Buffered External Reference DrivesMultiple ADCs
The buffered external reference mode allows for more
control over the MAX12527 reference voltage and
allows multiple converters to use a common reference.
The REFIN input impedance is >50MΩ.
Figure 12 shows the MAX6029 precision 2.048V bandgap
reference used as a common reference for multiple con-
verters. The 2.048V output of the MAX6029 passes
through a single-pole 10Hz LP filter to the MAX4230.
The MAX4230 buffers the 2.048V reference and pro-
vides additional 10Hz LP filtering before its output is
applied to the REFIN input of the MAX12527.
Unbuffered External Reference DrivesMultiple ADCsThe unbuffered external reference mode allows for pre-
cise control over the MAX12527 reference and allows
multiple converters to use a common reference.
Connecting REFIN to GND disables the internal refer-
MAX12527
Dual, 65Msps, 12-Bit, IF/Baseband ADC
______________________________________________________________________________________ 23
MAX4230
0.1µF
1µF
5
2
3
4
1
1
5
2
REFIN
VDD
GND
0.1µF
47Ω
3.3V
2.048V
16.2kΩ
REFOUT
0.1µF
REF_P
REF_N
COM_
0.1µF
0.1µF
0.1µF
2.2µF
0.1µF
3.3V
1.47kΩ
300µF
6V
NOTE: ONE FRONT-END REFERENCE CIRCUIT IS
CAPABLE OF SOURCING UP TO 15mA AND
SINKING UP TO 30mA OF OUTPUT CURRENT.
10µF0.1µF
REFIN
VDD
GND
REFOUT
0.1µF
REF_P
REF_N
COM_
0.1µF
0.1µF
0.1µF
2.2µF
0.1µF