Rainbow Electronics MAX1039 - Manual (Page 20)

MAX1036–MAX1039
2.7V to 5.5V, Low-Power, 4-/12-Channel
2-Wire Serial 8-Bit ADCs
20 ______________________________________________________________________________________
Differential Nonlinearity
Differential nonlinearity (DNL) is the difference between
an actual step width and the ideal value of 1LSB. A
DNL error specification of less than 1LSB guarantees
no missing codes and a monotonic transfer function.
Aperture Jitter
Aperture jitter (t AJ ) is the sample-to-sample variation in
the time between the samples.
Aperture Delay
Aperture delay (t AD ) is the time between the rising
edge of the sampling clock and the instant when an
actual sample is taken.
Signal-to-Noise Ratio
For a waveform perfectly reconstructed from digital sam-
ples, signal-to-noise ratio (SNR) is the ratio of full-scale
analog input (RMS value) to the RMS quantization error
(residual error). The ideal, theoretical minimum analog-
to-digital noise is caused by quantization error only and
results directly from the ADC’s resolution (N bits):
SNR = (6.02 ✕ N + 1.76)dB
INPUT VOLTAGE (LSB)
OUTPUT CODE
1...111
1...110
1...101
1...100
0...000
0...001
0...010
0...011
2 3
256
V REF
1LSB =
1 253 255 254
REF
256 0 252
Figure 12. Unipolar Transfer Function
INPUT VOLTAGE (LSB)
OUTPUT CODE
(TWO'S COMPLEMENT)
0...111
0...110
0...101
0...100
1...000
1...001
1...010
1...011
-1 -126 -125
256
V REF
1LSB =
0 +1 -127 +125 +127 +126
0...000
0...001
1...111
REF
+128 -128 +124
'-' INPUT
Figure 13. Bipolar Transfer Function
3V/5V V LOGIC = 3V/5V GND
SUPPLIES
DGND 3V/5V GND
0.1 µF
V
DD
DIGITAL
CIRCUITRY MAX1036
MAX1037
MAX1038
MAX1039
R* = 5 Ω
*OPTIONAL
Figure 14. Power-Supply and Grounding Connections