datasheetbank_Logo
Integrated circuits, Transistor, Semiconductors Search and Datasheet PDF Download Site

ML12179-5P View Datasheet(PDF) - LANSDALE Semiconductor Inc.

Part Name
Description
View to exact match
ML12179-5P
LANSDALE
LANSDALE Semiconductor Inc. LANSDALE
ML12179-5P Datasheet PDF : 11 Pages
1 2 3 4 5 6 7 8 9 10
ML12179
LANSDALE Semiconductor, Inc.
Figure 1. ML12179 Expanded Block Diagram
+5.0 V
2 VCC
C1
1 OSCin
8 OSCout
C2
NOTE: External 50 kresistor
across Pins 1 and 8 is necessary in
either crystal or driven mode.
VCO
4 Fin
1000 pF
Crystal
Oscillator
Prescaler
÷ 256
fr
Phase/Frequency
Detector
fv
Charge
Pump
GND
GNDP
3
5
+5.0 V
VP 7
6
PDout
To Loop Filter
PHASE CHARACTERISTICS
The phase comparator in the ML12179 is a high speed digital
phase/frequency detector circuit. The circuit determines the “lead”
or “lag” phase relationship and time difference between the lead-
ing edges of the VCO (fv) signal and the reference (fr) input. The
detector can cover a range of ±2π radian of fv/fr phase difference.
The operation of the charge pump output is shown in Figure 2.
fr lags fv in phase OR fv>fr in frequency
When the phase of fr lags that of fv or the frequency of fv is
greater than fr, the Do output will sink current. The pulse width
will be determined by the time difference between the two rising
edges.
fr leads fv in phase OR fv<fr in frequency
When the phase of fr leads that of fv or the frequency of fv is
less than fr, the Do output will source current. The pulse width
will be determined by the time difference between the two rising
edges.
fr = fv in phase and frequency
When the phase and frequency of fr and fv are equal, the charge
pump will be in a quiet state, except for current spikes when sig-
nals are in phase. This situation indicates that the loop is in lock
and the phase comparator will maintain the loop in its locked
state.
fr
(OSCin)
fv
(Fin ÷256)
PDout
Page 3 of 11
Figure 2. Phase/Frequency Detector and Charge Pump Waveforms
H
L
H
L
Sourcing Current Pulse
Z
Sinking Current Pulse
H = High voltage level; L = Low voltage level; Z = High impedance
NOTES: Phase difference detection range: –2π to 2π
Kp–Charge Pump Gain
|Isource| +
4π
|Isink|
=
|2.2|
+ |–2.2|
4π
=
1.1 mA
πradian
www.lansdale.com
Issue A
 

Share Link: 

datasheetbank.com [ Privacy Policy ] [ Request Datasheet ] [ Contact Us ]