MOTOROLA Freescale Semiconductor, Inc. SEMICONDUCTOR APPLICATION NOTE ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Order this document by AN1653/D AN1653 ASB205 Ċ MPX5000 Series Sensor Module Prepared by: Bill Lucas and Warren Schultz ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... A plug–in module that is part of a systems development tool set for pressure sensors is presented here. It provides an analog signal from an MPX5000 series sensor to a Motorola Sensor Development Controller, or can be used stand alone to provide power and signal connections to the sensor. PLUG–IN MODULE DESCRIPTION A summary of information for using systems development plug–in module ASB205 includes the schematic in Figure 2, connector pinout in Figure 3, a pin by pin description of functionality, specs in Tables 1–3, and a parts list in Table 4. Figure 4 in the Applications section provides a quick reference for making connections. A discussion of the design appears under the heading Design Considerations. Function The plug–in module shown in Figure 1 is designed to supply pressure and temperature inputs to a sensor development controller. The sensor output is filtered and buffered with a unity gain rail to rail amplifier. If desired, jumpers on the board allow direct connection of the sensor output to the controller. Connections are made through a DB–9 connector, which allows this board to be plugged directly into its controller. If physical separation is desired, a standard 9 wire straight–through serial cable can be inserted between the two boards. Alternately, connections for 5 volts, ground, and the output signal can be made through screw terminals at the top of the board. A socket for sensor connections makes changing from one pressure range to another relatively easy. Figure 1. ASB205 — MPX5000 Series Sensor Module REV 1 Motorola Sensor Device Data Motorola, Inc. 1998 For More Information On This Product, Go to: www.freescale.com 1 Freescale Semiconductor, Inc. AN1653 ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 J4 JT1 TP3 NC 3 JT2 2 +5 JT3 R5 300 VS1 JT4 2 JT5 1 CNTL R3 300 C1 C2 0.33 mF 0.01 mF D2 +5 RANGE R1 3 GND ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... R6 47 k 1 JT6 P1 1 – MC33202 2 D1 KGND RT1 10 k U2A + 1 B+ TP2 5 9 4 8 3 7 2 6 1 U1 MPX5010 VS2 R4 10 k 1% 750 OUT GND 2 5 C3 6 0.33 mF GND 7 TP1 – VS1 MC33202 J3 J1 U2B + RG R2 OPEN 750 DB9 J2 Figure 2. Schematic Electrical Characteristics The electrical characteristics in Tables 1, 2, & 3, apply to operation at 25 degrees Celsius, and unless otherwise specified a +5 volt input of 5.00 volts. The values in Tables 2 and 3 are nominal values. Table 1. Electrical Characteristics Characteristic Symbol Min Typ Max Units +5 4.75 5.0 5.25 Volts Pressure Sensor Output Voltage — Zero Pressure — Full Scale VS1 — — — — 200 4.7 — — mV Volts Temp Sensor Output Voltage VS2 — 2.5 — Volts Quiescent Current ICC — 25 — mA DC Supply Voltage 2 For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. AN1653 ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Table 2. Output Characteristics (VS1) Full Scale Pressure (kPa) Sensitivity (mV/kPa) Zero Pressure Offset (Volts) Full Scale Output Voltage (Volts) Full Scale Span (Volts) MPX5006* 6 750 .2 4.7 4.5 MPX5010* 10 450 .2 4.7 4.5 MPX5050 50 90 .2 4.7 4.5 MPX5100* 100 45 .2 4.7 4.5 MPX5700* 700 6.43 .2 4.7 4.5 MPX5999 1000 4.5 .2 4.7 4.5 Sensor *Included with ASB205 kit ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... Table 3. VS2 Versus Temperature Temperature °C RT Ohms VS2 Volts Temperature °C RT Ohms VS2 Volts 0 32773 1.17 40 5323 3.26 5 25456 1.41 45 4365 3.48 10 19932 1.67 50 3599 3.68 15 15725 1.94 55 2983 3.85 20 12497 2.22 60 2486 4.00 25 10000 2.50 65 2082 4.14 30 8055 2.77 70 1753 4.25 35 6528 3.03 75 1482 4.35 Content Board contents are described by the following parts list and the schematic in Figure 2. A pin by pin circuit description follows in the next section. power, ground, and sensor output connections can be made through screw terminals at the top of the board. The screw terminals and the DB–9 are wired in parallel. DB–9 connector pinouts are shown in Figure 3. Table 4. Parts List Item Quantity Reference Part 1 2 C1,C3 .33 µF Ceramic 2 1 C2 .01 µF Ceramic 3 2 D1 LED (RED) 4 1 D2 LED (RED) 5 4 TP1,TP2,TP3,GND Test Point 6 6 JT1–JT6 Screw Terminal 7 2 J1,J2 Jumper–Wire 8 1 P1 DB9 Connector 9 2 RT1 10K Thermistor 10 1 R4 10K 1% 11 2 R2,R1 750 12 2 R5,R3 300 13 1 R6 47K 14 1 U1 MPX5010 15 1 U2 MC33202 Pin by Pin Description Inputs and outputs are grouped into two connectors. A DB–9 connector provides a plug–in feature. If this connector is used, no other connections are necessary. Alternately, Motorola Sensor Device Data 5 9 4 8 3 7 2 6 1 +5 OPEN VS2 GND VS1 OPEN KGND CNTL GND Figure 3. DB–9 Pinout DB–9 Connector +5: 5 volt power is supplied through pin 5 on the DB–9 connector. GND: The ground connection is on pin one. It connects the sensor’s analog ground to the controller’s digital ground. KGND: An additional ground connection, labeled KGND, is made on pin 2. As shipped, KGND is tied to GND via jumper J1. If J1 is opened, KGND provides a separate return for the temperature sensor. This feature can be helpful if a cable is used between the sensor module and its controller. For More Information On This Product, Go to: www.freescale.com 3 Freescale Semiconductor, Inc. