MV95308 Datasheet, PDF (7/9 Pages) Zarlink Semiconductor Inc – 30MHz 8-BIT CMOS VIDEO DAC

APPLICATIONS INFORMATION
RS-343A and RS-170 Video Generation
For generation of RS-343A compatible video levels (see
Fig.4) it is recommended that a singly terminated 75Ω load
be used with an R_SET resistor value of approximately 1.82kΩ
Similarly for the generation of RS-170 video levels a
singly terminated 75Ω load should be used but in association
with an R_SET value of approximately 1.29kΩ to provide the
increased voltage range.
Non-Video Applications
The MV95308 may be used in non-video applications as
explained in the pin description for STRDAC mode.The
relationship between R_SET and the full scale output current
has been explained previously and for a singly terminated
75Ω load an R_SET resistor value of approximately 1.19kΩ
should be used.
MV95308
PCB LAYOUT CONSIDERATIONS
The PCB layout should provide low noise on the
MV95308 power and ground lines by shielding the digital
inputs and providing adequate decoupling. The PCB should
utilise both power and ground planes for best performance,
connecting both planes to their respective regular PCB
planes through a ferrite bead located as close as possible to
the device. For best performance, a 100nF capacitor should
be used to decouple the reference and supply pins.
Decoupling should take place as close to the device as
possible to reduce lead inductance. The digital inputs to the
device should be isolated as much as possible from the
analog outputs and other analog circuitry and should not
overlay the analog ground and power planes.
To reduce noise pick-up, long clock lines to the device
should be avoided. For best performance the analog output
should have a 75Ω load connected to analog ground.
Fig.4 Composite video output waveform
Fig.5 Applications/test board
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