Datasheet.kr   

QT114 데이터시트 PDF




QUANTUM에서 제조한 전자 부품 QT114은 전자 산업 및 응용 분야에서
광범위하게 사용되는 반도체 소자입니다.


 

PDF 형식의 QT114 자료 제공

부품번호 QT114 기능
기능 CHARGE-TRANSFER QLEVEL SENSOR IC
제조업체 QUANTUM
로고 QUANTUM 로고


QT114 데이터시트 를 다운로드하여 반도체의 전기적 특성과 매개변수에 대해 알아보세요.




전체 12 페이지수

미리보기를 사용할 수 없습니다

QT114 데이터시트, 핀배열, 회로
www.DataSheet4U.com
QProx™ QT114
CHARGE-TRANSFER QLEVELSENSOR IC
! Limit sensing of almost any fluid or powder
! 2-Tier level sensor - Hi / Low limits with one probe
! Only one external part required - a 5¢ capacitor
! Uses internal probes or external electrodes
! Active high or active low outputs
! Slosh filter averages response of moving fluids
! LED drive capable on both outputs
! 2.5 to 5V 20µA single supply operation
! HeartBeat™ health indicator on both outputs
Vcc
Out1
Out2
Filt
1
2
3
4
8 Gnd
7 Sns2
6 Sns1
5 Pol
APPLICATIONS -
! Process controls
! Vending machines
! Automotive fluids
! Consumer appliances
! Medical fluid sensing
! Soil moisture sensing
DESCRIPTION -
The QT114 QuickLevel™ charge-transfer (“QT”) sensor IC is specifically designed to detect point level in fluids
and powders. It will project a sense field through almost any dielectric, like glass, plastic, or ceramic, to sense
level on the inside of a vessel, from its exterior. It has the unique capability of independently sensing two trip
points when used with structured electrodes having two tiers.
The QT114 does not have sensing timeouts, drift compensation, or other functions which would interfere with
level sensing. Its threshold levels are fixed, and the amount of signal required to exceed a threshold is dependent
on circuit gain and electrode size and loading, all of which are under the control of the designer.
The QT114 requires only a single inexpensive capacitor in order to function. One or two LEDs can also be added
to provide a visual sensing indication.
Power consumption is under 20mA in most applications, allowing operation from Lithium cells for many years. In
most cases the power supply needs only minimal regulation.
The QT114 employs numerous signal acquisition and processing techniques pioneered by Quantum. No external
switches, opamps, or other analog components aside from CS are required.
A unique feature is the 'slosh filter', a detection integrator which averages detections over a rolling 15 second
interval before activating or deactivating the OUT pins. This filter allows use of the QT114 with violently moving
fluids, for example in a moving vehicle, that would otherwise cause the outputs to flicker between two states.
The device also includes selectable output polarity, allowing both output lines to be made either active-high or
active-low. It also includes the Quantum-pioneered HeartBeat™ signal, allowing a host controller to monitor the
health of the QT114 continuously if desired. By using the charge transfer principle, the IC delivers a level of
performance clearly superior to older technologies. It is specifically designed to replace electromechanical
devices like float switches, thermistors, and conductance probes.
TA
00C to +700C
-400C to +850C
Quantum Research Group Ltd
AVAILABLE OPTIONS
SOIC
QT114-S
QT114-IS
8-PIN DIP
QT114-D
-
Copyright © 1999 Quantum Research Group Ltd
R1.03




QT114 pdf, 반도체, 판매, 대치품
Figure 2-4 Single Level Internal Planar Probe
Figure 2-5 Single Level Internal Spiral Wire Probe
T2 T2
Figure 2-6 Twin-Level Internal Planar Probe
Figure 2-7 Twin-Level Internal Spiral Wire Probe
Spiral wire probes have the disadvantage of not being as
rugged as a solid disc probe.
2.2.3 SIDE-ENTRY PROBES
Another type is a side-entry probe (Figure 2-8), which
requires an entry point into the vessel wall, but may have the
advantage of accessibility in certain cases. These can be
made of simple metal rod, insulated in almost any plastic if
required.
2.2.4 COAXIAL PROBES
Another type of internal probe is the coaxial probe (Figure
2-10); these are most useful with oils or similar fluids having
a low dielectric constant; the inner rod is connected to the
signal connection, and together with the outer grounded
cylinder forms a capacitor whose dielectric is either air or oil.
Keeping the gap between rod and cylinder to a minimum
increases the 'gain' of the electrode.
Coaxial probes are more expensive to make, and can have
problems with vibration if they are not constructed robustly.
The outer cylinder should be perforated at key spots to allow
fluid to fill and drain the cavity without trapping air bubbles
inside. The outer cylinder can also be made of a wire mesh.
The outer cylinder does not have to be coated in plastic,
even when used with water-based fluids. When used with
oils, the inner rod does not require insulation either.
2.2.5 BARE METAL PROBES
Bare metal internal probes can be used, for example with
nonconductive fluids like oils, without difficulty. This applies
to all probe types described above.
Bare probes can also be used with aqueous fluids, but in
these cases a 1,000pF (1nF) ceramic NPO capacitor should
be inserted between the probe and the QT114 to block DC
current flows.
A bare internal probe used with conductive fluids and an
in-line blocking capacitor will generate a huge, robust
capacitive response that will not readily permit the use of a
2-level probe due to signal saturation. Even the slightest
amount of bare metal exposed to the fluid will usually
generate an immediate, large response with aqueous fluids.
-4-

