AD7873ARQZ Analog Devices Inc, AD7873ARQZ Datasheet
AD7873ARQZ
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AD7873ARQZ Summary of contents
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FEATURES 4-wire touch screen interface On-chip temperature sensor: −40°C to +85°C On-chip 2.5 V reference Direct battery measurement ( Touch pressure measurement Specified throughput rate of 125 kSPS Single supply 2 5.25 ...
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AD7873 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Product Highlights ........................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Timing Specifications .................................................................. 5 Absolute Maximum Ratings............................................................ 6 Thermal Resistance ...................................................................... 6 ...
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SPECIFICATIONS 2.5 V internal or external REF Table 1. Parameter DC ACCURACY Resolution No Missing Codes 2 Integral Nonlinearity 2 Differential Nonlinearity 2 Offset Error 2 Gain Error Noise ...
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AD7873 Parameter LOGIC OUTPUTS Output High Voltage Output Low Voltage PENIRQ Output Low Voltage Floating-State Leakage Current 5 Floating-State Output Capacitance Output Coding CONVERSION RATE Conversion Time Track-and-Hold Acquisition Time Throughput Rate POWER REQUIREMENTS ...
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TIMING SPECIFICATIONS unless otherwise noted MIN MAX 1 Table 2. Timing Specifications Parameter Limit MIN MAX DCLK 2 t 1.5 ACQ ...
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AD7873 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter +V to GND CC Analog Input Voltage to GND Digital Input Voltage to GND Digital Output Voltage to GND V to GND REF Input Current to ...
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PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS PIN 1 INDICATOR AUX AD7873 REF +V 3 TOP VIEW CC (Not to Scale) PENIRQ 4 Figure 3. LFCSP Pin Configuration Table 5. Pin Function Descriptions Pin No. QSOP/ Mnemonic LFCSP TSSOP ...
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AD7873 TERMINOLOGY Integral Nonlinearity Integral nonlinearity is the maximum deviation from a straight line passing through the endpoints of the ADC transfer function. The endpoints of the transfer function are zero scale, a point 1 LSB below the first code ...
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TYPICAL PERFORMANCE CHARACTERISTICS 207 206 205 204 203 202 201 200 199 198 –40 – TEMPERATURE (°C) Figure 5. Supply Current vs. Temperature 230 f 220 SAMPLE V REF 210 200 190 180 170 160 150 2.2 ...
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AD7873 7.5 6.5 5.5 4.5 3.5 2.5 1.5 0 SAMPLE RATE (kHz) Figure 11. Reference Current vs. Sample Rate X– 6 Y– 2.0 2.5 3.0 3.5 ...
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CC Figure 17. Internal V vs. +V REF CC 850 800 TEMP1 95.95mV 750 700 650 600 TEMP0 550 500 450 –40 ...
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AD7873 100mV p-p SINE WAVE – 2.5V EXT REFERENCE REF 125kHz, = 20kHz SAMPLE IN –40 –60 –80 –100 –120 ...
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CIRCUIT INFORMATION The AD7873 is a fast, low power, 12-bit, single-supply analog- to-digital converter (ADC). The AD7873 can be operated from a 2 5.25 V supply. When operated from either supply ...
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AD7873 ANALOG INPUT Figure 26 shows an equivalent circuit of the analog input structure of the AD7873 that contains a block diagram of the input multiplexer, the differential input of the ADC, and the differential reference. Table 6 shows the ...
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Acquisition Time The track-and-hold amplifier enters tracking mode on the falling edge of the fifth DCLK after the start bit is detected (see Figure 35). The time required for the track-and-hold amplifier to acquire an input signal depends on how ...
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AD7873 the AD7873 is approximately 70 Ω. In this mode of operation, therefore, some voltage is likely to be lost across the internal switches, and it is unlikely that the internal switch resistance will track the resistance of the touch ...
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Battery Measurement The AD7873 can monitor a battery voltage from Figure 31 shows a block diagram of a battery voltage monitored through the V pin. The voltage to the +V BAT maintained at the desired ...
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AD7873 PEN INTERRUPT REQUEST The pen interrupt equivalent circuitry is outlined in Figure 33. By connecting a pull-up resistor (10 kΩ to 100 kΩ) between +V and this CMOS logic open-drain output, the PENIRQ output remains high normally. If PENIRQ ...
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CONTROL REGISTER The control word provided to the ADC via the DIN pin is shown in Table 7. This provides the conversion start, channel addressing, ADC conversion resolution, configuration, and power-down of the AD7873. Table 7 provides detailed information on ...
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AD7873 Table 8. Power Management Options PENIRQ PD1 PD0 Description 0 0 Enabled This configuration results in immediate power-down of the on-chip reference as soon as PD1 is set to 0. The ADC powers down only between conversions. When PD0 ...
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SERIAL INTERFACE Figure 36 shows the typical operation of the serial interface of the AD7873. The serial clock provides the conversion clock and also controls the transfer of information to and from the AD7873. One complete conversion can be achieved ...
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AD7873 16 Clocks per Cycle The control bits for the next conversion can be overlapped with the current conversion to allow for a conversion every 16 DCLK cycles, as shown in Figure 38. This timing diagram also allows the possibility ...
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GROUNDING AND LAYOUT For information on grounding and layout considerations for the AD7873, refer to Application Note AN-577, Layout and Grounding Recommendations for Touch Screen Digitizers. PCB DESIGN GUIDELINES FOR CHIP SCALE PACKAGE The lands on the chip scale package ...
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AD7873 OUTLINE DIMENSIONS 0.197 0.193 0.189 16 9 0.158 0.154 0.244 0.150 1 0.236 8 0.228 PIN 1 0.069 0.065 0.053 0.049 0.010 0.025 0.012 0.004 SEATING BSC 0.008 PLANE COPLANARITY 0.004 COMPLIANT TO JEDEC STANDARDS MO-137-AB Figure 40. 16-Lead ...
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... AD7873ARQ-REEL7 –40°C to +85°C 3 AD7873ARQZ –40°C to +85°C 3 AD7873ARQZ-REEL –40°C to +85°C 3 AD7873ARQZ-REEL7 –40°C to +85°C AD7873BRQ –40°C to +85°C AD7873BRQ-REEL –40°C to +85°C AD7873BRQ-REEL7 –40°C to +85°C 3 AD7873BRQZ –40°C to +85°C ...
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AD7873 NOTES Rev Page ...
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NOTES Rev Page AD7873 ...
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AD7873 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C02164-0-9/06(E) T Rev Page ...