DS90UR907Q_10 Datasheet, PDF (16/26 Pages) National Semiconductor (TI) – 5 - 65 MHz 24-bit Color FPD-Link to FPD-Link II Converter

FIGURE 17. 8–bit FPD-LInk Mapping: MSB's on RxIN3
30105066
EMI REDUCTION FEATURES
Spread Spectrum Compatibility
The RxCLKIN of the FPD-Link input is capable of tracking
spread spectrum clocking (SSC) from a host source. The Rx-
CLKIN will accept spread spectrum, tracking up to 35kHz
modulation and ±0.5, ±1 or ±2% deviations (center spread).
The maximum conditions for the RxCLKIN input are: a mod-
ulation frequency of 35kHz and amplitude deviations of ±2%
(4% total).
SIGNAL QUALITY ENHANCERS
VOD Select (VODSEL)
The DS90UR907Q differential output voltage may be in-
creased by setting the VODSEL pin High. When VODSEL is
Low, the DC VOD is at the standard (default) level. When
VODSEL is High, the DC VOD is increased in level. The in-
creased VOD is useful in extremely high noise environments
and also on extra long cable length applications. When using
de-emphasis it is recommended to set VODSEL = H to avoid
excessive signal attenuation especially with the larger de-
emphasis settings. This feature may be controlled by the
external pin or by register.
TABLE 2. Differential Output Voltage
Input
VODSEL
VOD
mV
Effect
VOD
mVp-p
H
±450
900
L
±300
600
De-Emphasis (De-Emph)
The De-Emph pin controls the amount of de-emphasis be-
ginning one full bit time after a logic transition that the device
drives. It is the signal conditioning function for use in com-
pensating against cable transmission loss. This pin should be
left open for standard switching currents (no de-emphasis) or
if controlled by register. De-emphasis is selected by connect-
ing a resistor on this pin to ground, with R value between 0.5
kΩ to 1 MΩ, or by register setting. When using De-Emphasis
it is recommended to set VODSEL = H.
TABLE 3. De-Emphasis Resistor Value
Resistor Value (kΩ)
De-Emphasis Setting
Open
Disabled
0.6
- 12 dB
1.0
- 9 dB
2.0
- 6 dB
5.0
- 3 dB
FIGURE 18. De-Emph vs. R value
30105060
POWER SAVING FEATURES
Power Down Feature (PDB)
The DS90UR907Q has a PDB input pin to ENABLE or POW-
ER DOWN the device. This pin is controlled by the host and
is used to save power, disabling the link when the display is
not needed. In the POWER DOWN mode, the high-speed
driver outputs are both pulled to VDD and present a 0V VOD
state. Note – in POWER DOWN, the optional Serial Bus Con-
trol Registers are RESET.
www.national.com
16