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.

Excellent THD and SNR

The WFD20 has a THD of -92 dB (typical) at 1 MHz and a 71 dB SNR (typical).

Medium Speed and High Resolution

The WDF20 offers 180 MHz max. sample speed at 16 bit resolution.

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.

Resolution 20 bit
Sample rate 1.5 kHz - 2 MHz in warp mode, 0 - 1.5 MHz in normal mode
Pattern depth 4M words
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
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
Dynamic characteristics
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

(conditions: 1.67 MS/s, 800 kHz filter on)

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
Clock & Trigger inputs
Input impedance > 1 MOhm
Threshold level 3.3 V CMOS/TTL (5 V tolerant)

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