參數(shù)資料
型號(hào): QT320-IS
廠商: Electronic Theatre Controls, Inc.
英文描述: 2 CHANNEL PROGAMMABLE ADVANCED SENSOR IC
中文描述: 2頻道PROGAMMABLE先進(jìn)傳感器IC
文件頁(yè)數(shù): 11/18頁(yè)
文件大小: 960K
代理商: QT320-IS
3.4 ESD ISSUES
In cases where the electrode is placed behind a dielectric
panel, the device will usually be well protected from static
discharge. However, even with a plastic or glass panel,
transients can still flow into the electrode via induction, or in
extreme cases, via dielectric breakdown. Porous materials
may allow a spark to tunnel right through the material;
partially conducting materials like 'pink poly' static dissipative
plastics will conduct the ESD right to the electrode. Panel
seams can permit discharges through edges or cracks.
Testing is required to reveal any problems. The QT320 has
internal diode protection which can absorb and protect the
device from most induced discharges, up to 20mA; the
usefulness of the internal clamping will depend on the
dielectric properties, panel thickness, and rise time of the
ESD transients.
ESD protection can be enhanced with an added resistor as
shown in Figure 3-1. Because the charge and transfer times
of the QT320 are 1us in duration, the circuit can tolerate
values of Re which result in an RC 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.
3.5 EMC ISSUES
Electromagnetic and electrostatic susceptibility are often a
problem with capacitive sensors. QT320 behavior under these
conditions can be improved by adding the series-R shown in
Figure 3-1, exactly as shown for ESD protection. The resistor
should be placed next to the chip.
This works because the inbound RC network formed by Re
and Cs has a very low cutoff frequency which can be
computed by the formula:
Fc
=
1
2
ReCs
If Re = 10K and Cs = 10nF, then Fc = 1.6kHz.
This leads to very strong suppression of external fields.
Nevertheless, it is always wise to reduce lead lengths by
placing the QT320 as close to the electrodes as possible.
Likewise, RF emissions are sharply curtailed by the use of
Re, which bandwidth limits RF emissions based on the value
of Re and Cx, the electrode capacitance.
Line conducted EMI can be reduced by making sure the
power supply is properly bypassed to chassis ground. The
OUT lines can also be paths for conducted EMI, and these
can be bypassed to circuit ground with an RC filter network.
4 PARAMETER CLONING
The cloning process allows user-defined settings to be loaded
into internal eeprom, or read back out, for development and
production purposes.
The QTM300CA cloning board in conjunction with QT3View
software simplifies the cloning process greatly. The E3B eval
board has been designed with a connector to facilitate direct
connection with the QTM300CA. The QTM300CA in turn
connects to any PC with a serial port which can run QT3View
software (included with the QTM300CA and available on
Quantum
s web site).
The connections required for cloning are shown in Figure 4-1.
Further information on the cloning process can be found in
the QTM300CA instruction guide. Section 3.3.2 discusses
wiring issues associated with cloning.
The parameters which can be altered are shown in Table 4-1
(next page).
Parameters that can be altered for each channel
independently are:
Threshold
Hysteresis
Detect Integrator A
Detect Integrator B
Max On-Duration
Output Mode
Parameters that are common to the entire part are:
Detect Integrator Speed
Negative Drift Compensation
Positive Drift Compensation
Sleep Cycles
It is possible for an on-board host controller to read and
change the internal settings via the interface, but doing so will
inevitably disturb the sensing process even when data
transfers are not occuring. The additional capacitive loading
of the interface pins will contribute to Cx; also, noise on the
interface lines can cause erratic operation.
The internal eeprom has a life expectancy of 100,000
erase/write cycles.
A serial interface specification for the device can be obtained
by contacting Quantum.
l
Q
11
QT320/R1.03 08/02
Figure 4-1 Clone interface wiring
8
VDD
S2A
S1A
2
6
3
4
S2B
S1B
5
S
OUT2
VSS
7
OUT2
SENSOR 2
SENSOR 1
OUT1
OUT1
1
Vdd
CS1
G
S
S
CS2
相關(guān)PDF資料
PDF描述
QT60040-S IC-SMD-QPROX MATRIX SENSOR
QT60040 4-KEY CHARGE-TRANSFER IC
QT60040-D 4-KEY CHARGE-TRANSFER IC
QT60040-IS 4-KEY CHARGE-TRANSFER IC
QT60161B 16 KEY QMATRIX KEYPANEL SENSOR IC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
QT320-ISG 功能描述:SENSOR IC TOUCH PROG 2CH 8-SOIC RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 觸摸屏控制器 系列:QProx™ 標(biāo)準(zhǔn)包裝:96 系列:- 類型:- 觸摸面板接口:- 輸入數(shù)/鍵:- 分辨率(位):- 評(píng)估套件:* 數(shù)據(jù)接口:- 數(shù)據(jù)速率/采樣率 (SPS,BPS):- 電壓基準(zhǔn):- 電源電壓:- 電流 - 電源:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:16-TSSOP(0.173",4.40mm 寬) 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:帶卷 (TR)
QT320-S 功能描述:SENSOR IC TOUCH PROG 2CH 8-SOIC 制造商:microchip technology 系列:QProx?? 包裝:管件 零件狀態(tài):停產(chǎn) 觸摸屏:2 線電容 分辨率(位):16 b 接口:串行 電壓基準(zhǔn):內(nèi)部 電壓 - 電源:1.8 V ~ 5.25 V 電流 - 電源:600μA 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應(yīng)商器件封裝:8-SO 基本零件編號(hào):QT320 標(biāo)準(zhǔn)包裝:95
QT-35B 功能描述:印刷電路板和試驗(yàn)板 TEST SOCKET 60 TIE POINTS, BREADBOARD RoHS:否 制造商:3M Electronic Solutions Division 產(chǎn)品:Jumper & Insulated Wires 描述/功能:Jumper wire, 22 AWG 0.1 inch 長(zhǎng)度:0.1 in 寬度:
QT-35S 功能描述:印刷電路板和試驗(yàn)板 TEST SOCKET 350 TIE POINTS, SOLDERLESS RoHS:否 制造商:3M Electronic Solutions Division 產(chǎn)品:Jumper & Insulated Wires 描述/功能:Jumper wire, 22 AWG 0.1 inch 長(zhǎng)度:0.1 in 寬度:
QT3F 制造商:Switchcraft 功能描述:QG TWIST INSERT 3 P