MAX12527 Datasheet, PDF (23/28 Pages) Maxim Integrated Products – Dual, 65Msps, 12-Bit, IF/Baseband ADC

Dual, 65Msps, 12-Bit, IF/Baseband ADC
3.3V
0.1µF
1
MAX6029
(EUK21)
5 ^16.2kΩ
1µF
2
NOTE: ONE FRONT-END REFERENCE CIRCUIT IS
CAPABLE OF SOURCING UP TO 15mA AND
SINKING UP TO 30mA OF OUTPUT CURRENT.
0.1µF
2.2µF
3
5
MAX4230
4
2
2.048V
0.1µF
1
47Ω
300µF
6V
1.47kΩ
0.1µF
REFIN
V_DD
REF_P
MAX12527
REF_N
REFOUT
GND
COM_
10µF 0.1µF
0.1µF
0.1µF
0.1µF
3.3V
0.1µF
2.2µF
REFIN
V_DD
REF_P
MAX12527
REF_N
10µF 0.1µF
0.1µF
0.1µF
0.1µF
REFOUT
GND
COM_
0.1µF
Figure 12. External Buffered (MAX4230) Reference Drive Using a MAX6029 Bandgap Reference
Buffered External Reference Drives
Multiple 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 Drives
Multiple ADCs
The 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-
______________________________________________________________________________________ 23