UG-478 Datasheet, PDF (9/40 Pages) Analog Devices – Evaluation Board for the AD7176-2—24-Bit, 250 kSPS Sigma-Delta ADC with 20 μs Settling

Evaluation Board User Guide
+5V
0.1µF
R92
R68
R91 R72 R34
IN0
R65
IN1
R93
C19
AD8656
C59
R105 R100 R39
+5V
0.1µF
6
7
8
AVSS AVDD1 AVDD2
21 AIN0
C23
22 AIN1
0.1µF
R99
R106
R109
R107
IN2
R117
IN3
R116
R115 R110 R47
C28
AD8656
C27
R125 R120 R46
R119
R126
AD7176-2
0.1µF
4 REFOUT
23 AIN2
C26
24 AIN3
REF+
3
SCLK 13
DIN 12
DOUT/RDY ¹¹
CS ¹⁴
REF–
2
0.1µF
+5V
+5V
0.1µF
ADR445*
5V VREF
0.1µF
0.1µF
4.7µF
*USING ADR444 (4.096V REFERENCE) IN PLACE OF
THE ADR445 ALLOWS THE ENTIRE CCT TO BE
OPERATED FROM A SINGLE +5V SUPPLY RAIL.
Figure 6. Setup for the AD8656 Amplifiers
Table 5. R/C Values Used with AD8656 Amplifiers (Gain = 2)
U8
Component
Status
R65
0Ω
R68
1 kΩ, 0.1%
R72 ¹
0Ω
R91
10 Ω
R92
1 kΩ, 0.1%
R93
0Ω
R99
1 kΩ, 0.1%
R100¹
0Ω
R105
10 Ω
R106
1 kΩ, 0.1%
R34
0Ω
R39
0Ω
C19
270 pF
C59
270 pF
C23
680 pF
Component
R107
R109
R110²
R115
R116
R117
R119
R120²
R125
R126
R46
R47
C27
C28
C26
U12
Status
0Ω
1 kΩ, 0.1%
0Ω
10 Ω
1 kΩ, 0.1%
0Ω
1 kΩ, 0.1%
0Ω
10 Ω
1 kΩ, 0.1%
0Ω
0Ω
270 pF
270 pF
680 pF
1 _{Remove R72 and R100 when connecting the ADA4940-1 to the AD7176-2.}
2 _{Remove R110 and R120 when connecting the AD8475 to the AD7176-2.}
UG-478
Rev. 0 | Page 9 of 40