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THS1031 Datasheet, PDF (13/26 Pages) Texas Instruments – 2.7 V . 5.5 V, 10-BIT, 30 MSPS CMOS ANALOG-TO-DIGITAL CONVERTER
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THS1031
2.7 V – 5.5 V, 10-BIT, 30 MSPS
CMOS ANALOG-TO-DIGITAL CONVERTER
SLAS242A – NOVEMBER 1999 – REVISED JANUARY 2000
PRINCIPLES OF OPERATION
Table 1. Mode Selection
MODES
ANALOG INPUT
INPUT
SPAN
MODE
PIN
REFSENSE
PIN
VREF
PIN
REFTS
PIN
REFBS
PIN
AIN
AIN
Top/bottom
AIN
AIN
AIN
AIN
Center span
AIN
AIN
External
reference
AIN
1V
2V
1+Ra/Rb
External VREF
1V
2V
1+Ra/Rb
VREF
2 V max
AVDD
AVDD
AVDD
AVDD/2
AVDD/2
AVDD/2
AVDD/2
AVDD/2
AGND
Short together
AGND
AGND
Short together
AGND
Mid Ra & Rb
Short together to Ra
AVDD
External
NC
Short together
AGND
AGND
AGND
Mid Ra & Rb
AVDD
See Note 1
NC
Ra
External
See Note 1
Short together to the
common mode voltage
Voltage within supply
(REFTS–REBS) = 2 V max
Differential
input
AIN is input 1
REFTS & REFBS
are shorted
together for input 2
1V
2V
VREF
AVDD/2
AVDD/2
AVDD/2
Short together
AGND
NC
AVDD
External
Short together AVDD/2
NOTE 1: In external reference mode, VREF can be available for external use with CENTER SPAN setup.
FIGURE
8, 15
9, 16
10, 15, 16
10, 15, 16
8, 14
9, 14
10, 14
11, 14
12, 13
17
reference operations
VREF-pin reference
The voltage reference sources on the VREF pin are controlled by the REFSENSE pin as shown in Table 2.
REFSENSE
AGND
AVDD
Short to VREF
Connect to Ra/Rb
Table 2. VREF Reference Selection
VREF
2V
The internal reference is disabled and an external reference should be connected to VREF pin if mode = AVDD/2
1V
1+Ra/Rb
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