Output Data - Texas Instruments DAC5687 EVM User Manual

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Pin Description
11 CMOS data bit 10
12 GND
13 CMOS data bit 9
14 GND
15 CMOS data bit 8
16 GND
17 CMOS data bit 7
Pin Description
1 CMOS data bit 0 (LSB)
2 GND
3 CMOS data bit 1
4 GND
5 CMOS data bit 2
6 GND
7 CMOS data bit 3
8 GND
9 CMOS data bit 4
10 GND
11 CMOS data bit 5
12 GND
13 CMOS data bit 6
14 GND
15 CMOS data bit 7
16 GND
17 CMOS data bit 8
4.3

Output Data

The DAC5687 EVM can be configured to drive a doubly terminated 50-Ω cable or provide unbuffered
differential outputs.
4.3.1 Transformer-Coupled Signal Output
The factory-set configuration of the demonstration board provides the user with single-ended output
signals at SMA connectors J5 and J19. The DAC5687 outputs are configured to drive a doubly terminated
50-Ω cable using a 4:1 impedance ratio transformer with the center tap of the transformers connected to
+3.3 VA as shown in
shown in Table 4. The common mode input voltage of T1 and T2 can be adjusted by using the resistor
divider networks. With the board configured to use transformer T5 per Table 4, the DAC outputs will be
summed together and provide 40-mA full-scale output power at SMA connector J11.
Configuration
1:1 Impedance ratio
transformer
(1)
All component values are per the schematic except where shown in parenthesis.
SLWU017B – APRIL 2005 – Revised March 2007
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Table 2. Input Connector J13 (Data A Bus) (continued)
Table 3. Input Connector J14 (Data B Bus)
Table 4. When using a 1:1 impedance ratio transformer, configure the EVM as
Table 4. Transformer Output Configuration
(1)
Components Installed
R5 (49.9), R10 (49.9), R19 (49.9), R20 (49.9), R21, R22,
R23, R26, C60, C61, T1(1:1), T2 (1:1)
Pin Description
28 GND
29 CMOS data bit 1
30 GND
31 CMOS data bit 0 (LSB)
32 GND
33
34 GND
Pin Description
18 GND
19 CMOS data bit 9
20 GND
21 CMOS data bit 10
22 GND
23 CMOS data bit 11
24 GND
25 CMOS data bit 12
26 GND
27 CMOS data bit 13
28 GND
29 CMOS data bit 14
30 GND
31 CMOS data bit 15 (MSB)
32 GND
33
34 GND
Components Not Installed
R6-R9, R24, R27-R33
Circuit Description
DAC5687 EVM 23