AD7731BNZ Analog Devices Inc, AD7731BNZ Datasheet
AD7731BNZ
Specifications of AD7731BNZ
Related parts for AD7731BNZ
AD7731BNZ Summary of contents
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FEATURES 24-Bit Sigma-Delta ADC 16 Bits p-p Resolution at 800 Hz Output Rate Programmable Output Rates up to 6.4 kHz Programmable Gain Front End 0.0015% Nonlinearity Buffered Differential Inputs Programmable Filter Cutoffs FAST Step™* Mode for Channel Sequencing Single ...
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AD7731–SPECIFICATIONS Parameter STATIC PERFORMANCE (CHP = Missing Codes 2 Output Noise and Update Rates Integral Nonlinearity 2 Offset Error 2 Offset Drift vs. Temperature 5 Offset Drift vs. Time 2, 6 Positive Full-Scale Error ...
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Parameter 13 Absolute/Common-Mode Voltage Reference Input REF IN(+) – REF IN (–) Voltage REF IN(+) – REF IN (–) Voltage Reference DC Input Current Reference DC Input Current 14 Absolute/Common-Mode Voltage NO REF Trigger Voltage LOGIC INPUTS Input Current All ...
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AD7731 NOTES 1 Temperature Range: – + Sample tested during initial release missing codes performance with CHP = 0 and SKIP = bits. 4 The offset (or zero) numbers with CHP ...
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... Digital Output Voltage to DGND ......... –0 Output Voltage (D0, D1) to DGND ...... –0 Operating Temperature Range Industrial (B Version) ....................................... –40°C to +85°C Storage Temperature Range ............................ –65°C to +150°C Junction Temperature ..................................................... +150°C ORDERING GUIDE Model (Z = RoHS) AD7731BN AD7731BNZ AD7731BR AD7731BR-REEL AD7731BR-REEL7 AD7731BRZ AD7731BRZ-REEL AD7731BRZ-REEL7 AD7731BRU AD7731BRU-REEL ...
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AD7731 BUFFER AMPLIFIER THE BUFFER AMPLIFIER PRESENTS A HIGH IMPEDANCE INPUT STAGE BURNOUT CURRENTS FOR THE ANALOG INPUTS ALLOWING SIGNIFICANT EXTERNAL SOURCE TWO 100nA BURNOUT IMPEDANCES CURRENTS ALLOW THE USER TO EASILY DETECT SEE PAGE TRANSDUCER HAS ...
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INPUT CHOPPING THE ANALOG INPUT TO THE PART CAN BE CHOPPED. IN CHOPPING MODE, THE INPUT IS CHOPPEDAND THE OUTPUT OF THE FIRST STAGE FILTER IS CHOPPED REMOVING ERRORS IN THAT PATH. THE DEFAULT CONDITION IS CHOPPING DISABLED SEE PAGE ...
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AD7731 Pin Pin No. Mnemonic Function 3 MCLK OUT When the master clock for the device is a crystal/resonator, the crystal/resonator is connected between MCLK IN and MCLK OUT external clock is applied to the MCLK IN, MCLK ...
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Pin Pin No. Mnemonic Function RDY 20 Logic output. Used as a status output in both conversion mode and calibration mode. In conversion mode, a logic low on this output indicates that a new output word is available from the ...
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AD7731 OUTPUT NOISE AND RESOLUTION SPECIFICATION The AD7731 has a number of different modes of operation of the on-chip filter and chopping features. These options are discussed in more detail in later sections. The part can be programmed either to ...
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Output Noise (CHP = 1, SKIP = 0) Table III shows the output rms noise for some typical output update rates and –3 dB frequencies for the AD7731 when used in chopping mode (CHP of Filter Register = 1) and ...
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AD7731 Register Name Type Size Communications Write Only 8 Bits Register Status Register Read Only 8 Bits ...
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Communications Register (RS2-RS0 = The Communications Register is an 8-bit write-only register. All communications to the part must start with a write operation to the Communications Register. The data written to the Communications Register determines whether the ...
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AD7731 Bit Bit Location Mnemonic CR3 ZERO CR2-CR0 RS2-RS0 Status Register (RS2-RS0 = 0, 0, 0); Power-On/Reset Status: CX Hex The Status Register is an 8-bit read-only register. To access the Status Register, the user must write to the Communications ...
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Data Register (RS2-RS0 = 0, 0, 1); Power On/Reset Status: 000000 Hex The Data Register on the part is a read-only register that contains the most up-to-date conversion result from the AD7731. Figure 5 shows a flowchart for reading from ...
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AD7731 MD2 MD1 MD0 Operating Mode Sync (Idle) Mode. In this mode, the modulator and filter are held in reset mode and the AD7731 is not processing any new samples or data. Placing the part in this ...
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Bit Bit Location Mnemonic B/U MR12 MR11 DEN MR10–MR9 D1–D0 MR8 WL MR7 HIREF MR6–MR4 RN2–RN0 REV. A REV. 0 Description Bipolar/Unipolar Bit this bit selects bipolar operation and the output coding is 00...000 for negative full-scale ...
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AD7731 Bit Bit Location Mnemonic MR3 BO MR2–MR0 CH2–CH0 Filter Register (RS2-RS0 = 0, 1, 1); Power-On/Reset Status: 2002 Hex The Filter Register is a 16-bit register from which data can either be read or to which data can be ...
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CHOP SKIP Bit Bit Location Mnemonic FR3 ZERO FR2 CHP FR1 SKIP FR0 FAST Offset Calibration Register (RS2–RS0 = The AD7731 contains three 24-bit Offset Calibration Registers, labeled Offset ...
