TDA4885 Datasheet, PDF (9/56 Pages) NXP Semiconductors – 150 MHz video controller with I2C-bus

Philips Semiconductors
150 MHz video controller with I²C-bus
7.9 Gain modulation
To achieve brightness uniformity over the screen scan
dependent gain modulation is possible. With open-circuit
pins the gain will be reduced by 20% giving the possibility
of symmetrical gain modulations (±18%) with ±1 V related
to the open-circuit voltage of about 2.0 V at any gain
setting.
If the gain modulation feature will not be used pins GM₁,
GM₂ and GM₃ should be grounded to profit by maximum
voltage gain.
7.10 I²C-bus control
The TDA4885 contains an I²C-bus receiver for several
control functions:
1. Contrast control with 6-bit DAC
2. Brightness control with 6-bit DAC
3. OSD contrast control with 4-bit DAC
4. Gain control for each channel with 6-bit DAC
5. Internal feedback reference and external reference
voltage control for each channel with 8-bit DAC
6. Control register with control bits FPOL, DISV, DISO
and PEDST
7. Test register for production tests only.
All registers are set to logic 0 (minimum value for control
registers) after power-up and after internal power-on reset
of the I²C-bus.
Product specification
TDA4885
1997 Nov 25
9