Texas Instruments ADS7853EVM-PDK, Руководство пользователя, Страница: 6 / 41

FSR
0 V
AINP_x
AINM_x
Single-Ended Configuration
ADSxx53
FSR / 2
FSR
0 V
AINP_x
AINM_x
Pseudo-Differential Configuration
ADSxx53
FSR / 2
JP7/JP8:
Shunt 1-2
JP7/JP8:
Shunt 2-3
EVM Analog Interface
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2.1 Analog Input Range Settings
The full-scale range (FSR) of the ADSxx53 device can be programmed to either from (0 to 1 × V
ref
) or (0 to
2 × V
ref
) range by setting bit B9 of the ADSxx53 configuration register. This register is common to both
ADCs in the device (ADC_A and ADC_B). Configure the full-scale range setting in the EVM by navigating
to the
ADSxx53EVM Settings page on the grpahical user interface (GUI); see section Section 6.3 for more
information. Install jumpers JP3 and JP4 when supporting the 0 to 1 × V
ref
range, and remove jumpers JP3
and JP4 when supporting the 0 to 2 x V
ref
range, as shown in Table 3 .
Table 3. Analog Input Range Jumpers
Jumper Number Default Position Description
JP3 Installed Install for FSR = 0 to 1 × V
ref
; remove for FSR = 0 to 2 × V
ref
.
JP4 Installed Install for FSR = 0 to 1 × V
ref
; remove for FSR = 0 to 2 × V
ref
.
2.2 Single-Ended or Pseudo-Differential Input Configuration
The ADSxx53 dual, simultaneous ADC supports single-ended or pseudo-differential analog input signals.
To support single-ended inputs, set bit B7 in the configuration (CFR) register to 0 (CFR.B7 = 0), and
connect ADC inputs AINM_A and AINM_B to GND. These devices can also be programmed to support
pseudo-differential inputs by setting bit B7 in the CFR register to 1 (CFR.B7 = 1). In this configuration,
AINM_A is connected to FSR_ADC_A / 2, and AINM_B is connected to FSR_ADC_B / 2. Note that bit
CFR.B7 is common to both ADCs. By configuring jumpers JP7 and JP8 on the ADSxx53EVM, the
negative inputs of the ADC can be connected to GND to support the single-ended configuration, or
connected to FSR/2 when programmed to support pseudo-differential inputs, as shown in
Figure 2 . See
Section 6.3 for more information.
Figure 2. Single-Ended or Pseudo-Differential Input Configuration
2.3 Bipolar Input-Signal Configuration
The ADSxx53EVM-PDK supports both bipolar or unipolar input signals on the J1 (JP1.2) and J2 (JP2.2)
analog interface connectors. When jumpers JP9 and JP10 are closed, the inverting amplifier (OPA836) is
biased at the appropiate common-mode voltage level to support bipolar signals on the analog interface
connectors. In this configuration, apply a bipolar input signal with 0-V common-mode voltage.
6 ADS8353EVM-PDK and ADS7853EVM-PDK SBAU210A – June 2014 – Revised August 2014
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