82845G Datasheet, PDF (153/193 Pages) Intel Corporation – Intel 82845G/82845GL/82845GV Graphics and Memory Controller Hub (GMCH)

Electrical Characteristics
Figure 6-1. System Bus HCLKP/N VCROSS Range
550
Vcross(rel) Max
500
450
400
350
Vcross Range
For VHigh < 0.71V
Vcross Range
For VHigh > 0.71V
300
Vcross(rel) Min
250
200
625 650 675 700 725 750 775 800 825 850
VHigh Average (mV) (Measured)
Vcross(rel) Max = 0.5 (Vhavg - 0.710) + .550
Vcross(rel) Min = 0.5 (Vhavg - 0.710) + .250
6.6
6.6.1
DAC Characteristics
The GMCH DAC (digital-to-analog converter) consists of three identical 8-bit DACs to provide
red, green, and blue color components. Each DAC can output a current from 0 to 255 units of
current, where one unit of current (LSB) is defined based on the VESA video signal standard.
DAC DC Characteristics
Table 6-7. DAC DC Characteristics: Functional Operating Range (VCCDAC = 1.5 V ±5%)
Parameter
Min Typical Max Units
Notes
DAC Resolution
Max Luminance (full-scale)
Min Luminance
LSB Current
Integral Linearity (INL)
Differential Linearity (DNL)
Video channel-channel voltage
amplitude mismatch
Monotonicity
8
0.665
0.700
0.770
0.000
73.2
–1.0
+1.0
–1.0
+1.0
6
Guaranteed
Bits Note 1
V
Notes 1, 2, 4, white video level
voltage
V
Notes 1, 3, 4, black video level
voltage
µA Notes 4, 5
LSB Notes 1, 6
LSB Notes 1, 6
% Notes 7
NOTES:
1. Measured at each R,G,B termination according to the VESA Test Procedure – Evaluation of Analog Display
Graphics Subsystems Proposal (Version 1, Draft 4, December 1, 2000)
2. Max steady-state amplitude
3. Min steady-state amplitude
4. Defined for a double 75 Ω termination
5. Set by external reference resistor value
6. INL and DNL measured & calculated according to VESA Video Signal Standards
7. Max full-scale voltage difference among R,G,B outputs (percentage of steady-state full-scale voltage)
Intel^® 82845G/82845GL/82845GV GMCH Datasheet
153