AD7265 Analog Devices, AD7265 Datasheet
AD7265
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AD7265 Summary of contents
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... High Throughput with Low Power Consumption. The AD7265 offers a 1 MSPS throughput rate with 9 mW maximum power dissipation when operating The AD7265 offers both a standard and a 2 × ...
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... Rev. A Changes to Format .............................................................Universal Changes to Reference Input/Output Section ................................ 4 Changes to Table 4............................................................................ 7 Changes to Terminology Section.................................................. 11 Changes to Figure 24 and Differential Mode Section................ 15 Changes to Figure 29...................................................................... 16 Changes to AD7265 to ADSP-BF53x Section............................. 24 Updated Outline Dimensions ....................................................... 27 Changes to Ordering Guide .......................................................... 27 Digital Inputs .............................................................................. 18 V ............................................................................................ 18 DRIVE Modes of Operation ....................................................................... 19 Normal Mode ...
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... IN− CM REF V ± IN− CM REF Rev Page AD7265 Test Conditions/Comments kHz sine wave; differential mode kHz sine wave; single-ended and IN pseudo differential modes kHz sine wave; differential mode kHz sine wave; single-ended and ...
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... AD7265 Parameter DC Leakage Current Input Capacitance REFERENCE INPUT/OUTPUT 8 Reference Output Voltage Long-Term Stability 2 Output Voltage Hysteresis Reference Input Voltage Range DC Leakage Current Input Capacitance Output Impedance CAP CAP Reference Temperature Coefficient V Noise REF LOGIC INPUTS Input High Voltage, V INH ...
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... A > 85°C to 125° and D B are three-state disabled OUT OUT = high impedance OUT OUT high impedance OUT OUT high impedance OUT OUT ) and timed from a voltage level of 1 AD7265 1 . ...
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... AD7265 ABSOLUTE MAXIMUM RATINGS Table 3. Parameter V to AGND DGND DGND DRIVE V to AGND DRIVE AGND to DGND Analog Input Voltage to AGND Digital Input Voltage to DGND Digital Output Voltage to GND V to AGND REF Input Current to Any Pin Except 1 Supplies ...
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... ADC A and ADC B. In addition, Pin D decoupling capacitors. If the REF SELECT pin is tied to a logic high, an external reference can be supplied to the AD7265 through the Analog Supply Voltage, 2 5.25 V. This is the only supply voltage for all analog circuitry on the AD7265. The DD AV and transient basis ...
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... This pin should be decoupled to DGND. The voltage at this pin may be different than that at AV should never exceed either by more than 0 Digital Supply Voltage, 2 5.25 V. This is the supply voltage for all digital circuitry on the AD7265. The DV DD and AV voltages should ideally be at the same potential and must not be more than 0.3 V apart even transient basis ...
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... CODE Figure 8. Typical DNL 1 5V DIFFERENTIAL MODE 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 500 1000 1500 2000 2500 3000 CODE Figure 9. Typical INL AD7265 = 3V DRIVE = 1MSPS 400 450 500 = 3V DRIVE 3500 4000 = 3V DRIVE 3500 4000 ...
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... AD7265 1.0 V DIFFERENTIAL MODE 0.8 POSITIVE DNL 0.6 0.4 POSITIVE INL 0.2 0 –0.2 NEGATIVE INL –0.4 –0.6 NEGATIVE DNL –0.8 –1.0 0 0.5 1.0 1.5 V (V) REF Figure 10. Linearity Error vs. V 12.0 11.5 11 10.5 SINGLE-ENDED MODE 10 9.5 DD SINGLE-ENDED MODE 9 8.5 DIFFERENTIAL MODE DIFFERENTIAL MODE 8.0 7.5 7.0 0 0.5 1.0 1.5 2.0 2.5 3.0 V (V) REF Figure 11. Effective Number of Bits vs. V 2.5010 2 ...
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... N-bit converter with a sine wave input is given by Signal-to-(Noise + Distortion) = (6.02N + 1.76) dB Therefore, for a 12-bit converter, this is 74 dB. Total Harmonic Distortion (THD) Total harmonic distortion is the ratio of the rms sum of harmonics to the fundamental. For the AD7265 defined as THD where the rms amplitude of the fundamental. 1 ...
