Datasheet

Maxim Integrated │ 20
MAX11166/MAX11167 16-Bit, 500ksps/250ksps, ±5V SAR ADCs
with Internal Reference in TDFN
www.maximintegrated.com
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 (V
AIN+
- V
AIN-
greater than +K x V
REF
, K =
5.000/4.096).
2) This is also the code for an underranged analog input
(V
AIN+
- V
AIN-
less than -K x V
REF
, K = 5.000/4.096)
Table 2. List of Recommended ADC Driver Op Amps for MAX11166/MAX11167
Figure 3. Bipolar Transfer Function
Table 3. Transfer Function Example
AMPLIFIER
INPUT-NOISE
DENSITY
(nV/√Hz)
SMALL-SIGNAL
BANDWIDTH
(MHz)
SLEW RATE
(V/µs)
THD
(dB)
I
CC
(mA)
COMMENTS
MAX9632 1 55 30 -128 3.9 Low noise, THD at 10kHz
MAX9633 3 27 18 -128 3.5 Low noise, dual amp, THD at 10kHz
CODE TRANSITION BIPOLAR INPUT (V) DIGITAL OUTPUT CODE (HEX)
+FS - 1.5 LSB +4.999771 FFFE - FFFF
Midscale + 0.5 LSB +0.000076 8000 - 8001
Midscale 0 8000
Midscale - 0.5 LSB -0.000076 7FFF - 8000
-FS + 0.5 LSB -4.999924 0000 - 0001
2
-FS
FFFF
8001
8000
0000
0001
7FFE
OUTPUTCODE (hex)
INPUT VOLTAGE (LSB)
7FFF
0
FULL-SCALE
TRANSITION
-FS
FFFE
-FS + 0.5 × LSB
+FS - 1.5 × LSB
+FS =
5 x V
REF
4.096
LSB =
+FS - (-FS)
65536
-FS =
-5 x V
REF
4.096