AD9887 Datasheet, PDF (16/40 Pages) Analog Devices – Dual Interface for Flat Panel Displays

AD9887
Table V. VCO Frequency Ranges
PV1 PV0
0
0
0
1
1
0
1
1
Pixel Clock
Range (MHz)
12–35
35–70
70–110
110–140
K_VCO Gain
(MHz/V)
150
150
150
180
Table VI. Charge Pump Current/Control Bits
Ip2
Ip1
Ip0
Current (␮A)
0
0
0
50
0
0
1
100
0
1
0
150
0
1
1
250
1
0
0
350
1
0
1
500
1
1
0
750
1
1
1
1500
3. The 3-Bit Charge Pump Current Register. This register
allows the current that drives the low pass loop filter to be
varied. The possible current values are listed in Table VI.
provides 32 phase-shift steps of 11.25° each. The Hsync
signal with an identical phase shift is available through the
HSOUT pin. Phase adjustment is still available if the pixel
clock is being provided externally.
4. The 5-Bit Phase Adjust Register. The phase of the generated
sampling clock may be shifted to locate an optimum sam-
pling point within a clock cycle. The Phase Adjust register
The COAST allows the PLL to continue to run at the same
frequency, in the absence of the incoming Hsync signal. This
may be used during the vertical sync period, or any other
time that the Hsync signal is unavailable. The polarity of
the COAST signal may be set through the Coast Polarity Bit.
Also, the polarity of the Hsync signal may be set through the
HSYNC polarity Bit. If not using automatic polarity
detection, the HSYNC and COAST polarity bits should
be set to match the Polarity of their respective signals.
Table VII. Recommended VCO Range and Charge Pump Current Settings for Standard Display Formats
Standard
Resolution
Refresh
Rate (Hz)
Horizontal
Frequency
(kHz)
VGA
640 × 480
60
31.5
72
37.7
75
37.5
85
43.3
SVGA
800 × 600
56
35.1
60
37.9
72
48.1
75
46.9
85
53.7
XGA
1024 × 768
60
48.4
70
56.5
75
60.0
80
64.0
85
68.3
SXGA
1280 × 1024
60
64.0
75
80.0
85
91.1
UXGA
1600 × 1200
60
65
70
75
85
75.0
81.3
87.5
93.8
106.3
*Graphics sampled at one-half the incoming pixel rate using Alternate Pixel Sampling mode.
Pixel Rate
(MHz)
25.175
31.500
31.500
36.000
36.000
40.000
50.000
49.500
56.250
65.000
75.000
78.750
85.500
94.500
108.000
135.000
157.500*
162.000*
175.500*
189.000*
202.500*
229.500*
VCORNGE
00
00
00
00
00
01
01
01
01
01
10
10
10
10
10
11
10
10
10
10
10
11
CURRENT
101
101
110
110
101
101
101
101
110
110
101
101
101
101
110
110
110
110
110
110
110
110
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