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 VS1: The pressure sensor output signal, VS1, is on pin 3. This is the sensor’s output, filtered and then buffered with a unity gain amplifier. If direct connection to the sensor’s output is preferred, it will appear on this pin when Jumper J2 is open, and a wire is soldered into Jumper J3. Test Points TP1–TP3, & GND Test points TP1, TP2, & TP3 provide access to output signals. TP1 is connected to the filtered and buffered pressure sensor output signal. TP2 is connected to the thermistor output signal, and TP3 is connected to sensor’s output. A test point for ground is also provided. VS2: A temperature dependent output signal is supplied on pin 4. It is supplied from a thermistor that has a nominal output voltage of 2.5 volts at 25 degrees C. This thermistor sees a temperature rise due to power dissipation on the board, and typically reads several degrees higher than ambient in still air. Indicator Lights +5: The +5 light is provided to indicate the presence of 5 volt power. CNTL: A control signal is supplied on pin 6. It is normally high, and switches low to light the RANGE light when the sensor’s full scale pressure is exceeded. With code modifications, the pressure at which this transition occurs can be changed, and the signal used to control an external device. Board Code: A board code that lets the controller know that this is an MPX5000 series module is supplied with a ground on pin 8 and an open on pin 7. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... AN1653 Pin 9: There is no connection made to Pin 9 on this board. However, power supply voltage B+ will be present on this pin when plugged into a Motorola Sensor Development Controller. Screw Terminals Connections for +5, VS1, CNTL, KGND, & GND are wired in parallel with the DB–9 connector. As shipped, KGND and GND are tied together with Jumper J1. A no connect terminal labeled, NC, is tied to Jumper J4 which is open. If a wire is placed in J4, this terminal is then connected to the sensor output. GND B+ RANGE: The RANGE indicator light turns on when the sensor’s full scale pressure range is exceeded. APPLICATION EXAMPLE An application example shown in Figure 4 illustrates system connections to an ASB200 control board and a pressure source. This arrangement can be run stand alone, or the ASB200 can be connected to an MMDS or MMEVS system for code development. The two boards are designed such that the DB–9 connectors plug into each other. Once they are plugged in it is only a matter of connecting a power supply and a pressure source to get a system up and running. If physical separation between the sensor location and the controller is desired, a standard 9 wire straight–through serial cable can be used between the two boards. Measuring different pressure ranges is facilitated by using a socket for the sensor that is supplied on the board. Pads for an MPX5006 are also provided. To use the MPX5006, it is necessary to have the 6 pin socket empty, snap in the MPX5006, and then solder its leads to the pads that are provided. The correct orientation is with its marking facing the front of the board. 7.5–26 VDC LCD MOTOROLA ASB200 NC +5 VS1 CNTL KGND GND MOTOROLA ASB205 PRESSURE (TOP PORT) OR VACUUM* (BOTTOM PORT) *VACUUM PORT IS NOT AVAILABLE ON MPX5006 +5 VS2 VS1 KGND GND SENSOR DEVELOPMENT CONTROLLER 4 Figure 4. Application Example For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 DESIGN CONSIDERATIONS capacitance, in the event that a cable is used between the plug–in module and controller. For applications where the sensor and micro–controller are on the same board, an MC33502 is a better choice, due to its lower offset voltage. CONCLUSION The ASB205 plug–in module is part of a systems development tool set for pressure sensors. It provides pressure and temperature input signals to a Motorola Sensor Development Controller, or can be used stand alone to provide power and signal connections to MPX5000 series sensors. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... MPX5000 sensors are plug and play devices in most applications, particularly when connected to a micro–controller with an 8 bit A/D converter. Although micro’s with 8–bit A/D’s are most common, higher resolution A/D’s, such as the one on the 68HC705JP7 in this tool set, are becoming increasingly popular. With these higher resolution A/D’s, the noise that is inherent to piezo–resistive bridges becomes a design consideration. For that reason, the sensor’s output is filtered with a single pole filter, and then buffered with a unity gain buffer. An MC33202 rail to rail operational amplifier was chosen for its ability to drive cable AN1653 Motorola Sensor Device Data For More Information On This Product, Go to: www.freescale.com 5 AN1653 Freescale Semiconductor, Inc. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... NOTES 6 For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 AN1653 ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... NOTES Motorola Sensor Device Data For More Information On This Product, Go to: www.freescale.com 7 Freescale Semiconductor, Inc. ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005 Freescale Semiconductor, Inc... AN1653 Motorola reserves the right to make changes without further notice to any products herein. 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