AD7880 Analog Devices, AD7880 Datasheet
AD7880
Specifications of AD7880
Available stocks
Related parts for AD7880
AD7880 Summary of contents
Page 1
... V supply. Fast bus access times and standard control inputs ensure easy interfacing to modern microprocessors and digital signal processors. The AD7880 features a total throughput time and can convert full power signals kHz with a sampling fre- quency of 66 kHz. In addition to the traditional dc accuracy specifications such as ...
Page 2
... AD7880–SPECIFICATIONS Parameter B Versions 2 DYNAMIC PERFORMANCE 3 Signal-to-Noise Ratio (SNR) 70 Total Harmonic Distortion (THD) –80 Peak Harmonic or Spurious Noise –80 Intermodulation Distortion (IMD) Second Order Terms –80 Third Order Terms –80 DC ACCURACY Resolution 12 Integral Nonlinearity 1 Differential Nonlinearity 1 Full-Scale Error 15 Bipolar Zero Error ...
Page 3
... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD7880 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...
Page 4
... AD7880BN – + AD7880BQ – + AD7880CN – + AD7880CQ – + AD7880BR – + AD7880CR – + Plastic DIP Cerdip SOIC (Small Outline Integrated Circuit). Pin Pin No. Mnemonic Function 1 V Analog Input. INA ...
Page 5
... CIRCUIT INFORMATION The AD7880 single supply 12-bit A/D converter. The part requires no external components apart from a 2.5 MHz ex- ternal clock and power supply decoupling capacitors. It contains a 12-bit successive approximation ADC based on a fast-settling voltage-output DAC, a high speed comparator and SAR, as well as the necessary control logic ...
Page 6
... AD7880 The AD7880 has two unipolar input ranges and Figure 5 shows the analog input for the range. The designed code transitions occur midway between successive integer LSB values (i.e., 1/2 LSB, 3/2 LSBs, 5/2 LSBs . . . FS –3/2 LSBs). The output code is straight binary with 1 LSB = FS/4096 = 5 V/4096 = 1 ...
Page 7
... In the case of the unipolar input configuration, unipolar offset error must be adjusted before full-scale error. Adjustment is achieved by trimming the offset of the op amp driving the ana- log input of the AD7880. This is done by applying an input voltage of 0.61 mV (1/2 LSB Figure 11 and adjusting ...
Page 8
... SAMPLE FREQUENCY = 61kHz INPUT FREQUENCY – kHz Figure 13. Effective Number of Bits vs. Frequency Total Harmonic Distortion (THD) THD is the ratio of the rms sum of harmonics to the rms value of the fundamental. For the AD7880, THD is defined as THD ...
Page 9
... ADC is the AD7880 address. TMS320C25 Figure 17. AD7880–TMS320C25 Interface Some applications may require that the conversion be initiated by the microprocessor rather than an external timer. One option is to decode the AD7880 CONVST from the address bus so that –9– AD7880 TIMER PA2 ADDRESS BUS ...
Page 10
... The AD7880 BUSY line can be used to interrupt the processor or, alternatively, software delays can ensure that con- version has been completed before a read to the AD7880 is at- tempted. Because of the nature of its interrupts, the 68000 requires additional logic (not shown in Figure 18) to allow interrupted correctly ...
Page 11
... V– LK3 Figure 21. Analog Input Buffering When it is required to drive the AD7880 with the input range, an external supply must be connected to V+ (see Figure 21). In bipolar operation, positive and negative supplies must be connected to V+ and V–. The AD711 is a general purpose op amp which could be used to drive the analog input of the AD7880 ...
Page 12
... This connector, the pinout of which is shown in Figure 23, contains all data, control and status signals of the AD7880 (with the ex- ception of the CONVST and the CLKIN inputs both of which are provided via SKT2 and SKT3 respectively). It also contains ...
Page 13
... Figure 24. Data Acquisition Circuit Using the AD7880 REV. 0 Figure 25. PCB Silkscreen for Figure 24 –13– AD7880 ...
Page 14
... AD7880 Figure 26. PCB Component Side Layout for Figure 24 Figure 27. PCB Solder Side Layout for Figure 24 –14– REV. 0 ...
Page 15
... IN ACCORDANCE WITH MIL-M-38510 REQUIREMENTS. 24-Lead SOIC (R-24) 0.614 (15.6) 0.598 (15. 0.299 (7.6) 0.291 (7. PIN 1 0.104 (2.65) 0.093 (2.35) 0.05 0.019 (0.49) 0.012 (0.3) 0.013 (0.32) (1.27) 0.004 (0.1) 0.014 (0.35) BSC 0.009 (0.23) –15– AD7880 0.001 0.03) 0.32 (8.128) 0.30 (7.62) 0.011 (0.28) 0.009 (0.23 0.320 (8.128) 0.291 (7.4) 0.180 (4.572) MAX 0.012 (0.305) 15 0.008 (0.203) 0 0.03 (0.75) 0.01 (0.25 0.05 (1.27) ...
Page 16
–16– ...