MAX1338 Datasheet, PDF (20/24 Pages) Maxim Integrated Products – 14-Bit, 4-Channel, Software-Programmable, Multiranging, Simultaneous-Sampling ADC

14-Bit, 4-Channel, Software-Programmable,
Multiranging, Simultaneous-Sampling ADC
0x1FFF
0x1FFE
0x1FFD
0x1FFC
0x0001
0x0000
0x3FFF
4 x V_REFADC
0x2003
0x2002
0x2001
0x2000
1 LSB = ^{4 x VREF}
2¹⁴
-8192 -8190
-1 0 +1
+8189 +8191
INPUT VOLTAGE (V_{AIN_+} - V_{AIN_-} IN LSBs)
Figure 9. ±5V Transfer Function
0x1FFF
0x1FFE
0x1FFD
0x1FFC
0x0001
0x0000
0x3FFF
2 x V_REFADC
0x2003
0x2002
0x2001
0x2000
1 LSB = ^{2 x VREF}
2¹⁴
-8192 -8190
-1 0 +1
+8189 +8191
INPUT VOLTAGE (V_{AIN_+} - V_{AIN_-} IN LSBs)
Figure 10. ±2.5V Transfer Function
0x1FFF
0x1FFE
0x1FFD
0x1FFC
0x0001
0x0000
0x3FFF
V_REFADC
ANALOG
POWER SUPPLY
+5V
AGND
FERRITE
BEAD
DIGITAL POWER SUPPLIES
+5V
+3V
GND
0x2003
0x2002
0x2001
0x2000
1 LSB = ^VREF
2¹⁴
-8192 -8190
-1 0 +1
+8189 +8191
INPUT VOLTAGE (V_{AIN_+} - V_{AIN_-} IN LSBs)
Figure 11. ±1.25V Transfer Function
Gain Error
Gain error indicates how well the slope of the actual
transfer function matches the slope of the ideal transfer
function. For the MAX1338, the gain error is the differ-
ence between the measured positive full-scale and
negative full-scale transition points minus the difference
between the ideal positive full-scale and negative full-
scale bipolar transition points.
AV_DD
AGND DVDD
DGND DRV_DD DRGND +5V
GND
MAX1338
DIGITAL
CIRCUITS
Figure 12. Power-Supply Grounding and Bypassing
Signal-to-Noise Ratio (SNR)
SNR is a measure of the converter’s noise characteris-
tics. For a waveform perfectly reconstructed from digi-
tal samples, SNR is the ratio of the full-scale analog
input (RMS value) to the RMS quantization error (resid-
ual error). The ideal, theoretical minimum analog-to-dig-
ital noise is caused by quantization noise error only and
results directly from the ADC’s resolution (N bits):
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