STDVE003A_08 Datasheet, PDF (15/41 Pages) STMicroelectronics – Adaptive 3.4 Gbps 3:1 TMDS/HDMI signal equalizer

STDVE003A
Functional description
several internal modules. The 10 mA current used by the transmitter block is also generated
using this reference current. It is important to ensure that the R_EXT value is within the ±1%
tolerance range of its typical value.
Table 6. Bias parameter
Parameter
Min
Typ
Max
Unit
Bandgap voltage
1.2
V
The output voltage swing depends on 3 components: supply voltage (V_supply), termination
resistor (R_T) and current drive (I_drive). The supply voltage can vary from 3.3 V ±5%,
termination resistor can vary from 50 Ω ±10%.
The voltage on the output is given by:
V_supply −I_drive x R_T.
The variation on I_drive must be controlled to ensure that the voltage on HDMI output is within
the HDMI specification under all conditions.
This is achieved when:
400 mV ≤I_drive x R_T ≤600 mV with typical value centered at 500 mV.
3.8
Timing between HPD and DDC
It is important to ensure that the I²C DDC interface is ready by the time the HPD detection is
complete.
As soon as the discovery is finished by the HPD detection, the configuration data is
exchanged between a source and sink through the I²C DDC interface. The STDVE003 Afs
DDC interface is ready for communication as soon as the power supply to the chip is
present and stable. When the desired port is enabled and the chip is out of shutdown mode,
the I²C DDC lines can be used for communication.
Thus, as soon as the HPD detection sequence is complete, the DDC interface can be
readily used. There is no delay between the HPD detection and I²C DDC interface to be
ready.
15/41