AD7291 Analog Devices, AD7291 Datasheet
AD7291
Specifications of AD7291
Related parts for AD7291
AD7291 Summary of contents
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... The conversion process can be controlled by a command mode where conversions occur across I operations or an autocycle mode selected through software control. The AD7291 includes a high accuracy band gap temperature sensor, which is monitored and digitized by the 12-bit ADC to give a resolution of 0.25°C. The AD7291 offers a programmable sequencer, which enables the selection of a preprogrammable sequence of channels for conversion ...
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... Serial Bus Address Byte ............................................................. 21 2 General I C Timing.................................................................... 21 Writing to the AD7291 .................................................................. 22 Writing Two Bytes of Data to a 16-Bit Register ..................... 22 Writing to Multiple Registers.................................................... 22 Reading Data From the AD7291.................................................. 23 Reading Two Bytes of Data from a 16-Bit Register ............... 23 Modes of Operation ....................................................................... 24 Command Mode ........................................................................ 24 Autocycle Mode.......................................................................... 26 Outline Dimensions ....................................................................... 27 Ordering Guide .......................................................................... 27 Rev ...
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... V DRIVE 0.3 × V DRIVE ±0.01 ±1 6 0.1 × V DRIVE Rev Page AD7291 = −40°C to +125° Unit Test Conditions/Comments kHz sine wave 5.4 kHz 4.6 kHz kHz ...
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... AD7291 Parameter LOGIC OUTPUTS Output High Voltage Output Low Voltage Floating State Leakage Current 3 Floating State Output Capacitance TEMPERATURE SENSOR—INTERNAL Operating Range Accuracy Resolution CONVERSION RATE Conversion Time 6 Autocycle Update Rate Throughput Rate POWER REQUIREMENTS DRIVE ...
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... SCL signal RCL t , rise time of the SCL signal after a repeated RCL1 start condition and after an acknowledge bit t , fall time of the SCL signal FCL Pulse width of the suppressed spike Power-up and acquisition time AD7291 = REF ...
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... AD7291 ABSOLUTE MAXIMUM RATINGS Table 4. Parameter V to GND1, GND GND1, GND DRIVE Analog Input Voltage to GND1 Digital Input Voltage to GND1 Digital Output Voltage to GND1 V to GND1 REF GND to GND1 Input Current to Any Pin Except Supplies Operating Temperature Range Storage Temperature Range ...
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... GND Ground. Ground reference point for all analog and digital circuitry on the AD7291. The GND pin should be con- nected to the ground plane of the system. All ground pins should ideally be at the same potential and must not be more than 0.3 V apart, even on a transient basis. Both D ...
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... AD7291 TYPICAL PERFORMANCE CHARACTERISTICS DRIVE f = 22.22ksps 400kHz –20 SCL f = 10kHz IN SNR = 71.209 THD = –81.66 –40 –60 –80 –100 –120 FREQUENCY (Hz) Figure 4. Typical FFT 1 25° 0.8 DRIVE V = 2.5V REF V 0 22.22ksps S 0 400kHz SCL 0.2 0 –0.2 –0.4 – ...
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... Figure 13. Channel-to-Channel Isolation DRIVE 0.5 1.0 1.5 EXTERNAL REFERENCE (V) = 400 kHz, f SCL 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –40 –25 – TEMPERATURE (°C) Figure 15. Temperature Accuracy AD7291 = DRIVE = 400kHz kHz 2 22.22 kSPS s 95 110 125 ...
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... AD7291 9 DRIVE 8 8.8 8.7 8.6 8.5 8.4 8.3 8.2 8.1 8 120 180 240 SCL FREQUENCY (kHz) Figure 16. Power vs. Throughput in Normal Mode 2.5 2.0 1.5 1.0 0.5 300 360 420 Figure 17. Full Shutdown Current vs. Supply Voltage for Various Rev Page Data Sheet DRIVE 0 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3 Temperatures –40°C +25°C +85°C +125°C 3 ...
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... The AD7291 is tested using the CCIF standard where two input frequencies near the top end of the input bandwidth are used. In this case, the second-order terms are usually distanced in frequency from the original sine waves while the third-order terms are usually at a frequency close to the input frequencies ...
