9.2.2.1 Power Up Sequence

The SN65LVDS93B-Q1 does not require a specific power up sequence.

It is permitted to power up IOVCC while VCC, VCCPLL, and VCCLVDS remain 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 (SN65LVDS93B-Q1 SHTDN input initially low):

1. Ramp up LCD power (maybe 0.5ms to 10ms) but keep backlight turned off.
2. Wait for additional 0-200ms to ensure display noise won’t occur.
3. Enable video source output; start sending black video data.
4. Toggle SN65LVDS93B-Q1 shutdown to SHTDN = V_IH.
5. Send >1ms of black video data; this allows the SN65LVDS93B-Q1 to be phase locked, and the display to show black data first.
6. Start sending true image data.
7. Enable backlight.

Power Down sequence (SN65LVDS93B-Q1 SHTDN input initially high):

1. Disable LCD backlight; wait for the minimum time specified in the LCD data sheet for the backlight to go low.
2. Video source output data switch from active video data to black image data (all visible pixel turn black); drive this for >2 frame times.
3. Set SN65LVDS93B-Q1 input SHTDN = GND; wait for 250ns.
4. Disable the video output of the video source.
5. Remove power from the LCD panel for lowest system power.