Maxim MAX12557 User Manual download pdf (Page 23)

Buffered External Reference Drives

Multiple ADCs

The buffered external reference mode allows for more

control over the MAX12557 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 MAX4250 buffers the 2.048V reference and pro-

vides additional 10Hz LP filtering before its output is

applied to the REFIN input of the MAX12557.

Unbuffered External Reference Drives

Multiple ADCs

The unbuffered external reference mode allows for pre-

cise control over the MAX12557 reference and allows

multiple converters to use a common reference.

Connecting REFIN to GND disables the internal refer-

MAX12557

Dual, 65Msps, 14-Bit, IF/Baseband ADC

______________________________________________________________________________________ 23

MAX4230

0.1µF

1µF

REFIN

GND

0.1µF

47Ω

3.3V

2.048V

16.2kΩ

REFOUT

0.1µF

REF_P

REF_N

COM_

0.1µF

2.2µF

0.1µF

3.3V

1.47kΩ

300µF

NOTE: ONE FRONT-END REFERENCE CIRCUIT IS

CAPABLE OF SOURCING UP TO 15mA AND

SINKING UP TO 30mA OF OUTPUT CURRENT.

10µF

0.1µF

REFIN

GND

REFOUT

0.1µF

REF_P

REF_N

COM_

0.1µF

2.2µF

0.1µF

10µF

0.1µF

MAX12557

MAX6029

(EUK21)

MAX12557

Figure 12. External Buffered (MAX4230) Reference Drive Using a MAX6029 Bandgap Reference

1 2 ... 18 19 20 21 22 23 24 25 26 27 28

MAX12557 1

Comments to this Manuals

No comments

Maxim MAX12557 User Manual Page 23

Comments to this Manuals

Related products and manuals for Unknown Maxim MAX12557