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... GND1 ANALOG INPUT Figure 20 shows an equivalent circuit of the analog input struc- ture of the AD7291. The two diodes, D1 and D2, provide ESD protection for the analog inputs. Care must be taken to ensure that the analog input signal never exceeds the internally generated LDO voltage of 2 the diodes to become forward biased and start conducting current into the substrate ...
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... Data Sheet ADC TRANSFER FUNCTION The output coding of the AD7291 is straight binary for the analog input channel conversion results and twos complement for the temperature conversion result. The designed code tran- sitions occur at successive LSB values (that is, 1 LSB, 2 LSBs, and so forth). The LSB size is V /4096 for the AD7291 ...
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... RESET The AD7291 includes a reset feature, which can be used to reset the device and the content of all internal registers including the command register to their default state. To activate the reset ...
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... The address pointer register is an 8-bit register in which the six LSBs are used as pointer bits to store an address that points to one of the AD7291’s data registers. The first byte following each write address is to the address pointer register, containing the address of one of the data registers. The six LSBs select the data register to which subsequent data bytes are written ...
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... AD7291 Table 9. AD7291 Register Addresses Hex Code 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A ...
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... COMMAND REGISTER (0x00) The command register is a 16-bit write-only register that is used to set the operating modes of the AD7291. The bit functions are outlined in Table 10. A two-byte write is necessary when writing to the command register. MSB denotes the first bit in the data stream. During power-up, the default content of the command register is all 0s ...
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... A 2-byte read is necessary to read data from this register. Table 14 and Table 15 show the contents of the first and second bytes of data to be read from the AD7291. Each AD7291 conversion result consists of four channel address bits (see Table 14 and Table 15) and the 12-bit data result. ...
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... Each pair of limit registers has one associated hysteresis register. All 27 registers are 16 bits wide; only the 12 LSBs of the registers are used for the AD7291. The four MSBs, D15 and D12, in these registers should contain 0s. During power-up, the contents of the DATA ...
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... There are two alert status registers in the AD7291; Alert Status Register A, which stores alerts for the analog voltage conversion channels (see Table 27 and Table 28) and Alert Status Register B, which stores alerts for the internal temperature sensor only (see Table 29 and Table 30) ...
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... I C INTERFACE Control of the AD7291 is carried out via the I serial bus. The AD7291 is connected to this bus as a slave device under the control of a master device such as the processor. SERIAL BUS ADDRESS BYTE The first byte the user writes to the device is the slave address 2 byte ...
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... The slave (AD7291) asserts an acknowledge on SDA. 16. The master asserts a stop condition on SDA to end the transaction. The previous example details writing to two registers only (the CH1 DATA However, the AD7291 can read from multiple registers in one write operation as shown in Figure 26 REG POINTER ...
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... Data Sheet READING DATA FROM THE AD7291 READING TWO BYTES OF DATA FROM A 16-BIT REGISTER Reading the contents from any of the 16-bit registers is a 2-byte read operation. In this protocol, the first part of the transaction writes to the register pointer. When the register address has ...
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... The read then takes place from the voltage or temperature conversion result register. For the first conversion to occur, the address pointer written to the AD7291 must point to the voltage conversion result register or T SENSE register. The conversion is completed while the first four channel address bits are read ...
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... The slave asserts an acknowledge on SDA. 12. The master sends the 7-bit slave address followed by the write bit (high). 13. The slave (AD7291) asserts an acknowledge on SDA. 14. The master receives a data byte, which contains the channel address bits and the four MSBs of the converted result for Channel V ...
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... Bit D0 of the command register to 1. When the command mode conversion is complete, the user can reenable autocycle mode by setting Bit the command register. In autocycle mode, the AD7291 does not enter partial power- down on receipt of a stop condition; therefore, conversions and alert monitoring continue to function. ...
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... Lead Frame Chip Scale Package [LFCSP_WQ] 20-Lead Lead Frame Chip Scale Package [LFCSP_WQ] Evaluation Board Rev Page 2.75 2. 0.25 MIN FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. Package Option CP-20-8 CP-20-8 AD7291 ...
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... AD7291 NOTES refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D08711-0-10/11(B) Rev Page Data Sheet ...