AD7661ASTZ Analog Devices Inc, AD7661ASTZ Datasheet
AD7661ASTZ
Specifications of AD7661ASTZ
Available stocks
Related parts for AD7661ASTZ
AD7661ASTZ Summary of contents
Page 1
FEATURES 2.5 V internal reference: typical drift 3 ppm/°C Guaranteed max drift 15 ppm/°C Throughput: 100 kSPS INL: ±2.5 LSB max (±0.0038% of full scale) 16-bit resolution with no missing codes S/(N+D min @ 20 kHz THD: –96 ...
Page 2
AD7661 TABLE OF CONTENTS Specifications..................................................................................... 3 Timing Specifications....................................................................... 5 Absolute Maximum Ratings............................................................ 7 ESD Caution.................................................................................. 7 Pin Configuration and Function Descriptions............................. 8 Definitions of Specifications ......................................................... 11 Typical Performance Characteristics ........................................... 12 Circuit Information ........................................................................ 16 Converter Operation.................................................................. 16 Typical ...
Page 3
SPECIFICATIONS Table 2. –40°C to +85°C, AVDD = DVDD = 5 V, OVDD = 2 5.25 V, unless otherwise noted Parameter RESOLUTION ANALOG INPUT Voltage Range Operating Input Voltage Analog Input CMRR Input Current 1 Input Impedance THROUGHPUT ...
Page 4
AD7661 Parameter DIGITAL INPUTS Logic Levels DIGITAL OUTPUTS 5 Data Format Pipeline Delay POWER SUPPLIES Specified Performance AVDD DVDD OVDD Operating Current 8 AVDD 9 AVDD 10 ...
Page 5
TIMING SPECIFICATIONS Table 3. –40°C to +85°C, AVDD = DVDD = 5 V, OVDD = 2 5.25 V, unless otherwise noted Parameter Refer to Figure 33 and Figure 34 Convert Pulse Width Time between Conversions CNVST LOW to ...
Page 6
AD7661 Table 4. Serial Clock Timings in Master Read after Convert DIVSCLK[1] DIVSCLK[0] SYNC to SCLK First Edge Delay Minimum Internal SCLK Period Minimum Internal SCLK Period Maximum Internal SCLK HIGH Minimum Internal SCLK LOW Minimum SDOUT Valid Setup Time ...
Page 7
ABSOLUTE MAXIMUM RATINGS 1 Table 5. AD7661 Stress Ratings Parameter Rating TEMP , REF, REFBUFIN, AVDD + 0 INGND, REFGND to AGND AGND – 0.3 V Ground Voltage Differences AGND, DGND, OGND ±0.3 V ...
Page 8
AD7661 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 6. Pin Function Descriptions 1 Pin No. Mnemonic Type Description 1, 36, AGND P Analog Power Ground Pin. 41 AVDD P Input Analog Power Pin. Nominally ...
Page 9
Pin No. Mnemonic Type Description DI/O When SER/PAR is LOW, this output is used as Bit 7 of the parallel port data output bus. RDC/SDIN When SER/PAR is HIGH, this input, part of the serial port, ...
Page 10
AD7661 1 Pin No. Mnemonic Type Description Primary Analog Input with a Range 2 TEMP AO Temperature Sensor Voltage Output. 46 REFBUFIN AI/O Reference Input Voltage. The reference output and the ...
Page 11
DEFINITIONS OF SPECIFICATIONS Integral Nonlinearity Error (INL) Linearity error refers to the deviation of each individual code from a line drawn from negative full scale through positive full scale. The point used as negative full scale occurs ½ LSB before ...
Page 12
AD7661 TYPICAL PERFORMANCE CHARACTERISTICS 2.5 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 0 16384 32768 CODE Figure 5. Integral Nonlinearity vs. Code 0.0 0.5 1.0 1.5 POSITIVE INL (LSB) Figure 6. Typical ...
Page 13
CODE IN HEX Figure 11. Histogram of 261,120 Conversions Input at the ...