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AD7731 READING FROM AND WRITING TO THE ON-CHIP REGISTERS The AD7731 contains a total of twelve on-chip registers. These registers are all accessed over a three-wire interface result, addressing of registers is via a write operation to the ...
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CALIBRATION OPERATION SUMMARY The AD7731 contains a number of calibration options as outlined previously. Table XVI summarizes the calibration types, the op- erations involved and the duration of the operations. There are two methods of determining the end of calibration. ...
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AD7731 CIRCUIT DESCRIPTION The AD7731 is a sigma-delta A/D converter with on-chip digital filtering, intended for the measurement of wide dynamic range, low-frequency signals such as those in strain-gage, pressure transducer, temperature measurement, industrial control or pro- cess control applications. ...
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ANALOG INPUT Analog Input Channels The AD7731 has six analog input pins (labelled AIN1 to AIN6) which can be configured as either three fully differential input channels or five pseudo-differential input channels. Bits CH0, CH1 and CH2 of the Mode ...
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AD7731 REFERENCE INPUT The AD7731’s reference inputs, REF IN(+) and REF IN(–), provide a differential reference input capability. The common- mode range for these differential inputs is from AGND to AV The nominal reference voltage, V (REF IN(+) – REF ...
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The operation mode can be changed to achieve optimum per- formance in various applications. The CHP bit should generally be set to 0 when using the AD7731 in applications where higher throughput rates are a concern or in applications where ...
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AD7731 Chop Mode (SKIP = 0, CHP = 1) With CHOP mode enabled and SKIP mode disabled, the sec- ond stage filter is presented with alternating first stage filter outputs and processes data accordingly. It has two primary functions. One ...
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Nonchop Mode (SKIP = 0, CHP = 0) With CHOP mode disabled and SKIP mode disabled, the only function of the second stage filter is to give the overall frequency response. Figure 11 shows the frequency response for the AD7731 ...
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AD7731 FASTStep™ Mode (SKIP = 0, FAST = 1) The second mode of operation of the second stage filter is in FASTStep™ mode which enables it to respond rapidly to step inputs even when the second stage filter is in ...
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CALIBRATION The AD7731 provides a number of calibration options that can be programmed via the MD2, MD1 and MD0 bits of the Mode Register. The different calibration options are outlined in the Mode Register and Calibration Operations sections. A calibra- ...
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AD7731 Internal Full-Scale Calibration An internal full-scale calibration is initiated on the AD7731 by writing the appropriate values ( the MD2, MD1 and MD0 bits of the Mode Register. In this calibration mode, the full-scale point used ...
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The system full-scale calibration needs to be performed as one part of a two part full calibration. However, once a full calibra- tion has been performed, additional system full-scale calibra- tions can be performed by themselves to adjust the part’s ...
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AD7731 USING THE AD7731 Clocking and Oscillator Circuit The AD7731 requires a master clock input, which may be an external CMOS compatible clock signal applied to the MCLK IN pin with the MCLK OUT pin left unconnected. Alternatively, a crystal ...
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Placing the part in standby mode reduces the total current typical when the part is operated from an external master clock, provided this master clock is stopped. If the external clock continues to run in standby mode, ...
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AD7731 SERIAL INTERFACE The AD7731’s programmable functions are controlled via a set of on-chip registers. Access to these registers is via the part’s serial interface. After power-on or RESET, the device expects a write to its Communications Register. The data ...
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Read Operation The reading of data from the part is from an output shift regis- ter. On initiation of a read operation, data is transferred from the specified register to the output shift register. This is a paral- lel shift ...
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AD7731 CONFIGURING THE AD7731 The AD7731 contains twelve on-chip registers which can be accessed via the serial interface. Figure 5 and Figure 6 have outlined a flowchart for the reading and writing of these registers. Table XIX and Table XX ...
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MICROCOMPUTER/MICROPROCESSOR INTERFACING The AD7731’s flexible serial interface allows for easy interface to most microcomputers and microprocessors. The pseudo-code of Table XVIII and Table XIX outline typical sequences for interfacing a microcontroller or microprocessor to the AD7731. Figures 18, 19 and ...
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AD7731 The 8XC51 is configured in its Mode 0 serial interface mode. Its serial interface contains a single data line result, the DATA OUT and DATA IN pins of the AD7731 should be connected together. This means that ...
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APPLICATIONS The on-chip PGA allows the AD7731 to handle analog input voltage ranges from 1.28 V. This makes the AD7731 suitable for a range of application areas from handling signals directly from a transducer to processing fully-conditioned ...
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AD7731 Pressure Measurement One typical application of the AD7731 where it is connected directly to a transducer is in pressure measurement. Figure 22 shows the AD7731 with a pressure transducer in a bridge arrangement. The differential output from the transducer ...
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THERMOCOUPLE JUNCTION + REF IN (+) V AD780 OUT REF IN (–) GND Figure 23. Temperature Measurement Using the AD7731 400 A REF IN (+) R1 6.25k R REF IN (– ...
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AD7731 Bipolar Input Signals As mentioned previously, some applications will require that the AD7731 handle input signals that are negative with respect to system ground. The number of applications requiring this are limited but with the addition of some external ...
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PAGE INDEX Topic FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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AD7731 0.210 (5.33) MAX 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 OUTLINE DIMENSIONS 24-Lead Plastic Dual In-Line Package [PDIP] Dimensions shown in inches and (millimeters) Narrow Body (N-24-1) 1.280 ...