82845G Datasheet, PDF (154/193 Pages) Intel Corporation – Intel 82845G/82845GL/82845GV Graphics and Memory Controller Hub (GMCH)

Electrical Characteristics
6.6.2 DAC Reference and Output Specifications
Table 6-8. DAC Reference and Output Specifications
Parameter
Reference resistor
RED, GREEN, BLUE
termination resistor
RED#,GREEN#,BLUE#
termination resistor
Video Filter Ferrite Bead
Video Filter Capacitors
Min Typical Max
137
75
37.5
75
3.3
Units
Notes
Ω
1% tolerance, 1/16 W
Ω
Note 1, 1% tolerance, 1/16 W
Ω
Note 2, 1% tolerance, 1/16 W
(applies to differential routing)
Ω
Note 3, @ 100 MHz, (each RED,
GREEN, BLUE output)
pF
Note 3, two capacitors per RED,
GREEN, BLUE output
NOTES:
1. VESA Video Signal Standard
2. Complement DAC channel output termination resistors are only required for differential video routing to the
VGA connector.
3. Video filter capacitors and ferrite bead arranged in a PI configuration (one PI filter for RED, GREEN, BLUE
outputs)
6.6.3 DAC AC Characteristics
Table 6-9. DAC AC Characteristics
Parameter
Min
Pixel Clock Frequency
RED, GREEN, BLUE Video
Rise Time
0.57
RED, GREEN, BLUE Video
Fall Time
Settling Time
Video channel-to-channel
output skew
Overshoot/ Undershoot
Noise Injection Ratio
0.57
-0.084
Typical
Max Units
Notes
350
MHz
Notes 1, 2, (10–90% of black-to-
1.43
ns white transition, at 350 MHz pixel
clock)
Notes 1, 3, (90–10% of white-to-
1.43
ns black transition, at 350 MHz pixel
clock)
0.86
ns Notes 1, 4, at 350 MHz pixel clock
0.714
ns Notes 1, 5, at 350 MHz pixel clock
+0.084
0.5
V
Notes 1, 6, Full-scale voltage step
of 0.7 V
% Notes 1, 7
NOTES:
1. Measured at each RED, GREEN, BLUE termination according to the VESA Test Procedure – Evaluation of
Analog Display Graphics Subsystems Proposal (Version 1, Draft 4, December 1, 2000)
2. R,G,B Max Video Rise/Fall Time: 50% of minimum pixel clock period
3. R,G,B Min Video Rise/Fall Time: 20% of minimum pixel clock period
4. Max settling time: 30% of minimum pixel clock period
5. Video channel-channel output skew: 25% of minimum pixel clock period
6. Overshoot/undershoot: ± 12% of black-white video level (full-scale) step function
7. Noise injection ratio: 0.5% of maximum luminance voltage (dc to max. pixel frequency)
154
Intel^® 82845G/82845GL/82845GV GMCH Datasheet