Datasheet

THS4520
ADS1672
R56
R55 R14
R15
R12
R11
R5 R10
R9 R8
R3
C10
(NI)
C18
C55
C14
(NI)
VCC
VCCRCM
RCM
-IN(J1or
P3-1)
+IN(J2or
P3-2)
R47
(NI)
R53
(NI)
R4
(NI)
R48
(NI)
R6
R50
(NI)
R54
(NI)
R13
(NI)
R49
(NI)
C64
(NI)
C65
(NI)
Analog Interface www.ti.com
Analog input signals to the THS4520/ADS1672 signal chain can be applied at connectors J1 (inverting
input, –IN) and J2 (noninverting input, +IN) or P3-1 (–IN) and P3-2 (+IN). The P3 connector is an SMT
plug on the top side of the PCB (as Figure 1 shows). The signal at +IN and –IN should be differential and
centered at 2.5V.
Figure 1. Location of Onboard Connectors J1, J2, W1, P1, P2, SW1, and P3
At the analog board inputs, +IN and –IN, there are termination resistors (R3, R6 = 49.9 Ω ) installed on the
board at J1 and J2 (as Figure 2 illustrates). These resistors are followed by a capacitor between the inputs
(C55 = 750pF) and resistors (R8, R10 = 383 Ω ) to the THS4520. Additional pads are available at the
inputs of the THS4520 to allow insertion of capacitor and/or resistor networks.
Figure 2. ADS1672EVM Input Signal Path
Note: If you are connecting the ADS1672EVM through the MMB0 board to ADCPro, there are no
modifications required.
4 ADS1672EVM and ADS1672EVM-PDK User's Guide SBAU147 – March 2009
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