MC33794芯片静电感应应用（可编辑）

MC33794芯片静电感应应用（可编辑） MC33794芯片静电感应应用 Freescale Semiconductor Document Number MC33794 Technical Data Rev 9 112006 Electric Field Imaging Device The MC33794 is intended for applications where noncontact sensing of MC33794 objects is desired When connected to external electrodes an electric field is createdThe MC33794 is intended for use in detecting objects in this electric field The IC generates a low-frequency sine wave The frequency is adjustable by using an external resistor and is optimized for 120 kHz The sine wave has very low harmonic content to reduce harmonic interference The MC33794 also contains support circuits for a microcontroller unit MCU ELECTRIC FIELD to allow the construction of a two-chip E-field system IMAGING DEVICE Features Supports up to 9 Electrodes and 2 References or Electrodes Shield Driver for Driving Remote Electrodes Through Coaxial Cables 50 V Regulator to Power External Circuit ISO-9141 Physical Layer Interface Lamp Driver Output Watchdog and Power-ON Reset Timer Critical Internal Nodes Scaled and Selectable for Measurement EK SUFFIX High-Purity Sine Wave Generator Tunable with External Resistor 54-LEAD SOICW-EP CASE 1390-02 Typical Applications Occupant Detection Systems Appliance Control Panels and Touch Sensors Linear and Rotational Sliders Spill Over Flow Sensing Measurement Refrigeration Frost Sensing Industrial Control and Safety Systems Security Proximity Detection for Wake-Up Features Touch Screens Garage Door Safety Sensing Liquid Level Sensing ORDERING INFORMATION Package Device Name Temperature Range TA Package Drawing MC33794EKR2 -40C to 85C 1390-02 54 SOICW-EP Freescale Semiconductor Inc 2006 All rights reserved INTERNAL BLOCK DIAGRAM 4 ABCD CONTROL LOGIC TEST 22 k Nominal 28 k CLK OSC R_OSC 7 0 0 E1E9 MUX 39 k REF_A REF_B OUT SHIELD_EN 28 k 150 SHIELD 7 0 0 300 REF_A and REF_B are not switched to ground when not selected MUX RECT IN LP_CAP LPF VDD VCC 10 nF GAIN AND RST OFFSET WD_IN POR WD LEVEL VCC VPWR REG ATTN SIGNAL VDD LAMP_SENSE AGND REG GND and HEAT SINK LAMP_MON PWR_MON VDD MON _ LAMP_GND LAMP CKT LAMP_OUT LAMP_CTRL ISO_OUT ISO-9141 ISO-9141 ISO_IN Note All Resistor Values are Nominal Figure 1 Simplified Functional Block Diagram MC33794 Sensors 2 Freescale Semiconductor SOICW-EP TERMINAL CONNECTIONS RST 1 54 LAMP_CTRL WD_IN 2 53 ISO-9414 NC 3 52 NC LAMP_GND 4 51 ISO_IN NC 5 50 NC LAMP_OUT 6 49 NC NC 7 48 NC LAMP_SENSE 8 47 ISO_OUT LAMP_MON 9 46 REF_B SHIELD_EN 10 45 REF_A D 11 44 E9 C 12 43 E8 B 13 42 E7 A 14 41 E6 SIGNAL 15 40 E5 LEVEL 16 39 E4 PWR_MON 17 38 E3 LP_CAP 18 37 E2 R_OSC 19 36 E1 NC 20 35 TEST NC 21 34 NC NC 22 33 NC NC 23 32 GND CLK 24 31 NC VDD MON 25 30 SHIELD _ VDD 26 29 AGND VPWR 27 28 VCC Figure 2 SOICW-EP Terminal Connections Table 1 SOICW-EP TERMINAL FUNCTION DESCRIPTION Terminal Terminal Formal Name Definition Name 1 RST Reset This output is intended to generate the reset function of a typical MCU It has a delay for Power-ON Reset level detectors to force a reset when VCC REG is out-of-range high or low and a watchdog timer that will force a reset if WD_IN is not asserted at regular intervals Timing is derived from the oscillator and will change with changes in the resistor attached to R_OSC 2 WD_IN Watchdog In This terminal must be asserted and deserted at regular interval in order to prevent RST from being asserted By having the MCU program perform this operation more often the allowed time a check that the MCU is running and executing its program is assured If this doesnít occur the MCU will be reset If the watchdog function is not desired this terminal may be connected to CLK to prevent a reset from being issued 3 5 7 NC No connect These terminals may be used at some future date and should be left open 2023 31 33 34 4850 52 4 LAMP_GND Lamp Ground This is the ground for the current from the lamp The current into LAMP_OUT flows out through this terminal 6 LAMP_OUT Lamp Driver This is an active low output