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... AD7265 The AD7265 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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... CIRCUIT INFORMATION The AD7265 is a fast, micropower, dual, 12-bit, single-supply, ADC that operates from a 2 5.25 V supply. When operated from either supply, the AD7265 is capable of throughput rates of 1 MSPS when provided with a 16 MHz clock. The AD7265 contains two on-chip, differential track-and-hold amplifiers, two successive approximation ADCs, and a serial interface with two separate data output pins ...
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... Analog Input Selection section. SOURCE Single-Ended Mode The AD7265 can have a total of 12 single-ended analog input channels. In applications where the signal source has high impedance recommended to buffer the analog input before R = 0Ω applying it to the ADC. The analog input range can be pro- ...
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... V range, respectively. The common mode REF REF must be in this range to guarantee the functionality of the AD7265. When a conversion takes place, the common mode is rejected, resulting in a virtually noise-free signal of amplitude −V +V corresponding to the digital codes 4096. If the REF 2 × ...
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... AD7265 Using an Op Amp Pair An op amp pair can be used to directly couple a differential signal to one of the analog input pairs of the AD7265. The circuit configurations illustrated in Figure 26 and Figure 27 show how a dual op amp can be used to convert a single-ended signal into a differential signal for both a bipolar and unipolar input signal, respectively ...
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... If the mode is changed from fully differential to pseudo-differential, for example, then the acquisition time would start again from this point. The selected input channels are decoded as shown in The analog input range of the AD7265 can be selected × V REF ...
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... V ± V Input Range REF REF DIGITAL INPUTS The digital inputs applied to the AD7265 are not limited by the maximum ratings that limit the analog inputs. Instead, the digital inputs can be applied and are not restricted by range is used. In the V REF /4096 when the ...
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... MODES OF OPERATION The mode of operation of the AD7265 is selected by controlling the (logic) state of the CS signal during a conversion. There are three possible modes of operation: normal mode, partial power- down mode, and full power-down mode. After a conversion pulled high determines which initiated, the point at which power-down mode, if any, the device enters ...
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... AD7265 To exit this mode of operation and power up the AD7265 again, a dummy conversion is performed. On the falling edge the device begins to power up and continues to power up as long held low until after the falling edge of the 10 SCLK. The device is fully powered up after approximately 1 μs has elapsed, and valid data results from the next conversion, as shown in Figure 36 ...
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... AD7265 must be in partial power-down for at least 67 μs in order for this power-up time to apply. When power supplies are first applied to the AD7265, the ADC may power up in either of the power-down modes or normal mode. Because of this best to allow a dummy cycle to elapse to ensure the part is fully powered up before attempting a valid conversion ...
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... SCLK can be ignored for the purposes of the timing descriptions in B. This OUT this section falling edge of SCLK is coincident with the A is shown. In OUT falling edge of acknowledged by the AD7265, and the next falling edge of SCLK will be the first registered after the falling edge ...
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... MICROPROCESSOR INTERFACING The serial interface on the AD7265 allows the part to be directly connected to a range of many different microprocessors. This section explains how to interface the AD7265 with some of the more common microcontroller and DSP serial interface protocols. AD7265 TO ADSP-218x The ADSP-218x family of DSPs interface directly to the AD7265 without any glue logic required ...
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... DSPs means only one serial port is necessary to read from both D pins simultaneously. Figure 44 shows both D OUT the AD7265 connected to Serial Port 0 of the OUT ADSP-BF53x. The SPORT0 Receive Configuration 1 register and SPORT0 Receive Configuration 2 register should be set up as outlined in Table 9 and Table 10. ...
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... AD7265 TO DSP563xx The connection diagram in Figure 46 shows how the AD7265 can be connected to the ESSI (synchronous serial interface) of the DSP563xx family of DSPs from Motorola. There are two on-board ESSIs, and each operates in synchronous mode (Bit SYN = 1 in CRB register) with internally generated word length frame sync for both TX and RX (Bit FSL1 = 0 and Bit FSL0 = 0 in CRB) ...
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... However, the analog ground plane should be allowed to run under the AD7265 to avoid noise coupling. The power supply lines to the AD7265 should use as large a trace as possible to provide low impedance paths and reduce the effects of glitches on the power supply line. ...
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... This board is a complete unit allowing control and communicate with all Analog Devices, Inc. evaluation boards ending in the CB designators. To order a complete evaluation kit, the particular ADC evaluation board (such as, EVAL-AD7265CB), the EVAL-CONTROL BRD2, and transformer must be ordered. See the relevant evaluation board technical note for more information ...
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... AD7265 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04674-0-11/06(A) T Rev Page ...