mxb7846 Maxim Integrated Products, Inc., mxb7846 Datasheet
mxb7846
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mxb7846 Summary of contents
Page 1
... The MXB7846 has one auxiliary ADC input. All analog inputs are fully ESD protected, eliminating the need for external TransZorb™ devices. The MXB7846 is guaranteed to operate with a supply voltage down to +2.375V when used with an external reference or +2.7V with an internal reference. In shut- down mode, the typical power consumption is reduced to under 0.5µ ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor ABSOLUTE MAXIMUM RATINGS , VBAT, DIN, CS, DCLK to GND ........................-0. Digital Outputs to GND...............................-0. X+, X-, Y+, Y-, AUX ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor ELECTRICAL CHARACTERISTICS (continued 2.7V to 3.6V 2.5V REF DCLK unless otherwise noted. Typical values are at T MIN ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor TIMING CHARACTERISTICS (Figure 2.7V to 3.6V 2.5V REF DCLK unless otherwise noted. Typical values are at T ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) INTEGRAL NONLINEARITY vs. DIGITAL OUTPUT CODE 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2 ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) INTERNAL REFERENCE VOLTAGE vs. TEMPERATURE 2.6 2.5 2.4 2.3 2.2 2 2.7V ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 250 f = 12.5kHz SAMPLE 225 200 175 150 ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor PIN NAME 1 V Positive Supply Voltage. Connect to pin 10 Position Input, ADC Input Channel Position Input, ADC Input ...
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... Diagram). Figure 2 shows a block diagram of the analog input sec- tion that includes the input multiplexer of the MXB7846, the differential signal inputs of the ADC, and the differ- ential reference inputs of the ADC. The input multiplexer switches between X+, X-, Y+, Y-, AUX, BAT, and the internal temperature sensor ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor BAT AUX REF Table 1. Input Configuration, Single-Ended Reference Mode (SER/DFR HIGH MEASUREMENT position ...
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... The PENIRQ output can be used to initiate an interrupt to the microprocessor, which can write a control word to the MXB7846 to start a conversion. Figure 6 shows the timing diagram for the PENIRQ pin function. The diagram shows that once the screen is ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor +IN X+ -IN Y- GND Figure 3. Single-Ended Y-Coordinate Measurement TOUCH SCREEN Figure 5. PENIRQ Functional Block Diagram 12 ______________________________________________________________________________________ REF REF+ 12-BIT ADC REF- ...
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... X-position, Y-position, and Z1-position. Use the following equation to calculate R R TOUCH + V - The MXB7846 provides two temperature measurement options: single-ended conversion and differential con- version. Both temperature measurement techniques rely + on the semiconductor junction’s temperature character- V istics. The forward diode voltage ( well-defined characteristic ...
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... The internal reference of the MXB7846 must also be disabled to maintain compatibility with the MXB7843. To disable the internal reference of the MXB7846 after power-up, a control byte with PD1 = 0 is required. (See Typical Operating Characteristics for power-up time of the reference from power down.) Although the internal reference may be overdriven with +2 ...
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... Start a conversion by clocking a control byte into DIN (Table 3) with CS low. Each rising edge on DCLK clocks a bit from DIN into the MXB7846’s internal shift register. After CS falls, the first arriving logic 1 bit defines the control byte’s START bit. Until the START bit arrives, any number of logic 0 bits can be clocked into DIN with no effect ...
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... OFF (SER/DFR LOW) Figure 9. Conversion Timing, 24-Clock per Conversion, 8-Bit Bus Interface The fastest the MXB7846 can run with CS held continu- ously low is 15 clock conversions. Figure 10 shows the serial-interface timing necessary to perform a conver- sion every 15 DCLK cycles connected low and DCLK is continuous, guarantee a start bit by first clock- ing in 16 zeros ...
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... Touch-Screen Controller with Internal Reference and Temperature Sensor The MXB7846 output data is in straight binary format as shown in Figure 12. This figure shows the ideal output code for the given input voltage and does not include the effects of offset, gain, or noise. ...
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... ADC are always on. The device remains fully powered after the current conver- sion completes. In this mode, the MXB7846 powers down after the cur- Power Modes rent conversion completes or on the next rising edge of CS, whichever occurs first. The next control byte received on DIN powers up the MXB7846 ...
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... This method solves the settling time problem for both single-ended and differential modes. The second option is to operate the MXB7846 in the dif- ferential mode only for the touch screen, and perform additional conversions with the same address until the input signal settles ...
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... The TMS320 reads in 1 data bit on each of the next 16 rising edges of DCLK. These bits represent the 12-bit conversion result followed by 4 trailing bits. 6) Pull CS high to disable the MXB7846 until the next conversion is initiated. Layout, Grounding, and Bypassing For best performance, use printed circuit (PC) boards with good layouts ...
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... Aperture Jitter TRANSISTOR COUNT: 12,000 PROCESS: 0.6µm BiCMOS 0.1µ DCLK DIN 4 MXB7846 X- BUSY 5 Y- DOUT 6 GND PENIRQ 7 BAT + AUX REF Aperture Delay ) is the time defined between the ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) 22 ______________________________________________________________________________________ Package Information PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH ...
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Touch-Screen Controller with Internal Reference and Temperature Sensor (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) Maxim cannot assume responsibility for ...