Texas Instruments DAC8771EVM, Руководство пользователя

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EVM Hardware Overview
5 SLAU727 – August 2017
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DAC8771 Evaluation Module
2.4 Powering the EVM
This section describes the various power configurations that can be used by the EVM.
2.4.1 PVDD/AVDD Supply
The PVDD, the buck-boost converter supply, and AVDD, the analog supply, of the DAC8771 are
connected to the same power net labeled PVDD/AVDD on the DAC8771EVM. Terminal block J3, shown
in
Figure 3 , allows for external voltage sources to be connected to the PVDD/AVDD supply. The
PVDD/AVDD supply must be provided regardless of whether the buck-boost converter is in use or not.
Figure 3. PVDD/AVDD, and DVDD Supply Connections
2.4.2 VPOS and VNEG Supplies
VPOS, the positive supply for the output signal chain, and VNEG, the negative supply for the output signal
chain, may be powered by the DAC8771 internal buck-boost converters or by off-board supply voltages.
WARNING
Permanent device damage may occur if externally supplying VPOS
or VNEG while the internal buck-boost supply is enabled.
When using the DAC8771 internal buck-boost converters to supply VPOS and VNEG, install JP1 and JP2
in the 1-2 position, or "inside" position, as indicated by
Table 3 .
When using external equipment to supply VPOS and VNEG, install JP1 and JP2 in the 2-3 position, or
"outside" position, as indicated by
Table 3 . In this configuration, the VPOS supply is connected to the
PVDD/AVDD net and the VNEG supply is connected to the EXT_VNEG. If bipolar supplies are used,
connect an appropriate negative supply voltage to AVSS through terminal block J4, as shown in
Figure 3 .
If unipolar supplies are used, connect AVSS to ground through terminal block J3.