Datasheet

3.3 EVM Stacking
3.4 The Output Operational Amplifier
1 2 3
JMP15
1 2 3
JMP15
Bottom
EVM
Top
EVM
1 2 3
JMP16
1 2 3
JMP16
TopEVM, J4A
BottomEVM, J4A
ShuntJ4A pins 1 and 2
ShuntJ4A pins 3 and 4
MonitorDACoutputof
topEVMonJ4A pin 5
MonitorDACoutputof
bottomEVMonJ4A pin 7
www.ti.com EVM Operation
The stacking of EVM is possible if there is a need to evaluate two DAC8564/65 devices to yield a total of
up to eight (DAC8564/65) channel outputs. A maximum of two EVMs are allowed since the output
terminal, J4, dictates the number of DAC channels that can be connected without output bus contention.
Table 3 shows how the DAC output channels are mapped into the output terminal, J4, with respect to the
jumper position of JMP11, JMP12, JMP13 and JMP14.
Table 3. DAC Output Channel Mapping
Reference Jumper Position Function
JMP11 1-2 DAC output (V
OUT
A) is routed to J4-2.
2-3 DAC output (V
OUT
A) is routed to J4-10.
JMP12 1-2 DAC output (V
OUT
B) is routed to J4-4.
2-3 DAC output (V
OUT
B) is routed to J4-12.
JMP13 1-2 DAC output (V
OUT
C) is routed to J4-6.
2-3 DAC output (V
OUT
C) is routed to J4-14.
JMP14 1-2 DAC output (V
OUT
D) is routed to J4-8.
2-3 DAC output (V
OUT
D) is routed to J4-16.
In order to allow exclusive control of each EVM that are stacked together, the DAC8564/65 must have
separate SYNC signal. This is accomplished in hardware by routing the SYNC signal of the first EVM
through CS (J2A/J2B pin 1) by shorting pins 1-2 of jumper JMP18. The second EVM should use the FSX
signal (J2A/J2B pin 7) to drive the SYNC signal by shorting pins 2-3 of the jumper JMP18. The outputs
can be mapped as described in Table 3 for each of the EVM stacked.
The EVM includes an optional signal conditioning circuit for the DAC output through an external
operational amplifier, U2. During stacking of EVM, only two DAC output channels can be monitored at any
given time for evaluation because of the way the odd numbered pins of J4 header (J4A-1 to J4A-7) are
configured. See the schematic included in this manual and Section 3.3 .
Figure 18. DAC8564/65 EVM Output Operational Amplifier Jumper Configuration for Stacking
The output operational amplifier is set to unity gain configuration by default but can be modified by simple
jumper settings. Nevertheless, the raw output of the DAC can be probed through the specified pins of J4
output terminal, which also provides mechanical stability when stacking or plugging into any interface
board. In addition, it provides easy access for monitoring up to two (DAC8564/65) DAC channels when
stacking two EVMs together (see Section 3.3 ).
SLAU252 – June 2008 DAC8564/65 Evaluation Module 19
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