Texas Instruments DAC5668, Manual

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DAC5668/88/89 Hardware Description
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• No VCXO installed. CDCM7005 in buffer mode which requires an input single-ended clock signal to
SMA connector J20.
• The DAC outputs are set by default to drive the TRF3703.
• The converter is set to operate with internal reference. Jumper J5 EXTLO is installed between pins 1
and 2.
• Full-scale output current set to 20 mA through RBIAS resistor R91.
4.1 Jumper Settings
The DAC5668/88/89EVM has onboard jumpers that allow the user to modify the board configuration.
Table 2 explains the functionality of the jumpers.
Table 2. Jumper List
JUMPER LABEL FUNCTION DEFAULT SETTING
CONDITION
SW1 BRD_RESET Resets the DAC and CDCM7005 devices
JP1 REF_CLK Chooses internal 10-MHz ref or external ref Internal Ref Pin 2-3
J1 VCXO_EN VCXO power down Disabled Unpopulated
JP2 VCXOB Chooses internal VCXO or external source External source Pin 2-3
JP3 VCXO Chooses internal VCXO or external source External source Pin 2-3
JP4 CLK1/CLKOUT Selects between CLK1 input to DAC or CLKOUT DAC CLKOUT Pin 2-3
output
JP5 CLK1C/LOCK Selects between CLK1C input to DAC or LOCK LOCK Pin 2-3
indicator DAC output
JP6 VFUSE Factory use only. Connect to 1.8VDD for normal 1.8 VDD Pin 1-2
operation.
J5 EXTLO Internal (GND) or external (3.3V) voltage reference Internal Reference Pin 1-2
CDC_PD Active-low power down of CDCM7005 Active CDCM7005 Pin 2-3
RESET DAC RESET Signal Unpopulated
CLKOUT_EN Active-low enable of CLKOUT signal buffer Enabled Buffer Pin 1-2
SYNC DAC SYNC Signal GND Pin 1-2
TX_ENABLE DAC TX_ENABLE Signal 3.3V Pin 2-3
4.2 Input/Output Connectors
Table 3 lists the input and output connectors on the DAC5668/88/89EVM.
Table 3. Input and Output Connections
REFERENCE LABEL CONNECTOR DESCRIPTION
DESIGNATOR TYPE
J2 34-pin Header A-bus input data to the DAC.
J3 IOUTB1 SMA Optional IOUTB1 output.
J4 IOUTB2 SMA DACB transformer output. Optional IOUTB2 output.
J6 RFOUT SMA RF output from TRF3703.
J7 34-pin Header B-bus input data to the DAC.
J8 IOUTA1 SMA Optional IOUTA1 output.
J9 IOUTA2 SMA DACA transformer output. Optional IOUTA2 output.
J10/J11 +5V Banana Plug +5-V connection pair. Required only for RF measurements.
J12 USB_CONN USB USB connector for software communication.
J13/J14 +1.8V Banana Plug +1.8-V connection pair.
J15/J16 3.3V Banana Plug +3.3-V connection pair.
J17 OUTCLK2 Y3A SMA Optional CDCM7005 clock output.
J18 OUTCLK2 Y4A SMA Optional CDCM7005 clock output.
6 DAC5668/88/89EVM SLAU241A – June 2008 – Revised March 2010
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