MAX149BEPP View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX149BEPP

+2.7V to +5.25V, Low-Power, 8-Channel, Serial 10-Bit ADCs

Maxim Integrated 

+2.7V to +5.25V, Low-Power, 8-Channel,

Serial 10-Bit ADCs

ANALOG

INPUTS

+

1 CH0

2 CH1

VDD 20

SCLK 19

3 CH2 MAX148

MAX149

4 CH3

CS 18

DIN 17

5 CH4

SSTRB 16

6 CH5

DOUT 15

7 CH6

DGND 14

8 CH7

AGND 13

9 COM

REFADJ 12

10 SHDN

VREF 11

0.1µF

0.1µF

+2.5V

Figure 20. MAX148/MAX149 QSPI Connections, External Reference

+3V +3V

1µF

(POWER SUPPLIES)

SCK

PCS0

MOSI

MC683XX

MISO

(GND)

XF

CLKX

TMS320LC3x

CLKR

DX

DR

FSR

CS

SCLK

MAX148

MAX149

DIN

DOUT

SSTRB

Figure 21. MAX148/MAX149-to-TMS320 Serial Interface

20  

Layout, Grounding, and Bypassing

For best performance, use PCBs. Wire-wrap boards

are not recommended. Board layout should ensure that

digital and analog signal lines are separated from each

other. Do not run analog and digital (especially clock)

lines parallel to one another, or digital lines underneath

the ADC package.

Figure 19 shows the recommended system ground con-

nections. Establish a single-point analog ground (star

ground point) at AGND, separate from the logic ground.

Connect all other analog grounds and DGND to the star

ground. No other digital system ground should be con-

nected to this ground. For lowest-noise operation, the

ground return to the star ground’s power supply should

be low impedance and as short as possible.

High-frequency noise in the VDD power supply may

affect the high-speed comparator in the ADC. Bypass

the supply to the star ground with 0.1FF and 1FF capaci-

tors close to pin 20 of the MAX148/MAX149. Minimize

capacitor lead lengths for best supply-noise rejection.

If the power supply is very noisy, a 10I resistor can be

connected as a lowpass filter (Figure 19).

Share Link: