Datasheet

Q1
Depletion Mode
RZ1
C2
RZ2
C3
RZ4
C5
RZ3
C4
RZ5
C6
RCM
Rlin
15.8k
Rvi
R7
0
R8
0
R5
10k
V/I-1 V/I-0
V/I-4V/I-3 V/I-5
V/I-2
OPA_OUT
R9
0
REFout R_set
RSET
REFin
Io Vcc Vgate
F1
F2
D1
C8
220pF
C9
2.2uF
C10
0.01uF
R_lin
Cfilter
Iin
Vo
OPA In +
VCC
VCC
SI
5
SO
2
HOLD
7
WP
3
Vcc
8
Vss
4
SCK
6
CS
1
U2
25C040
R11
30.1k
R10
36.5k
C13
330pF
C12
1nF
Charge Pump
24
5
3
U3
2
3
1
D2
VCC C11
0.01uF
C1
0.1uF
Iout
FET
CP
CP_ON
Vout
Bypass
Bypass
CP_OFF
VCC
GND GND GND GND GND GND
RL
R2
100
R3
100
R4
100
CS2
Load
Buf
Bypass
BBLOGO
TI LOGO
No Load
FET
1
2
3
J5
RTD_CON
1
2
3
JMP5
1
2
3
JMP4
1
2
3
JMP6
1
2
3
JMP1
1
2
3
JMP7
1
2
3
JMP2
1
2
3
JMP3
1
2
J4
1
2
J3
Jumper Comments
1-2 = No Load (Voltage Mode)
2-3 = Load (Current Mode)
JMP4
1-2 = Current Mode
2-3 = Use Charge Pump
Charge Pump (Voltage Mode):
1-2 = Use Buffer
2-3 = Bypass Buffer
1-2 = Current Mode
2-3 = Voltage Mode
JMP5
JMP6
JMP3
JMP1
JMP2
JMP7
1-2 = Use FET
2-3 = Bypass FET
1-2 = Use FET
2-3 = Bypass FET
1-2 = No Charge Pump CLK
2-3 = Charge Pump CLK = SPI_SCK
R1
49.9k
VCC
R6
Iout
Vo_XTR108
Io_XTR108
499
6.34k
12.1k
Steward HZ0603
Steward HZ0603
Io+
Io -
Vo +
Vo -
Rz
Rcm
RTD
Io+
Io -
Vo +
Vo -
Rz
Rcm
RTD
SPI_SCK
SPI_DIO
SPI_CS1
SPI_SCK
SPI_DIO
SPI_CS1
BAV99RWT1
1SS355TE-17
Male
SCK SDIO
OPA In -
Vo +
Vo -
CS1
RTD
Rz
Rcm
Io +
Io -
1
2
3
J1
SPI
SDIO
SCK
CS1
Note: 100V cap
V/I-0
1
V/I-1
2
V/I-2
3
V/I-3
4
V/I-4
5
V/I-5
6
Cfilter
7
Rlin
8
Vo
9
Iin
10
Iret
12
Io
11
Vs
13
Vgate
14
REFin
20
REFout
21
Rset
19
CS2
15
CS1
18
SCLK
17
SDIO
16
OPA+In
24
OPA-In
23
OPA OUT
22
MUX
PGA V/I
Voltage
Sub-Reg
SR and Control Circuits
Reference
Driver
Linearization
U1
XTR108
SPI_SCK
CF
0.01uF
1
9
2
10
3
11
4
12
5
13
6
14
7
15
8
J2
DB15
C7
CAP
Rz
Rcm
1
2
3
JMP8
JMP8
1-2 = 2-Wire RTD
2-3 = 3-Wire RTD
3-Wire RTD
2-Wire RTD
www.ti.com Hardware Documentation
Figure 35 shows the XTR108EVM-USB Sensor Board schematic.
Figure 35. XTR108EVM-USB Sensor Board Schematic
7.2 Layouts
Refer to Figure 15 for the XTR108EVM-USB Interface Board component-side layout. Refer to Figure 16
for the XTR108EVM-USB Sensor Board component-side layout.
49
SBOU123–March 2012 XTR108EVM-USB Evaluation Board and Software Tutorial
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