Device Modes and Settings
6
SLAU773 – May 2018
Copyright © 2018, Texas Instruments Incorporated
DAC5652AEVM User's Guide
3.2.2.1
Unbuffered Differential Output
To provide unbuffered differential outputs, the EVM must be configured as follows: Remove R3, R13, T1,
and T2; Install R10, R12, R15, R18, R25, R29, J6, and J28.
3.2.2.2
Internal Reference Operation
The full-scale output current is set by applying an external resistor (R
SET
) between the BIASJ pins of the
DAC5652A and ground. The full-scale output current can be adjusted from 20 mA down to 2 mA by
varying R
SET
or changing the externally applied reference voltage. The full-scale output current, I
OUTFS
, is
defined as: I
OUTFS
= 32 × (V
EXTIO
/ R
SET
), where V
EXTIO
is the voltage at pin EXTIO. This voltage is 1.2 V
(typical) when using the internally provided band-gap reference voltage source. On the DAC5652AEVM,
R23 is used to set the output current of channel A and R22 is used to set channel B.
4
Device Modes and Settings
4.1
Sleep Mode
The DAC5652AEVM provides a means of placing the DAC5652A into a power-down mode. This mode is
activated by placing jumper J10 between pins 5 and 6.
4.2
Gain Set
The full-scale output current on the DAC5652A can be set two ways: both channels independently or
simultaneously. For independent gain control, set GSET to a logic low. This mode is activated by placing
jumper J10 between pins 7 and 8. For simultaneous mode, set GSET to a logic high. This mode is
activated by placing jumper J10 between pins 8 and 9.
5
Input Data Mode
The DAC5652AEVM provides a means of placing the DAC5652A into a dual-port data input mode or
interleaved mode. With MODE set to a logic high (JP10 set to 2 and 3), the device operates in dual-port
mode. With MODE set to a logic low (JP10 set to 1 and 2), the device operates in interleave mode.
6
Quick-Start Procedure
1. Connect EVM to TSW1400 board through the CMOS connectors
2. Apply 3.3-V power to J11 and J13; connect ground to J12, J14
3. Setup the clock signals through the HP8133A
•
Inject 100 MHz to the external input
•
Set channel 1 and 2 with
–
3.3-V amplitude
–
1.65-V offset
–
Divide by 1
–
0-ps delay
•
Connect channel 1 output to CMOS clock input (J7) of the TSW1400
•
Connect channel 2 output to J3 on the DAC5652AEVM
4. Connect DAC output J1 to the spectrum analyzer
5. Setup the TSW1400. Launch the HSDCpro software and connect the TSW1400EVM to the PC.
•
Click the DAC tab. Set sample rate to 100 MSPS (that is, match the clock rate)
•
Select the CMOS .ini file using the dropdown button on upper left corner of the GUI
•
Select Offset Bin
•
On the lower left corner of the HSDCpro GUI under I/Q Mutlitone Generator enter 1 for number of
tones and tone center as 10M.