capable of sinking current of a typical indicator lamp One end of the lamp should be connected to a positive supply for example battery voltage and the other side to this terminal The current is limited to prevent damage to the IC in the case of a short or surge during lamp turn-on or burn-out MC33794 Sensors Freescale Semiconductor 3 Table 1 SOICW-EP TERMINAL FUNCTION DESCRIPTION continued Terminal Terminal Formal Name Definition Name 8 LAMP_SENSE Lamp Sense This terminal is normally connected to the LAMP_OUT terminal The voltage at this terminal is reduced and sent to LAMP_MON so the voltage at the lamp terminal is brought into the range of the analog-to-digital converter ADC in the MCU 9 LAMP_MON Lamp Monitor This terminal is connected through a voltage divider to the LAMP_SENSE terminal The voltage divider scales the voltage at this terminal so that battery voltage present when the lamp is off is scaled to the range of the MCU ADC With the lamp off this terminal will be very close to battery voltage if the lamp is not burned out and the terminal is not shorted to ground This is useful as a lamp check 10 SHIELD_EN Shield Driver This terminal is used to enable the shield signal The shield is disabled when SHIELD_EN is a logic low ground 1114 A B C D Selector Inputs These input terminals control which electrode or reference is active Selection values are shown in Table 5 Electrode Selection page 10 These are logic level inputs 15 SIGNAL Undetected Signal This is the undetected signal being applied to the detector It has a DC level with the low radio frequency signal superimposed on it Care must be taken to minimize DC loading of this signal A shift of DC will change the center point of the signal and adversely affect the detection of the signal 16 LEVEL Detected Level This is the detected amplified and offset representation of the signal voltage on the selected electrode Filtering of the rectified signal is performed by a capacitor attached to LP_CAP 17 PWR_MON Power Monitor This is connected through a voltage divider to VPWR It allows reduction of the voltage so it will fall within the range of the ADC on the MCU 18 LP_CAP Low-Pass Filter Capacitor A capacitor on this terminal forms a low pass filter with the internal series resistance from the detector to this terminal This terminal can be used to determine the detected level before amplification or offset is applied A 10 nF capacitor connected to this terminal will smooth the rectified signal More capacitance will increase the response time 19 R_OSC Oscillator Resistor A resistor from this terminal to circuit ground determines the operating frequency of the oscillator The MC33794 is optimized for operation around 120 kHz 24 CLK Clock This terminal provides a square wave output at the same frequency as the internal oscillator The edges of the square wave coincide with the peaks positive and negative of the sine wave 25 VDD MON VDD Monitor This is connected through an internal voltage divider to VDD REG It allows _ reduction of the voltage so it will fall within the range of the ADC on the MCU 26 VDD VDD Capacitor A capacitor is connected to this terminal to filter the internal analog regulated supply This supply is derived from VPWR through internal VDD REG 27 VPWR Positive Power Supply 12 V power applied to this terminal will be converted to the regulated voltages needed to operate the part It is also converted to 50 V internal VCC REG and 85 V internal VDD REG to power the MCU and external devices 28 VCC 50 V Regulator Output This output terminal requires a 47 μF capacitor and internal VCC REG provides a regulated 50 V for the MCU and for internal needs of the MC33794 29 AGND Analog Ground This terminal is connected to the ground return of the analog circuitry This ground should be kept free of transient electrical noise like that from logic switching Its path to the electrical current return point should be kept separate from the return for GND 30 