MAX11166 Datasheet, PDF (20/33 Pages) Maxim Integrated Products – 16-Bit, 500ksps/250ksps, ±5V SAR ADCs with Internal Reference in TDFN

MAX11166/MAX11167
16-Bit, 500ksps/250ksps, ±5V SAR ADCs
with Internal Reference in TDFN
degraded significantly. It is recommended to insert
an external RC filter at the MAX11166/MAX11167
AIN+ input to attenuate out-of-band input noise and
preserve the ADCs SNR. The effective RMS noise at
the MAX11166/MAX11167 AIN+ input is 64FV, thus
additional noise from a buffer circuit should be sig-
nificantly lower in order to achieve the maximum SNR
performance.
3) THD performance: The input buffer amplifier used
should have a comparable THD performance with that
of the MAX11166/MAX11167 to ensure the THD of the
digitized signal is not degraded.
Table 2 summarizes the operational amplifiers that are
compatible with the MAX11166/MAX11167. The MAX9632
has sufficient bandwidth, low enough noise and distor-
tion to support the full performance of the MAX11166/
MAX11167. The MAX9633 is a dual amp and can support
buffering for true pseudo-differential sampling.
Transfer Function
The ideal transfer characteristic for the MAX11166/
MAX11167 is shown in Figure 3. The precise location of
various points on the transfer function are given in Table 3.
1) This is also the code for an overranged analog
input (VAIN+ - VAIN- greater than +K x VREF, K =
5.000/4.096).
2) This is also the code for an underranged analog input
(VAIN+ - VAIN- less than -K x VREF, K = 5.000/4.096)
FFFF
FFFE
8001
8000
7FFF
7FFE
+FS = ^{5 x VREF}
4.096
-FS = ^{-5 x VREF}
4.096
LSB =+F6S5-5(3-6FS)
FULL-SCALE
TRANSITION
0001
0000
-FS
-FS + 0.5 × LSB
0
+FS - 1.5 × LSB
-FS
INPUT VOLTAGE (LSB)
Figure 3. Bipolar Transfer Function
Table 2. List of Recommended ADC Driver Op Amps for MAX11166/MAX11167
AMPLIFIER
MAX9632
MAX9633
INPUT-NOISE
DENSITY
(nV/√Hz)
1
3
SMALL-SIGNAL
BANDWIDTH
(MHz)
55
27
SLEW RATE
(V/µs)
30
18
THD
(dB)
-128
-128
I_CC
(mA)
COMMENTS
3.9 Low noise, THD at 10kHz
3.5 Low noise, dual amp, THD at 10kHz
Table 3. Transfer Function Example
CODE TRANSITION
+FS - 1.5 LSB
Midscale + 0.5 LSB
Midscale
Midscale - 0.5 LSB
-FS + 0.5 LSB
BIPOLAR INPUT (V)
+4.999771
+0.000076
0
-0.000076
-4.999924
DIGITAL OUTPUT CODE (HEX)
FFFE - FFFF
8000 - 8001
8000
7FFF - 8000
0000 - 0001²
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