DA9275.007
19 February 2004
MAS9275
IC FOR 10.00 – 36.00 MHz VCXO
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DESCRIPTION
MAS9275 is a VCXO IC to be used in making
VCXO modules for telecommunication and other
applications. To build a complete VCXO only one
additional component, a crystal, is needed.
Square Wave (CMOS) Output
Very Low Phase Noise
Low Power
Wide Supply Voltage Range
Very High Level of Integration
Low Cost
FEATURES
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Very small size
Minimal current consumption
Wide operating temperature range
Phase noise <-130 dBc/Hz at 1 kHz offset
Square wave (CMOS) output
APPLICATIONS
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VCXO for telecommunications systems
VCXO for set-top boxes
VCXO for MPEG
BLOCK DIAGRAM
PD
VC
OUT
MAS9275
VDD
VSS
X1
X'Tal
X2
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DA9275.007
19 February 2004
PIN DESCRIPTION
Pin Description
Crystal/Varactor Oscillator Input
Voltage Control Input
Power Supply Ground
Buffer Output
Power Supply Voltage
Tri State
Crystal Oscillator Output
Symbol
X1
VC
VSS
OUT
VDD
PD
X2
x-coordinate
209
425
600
1029
841
379
197
y-coordinate
161
165
175
1030
1016
1028
1030
Note
Note:
Because the substrate of the die is internally connected to GND, the die has to be connected to GND or
left floating. Please make sure that GND is the first pad to be bonded. Pick-and-place and all component
assembly are recommended to be performed in ESD protected area.
Note:
Pad coordinates are measured from the left bottom corner of the chip to the center of the pads. The
coordinates may vary depending on sawing width and location, however, distances between pads are accurate.
ABSOLUTE MAXIMUM RATINGS
Parameter
Supply Voltage
Input Pin Voltage
Power Dissipation
Storage Temperature
ESD Rating
Symbol
V
DD
-
V
SS
P
MAX
T
ST
HBM
Conditions
Min
-0.3
V
SS
-0.3
-55
Max
6.0
V
DD
+ 0.3
100
120
2
Unit
V
V
mW
o
C
kV
Note
RECOMMENDED OPERATION CONDITIONS
Parameter
Supply Voltage
Supply Current
Operating Temperature
Voltage Control Line
Impedance
Crystal Pulling Sensitivity
Crystal Load Capacitance
Symbol
V
DD
I
DD
T
OP
Vc
IMP
S
C
L
Conditions
VDD = 2.8 V
-40
MAS9275A,
MAS9275B
V
C
= 1.65 V
MAS9275A1
MAS9275B2
MAS9275B3
MAS9275C2
MAS9275C3
MAS9275C4
1
30
8
10
10.5
10
10.5
10.5
Min
2.5
Typ
2.8
2.3
Max
5.5
+85
Unit
V
mA
o
C
MΩ
ppm/pF
pF
2)
2)
2)
Note
1)
Note 1:
It is recommend to connect a 1 nF capacitor to the VDD pin (either in a module or in an end
application).
Note 2:
Crystal Load Capacitance is typically 8.2 pF, when V
C
= 2.5 V.
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DA9275.007
19 February 2004
ELECTRICAL CHARACTERISTICS
(recommended operation conditions)
Parameter
Frequency Range
Voltage Control Range
Voltage Control Sensitivity
Output Voltage (10 pF, VDD 2.7 V)
Output Voltage (10 pF, VDD 5.0 V)
Rise and Fall Time (10 - 50 pF)
Output Symmetry
Startup Time
Tri State Output Buffer
ON State
OFF State
Tri State Output Buffer
ON State
OFF State
Symbol
f
o
V
C
V
CSENS
V
out
V
out
Min
10.00
0
Typ
Max
36.00
VDD
Unit
MHz
V
ppm/V
Vpp
Vpp
Note
1)
2)
100
2.3
4.5
10
40-60
ns
%
ms
V
3)
4)
T
START
PD
0
1.6
PD
1.6
0
2
0.55
VDD
V
VDD
0.55
Note 1:
An R
S
< 20
Ω
crystal provides 36 MHz maximum frequency. With an R
S
= 70
Ω
crystal the maximum
frequency is typically 20 MHz.
Note 2:
VC sensitivity value depends on the crystal used. With a 30 ppm/pF crystal typical values are:
A1 > 100 ppm/V, B2 > 75 ppm/V, B3 > 60 ppm/V, C2 > 75 ppm/V, C3 > 60 ppm/V, C4 > 55 ppm/V.