SHIELD Shield Driver This terminal connects to cable shields to cancel cable capacitance MC33794 Sensors 4 Freescale Semiconductor Table 1 SOICW-EP TERMINAL FUNCTION DESCRIPTION continued Terminal Terminal Formal Name Definition Name 32 GND Ground This terminal and metal backing is the IC power return and thermal radiator conductor 35 TEST Test Mode Control This terminal is normally connected to circuit ground There are special operating modes associated with this terminal when it is not at ground 3644 E1E9 Electrode Connections These are the electrode terminals They are connected either directly or through coaxial cables to the electrodes for measurements When not selected these outputs are grounded through the internal resistance 45 46 REF_A Reference Connections These terminals can be individually selected to measure a known capacitance REF_B Or as additional electrodes value Unlike E1-E9 these two inputs are not grounded when not selected E10 E11 47 ISO_OUT ISO-9141 Output This terminal translates ISO-9141 receive levels to 50 V logic levels for the MCU 51 ISO_IN ISO-9141 Input This terminal accepts data from the MCU to be sent over the ISO-9141 communications interface It translates the 50 V logic levels from the MCU to transmit levels on the ISO-9141 bus 53 ISO-9141 ISO-9141 Bus This terminal connects to the ISO-9141 bus It provides the drive and detects signaling on the bus and translates it from the bus level to logic levels for the MCU 54 LAMP_CTRL Lamp Control This signal is used to control the lamp driver A high logic level turns on the lamp MC33794 Sensors Freescale Semiconductor 5 IMUM RATINGS Table 2 imum Ratings All voltages are with respect to ground unless otherwise noted Exceeding these ratings may cause a malfunction or permanent damage to the device Rating Symbol Value Unit Peak VPWR Voltage VPWRPK 40 V Double Battery VDBLBAT V 1 Minute imum TA 30?C 265 ESD Voltage V Human Body Model 1 VESD1 ?2000 Machine Model 2 VESD2 ?200 Storage Temperature TSTG -55 to 150 ?C Operating Ambient Temperature TA -40 to 85 ?C Operating Junction Temperature TJ -40 to 150 ?C Thermal Resistance ?CW Junction-to-Ambient 3 RθJA 41 Junction-to-Case 4 RθJC 02 Junction-to-Board 5 RθJB 30 Lead Soldering Temperature for 10 Seconds TSOLDER 260 ?C Notes 1 ESD1 performed in accordance with the Human Body Model CZAP 100 pF RZAP 1500 2 ESD2 performed in accordance with the Machine Model CZAP 200 pF RZAP 0 3 Junction temperature is a function of on-chip power dissipation package thermal resistance mounting site board temperature ambient temperature air flow power dissipation of other components on the board and board thermal resistance In accordance with SEMI G38-87 and JEDEC JESD51-2 with the single layer board horizontal 4 Indicates the average thermal resistance between the die and the case top surface as measured by the cold plate method MILSPEC 883 Method 10121 with the cold plate temperature used for the case temperature 5 Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8 Board temperature is measured on the top surface of the board near the package MC33794 Sensors 6 Freescale Semiconductor STATIC ELECTRICAL CHARACTERISTICS Table 3 Static Electrical Characteristics Characteristics noted under conditions 90 V ? VPWR ? 18 V -40? C ? TA ? 85?C unless otherwise noted Typical values noted reflect the approximate parameter means at TA 25C under normal conditions unless otherwise noted Voltages are relative to GND unless otherwise noted Characteristic Symbol Min Typ Unit Voltage Regulators 50 V Regulator Voltage VCC V 70 V ? VPWR ? 18 V 10 mA ? IL ? 75 mA CFILT 47 μF 475 50 525 Analog Regulator Voltage VANALOG V 90 V ? VPWR ? 