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參數(shù)資料
| 型號： | MC33794DWBR2 |
| 廠商： | Freescale Semiconductor |
| 文件頁數(shù)： | 4/18頁 |
| 文件大小： | 0K |
| 描述： | IC SENSOR ELECTRIC FIELD 54-SOIC |
| 標準包裝： | 1,000 |
| 類型： | 傳感器接口 |
| 輸入類型： | 邏輯 |
| 輸出類型： | 邏輯 |
| 接口： | ISO9141 |
| 電流 - 電源： | 7mA |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 54-BSSOP（0.295"，7.50mm 寬）裸露焊盤 |
| 供應商設備封裝： | 54-SOIC W EP |
| 包裝： | 帶卷 (TR) |
Sensors
12
Freescale Semiconductor
MC33794
RECT
The rectifier circuit detects the level from MUX IN by
offsetting the midpoint of the sine wave to zero volts and
inverting the waveform when it is below the midpoint. It is
important to avoid DC loading of the signal, which would
cause a shift in the midpoint voltage of the signal.
LPF
The rectified sine wave is filtered by a low pass function
formed by an internal resistance and an external capacitance
attached to LP_CAP. The nominal value of the internal
resistance is 50 k. The value of the external capacitor is
selected to provide filtering of noise while still allowing the
desired settling time for the detector output. A 10 nF
capacitor would allow 99% settling in less than 5.0 ms. In
practice, it is recommended you wait at least 1.5 ms after
selecting an electrode before reading LEVEL.
GAIN AND OFFSET
This circuit multiplies the detected and filtered signal by a
gain and offsets the result by a DC level. This results in an
output range that covers 1.0 V to 4.0 V for capacitive loading
of the field in the range of 10 pF to 100 pF. This allows higher
sensitivity for a digital-to-analog converter with a 0 V-to-5.0 V
input range.
ATTN
This circuit passes the undetected signal to SIGNAL for
external use.
SHIELD_EN
A logic low on this input disables the shield drive. The
purpose of doing this is to be able to detect that the shield
signal is not working or the connection to the coax shields is
broken. If either of these conditions exists, there will be little
or no change in the capacitance measured when the
SHIELD_EN is changed. If the SHIELD output is working and
properly connected, the capacitance of the coax will not be
cancelled when this terminal is asserted and the measured
capacitance will appear to change by approximately the
capacitance between the center conductor and the shield in
the coax.
LAMP CKT
This section controls the operation of the LAMP_OUT
terminal. When LAMP_CTRL is asserted, LAMP_OUT is
pulled to LAMP_GND. If one side of an indicator lamp or LED
(with appropriate current setting resistor) is connected to a
positive voltage source and the other is connected to
LAMP_OUT, and LAMP_GND is connected to ground, the
lamp will light. This circuit provides current limiting to prevent
damage to itself in the case of a shorted lamp or during a
high-surge condition typical of an incandescent lamp
burnout.
LAMP_GND should always be connected to ground even
if the lamp circuit is not used.
ISO-9141
This circuit connects to an ISO-9141 bus to allow remote
communications. ISO_IN is data from the bus to the MCU
and ISO_OUT is data to drive onto the bus from the MCU.
POR/WD
This circuit is a combined Power-ON Reset and watchdog
timer. The RST output is held low until a certain amount of
time after the VCC REG output (VCC) has remained above a
minimum operating threshold. If VCC falls below the level at
any time, RST is pulled low again and held until the required
time after VCC has returned high. An over voltage circuit is
also included, which will force a reset if VCC rises above a
maximum voltage. The watchdog function also can force RST
low if too long an interval is allowed to pass between positive
transitions on WD_IN.
INTERNAL VCC REGULATOR
This circuit converts an unregulated voltage from VIN to a
regulated 5.0 V source, which is used internally and available
for other components requiring a regulated voltage source.
INTERNAL VDD REGULATOR
This is a regulator for analog devices that require more
than 5.0 V. This is used by the device and some current is
available to operate op-amps and other devices. By having
this higher voltage available, some applications can avoid the
need for a rail-to-rail output amplifier and still achieve the 0 V-
to-5.0 V output for a digital-to-analog converter input.
VDD_MON is a divided output from internal VDD REG, which
allows a 0.0 V-to-5.0 V ADC to measure VDD. Normal value
for VDD is 8.5 Volts.
CONTROL LOGIC
This contains the logic that decodes and controls the
MUXes and some of the test modes
APPLICATION INFORMATION
The MC33794 is intended to be used where an object’s
size and proximity are to be determined. This is done by
placing electrodes in the area where the object will be. The
proximity of an object to an electrode can be determined by
the increase in effective capacitance as the object gets closer
to the electrode and modifies the electric field between the
electrode and surrounding electrically common objects. The
shape and size of an object can be determined by using
multiple electrodes over an area and observing the
capacitance change on each of the electrodes. Those that
don’t change have nothing near them, and those that do
change have part of the object near them.
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相關代理商/技術參數(shù) |
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|---|---|
| MC33794EK | 功能描述:近程傳感器 ODS 54LD RoHS:否 制造商:Vishay Semiconductors 感應方式:Optical 感應距離:1 mm to 200 mm 電源電壓:2.5 V to 3.6 V 安裝風格:SMD/SMT 輸出配置:Digital 最大工作溫度:+ 85 C 最小工作溫度:- 25 C 系列:VCNL3020 |
| MC33794EKR2 | 功能描述:近程傳感器 ODS 54LD RoHS:否 制造商:Vishay Semiconductors 感應方式:Optical 感應距離:1 mm to 200 mm 電源電壓:2.5 V to 3.6 V 安裝風格:SMD/SMT 輸出配置:Digital 最大工作溫度:+ 85 C 最小工作溫度:- 25 C 系列:VCNL3020 |
| MC33797BPEW | 功能描述:功率驅動器IC Four Channel Squib Dr RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| MC33797BPEWR2 | 功能描述:功率驅動器IC Four Channel Squib Dr RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| MC33813AE | 功能描述:功率驅動器IC 1 CYL SM ENG CONTROL IC RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
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