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5.2
Digital Control
The digital control signals SYNC and SCLK can be applied directly to J2 (top or bottom side). The serial
data input must be applied to J2B pin 11 or the test point labeled SDI found beside J2. The DAC7811
EVM can also be connected directly to a DSP or microcontroller interface board such as the 5-6K
Interface Board, the HPA-MCU Interface Board, or the HPA449. See the DAC7811 product folder on the
TI Web site (www.ti.com) for a current list of compatible interface and/or accessory boards.
5.3
Frame Synchronization (SYNC)
Connector J2 pin 7 applies the frame synchronization control to the DAC7811's SYNC pin. When using a
5-6K Interface or HPA-MCU Interface Board, J2 pin 7 ties the SYNC pin to the Frame Sync pin of the DSP
or STE pin of the microcontroller. A 16-bit command+data word is then applied to the SDI input of the
DAC7811. Releasing the active low SYNC pin updates the DAC output.
The DAC7811 powers up in the daisy-chain mode which must be used when two or more devices are
connected in tandem. The SCLK and SYNC signals are shared across all devices while the SDO output of
the first device connects to the SDIN input of the following device, and so forth. In this configuration, 16
SCLK cycles for each DAC7811 in the chain are required. For n devices in a daisy-chain configuration,
16n SCLK cycles are required to shift in the entire input data stream. After 16n active SCLK edges are
received following a falling SYNC, the data stream becomes complete, and SYNC can brought high to
update the DAC outputs. Up to seven DAC7811EVMs can be used in this mode simultaneously.
5.4
Default Jumper Locations
Table 5
provides a list of jumpers and switches found on the EVM and their factory default conditions.
Jumper
Shunt
W1
closed
W2
Pins 1-2
SW1
RIGHT
R12
OPEN
6
EVM Bill of Materials and Schematic
Table 6
contains a complete bill of materials for the modular DAC7811 EVM. The schematic diagram is
also provided for reference.
Designators
C1
C2 C3 C6 C7 C8 C10
C4
C9
J1 J2 (top side)
J1B J2B(bottom side)
J3 (top side)
J3B (bottom side)
R1 R13
R3 R4
SLAU163 – September 2005
Table 5. List of Jumpers and Switches
Applies the DAC7811 current output to U2. W1 is fixed with a 0-Ω resistor.
Controls which pin on J1 the output voltage from U2 is applied to. Default is pin 4. Output voltage from
the EVM can also be monitored on TP2, which is useful for daisy-chain operating mode.
Controls analog output voltage (default is ± Vref)
R12 can be replaced by removing the 0-Ω resistor found at W1 to provide the current output directly
from the DAC7811 to J1 pin 2.
Table 6. Bill of Materials
Description
2.2 µF, 0805, Ceramic
0.1 µF, 0603, Ceramic, X7R, 50V
18 pF, 0603, Ceramic, COG
10 µF, 1206, Ceramic, Y5V
10 Pin, Dual Row, SMT Header (20 Pos.)
10 Pin, Dual Row, SMT Socket (20 Pos.)
5 Pin, Dual Row, SMT Header (10 Pos.)
5 Pin, Dual Row, SMT socket (10 Pos.)
20K Ω, 0603, 5%, 0.1 W resistor
20K Ω, 4mm POT
EVM Bill of Materials and Schematic
Position Jumper Description
Manufacturer
TDK
TDK
TDK
TDK
Samtec
Samtec
Samtec
Samtec
Yageo America
Bourns
Mfg. Part Number
C2012X5R1A225K
C1608X7R1H104K
C1608COG1H180J
C3216Y5V1C106Z
TSM-110-01-T-DV-P
SSW-110-22-F-D-VS-K
TSM-105-01-T-DV-P
SSW-105-22-F-D-VS-K
9C06031A2002JLHFT
3214W-1-203E
DAC7811EVM
5
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