4페이지










QT114 전자부품, 판매, 대치품
swing, with an intermediate count at about 200 between the
two. Thus, the lower electrode level should cause a signal
swing that (when 'dry') starts at 300 or more and when
covered ends at about 200. The upper electrode when
covered should generate a signal level of 100 or less.
There is a hysteresis of 3 counts around both T1 and T2.
The signal can be viewed for setup purposes with an
oscilloscope via a 10x or FET probe connected to a 2M ohm
resistor as shown in Figure 1-1; the resistor is required to
reduce the loading effect of the scope probe capacitance.
When viewed this way the signal will appear as a declining
slope (Figure 3-1). The duration of the slope corresponds to
the burst length: each count of burst takes approximately 7
microseconds on average. The ‘low level’ threshold at 250
counts is at 1750 microseconds from the start of the
waveform, while the 150 count ‘upper’ threshold is at about
1050 microseconds from the start, at 3 volts Vcc. These trip
points can be easily observed by monitoring the OUT lines
while watching the signal on a scope, by increasing Cx
loading until each OUT line activates in turn. FILT should be
off to speed up response during testing.
The QT114's internal clock is dependent on Vcc; as a result,
the threshold points in terms of delay time from the start of
the burst are also substantially dependent on Vcc, but they
are always fixed in terms of signal counts. A regulated power
supply is strongly advised to maintain the proper calibration
points.
Potentiometer adjustment: The external potentiometer
shown in Figure 1-1 is optional and in most cases not
required. In situations where the electrode pickup signal is
weak, trimming may be necessary on a production basis to
make the device sensitive enough. Trimming affects the
baseline reference of the signal, and thus effects the amount
of change in the signal required to cause a threshold
crossing.
Potentiometer trimming is not a substitute for a good choice
of Cs. In low signal situations Cs should still be determined
by design to allow the baseline signal to be just beyond T1
as viewed on a scope. The trimmer should then be added
and the baseline adjusted to the necessary final resting
point.
The trimmer should never be adjusted so that the resistance
from ground to SNS1 or SNS2 is less than 200K ohms. If the
resistance is less than this amount, the gain of the circuit will
be appreciably reduced and it may stop functioning
altogether. A 200K resistor from the wiper to ground can
be added to limit trim current at the extremes of wiper
travel.
3.3 INTERFACING
3.3.1 OUT LINES AND POLARITY SELECTION
The QT114 has two OUT pins, OUT1 and OUT2, which
correspond to the crossings of signal at T1 and T2
respectively. Each output will become active after the
threshold is crossed, and after the slosh filter (if enabled)
has settled to its final state. The polarity of the OUT lines
is determined by pin 5, 'POL', as follows:
POL = Gnd
POL = Vcc
Outputs active low
Outputs active high
There is no timeout on these outputs; the OUT lines will
remain active for as long as the thresholds are crossed.
The OUT lines can sink up to 5mA of non-inductive current.
If an inductive load is used, like a small relay, the load
should be diode clamped to prevent device damage.
POL strapping can be changed 'on the fly'.
Cycling and Stiction: Care should be taken when the QT114
and the loads are powered from the same supply, and the
supply is minimally regulated. The QT114 derives its internal
references from the power supply, and sensitivity shifts can
occur with changes in Vcc, as happens when loads are
switched on. This can induce detection ‘cycling’, whereby a
trip point is crossed, the load is turned on, the supply sags,
the trip is no longer sensed, the load is turned off, the supply
rises and the trip point is reacquired, ad infinitum. To prevent
this occurrence, the outputs should only be lightly loaded if
the device is operated from a poorly regulated supply.
Detection ‘stiction’, the opposite effect, can occur if a load is
shed when an Out line becomes active.
3.3.2 HEARTBEAT™ OUTPUT
Both OUT lines have a full-time HeartBeat™ ‘health’
indicator superimposed on them. These operate by taking
both OUT pins into a 3-state mode for 350µs once before
every QT measurement burst. This state can be used to
determine that the sensor is operating properly, or, it can be
ignored using one of several simple methods.
If active-low polarity is selected, the HeartBeat indicator can
be sampled by using a pulldown resistor on one or both OUT
lines, and feeding the resulting negative-going pulse(s) into a
counter, flip flop, one-shot, or other circuit (Figure 3-2). In
this configuration, the pulldown resistor will create
negative-going HeartBeat pulses when the sensor is not
detecting fluid; when detecting fluid, the OUT line will remain
low for the duration of the detection, and no pulse will be
evident. Conversely, a pull-up resistor will show HeartBeat
pulses when the line is low (detecting).
If active-high OUT polarity is selected, the pulses will only
appear if there is a pull-up resistor in place and the fluid is
not present (no detection, low output), or, if there is a
pull-down resistor and the output is active (high output).
If the sensor is wired to a microprocessor as shown in Figure
3-3, the microprocessor can reconfigure the load resistor to
either ground or Vcc depending on the output state of the
QT114, so that the pulses are evident in either state with
either POL setting.
Figure 3-1 Burst Waveform at 2M Pickoff Resistor
-7-

7페이지


구       성 총 12 페이지수
다운로드[ QT114.PDF 데이터시트 ]

당사 플랫폼은 키워드, 제품 이름 또는 부품 번호를 사용하여 검색할 수 있는

포괄적인 데이터시트를 제공합니다.


구매 문의
일반 IC 문의 : 샘플 및 소량 구매
-----------------------------------------------------------------------

IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한
광범위한 전력 반도체를 판매합니다.

전력 반도체 전문업체

상호 : 아이지 인터내셔날

사이트 방문 :     [ 홈페이지 ]     [ 블로그 1 ]     [ 블로그 2 ]



관련 데이터시트

부품번호상세설명 및 기능제조사
QT110

SENSOR ICs

QUANTUM
QUANTUM
QT1100A-ISG

10 KEY QTOUCH SENSOR IC

QUANTUM
QUANTUM

DataSheet.kr       |      2020   |     연락처      |     링크모음      |      검색     |      사이트맵