ZHCSBQ4B September 2013 – September 2014 SN65LVDS822
PRODUCTION DATA.
NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The SN65LVDS822 is a simple deserializer that ignores bit representation in the LVDS stream. The CMOS output pin order was chosen so that if the color mapping within the LVDS stream matches the common VESA standard, the parallel output bus of red/green/blue fans out sequentially, which matches the order that many LCD panels require. Some LCD panels require a reversed order; for those, set pin “SWAP” high to reverse the output bus and simplify PCB routing. Figure 19 shows the application setup when SWAP is in different statuses.
Any color bit mapping is supported, by correctly connecting the output to the panel. However, bit “RSV” is ignored and unavailable for use.
DESIGN PARAMETERS | VALUE |
---|---|
VDD Main Power Supply | 3 - 3.6 V |
VDDIO Power Supply for CMOS Outputs | 1.65 - 3.6 V |
Input LVDS Clock Frequency | 4 - 54 MHz |
RID Differential Input Termination Resistance | 80 - 132 Ω |
LVDS Input Channels | 2 or 4 |
Output Load Capacitance | 1 pF |
The implementation operates from the power provided by two banana jack connectors (P1 and P3) common ground. The VDD pin (P1) is connected to the main power supply to the SN65LVDS822 device and must be 3.3 V (±10%). The VDDIO pin (P3) is connected to the power supply of the SN65LVDS822 CMOS outputs and must be in the range of 1.8 to 3.3 V.
Color Bit Mapping shows the CMOS output and bit mapping. Because some LCD panels require a reversed order, the SN65LVDS822 device is capable of reversing the output bus and simplifying PCB routing. When the pin is tied to high, the CMOS outputs are in normal order, otherwise the CMOS outputs are in reverse order.
The SN75LVDS822 does not require a specific power up sequence.
It is permitted to power up IOVCC while VCC remains powered down and connected to GND. The input level of the SHTDN during this time does not matter as only the input stage is powered up while all other device blocks are still powered down. It is also permitted to power up all 3.3V power domains while IOVCC is still powered down to GND. The device will not suffer damage. However, in this case, all the I/Os are detected as logic HIGH, regardless of their true input voltage level. Hence, connecting SHTDN to GND will still be interpreted as a logic HIGH; the LVDS output stage will turn on. The power consumption in this condition is significantly higher than standby mode, but still lower than normal mode. The user experience can be impacted by the way a system powers up and powers down an LCD screen. The following sequence is recommended:
Power up sequence (SN75LVDS83B SHTDN input initially low):
Power Down sequence (SN75LVDS83B SHTDN input initially high):