ML6431CH View Datasheet(PDF) - Micro Linear Corporation
Part Name
Description
Manufacturer
ML6431CH
Micro Linear Corporation
ML6431CH Datasheet PDF : 33 Pages
| |||
ML6430/ML6431
FUNCTIONAL DESCRIPTION (Continued)
FREERUN MODE
Both the ML6430 and ML6431 can be used in Freerun
mode. The ML6431 is recommended for applications
requiring a more robust Freerun mode of operations.
Figure 4 and Figure 4a describe the state diagrams for
both the ML6430 and ML6431. Note that the ML6431
includes a faster path to go from FREERUN MODE #1 to
FREERUN MODE #2.
Freerun mode: FREERUN MODE #1 is entered when
the freerun pin is toggled high while the ML6430/
ML6431 is horizontally locked (i.e. internal horizontal
locked signal is present). In this mode, the digital
frequency value stored in the line-locked PLL is held
and the ML6430/ML6431 will freerun at a frequency
very close to that of the last locked video source.
Freerun mode #1 is best used by physically tying the
NoSignal pin to the freerun pin as shown in Figures 9
or 10. FREERUN MODE #2 is entered when the
freerun pin is toggled high while the ML6430/Ml6431
is not horizontally locked to a video source. In this
mode, a ROM lookup table is used to set the freerun
frequency of the ML6430/ML6431. In this mode the
output frequency is as accurate as the Crystal plus the
accuracy of the look up table. See Figures 4 and 4a
for the NoSignal-Locked-Freerun state machine
diagram.
NoSignal: NoSignal will go low if video is present for
one entire field. NoSignal will be high if video is not
present for one entire field.
Locked (ML6430): The ML6430 must be line
(horizontal) locked to an input video source and also
be vertically locked before the locked detect signal
goes high. When a video source is removed, the
locked signal may be high or low. Please note that the
locked pin is the logical AND of the internal
horizontal locked and vertical locked signals. For
example, the internal horizontal locked signal may be
high even though the locked pin is asserted low.
POWER UP
ML6430 W/
FREERUN PIN
"LOW" (TYPICAL)
HORIZONTAL
LOCKED
SIGNAL
PRESENT
2
TOGGLE
FREERUN PIN
"HIGH"
IF NO VIDEO
FOR > 1 FRAME
HORIZONTAL
LOCKED
IF INPUT VIDEO
FOR > 1 FRAME
NO SIGNAL
PRESENT
3
INPUT VIDEO
WITHIN ±6%
RANGE
INPUT VIDEO
OUTSIDE ±6%
RANGE
HORIZONTAL
UNLOCKED
SIGNAL
PRESENT
1
IF NO VIDEO
FOR > 1 FRAME
HORIZONTAL
UNLOCKED
IF INPUT VIDEO
FOR > 1 FRAME
NO SIGNAL
PRESENT
4
TOGGLE
FREERUN PIN
"HIGH"
TOGGLE
FREERUN PIN
"HIGH"
FREERUN PIN
"LOW"
FREERUN PIN
"LOW"
TOGGLE
FREERUN PIN
"HIGH"
FREERUN
MODE #1
5
FREERUN
MODE #2
6
POWER UP
ML6430 W/
FREERUN PIN
"HIGH" (TYPICAL)
Figure 4. ML6430 Freerun Mode State Diagram
12
Share Link: 