The WFD20 is a 20 bit Waveform Digitizer for medium-speed / high resolution waveform capturing and analyzing. The module combines an excellent dynamic performance with a very high DC accuracy. The module features a fully differential input path to reduce common-mode level disturbances. If the internal DC-offset voltage source is used, the negative input can still be used as a GND Sense input, so the DC performance won’t be compromised due to ground currents. The module has 8 input ranges from 0.544 Vpp to 8.16 Vpp, which allows easy adaptation to a wide range of Unit Under Test output voltages.
A filter-bank with 3 Low Pass filters (40 kHz, 250 kHz and 800 kHz) provide excellent signal conditioning to obtain the best result in dynamic performance: low noise and anti-aliasing. The special combination of four 18 bit ADCs to a 20 bit converter gives an excellent SNR and linearity and a resolution down to 0.52 µV. With 4M-word (12M-byte) of memory a large number of samples can be captured. All these features ensure a very accurate result when performing analog measurements. The unit is very suitable for testing DAC linearity and dynamic performance.
A filter-bank with 3 Low Pass filters (40 kHz, 250 kHz and 800 kHz) provide excellent signal conditioning to obtain the best result in dynamic performance: low noise and anti-aliasing. The special combination of four 18 bit ADCs to a 20 bit converter gives an excellent SNR and linearity and a resolution down to 0.52 µV. With 4M-word (12M-byte) of memory a large number of samples can be captured. All these features ensure a very accurate result when performing analog measurements. The unit is very suitable for testing DAC linearity and dynamic performance.
Block Diagram
Key Features
- 2 MHz max sample speed
- 20 bit resolution
- Fully differential input
- 8 input ranges
- Selectable filters to reduce out-of-band noise
- -119 dB THD typical (f-in = 1 kHz)
- 96 dB SNR typical (DC - 800 kHz)
- Programmable DC-offset voltage
- For ATX series hardware platform
Downloads
Technical Specifications
General
Resolution | 20 bit |
Sample rate | 1.5 kHz - 2 MHz in warp mode, 0 - 1.5 MHz in normal mode |
Pattern depth | 4M words |
Input characteristics
Input impedance | 100 MOhm |
Input ranges | 0.544 Vpp, 0.816 Vpp, 1.36 Vpp, 2.04 Vpp, 2.72 Vpp, 4.08 Vpp, 5.44 Vpp, 8.16 Vpp |
Input filters | Bypass, 40 kHz (4-pole Butterw.), 250 kHz (5-pole Butterworth), 800 kHz (7-pole elliptic) |
Bandwidth -3 dB (typical) | 2 MHz (8.16 Vpp range) |
0.1 dB flatness (typical) | 400 kHz (8.16 Vpp range) |
Input configuration | Differential / Single Ended (-Input to Gnd, Gnd-sense or DC offset) |
Input Common mode range | +/- 10 V |
Accuracy (DC-offset off, filter bypass)
Absolute accuracy | ±(40 µV + 10 ppm of range) |
Non Linearity error | ±8 ppm of range (3 ppm typical) |
Temperature drift (typical) | ±(1 ppm of range + 2 ppm of reading)/ºC |
DC-offset source
Resolution | 19 bit (20 µV) |
Voltage range | -5 V to +5 V |
DC-offset accuracy | ±(50 µV + 12 ppm of value) |
Non Linearity | ±10 ppm of range |
Dynamic characteristics
(conditions: 1.67 MS/s, 800 kHz filter on)SNR (5 Vpp, 1 kHz input) | 93 dB |
SNR (5 Vpp, 10 kHz input) | 92 dB |
SNR (5 Vpp, 100 kHz input) | 91 dB |
SNR (1 kHz input, A-weighted) | 105 dB (BW 20 Hz - 20 kHz) |
THD (2 Vpp, 1 kHz input) | -110 dB |
THD (2 Vpp, 10 kHz input) | -106 dB |
THD (2 Vpp, 100 kHz input) | -92 dB |
SFDR (2 Vpp, 1 kHz input) | 108 dB |
Clock & Trigger inputs
Input impedance | > 1 MOhm |
Threshold level | 3.3 V CMOS/TTL (5 V tolerant) |