Analog Input Connections; Avdd Voltage Settings - Texas Instruments ADS7041EVM-PDK User Manual

Power Supplies
Reference Designator
J3
P2
3 Power Supplies
The ADS7041 supports a wide range of operation on its analog supplies. The AVDD can operate from
1.8V to 3.6V. The DVDD operates from 1.65 V to 3.6 V, independent of the AVDD supply.
The analog portion of the ADS7041EVM-PDK operates from a 5-V supply. The ADS7041EVM-PDK is
configured to use the onboard regulated analog 5-V supply that in turn generates an AVDD analog supply
using the low-noise TPS79101 LDO. This supply is nominally set to 3.3 V at the factory, but this voltage
maybe changed to any value within the valid range, by modifying the value of R46 as per
any intermediate value needs to be set, the detailed formula to arrive at these values are available in the
TPS79101 (SGLS160) datasheet.
AVDD Voltage
1.8 V
2.0 V
2.5 V
3.0 V
3.3 V (default)
3.6 V
Alternatively, AVDD may be set by connecting an external power source through P3.
the modifications required for on-board or external AVDD supply.
Onboard regulated AVDD (set to 3.3 V)
The external AVDD supply applied to external connector P3 must not exceed
3.6 V as this may damage the device. The external AVDD supply must be in
the range of 1.8 V to 3.6 V for proper operation of the ADS7041EVM.
The digital portion of the ADS7041 ADC operates from a 3.3-V supply from the Simple Capture Card. The
buffer U12 is included to ensure that the SDO can be driven to the controller with minimal distortion.
4
ADS7041EVM-PDK
Table 2. Analog Input Connections
Signal Description
INP Positive single-ended input provided at the SMA
INP Alternate location to provide the positive single-ended input. Normally not populated on
the board.
Table 3. AVDD Voltage Settings
R46
14.2 kΩ
19.1 kΩ
31.6 kΩ
43.7 kΩ
51.1 kΩ
59.0 kΩ
Table 4. AVDD Voltage Settings
AVDD Source
External AVDD
Copyright © 2014, Texas Instruments Incorporated
R45
30.1 kΩ
30.1 kΩ
30.1 kΩ
30.1 kΩ
30.1 kΩ
30.1 kΩ
Position
P3
P3
R47
CAUTION
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Table 3. In case
C34
33 pF
27 pF
22 pF
15 pF
15 pF
15 pF
Table 4 describes
Setting
Closed
Open
Disassembled
SBAU239 – November 2014
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