18 V CFILT 47 μF 8075 85 8925 Out-of-Range Voltage Detector Terminal name VCC 50 V Low Voltage Detector VLV5 40 452 472 V 50 V High Voltage Detector VHV5 526 555 583 V 50 V Out-of-Range Voltage Detector Hysteresis VHYS5 005 V ISO-9141 Communications Interface Input Low Level 6 VIFINLO 030 033 VV Input High Level 6 VIFINHI 053 07 VV Input Hysteresis 6 VIFINHYS 02 VV Output Low 6 VIFOLO 02 VV Output High 6 VIFOHI 08 VV Output Breakdown VIFZ V IOUT 20 mA 40 Output Resistance RIFON IOUT 40 mA 58 Current Limit IIFLIM mA Sinking Current with VOUT 03 VPWR IN 60 90 120 Output Propagation Delay TIFDLY μs Out to ISO-9141 CLOAD 20 pF 80 ISO In Logic Output Low VIFOLO V ISINK 10 mA 10 Logic Output Pull-Up Current IIFPU μA VOUT 0 V 100 Input to Output Propagation Delay TIFDLY μs ISO-9141 to ISO_IN R 10 k C 470 pF 70 V ? VPWR ? 54 L L 18 V Notes 6 Ratio to VPWR MC33794 Sensors Freescale Semiconductor 7 Table 3 Static Electrical Characteristics continued Characteristics noted under conditions 90 V ? VPWR ? 18 V -40?C ? TA ? 85?C unless otherwise noted Typical values noted reflect the approximate parameter means at TA 25C under normal conditions unless otherwise noted Voltages are relative to GND unless otherwise noted Characteristic Symbol Min Typ Unit Electrode Signals Total Variance Between Electrode Measurements 7 ELVVAR All CLOAD 15 pF 30 Electrode imum Harmonic Level Below Fundamental 8 ELHARM dB 50 pF ? CLOAD ? 100 pF -20 Electrode Transmit Output Range ELTXV V 50 pF ? CLOAD ? 100 pF 10 80 Receive Input Voltage Range RXV 0 90 V Grounding Switch on Voltage SWVON V ISW 10 mA 50 Shield Driver Shield Driver Output Level SDTXV V 0 pF ? CLOAD ? 500 pF 10 80 Shield Driver Input Range SDIN 0 90 V Grounding Switch on Voltage 9 SWVON 15 V Logic IO CMOS Logic Input Low Threshold VTHL 03 VCC Logic Input High Threshold VTHH 07 VCC Voltage Hysteresis VHYS 006 VCC Input Current IIN μA VIN VCC 10 50 VIN 0 V -50 50 Signal Detector Detector Output Resistance DETRO 50 k LP_CAP to LEVEL Gain AREC 36 40 44 AV LP_CAP to LEVEL Offset VRECOFF -33 -30 -27 V Notes 7 Verified by design Not tested in production 8 Verified by design and characterization Not tested in production 9 Current into grounded terminal under test 10 mA MC33794 Sensors 8 Freescale Semiconductor Table 3 Static Electrical Characteristics continued Characteristics noted under conditions 90 V ? VPWR ? 18 V -40?C ? TA ? 85?C unless otherwise noted Typical values noted reflect the approximate parameter means at TA 25C under normal conditions unless otherwise noted Voltages are relative to GND unless otherwise noted Characteristic Symbol Min Typ Unit Lamp Driver On Resistance RLDDSON IIN 400 mA 175 35 Current Limit ILDLIM A VOUT 10 V 07 17 On-Voltage VLDON V IOUT 400 mA 14 Breakdown Voltage VLDZ V IOUT 100 μA Lamp Off 40 Voltage Monitors LAMP_MON to LAMP_SENSE Ratio LMPMON 01950 020524 02155 VV PWR_MON to VPWR Ratio PWRMON 02200 02444 02688 VV VDD MON to VDD Ratio V 045 05 055 VV _ DD_MON Supply Quiescent supply current 11 Ipwr _ 70 _ mA VPWR 14 V 10 Notes 10 Verified by design and characterization Not tested in production 11 No external devices connected to internal voltage regulators MC33794 Sensors Freescale Semiconductor 9 DYNAMIC ELECTRICAL CHARACTERISTICS Table 4 Dynamic Electrical Characteristics Characteristics noted under conditions 90 V ? VPWR ? 18 V -40?C ? TA ? 85?C unless otherwise noted Typical values noted reflect the approximate parameter means at TA 25C under normal conditions unless otherwise noted Voltages are relative to GND unless otherwise noted Characteristic Symbol Min Typ Unit OSC OSC Frequency Stability 12 13 f STAB 10 OSC Center Frequency f OSC kHz R_OSC 39 k 120 Harmonic Content 12 OSCHARM dB 2nd through 4th Harmonic Level -20 5th and Higher -60 Shield Driver Shield Driver imum Harmonic level below Fundamental 12 SDHARM dB 10 pF ? CLOAD ? 500 pF -20 Shield Driver Gain Bandwidth Product 12 SDGBW MHz Measured at 120 kHz 45 POR POR Time-Out Period t PER 90 50 ms Watchdog Watchdog Time-Out Period tWDPER 50 68 250 ms Watchdog Reset Hold Time tWDHLD 90 50 ms Lamp Driver Short Circuit to Battery Survival Time t SCB 30 ms Notes 12 Verified by design and characterization Not tested in production 13 Does not include errors in external reference parts