AD7890ARZ-10 Analog Devices Inc, AD7890ARZ-10 Datasheet
AD7890ARZ-10
Specifications of AD7890ARZ-10
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AD7890ARZ-10 Summary of contents
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GENERAL DESCRIPTION The AD7890 is an eight-channel 12-bit data acquisition system. The part contains an input multiplexer, an on-chip track/hold amplifier, a high-speed 12-bit ADC, a 2.5 V reference and a high speed, serial interface. The part operates from ...
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AD7890–SPECIFICATIONS Parameter A Versions DYNAMIC PERFORMANCE 2 Signal to (Noise + Distortion) Ratio 70 2 Total Harmonic Distortion (THD) –78 2 Peak Harmonic or Spurious Noise –79 Intermodulation Distortion 2nd Order Terms –80 3rd Order Terms –80 2 Channel-to-Channel Isolation ...
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Parameter A Versions LOGIC OUTPUTS Output High Voltage, V 4.0 OH Output Low Voltage, V 0.4 OL Serial Data Output Coding AD7890-10 AD7890-4 AD7890-2 CONVERSION RATE Conversion Time 5 Track/Hold Acquisition Time 2 POWER REQUIREMENTS ...
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AD7890 TIMING CHARACTERISTICS Limit at T Parameter ( Versions 100 CLKIN 2.5 0.3 × CLK IN LO CLK × CLK IN HI CLK ...
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Pin Mnemonic Description 1 AGND Analog Ground. Ground reference for track/hold, comparator and DAC. 2 SMODE Control Input. Determines whether the part operates in its External Clocking (slave) or Self-Clocking (master) serial mode. With SMODE at a logic low, the ...
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AD7890 Pin Mnemonic Description Analog Input Channel 2. Single-ended analog input. The analog input range on is ± (AD7890 IN2 10 4.096 V (AD7890-4) and 2.5 V (AD7890-2). The channel ...
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TERMINOLOGY Signal to (Noise + Distortion) Ratio This is the measured ratio of signal to (noise + distortion) at the output of the A/D converter. The signal is the rms amplitude of the fundamental. Noise is the rms sum of ...
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AD7890 CONTROL REGISTER The Control Register for the AD7890 contains 5 bits of informa- tion as described below. Six serial clock pulses must be provided to the part in order to write data to the Control Register (seven if the ...
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CIRCUIT DESCRIPTION Analog Input Section The AD7890 is offered as three part types, the AD7890-10 which handles a ± input voltage range, the AD7890-4 which handles 4.096 V input range and the AD7890-2 which ...
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AD7890 Track/Hold Section The SHA IN input on the AD7890 connects directly to the input stage of the track/hold amplifier. This is a high impedance input with input leakage currents of less than 50 nA. Connect- ing the MUX OUT ...
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CONVST (I) RFS (O) SCLK (O) DATA OUT (O) NOTE: (I) SIGNIFIES AN INPUT; (O) SIGNIFIES AN OUTPUT. PULL-UP RESISTOR ON SCLK. When using the device in the External-Clocking Mode, the out- put register can be read at any time ...
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AD7890 CONVST SCLK RFS TFS CONVERSION IS INITIATED AND TRACK/HOLD GOES INTO HOLD In the Self-Clocking Mode, the AD7890 indicates when conver- sion is complete by bringing the RFS line low and initiating a serial data transfer. In the external ...
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The duration of the internal pulse can be seen on the C pin. The C pin goes from a low to a high when a serial EXT write to the part is initiated (on the falling edge of TFS). It ...
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AD7890 TFS ( SCLK ( DATA IN ( NOTE: (I) SIGNIFIES AN INPUT; (O) SIGNIFIES AN OUTPUT. PULL-UP RESISTOR ON SCLK. Write Operation Figure 9 shows a write operation to the Control ...
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TFS ( SCLK ( DATA IN ( NOTE: (I) SIGNIFIES AN INPUT; (O) SIGNIFIES AN OUTPUT. SIMPLIFYING THE INTERFACE To minimize the number of interconnect lines to the AD7890, the user can connect the ...
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AD7890 AD7890–68HC11 Interface An interface circuit between the AD7890 and the 68HC11 microcontroller is shown in Figure 13. For the interface shown, the AD7890 is configured for its external clocking mode while the 68HC11’s SPI port is used and the ...
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DATA OUT to be clocked into the DSP on the edges of the CLK IN signal. When writing data to the AD7890, the processor’s data hold time is sufficiently long to cater for the delay between the two clocks. The ...
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AD7890 In the external clocking mode possible to write data to the Control Register or read data from the output register while a conversion is in progress. The same data is presented in Figure Figure ...
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Effective Number of Bits The formula for Signal to (Noise + Distortion) Ratio (See Ter- minology section) is related to the resolution or number of bits in the converter. Rewriting the formula, below, gives a measure of performance expressed in ...
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AD7890 PIN 1 0.02 (0.5) 0.016 (0.41) PIN 1 0.225 (5.715) MAX 0.125 (3.175) MIN PIN 1 0.012 (0.3) 0.004 (0.1) OUTLINE DIMENSIONS Dimensions shown in inches and (mm). Plastic DIP (N-24 0.260 0.001 (6.61 0.03 ...