MAX1191ETI+ Maxim Integrated Products, MAX1191ETI+ Datasheet - Page 21

• Manufacturer Part Number: MAX1191ETI+
• Description: IC ADC 8BIT 7.5MSPS DUAL 28-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX1191ETI+

• Number Of Bits: 8
• Sampling Rate (per Second): 7.5M
• Data Interface: Parallel
• Number Of Converters: 2
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-WFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 10 shows the MAX6061 precision bandgap ref-
erence used as a common reference for multiple con-
verters. The 1.248V output of the MAX6061 is divided
down to 1.023V as it passes through a one-pole, 10Hz,
lowpass filter to the MAX4250. The MAX4250 buffers
the 1.023V reference before its output is applied to the
MAX1191. The MAX4250 provides a low offset voltage
(for high gain accuracy) and a low noise level.
Figure 10. External Buffered (MAX4250) Reference Drive Using a MAX6062 Bandgap Reference
NOTE: ONE FRONT-END REFERENCE
CIRCUIT PROVIDES ±15mA OF OUTPUT
DRIVE AND SUPPORTS OVER 1000 MAX1191s.
0.1µF
3V
MAX6061
Ultra-Low-Power, 7.5Msps, Dual 8-Bit ADC
1
3
______________________________________________________________________________________
2
1µF
LOWPASS
1.248V
FILTER
10Hz
3
4
MAX4250
1%
20kΩ
1%
90.9kΩ
5
2
3V
1
0.1µF
15Ω
The unbuffered external reference mode allows for pre-
cise control over the MAX1191 reference and allows
multiple converters to use a common reference.
Connecting REFIN to GND disables the internal refer-
ence, allowing REFP, REFN, and COM to be driven
directly by a set of external reference sources.
Unbuffered External Reference Drives
0.33µF
0.33µF
0.33µF
0.33µF
0.33µF
0.33µF
0.1µF
0.1µF
1.023V
24
27
26
25
24
27
26
25
REFIN
REFP
REFN
COM
REFIN
REFP
REFN
COM
MAX1191
MAX1191
N = 1000
N = 1
GND
GND
V
V
DD
DD
0.1µF
Multiple ADCs
2.2µF
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