MAX149AEAP Maxim Integrated Products, MAX149AEAP Datasheet - Page 20

• Manufacturer Part Number: MAX149AEAP
• Description: ADC (A/D Converters) Integrated Circuits (ICs)
• Manufacturer: Maxim Integrated Products

Specifications of MAX149AEAP

• Architecture: SAR
• Conversion Rate: 133 KSPs
• Input Type: Voltage
• Maximum Power Dissipation: 640 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-20
• Minimum Operating Temperature: - 40 C
• Lead Free Status / Rohs Status: No

+2.7V to +5.25V, Low-Power, 8-Channel,
Serial 10-Bit ADCs
Figure 20. MAX148/MAX149 QSPI Connections, External Reference
Figure 21. MAX148/MAX149-to-TMS320 Serial Interface
20
_____________________________________________________________________________________
TMS320LC3x
ANALOG
INPUTS
CLKX
CLKR
FSR
DX
DR
XF
10
1
2
3
4
5
6
7
8
9
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
COM
SHDN
CS
SCLK
DIN
DOUT
SSTRB
MAX148
MAX149
MAX148
MAX149
REFADJ
SSTRB
DGND
DOUT
AGND
SCLK
VREF
V
DIN
CS
DD
20
19
18
17
16
15
14
13
12
11
0.1µF
0.1µF
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 V
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).
+2.5V
Layout, Grounding, and Bypassing
1µF
+3V
+3V
(POWER SUPPLIES)
SCK
PCS0
MOSI
MISO
MC683XX
(GND)
DD
power supply may