s eeprom during development and in production. Cloned setups can dramatically alter the behavior of each channel, independently ...
Page 3
... QT320 via earth. The QT320's PCB however can be physically quite small, so there may be little ‘free space’ coupling (Cx1 in Figure 1-4) between it and the environment to complete the return path. If the QT320 circuit ground cannot be grounded via the supply connections, then IZE 3 ’ ...
Page 4
... Cx lower and is encouraged. In the case of the QT320, sensitivity can be high enough (depending on Cx and Cs) that 'walk-by' signals are a concern; if this is a problem, then some form of rear shielding may be required. ...
Page 5
... Where ground plane is required (for example, under and around the QT320 itself) the sense wires should have minimized adjacency to ground. 2. Connect a small capacitor (~5pF) between S1a or S1b ...
Page 6
... Figure 1-9 Bursts when SC > 0 1.5 TIMING The QT320 runs two sensing bursts, one per channel, each acquisition cycle (Figure 1-9). The bursts are successive in time, with Channel 2 firing first. The basic QT320 timing parameters are: Ti Basic timing interval Tbs Burst spacing Tbd1 Burst duration, Channel 1 ...
Page 7
... Quantum’s QT3View software calculates an estimate of response time based on these parameters. 1.6 EXTERNAL RECALIBRATION The QT320 has no recalibration pin; a forced recalibration is accomplished only when the device is powered up. However, supply drain is low enough that the IC can be powered from a logic gate or I/O pin of an MCU; driving the Vdd pin low and high again can serve as a forced recalibration. The source resistance of many CMOS gates and MCU’ ...
Page 8
... If THR1 = 10 and HYS1 = 2, the hysteresis zone will represent 20% of the threshold level. In this example the ‘hysteresis zone’ is the region from counts of signal level. Only (NDC) when the signal falls back to 7 will the OUT pin become inactive. Figure 2-2 Detect Integrator Filter Operation 8 QT320/R1.03 08/02 ...
Page 9
... See Figure 2-2 for operation usually desirable to suppress detections generated by sporadic electrical noise or from quick contact with an object. To accomplish this, the QT320 incorporates two detection integrator (‘DI’) counters per channel that serve to confirm detections and slow down response time. The counter pairs operate independently for each sensing channel ...
Page 10
... cloning connector is used, place this close to the QT320 (Figure 4-1). Placing the cloning connector far from the QT320 will increase the load capacitance Cx of the sensor and decrease sensitivity, as some of the cloning lines are sense lines ...
Page 11
... Re which result timeconstant of about 200ns. The ‘C’ of the RC is the Cx load on the distant side from the QT320. Thus, for a Cx load of 20pF, the maximum Re should be 10K ohms. Larger amounts of Re will result in an increasingly noticeable loss of sensitivity. ...
Page 12
... Requires pullup resistor on OUT2 - - Tndc = (NDC + Tbs (note1) Tndc = (NDC + 1) x Tbs (note2) Tpdc = (PDC + Tbs (note1) Tpdc = (PDC + 1) x Tbs (note2) Burst rep interval = Tbs = QT320/R1.03 08/02 Unit Counts Counts Burst Cycles Seconds - - - Counts Counts ...
Page 13
... 5.4 SIGNAL PROCESSING Symbol Description 5.5 DC SPECIFICATIONS Vdd = 3.0V 10nF 5pF recommended range, unless otherwise noted Symbol Description DD DDW DD DDS Min Typ Max Min Typ Max Min Typ Max +150 Units Notes Units Notes Units Notes QT320/R1.03 08/ ...
Page 14
... Cx Load Figure 5-2 Typical Ch 2 Sensitivity vs. Cx; Threshold = 16, Vdd = 3.0 10.00 1.00 0.10 0. Load Figure 5-4 Typical Ch 2 Sensitivity vs. Cx; Threshold = 6, Vdd = 3.0 QT320/R1.03 08/02 4.5nF 9nF 19nF 43nF 74nF 124nF 200nF 50 4.7nF 9nF 19nF 43nF 74nF 124nF 200nF 50 ...
Page 15
... Figure 5-6 Typical Ch 2 burst length vs Cx, Cs; 180 160 140 120 100 1.5 2 2.5 3 3.5 Power Supply (Volts) Figure 5-7 Typical total burst spacing vs. Vdd Tbd < 10ms 15 5.000 0.000 52 118 228 507 884 1450 2357 Sampling Capacitor (nF) Vdd = 3.0 4 4.5 5 5.5 QT320/R1.03 08/ 0pF Cx = 21pF Cx = 48pF Load (pF) ...
Page 16
... Figure 5-9 Idd current vs Cs; Vdd = 3 Sampling Capacitor (nF) Figure 5-10 Idd current vs Cs; Vdd = 5.0 16 Sleep Cycles None One Two Three Five 50 60 Sleep Cycles None One Two Three Five Ten 50 60 Sleep Cycles None One Two Three Five Ten 50 60 QT320/R1.03 08/02 ...
Page 17
... L2 L Inches Min Max 0.24 0.28 0.3 0.325 0.355 0.4 0.3 - 0.027 0.037 0.014 0.022 0.045 0.07 0.008 0.012 0.1 - 0.015 - 0.115 0.15 - 0.21 0.43 H φ h Inches Min Max 0.205 0.213 0.3 0.33 0.203 0.212 0.05 0.012 0.02 0.004 0.013 0.07 0.08 0.007 0.01 0.02 0.035 QT320/R1.03 08/ Notes Typical BSC e E Notes BSC ...
Page 18
Tel: +44 (0)23 8056 5600 Fax: +44 (0)23 8045 3939 This device expressly not for use in any medical or human safety related application without the express written consent of an officer of the company. Corporate Headquarters 1 Mitchell ...