• Use with “pullable” 14pF crystals – no external pad-
ding capacitors required
• Small circuit board footprint (8-pin 0.150″ SOIC)
• Custom frequency selections available - contact your
local AMI Sales Representative for more information
PLL Clock Generator IC with VCXO
PLL Clock Generator IC with VCXO
PLL Clock Generator IC with VCXOPLL Clock Generator IC with VCXO
2.0 Description
The FS6128 is a monolithic CMOS clock generator IC
designed to minim ize cost a nd com ponen t coun t i n d igital
video/audio systems.
At the core of the FS6128 is circu itry that implements a
voltage-controlle d crystal oscillator (VCXO) when an external resonator (nominally 13.5MHz) is attached. The
VCXO allows device f requenc ies to b e precis el y adjusted
for use in systems that have frequency matching requirements, such as digital satellite receivers.
A high-resolution ph ase-locked loop gener ates an output
clock (CLK) through a pos t-divider. T he CLK f requenc y is
ratiometrically derived from the VCXO frequency. The
locking of the CLK frequency to other system reference
frequencies can el iminate unpredicta ble artifacts in video
systems and reduce electromagnetic interference (EMI)
due to frequency harmonic stacking.
American Microsystems, Inc. reserves the right to change the detail specifications as may be required to permit improvements in the design of its products.
PLL Clock Generator IC with VCXOPLL Clock Generator IC with VCXO
AMERICAN MICROSYSTEMS, INC.
April 2000
Table 2: Pin Descriptions
Key: AI = Analog Input; AO = Analog Output; DI = Digital Input; DIU = Input with Internal Pull-Up; DID = Input with Internal Pull-Down; DIO = Digital Input/Output; DI-3 = Three-Level Digital Input,
DO = Digital Output; P = Power/Ground; # = Active Low pin
The VCXO provides a tunab le, low-jitter frequenc y reference for the rest of the FS6128 system components.
Loading capacitance for the crystal is internal to the
FS6128. No external components (other than the resonator itself) are required for operation of the VCXO.
Continuous fine-tuning of the VCXO f requency is accom plished by varying the voltage on the XTUNE pin. The
value of this voltage controls the effective capacitance
presented to the crystal. The actual amount that this loa d
capacitance change will alter the oscillat or frequency depends on the characteris tics of the crystal as well as the
oscillator circuit itself.
It is important that the cr ystal load capacitance is spec ified correctly to “center” the tuning range. See Table 5.
A simple formula to obtain the “pulling” capability of a
crystal oscillator is:
6
ppmf
)(
=∆
2
where:
C
the shunt (or holder) capacitance of the crystal
0 =
C
the motional capacitance of the crystal
1 =
C
and CL2 = the two extremes (minimum and maximum)
L1
of the applied load capacitance presented by the
FS6128.
()
()()
×−×
CCC
10
LL
121
+×+×
CCCC
LL
1020
EXAMPLE: A crystal with the following parameters is
used: C
and maximum C
range (peak-to-peak) is:
= 0.025pF and C0 = 6pF. Using the minim um
1
f300
=∆
= 10pF, and CL2 = 20pF, the tuning
L1
()
.
10200250
()()
6
×−×
10
1062062
+×+×
ppm
=
.
3.2 Phase-Locked Loop (PLL)
The on-chip PLL is a standard frequency- and phaselocked loop architecture. The PLL multiplies the r ef er ence
oscillator frequenc y to the desired out put frequency b y a
ratio of integers. The frequency multiplication is exact
with a zero synthesis error (unless otherwise specified).
PLL Clock Generator IC with VCXOPLL Clock Generator IC with VCXO
April 2000
4.0 Electrical Specifications
Table 3: Absolute Maximum Ratings
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These conditions represent a stress rating only, and functional operation of the device at
these or any other conditions above the operational limits noted in this specification is not implied. Exposure to maximum rating conditions for extended conditions may affect device performance,
functionality, and reliability.
PARAMETERSYMBOLMIN.MAX.UNITS
Supply Voltage (VSS = ground)V
Input Voltage, dcV
Output Voltage, dcV
Input Clamp Current, dc (VI < 0 or VI > VDD)I
Output Clamp Current, dc (VI < 0 or VI > VDD)I
Storage Temperature Range (non-condensing)T
Ambient Temperature Range, Under BiasT
Junction TemperatureT
Lead Temperature (soldering, 10s)260°C
Input Static Discharge Voltage Protection (MIL-STD 883E, Method 3015.7)2kV
DD
I
O
IK
OK
S
A
J
VSS-0.57V
VSS-0.5VDD+0.5V
VSS-0.5VDD+0.5V
-5050mA
-5050mA
-65150°C
-55125°C
125°C
CAUTION: ELECTROSTATIC SENSITIVE DEVICE
Permanent damage resulting in a loss of functionality or performance may occur if this device is subject ed to a high-energy electrostatic discharge.
PLL Clock Generator IC with VCXOPLL Clock Generator IC with VCXO
AMERICAN MICROSYSTEMS, INC.
April 2000
Table 5: DC Electrical Specifications
Unless otherwise stated, VDD = 3.3V ± 10%, no load on any output, and ambient temperature range TA = 0°C to 70°C. Parameters denoted with an asterisk ( * ) represent nominal characterization
data and are not production tested to any specific limits. Where given, MIN and MAX characterization data are ± 3σ from typical. Negative currents indicate current flows out of the device.
High-Level Output Source Current *I
Low-Level Output Sink Current *I
Output Impedance *
Short Circuit Source Current *I
Short Circuit Sink Current *I
C
I
DD
DD
L(xtal)
OH
OL
z
OH
z
OL
OSH
OSL
f
= 13.5MHz; CL = 10pF, VDD = 3.6V30mA
XTAL
XIN = 0V, VDD = 3.6V3mA
Order crystal for this capacitance (parallel
load) at desired center frequency
Specified motional capacitance of the
1
crystal will affect pullability (see text)
L1
L2
@V(XTUNE)=minimum value
@V(XTUNE)=maximum value
f
= 13.5MHz; C
XTAL
(peak-to-peak)
Note: positive change of XTUNE =
positive change of VCXO frequency
R
=20Ω; CL = 20pF
XTAL
VO = 2.0V-40mA
VO = 0.4V17mA
VO = 0.1VDD; output driving high25
VO = 0.1VDD; output driving low25
VO = 0V; shorted for 30s, max.-55mA
VO = 3.3V; shorted for 30s, max.55mA
PLL Clock Generator IC with VCXOPLL Clock Generator IC with VCXO
April 2000
Table 6: AC Timing Specifications
Unless otherwise stated, VDD = 3.3V ± 10%, no load on any output, and ambient temperature range TA = 0°C to 70°C. Parameters denoted with an asterisk ( * ) represent nominal characterization
data and are not production tested to any specific limits. Where given, MIN and MAX characterization data are ± 3σ from typical.
Devices sold by AMI are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. AMI
makes no warranty, express, statutory implied or by description, regarding the information set forth herein or regarding the freedom
of the described devices from patent infringement. AMI makes no warranty of merchantability or fitness for any purposes. AMI reserves the right to discontinue production and change specifications and prices at any time and without notice. AMI’s products are
intended for use in commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment, are specifically not recommended without additional processing by AMI for such applications.
American Microsystems, Inc., 2300 Buckskin Rd., Pocatello, ID 83201, (208) 233-4690, FAX (208) 234-6796,
WWW Address: http://www.amis.com E-mail: [email protected]
ISO9001
ISO9001
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