Datasheet AD7490 (Analog Devices) - 9

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AD7490 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS
Figure 5 shows a typical FFT plot for the AD7490 at 1 MSPS sample rate and 50 kHz input frequency. Figure 7 shows the power supply rejection ratio vs. supply ripple frequency for the AD7490. The power supply rejection ratio is defined as the ratio of the power in the ADC output at full-scale frequency f, to the power of a 200 mV p-p sine wave applied to the ADC VDD supply of frequency fS. PSRR(dB)  Pf  =10 × log   Pfs  where: Pf is equal to the power at frequency f in ADC output. PfS is equal to power at frequency fS coupled onto the ADC VDD supply input. Here, a 200 mV p-p sine wave is coupled onto the VDD supply. 10 nF decoupling was used on the supply, and a 1 µF decoupling capacitor was used on the REFIN pin.
5 –20 8192 POINT FFT VDD = 3V/5V, 10nF CAP fSAMPLE = 1MSPS 200mV p-p SINE WAVE ON VDD f –30 –15 IN = 50kHZ REFIN = 2.5V, 1µF CAP SINAD = 70.697dB TA = 25°C THD = –79.171dB SFDR = –79.93dB –40 –35 B) –50 B) d d –55 NR ( RR ( S S –60 P –75 –70 VDD = 5V –95 –80 VDD = 3V –90 0 50 100 150 200 250 300 350 400 450 500
004
0 100k 200k 300k 400k 500k 600k 700k 800k 900k 1M
006
FREQUENCY (kHz) INPUT FREQUENCY (Hz)
02691- 02691- Figure 5. Dynamic Performance at 1 MSPS Figure 7. PSRR vs. Supply Ripple Frequency
75 –50 fS = MAX THROUGHPUT TA = 25°C V –55 DD = VDRIVE = 5.25V RANGE = 0V TO REFIN VDD = VDRIVE = 4.75V VDD = VDRIVE = 2.7V 70 –60 –65 VDD = VDRIVE = 3.6V B) d B) d 65 –70 VDD = VDRIVE = 3.6V HD ( INAD ( T S –75 60 –80 VDD = VDRIVE = 4.75V f V V S = MAX THROUGHPUT DD = VDRIVE = 2.7V –85 DD = VDRIVE = 5.25V TA = 25°C RANGE = 0V TO REFIN 55 –90 10 100 1000
005
10 100 1000
007
INPUT FREQUENCY (kHz) INPUT FREQUENCY (kHz)
02691- 02691- Figure 6. SINAD vs. Analog Input Frequency Figure 8. THD vs. Analog Input Frequency for Various Supply Voltages at 1 MSPS for Various Supply Voltages at 1 MSPS Rev. D | Page 8 of 28 Document Outline Features Functional Block Diagram General Description Product Highlights Revision History Specifications Timing Specifications Absolute Maximum Ratings ESD Caution Pin Configurations and Function Descriptions Typical Performance Characteristics Terminology Internal Register Structure Control Register Sequencer Operation Shadow Register Theory of Operation Circuit Information Converter Operation Analog Input ADC Transfer Function Handling Bipolar Input Signals Typical Connection Diagram Analog Input Channels Digital Input VDRIVE Reference Section Modes of Operation Normal Mode (PM1 = PM0 = 1) Full Shutdown (PM1 = 1, PM0 = 0) Auto Shutdown (PM1 = 0, PM0 = 1) Auto Standby (PM1 = PM0 = 0) Powering Up the AD7490 Serial Interface Power vs. Throughput Rate Microprocessor Interfacing AD7490 to TMS320C541 AD7490 to ADSP-21xx AD7490 to DSP563xx Application Hints Grounding and Layout PCB Design Guidelines for Chip Scale Package Evaluating the AD7490 Performance Outline Dimensions Ordering Guide