Datasheet AD9240 (Analog Devices) - 12
| Fabricante | Analog Devices |
| Descripción | Complete 14-Bit, 10 MSPS Monolithic A/D Converter |
| Páginas / Página | 25 / 12 — AD9240. Table I. Analog Input Configuration Summary. Input. Input Range … |
| Revisión | B |
| Formato / tamaño de archivo | PDF / 372 Kb |
| Idioma del documento | Inglés |
AD9240. Table I. Analog Input Configuration Summary. Input. Input Range (V). Figure. Connection. Coupling. Span (V). VINA1. VINB1. Comments
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AD9240 Table I. Analog Input Configuration Summary Input Input Input Range (V) Figure Connection Coupling Span (V) VINA1 VINB1 # Comments
Single-Ended DC 2 0 to 2 1 32, 33 Best for stepped input response applications, suboptimum THD and noise performance, requires ± 5 V op amp. 2 × VREF 0 to VREF 32, 33 Same as above but with improved noise performance due to 2 × VREF increase in dynamic range. Headroom/settling time requirements of ± 5 V op amp should be evaluated. 5 0 to 5 2.5 32, 33 Optimum noise performance, excellent THD performance. Requires op amp with VCC > +5 V due to insufficient headroom @ 5 V. 2 × VREF 2.5 – VREF 2.5 39 Optimum THD performance with VREF = 1, noise performance to improves while THD performance degrades as VREF increases 2.5 + VREF to 2.5 V. Single supply operation (i.e., +5 V) for many op amps. Single-Ended AC 2 or 0 to 1 or 1 or VREF 34 Suboptimum ac performance due to input common-mode level 2 × VREF 0 to 2 × VREF not biased at optimum midsupply level (i.e., 2.5 V). 5 0 to 5 2.5 34 Optimum noise performance, excellent THD performance. 2 × VREF 2.5 – VREF 2.5 35 Flexible input range, Optimum THD performance with VREF = 1. to Noise performance improves while THD performance degrades as 2.5 + VREF VREF increases to 2.5 V. Differential AC or 2 2 to 3 3 to 2 29–31 Optimum full-scale THD and SFDR performance well beyond the DC A/Ds Nyquist frequency. 2 × VREF 2.5 – VREF/2 2.5 + VREF/2 29–31 Same as 2 V to 3 V input range with the exception that full-scale to to THD and SFDR performance can be traded off for better noise 2.5 + VREF/2 2.5 – VREF/2 performance. 5 1.25 to 3.75 3.75 to 1.25 29–31 Widest dynamic range (i.e., ENOBs) due to optimum noise performance. 1VINA and VINB can be interchanged if signal inversion is required.
Table II. Reference Configuration Summary Reference Input Span (VINA–VINB) Operating Mode (V p-p) Required VREF (V) Connect To
INTERNAL 2 1 SENSE VREF INTERNAL 5 2.5 SENSE REFCOM INTERNAL 2 ≤ SPAN ≤ 5 AND 1 ≤ VREF ≤ 2.5 AND R1 VREF AND SENSE SPAN = 2 × VREF VREF = (1 + R1/R2) R2 SENSE AND REFCOM EXTERNAL 2 ≤ SPAN ≤ 5 1 ≤ VREF ≤ 2.5 SENSE AVDD (NONDYNAMIC) VREF EXT. REF. EXTERNAL 2 ≤ SPAN ≤ 5 CAPT and CAPB SENSE AVDD (DYNAMIC) Externally Driven VREF REFCOM EXT. REF. 1 CAPT EXT. REF. 2 CAPB REV. B –11–
Single-Ended DC 2 0 to 2 1 32, 33 Best for stepped input response applications, suboptimum THD and noise performance, requires ± 5 V op amp. 2 × VREF 0 to VREF 32, 33 Same as above but with improved noise performance due to 2 × VREF increase in dynamic range. Headroom/settling time requirements of ± 5 V op amp should be evaluated. 5 0 to 5 2.5 32, 33 Optimum noise performance, excellent THD performance. Requires op amp with VCC > +5 V due to insufficient headroom @ 5 V. 2 × VREF 2.5 – VREF 2.5 39 Optimum THD performance with VREF = 1, noise performance to improves while THD performance degrades as VREF increases 2.5 + VREF to 2.5 V. Single supply operation (i.e., +5 V) for many op amps. Single-Ended AC 2 or 0 to 1 or 1 or VREF 34 Suboptimum ac performance due to input common-mode level 2 × VREF 0 to 2 × VREF not biased at optimum midsupply level (i.e., 2.5 V). 5 0 to 5 2.5 34 Optimum noise performance, excellent THD performance. 2 × VREF 2.5 – VREF 2.5 35 Flexible input range, Optimum THD performance with VREF = 1. to Noise performance improves while THD performance degrades as 2.5 + VREF VREF increases to 2.5 V. Differential AC or 2 2 to 3 3 to 2 29–31 Optimum full-scale THD and SFDR performance well beyond the DC A/Ds Nyquist frequency. 2 × VREF 2.5 – VREF/2 2.5 + VREF/2 29–31 Same as 2 V to 3 V input range with the exception that full-scale to to THD and SFDR performance can be traded off for better noise 2.5 + VREF/2 2.5 – VREF/2 performance. 5 1.25 to 3.75 3.75 to 1.25 29–31 Widest dynamic range (i.e., ENOBs) due to optimum noise performance. 1VINA and VINB can be interchanged if signal inversion is required.
Table II. Reference Configuration Summary Reference Input Span (VINA–VINB) Operating Mode (V p-p) Required VREF (V) Connect To
INTERNAL 2 1 SENSE VREF INTERNAL 5 2.5 SENSE REFCOM INTERNAL 2 ≤ SPAN ≤ 5 AND 1 ≤ VREF ≤ 2.5 AND R1 VREF AND SENSE SPAN = 2 × VREF VREF = (1 + R1/R2) R2 SENSE AND REFCOM EXTERNAL 2 ≤ SPAN ≤ 5 1 ≤ VREF ≤ 2.5 SENSE AVDD (NONDYNAMIC) VREF EXT. REF. EXTERNAL 2 ≤ SPAN ≤ 5 CAPT and CAPB SENSE AVDD (DYNAMIC) Externally Driven VREF REFCOM EXT. REF. 1 CAPT EXT. REF. 2 CAPB REV. B –11–