MAX191BCWG Maxim Integrated Products, MAX191BCWG Datasheet - Page 21

• Manufacturer Part Number: MAX191BCWG
• Description: ADC (A/D Converters) Integrated Circuits (ICs)
• Manufacturer: Maxim Integrated Products

Specifications of MAX191BCWG

• Number Of Adc Inputs: 1
• Architecture: SAR
• Conversion Rate: 100 KSPs
• Resolution: 12 bit
• Input Type: Differential
• Interface Type: 3-Wire (SPI, QSPI, Microwire)
• Supply Voltage (max): 5 V
• Maximum Power Dissipation: 1067 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Package / Case: SO-24
• Minimum Operating Temperature: 0 C
• Lead Free Status / Rohs Status: No

Figure 21b. Offset (±10mV) and Gain (±1%) Trim Circuit
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 digi-
tal (especially clock) lines parallel to one another, or
digital lines underneath the ADC package.
Figure 23 shows the recommended system ground
connections. Establish a single-point ground (“star”
ground point) at AGND, separate from the logic
ground. Connect all other analog grounds and DGND
to it. No other digital-system ground should be con-
nected to this single-point analog ground. The ground
return to the power supply for this star ground should
be low impedance and as short as possible for noise-
free operation.
High-frequency noise in the V
affect the high-speed comparator in the ADC. Bypass
these supplies to the single-point analog ground with
V
* CONNECT AIN- TO AGND WHEN USING DUAL SUPPLIES
IN
10k
R7
10k
R8
10k
R6
VREF
with Internal Reference and Power-Down
0.1 F*
______________________________________________________________________________________
MAX480
10k
R5
100
10k
10k
R9*
20k
R1
R2
R3
49.9
VREF
R4
49.9
DD
R10*
power supply may
Low-Power, 12-Bit Sampling ADC
AIN -
AIN +
MAX191
D0–D11
Figure 22. Bipolar Transfer Function
Figure 23. Power-Supply Grounding Connection
SINGLE SUPPLY
DUAL SUPPLY
AIN- = 0V
(
AIN- = ––––
*OPTIONAL
01 . . . 111
01 . . . 110
00 . . . 010
00 . . . 001
00 . . . 000
11 . . . 111
11 . . . 110
11 . . . 101
10 . . . 001
10 . . . 000
V
+5V
DD
VREF
2
R* = 10
)
-VREF
––––
0V
2
AGND
MAX191
SUPPLIES
V
-5V
SS
DGND
––––
VREF
0V
2
+5V
CIRCUITRY
DIGITAL
–––– - 1LSB
VREF
DGND
VREF - 1LSB
GND
2
21