Note 3:
MAS9275A, MAS9275B
Note 4:
MAS9275C
Note 5:
If the Tri State Output Buffer is floating (i.e., PD pin not connected), the oscillator is ON in all models
(MAS9275A, -B and -C)
IC OUTLINES
1290 µm
X2
PD
VDD
OUT
X1
VC
VSS
MAS9275
Die map reference
1220 µm
Note 1:
MAS9275 pads are round with 80 µm diameter at opening.
Note 2:
Die map reference is the actual left bottom corner of the sawn chip.
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DA9275.007
19 February 2004
EXTERNAL COMPONENT SELECTION
MAS9275 requires a minimum number of external components for proper operation.
Quartz Crystal
The MAS9275 VCXO function consists of the
external crystal and the integrated VCXO oscillator
circuit. To assure the best system performance
(frequency pull range) and reliability, a crystal
device with the recommended parameters (shown
below) must be used, and the layout guidelines in
the following section must be followed. The
frequency of oscillation of a quartz crystal is
determined by its “cut” and by the load capacitors
Recommended Crystal Parameters:
Initial Accuracy at 25°C ±20 ppm
Temperature Stability ±30 ppm
Crystal Load Capacitance 10 pf (See Note1 below)
Crystal Shunt Capacitance, C0 2 pF Typical
C0/C1 Ratio Typical
≤
300
Equivalent Series Resistance 20
Ω
max. Crystals with higher ESR can be used if frequency is < 36 MHz. See
Note 2 under Electrical Characteristics on Page 3.
The external crystal must be connected as close to the chip as possible and should be on the same side of the
PCB as the MAS9275. There should be no vias between the crystal pins and the X1 and X2 device pins. There
should be no signal traces underneath or close to the crystal.
Note 1.
If the crystal with a load other than the nominal Crystal Load Capacitance as defined in Recommended
Operation Conditions on page 2 is used with MAS9275, the crystal has to have frequency offset in order to
have the nominal frequency at VC = 1.65 V or at VC = 2.5 V. Please see table below for offset frequencies vs.
crystal load. (Values are for a typical crystal with S = 30 ppm/pF.)
Crystal frequency
Crystal Load
A1
B2, C2
B3, C3, C4
B3, C3, C4
V
C
voltage
1.65 V
1.65 V
1.65 V
2.5 V
19.68
8
+0
+60
+85
+30
19.68
27.00
40.00
10
12.5
16
Offset in crystal frequency
-60
-150
-240
0
-75
-180
+25
-50
-155
-30
-105
-210
MHz
pF
ppm
ppm
ppm
ppm
connected to it. MAS9275 incorporates on-chip
variable load capacitors that “pull” (change) the
frequency of the crystal. The crystal specified for
use with the MAS9275B2 is designed to have zero
frequency error when the total of on-chip + stray
capacitance is 10 pF (See Note 1 on page 2 for
other capacitance options).
Note:
19.68 MHz crystal with 10 pF load capacitance used with MAS9275B2 or C2 may not require frequency
offset because of small deviation
For example:
For application using MAS9275B2 or C2 with nominal frequency of 27.00 MHz a crystal with 12.5 pF load has to
have a frequency of 27.00 MHz + ((27.00 MHz/10
6
) x (- 90)) = 26.99757 MHz.
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DA9275.007
19 February 2004
MODULATION RESPONSE
Figure 2.
Modulation response (gain).
MAS9275B2/C2 Modulation Response
2.00
0.00
-2.00
Gain (dB)
-4.00
-6.00
-8.00
-10.00
0.1
1
Frequency (kHz)
10
100
Gain (dB)
2
0
-2
-4
-6
-8
-10
0.1
MAS9275B3/C3 Modulation Response
1
Frequency (kHz)
10
100
TYPICAL APPLICATION
Vdd
1n
C1
MAS9275B2/B3/C2/C3
X2
1
2
20
19
18
PD
17
MAS9275
YYWW
XXXXX.X
X1
3
Vcontrol
R1
50k
47n
C2
4
Top marking:
YYWW = Year, Week
XXXXX.X = Lot number
VC
5
16
VDD
15
14
13
12
11
Modulation In
GND
6
7
8
9
10
C6
10n
OUT
5 (10)
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