Datasheet

5 Power Supplies
Power Supplies www.ti.com
The EVM accepts four power supplies.
• A dual ± V
S
dc supply for the dual-supply operational amplifers. Recommended: ± 6 VDC.
• A single 5-V dc supply for the analog section of the board (ADC + reference).
• A single 5-V or 3.3-V dc supply for the digital section of the board (output buffers U6).
There are two ways to provide these voltages.
1. Wire in voltages at test points on the EVM. See Table 5 .
Table 5. Power-Supply Test Points
Test Point Signal Description
TP1 +VA Apply +6 VDC. Positive supply for amplifier.
TP2 –VA Apply –6 VDC. Negative supply for amplifier.
TP3 +BVDD Apply 3.3 VDC or 5 VDC. See the ADC data sheet for full range.
TP4 +AVCC Apply 5 VDC.
2. Use the power connector J2, and derive the voltages elsewhere. The pin out for this connector is
shown in Table 6 . If using this connector, then set W1 jumper to connect +3.3VD or +5VD from
connector to +BVDD. Short between pins 1-2 to select +5VD, or short between pins 2-3 to select
+3.3VD as the source for the digital buffer voltage supply (+BVDD).
Table 6. Power Connector Pinout
Signal J1 Pin Signal
+VA (6 V) 1 2 –VA (–6 V)
+5VA 3 4 N/C
DGND 5 6 AGND
N/C 7 8 N/C
+3.3VD 9 10 +5VD
The voltage applied to the VDD pin of the ADC is controlled by W4. If pins 1 and 2 are shorted, then
+5VCC is applied to the ADC. If pins 2 and 3 are shorted, then the reference voltage selected by W3
powers the ADC. See Table 3 or the schematic drawings at the end of this user’s guide to determine how
power is supplied to the various ICs on the board.
ADS788xEVM 10 SLAU166B – October 2005 – Revised August 2008
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