Page 14
AD7661 –55 –35 – TEMPERATURE (°C) Figure 17. SNR, S/(N+D), and ENOB vs. Temperature –100 –105 –110 –115 –120 –55 –35 – TEMPERATURE (°C) Figure 18. THD and ...
Page 15
OVDD = 2.7V @ 85°C 45 OVDD = 2.7V @ 25° OVDD = 5V @ 85°C 20 OVDD = 5V @ 25° 100 150 C L (pF) Figure 23. ...
Page 16
AD7661 CIRCUIT INFORMATION IN REF REFGND 32,768C INGND The AD7661 is a very fast, low power, single supply, precise 16-bit analog-to-digital converter (ADC). The AD7661 is capable of converting 100,000 samples per second (100 kSPS) and allows power savings between ...
Page 17
Transfer Functions Using the OB/ 2C digital input, the AD7661 offers two output codings: straight binary and twos complement. The LSB size is V /65536, which is about 38.15 µV. The AD7661’s ideal REF transfer characteristic is shown in Figure ...
Page 18
AD7661 TYPICAL CONNECTION DIAGRAM Figure 26 shows a typical connection diagram for the AD7661. Analog Input Figure 27 shows an equivalent circuit of the input structure of the AD7661. The two diodes, D1 and D2, provide ESD protection for the ...
Page 19
The noise generated by the driver amplifier needs to be kept as low as possible in order to preserve the SNR and transition noise performance of the AD7661. The noise coming from the driver is filtered by the AD7661 ...
Page 20
AD7661 For applications that use multiple AD7661s more effective to use the internal buffer to buffer the reference voltage. Care should be taken with the voltage reference’s temperature coefficient, which directly affects the full-scale accuracy if this parameter ...
Page 21
CONVERSION CONTROL Figure 33 shows the detailed timing diagrams of the conversion process. The AD7661 is controlled by the CNVST signal, which initiates conversion. Once initiated, it cannot be restarted or aborted, even by the power-down input PD, until the ...
Page 22
AD7661 DIGITAL INTERFACE The AD7661 has a versatile digital interface; it can be interfaced with the host system by using either a serial or a parallel interface. The serial interface is multiplexed on the parallel data bus. The AD7661 digital ...
Page 23
MASTER SERIAL INTERFACE Internal Clock The AD7661 is configured to generate and provide the serial data clock SCLK when the EXT/ INT pin is held LOW. The AD7661 also generates a SYNC signal to indicate to the host when the ...
Page 24
AD7661 SLAVE SERIAL INTERFACE External Clock The AD7661 is configured to accept an externally supplied serial data clock on the SCLK pin when the EXT/ INT pin is held HIGH. In this mode, several methods can be used to read ...
Page 25
External Discontinuous Clock Data Read After Conversion Though the maximum throughput cannot be achieved using this mode the most recommended of the serial slave modes. Figure 41 shows the detailed timing diagrams of this method. After a conversion ...
Page 26
AD7661 MICROPROCESSOR INTERFACING The AD7661 is ideally suited for traditional dc measurement applications supporting a microprocessor, and for ac signal processing applications interfacing to a digital signal processor. The AD7661 is designed to interface either with a parallel 8-bit or ...
Page 27
APPLICATION HINTS BIPOLAR AND WIDER INPUT RANGES In some applications desirable to use a bipolar or wider analog input range such as ±10 V, ± Although the AD7661 has only one ...
Page 28
AD7661 OUTLINE DIMENSIONS 1.45 1.40 1.35 0.15 0.05 ROTATED 90 ° CCW 7.00 BSC SQ PIN 1 INDICATOR TOP VIEW 1.00 12° MAX 0.85 0.80 SEATING PLANE ORDERING GUIDE Model AD7661AST AD7661ASTRL AD7661ACP AD7661ACPRL 1 EVAL-AD7661CB 2 EVAL-CONTROL BRD2 ...