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MAX1213N Datasheet, PDF (14/21 Pages) Maxim Integrated Products – 1.8V, Low-Power, 12-Bit, 170Msps ADC for Broadband Applications
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1.8V, Low-Power, 12-Bit, 170Msps
ADC for Broadband Applications
Table 1. MAX1213N Digital Output Coding
INP ANALOG
INPUT VOLTAGE
LEVEL
> VCM + VFS / 4
VCM + VFS / 4
VCM
VCM - VFS / 4
< VCM + VFS / 4
INN ANALOG
INPUT VOLTAGE
LEVEL
OUT-OF-RANGE
ORP (ORN)
< VCM - VFS / 4
VCM - VFS / 4
VCM
1 (0)
0 (1)
0 (1)
VCM + VFS / 4
> VCM - VFS / 4
0 (1)
1 (0)
BINARY DIGITAL OUTPUT
CODE (D11P/N–D0P/N)
1111 1111 1111
(exceeds +FS, OR set)
1111 1111 1111 (+FS)
1000 0000 0000 or
0111 1111 1111 (FS/2)
0000 0000 0000 (-FS)
00 0000 0000
(exceeds -FS, OR set)
TWO’S-COMPLEMENT DIGITAL
OUTPUT CODE (D11P/N–D0P/N)
0111 1111 1111
(exceeds +FS, OR set)
0111 1111 1111 (+FS)
0000 0000 0000 or
1111 1111 1111 (FS/2)
1000 0000 0000 (-FS)
10 0000 0000
(exceeds -FS, OR set)
Applications Information
FSR Adjustments Using the Internal
Bandgap Reference
The MAX1213N supports a 10% (±5%) full-scale
adjustment range. To decrease the full-scale signal
range, add an external resistor value ranging from
13kΩ to 1MΩ between REFADJ and AGND. Adding a
variable resistor, potentiometer, or predetermined resis-
tor value between REFADJ and REFIO increases the
FSR of the data converter. Figure 6a shows the two
possible configurations and their impact on the overall
full-scale range adjustment of the MAX1213N. Do not
use resistor values of less than 13kΩ to avoid instability
of the internal gain regulation loop for the bandgap ref-
erence. See Figure 6b for the resulting FSR for a series
of resistor values.
CONFIGURATION TO INCREASE THE FSR OF THE MAX1213N
ADC FULL SCALE = REFT - REFB
REFT
REFERENCE REFB
BUFFER
1V
REFERENCE-
SCALING
AMPLIFIER
G
REFIO
CONTROL LINE
TO DISABLE
REFERENCE BUFFER
REFADJ
0.1µF
13kΩ TO
1MΩ
CONFIGURATION TO DECREASE THE FSR OF THE MAX1213N
ADC FULL SCALE = REFT - REFB
REFT
REFERENCE REFB
BUFFER
1V
REFERENCE-
SCALING
AMPLIFIER
G
REFIO
CONTROL LINE
TO DISABLE
REFERENCE BUFFER
REFADJ
MAX1213N
AVCC
AVCC / 2
Figure 6a. Circuit Suggestions to Adjust the ADC’s Full-Scale Range
MAX1213N
AVCC
AVCC / 2
0.1µF
13kΩ TO
1MΩ
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