ETC MT1530

M I C R O T U N E™
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
1 APPLICATIONS
•
•
•
Cable modems
Telephony over cable
Set-top box CATV
•
•
•
Lowest power consumption upstream amplifier available
Maximum output level of 64 dBmV
Low power-up/down transients of 4 mVp-p typical at 59 dBmV output
•
•
•
•
•
•
•
•
•
Best in class second harmonic distortion
Ultra low third harmonic distortion
Single +5V supply
63-dB Gain range
Gain programmable in 1-dB steps
Low transmit output noise floor: 131 nV / √Hz
Low transmit-disable output noise: 810 pV / √Hz
Two power-down modes
DOCSIS and EuroDOCSIS compatible
Preliminary and Proprietary
2 FEATURES
3 OVERVIEW
The Microtune 1530 (MT1530) is a low-cost programmable-gain power amplifier IC
for use in CATV upstream applications. Specifically, the MT1530 is optimized for the
DOCSIS upstream standard.
The device operates at a frequency range from 5 MHz to 65 MHz, and can output
64 dBmV through a 4:1 impedance-ratio transformer. Second harmonic distortion is
typically less than -70 dBc, and third harmonic distortion is typically less than
-55 dBc at a 59 dBmV output level. A 3-wire digital serial bus controls the variable
gain, with gain control available in 1-dB steps and a nominal 63-dB gain range.
The MT1530 may be disabled via an external control pin. The transmit-disable mode
not only minimizes output noise by shutting off the output stage, but also maintains
its output impedance at nominal levels. Output glitch transients are nominally less
than 4 mV at maximum gain settings during transmit enable/disable switching.
Operating from a single +5V supply, the amplifier’s typical current draw at maximum
gain, or minimum attenuation, is 102 mA. Additionally, internal circuitry reduces the
amplifier’s power consumption depending on gain setting. Transmit-disable mode
power supply current is reduced to a nominal of 14 mA. A shutdown mode further
reduces current to a nominal of 130 µA.
The MT1530 is available in a 20-pin SSOP package for the extended industrial
temperature range of -40°C to +85°C.
DS-00010
Rev 1.2 — December 2000
Page 1 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
4 ABSOLUTE MAXIMUM RATING S
Stresses greater than those listed in Table 1 may cause permanent damage to the
device. These are stress ratings only; functional operation of the device under
conditions other than those listed in the operational sections of this document is not
recommended or implied. Exposure to any of the absolute-maximum rating
conditions for extended periods of time may affect reliability.
Table 1
Stress Ratings
MIN
MAX
UNIT
VCC (VCC1, VCC2)
-0.7
6
V
VOUT+, VOUT-
-0.7
7.5
V
Input voltage levels (all inputs), VCM
−0.7
VCC + 0.7
V
+150
°C
+150
°C
+300
°C
Preliminary and Proprietary
PARAMETER
Junction temperature
Storage temperature range
-55
Lead temperature (soldering, 10 seconds)
5 DC ELECTRICAL CHARACTERIS TICS
The DC electrical characteristics listed in Table 2 are valid for the following
conditions unless otherwise noted. Typical parameters are at TA = +25°C.
•
VCC = +4.75V to +5.25V
•
•
•
TXEN = high
D7 = 1
TA = -40°C to +85°C
Table 2
DC Electrical Characteristics
PARAMETER
Supply voltage
Supply current,
transmit mode
SYMBOL
MIN
VCC
4.75
Gain code = 52 to 63
Gain code = 46 to 51
Supply current, shutdown mode (D7 = 0 or
SHDN = 0)
MAX
UNIT
5.25
V
102
129
59
75
37
47
ICC
14
19
mA
ICC
131
164
µA
ICC
Gain code = 45 to 0
Supply current, transmit-disable mode
(TXEN = low)
TYP
mA
Input high voltage
VIH
Input low voltage
VIL
Input high current
IIH
0
µA
Input low current
IIL
0
µA
2.0
V
0.8
V
DS-00010
Rev 1.2 — December 2000
Page 2 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
6 AC ELECTRICAL CHARACTERIS TICS
The AC electrical characteristics listed in Table 3 are valid for the following
conditions unless otherwise noted. Typical parameters are at TA = +25°C.
•
VCC = +4.75V to +5.25V
•
TXEN = SHDN = high
•
•
D7 = 1
VIN = 33 dBmV differential
•
•
Output impedance = 75Ω through a 4:1 impedance transformer
TA = -40°C to +85°C
Table 3
Preliminary and Proprietary
PARAMETER
AC Electrical Characteristics of the MT1530
SYMBOL
AV
Voltage gain
CONDITIONS
FIN = 5 MHz to
42 MHz
MIN
TYP
MAX
UNIT
Gain control word = 0
-33.6
-32.4
-31.1
dB
Gain control word = 63
28.1
VOUT = 59 dBmV, FIN = 42 MHz
1
Gain rolloff
VOUT = 59 dBmV, FIN = 65 MHz
1 dB Compression
point
1
AV = 29 dB, 42 MHz
65
Output step size
FIN = 5 MHz to 42 MHz
0.7
Transmit mode
noise
AV = 26 dB
P1dB
2
30.8
32.1
dB
-0.25
-0.5
dB
-0.9
-1.5
dB
67
dBmV
1
1.3
dB
131
150
nV / √Hz
AV = -26 dB
8.5
10.1
nV / √Hz
Transmit-disable
mode noise
TXEN = low, AV = 26 dB, FIN = 5 MHz to
65 MHz
810
pV / √Hz
Isolation in transmitdisable mode
TXEN = low, gain control word = 63,
FIN = 65 MHz
69
dB
TXEN Transient
duration
TXEN rise/fall time < 0.1µs
1.5
µs
2
2
2
TXEN Transient step
size
Input impedance
ZIN
Output impedance
ZOUT
Output return loss
RL
Third-order output
intercept
OIP3
2 Harmonic
distortion
HD2
3 Harmonic
distortion
HD3
nd
rd
Gain setting = 63
4
16
mVp-p
Gain setting = 51 or lower2
2
8
mVp-p
FIN = 5 MHz to 65 MHz, single-ended2
FIN = 5 MHz to 65 MHz
2
Input tones at 65 MHz and 66 MHz,
VIN = 28 dBmV/tone, VOUT = 53 dBmV/tone2
1.35
1.85
kΩ
75
Ω
10.7
15
dB
80
84
dBmV
FIN = 33 MHz, VOUT = +59 dBmV
-72
-66
dBc
FIN = 65 MHz, VOUT = +59 dBmV
-70
-64
dBc
FIN = 22 MHz, VOUT = +59 dBmV
-59
-55
dBc
FIN = 65 MHz, VOUT = +59 dBmV
-55
-51
dBc
1
Referenced to 10 MHz.
2
Guaranteed by design.
DS-00010
Rev 1.2 — December 2000
Page 3 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
7 TYPICAL PERFORMANCE
Preliminary and Proprietary
The following data is representative of a part measured in a typical application
circuit.
•
•
4:1 impedance ratio balun on the output
Zload = 75Ω, Vcc = 5V
•
TA = 25°C
0.30
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
0.20
0.10
0.00
5MHz
5MHz
15MHz
42MHz
65MHz
-0.10
-0.20
-0.30
0
5
10
15
20
25
30
35
40
45
50
55
0
60
5
10
15
20
25
Gain Code
Figure 1
30
35
40
45
50
55
60
Gain Code
Voltage Gain vs. Gain Code
Figure 2
1.8
Differential Gain Linearity vs. Gain Code
100
Referenced to 5MHz
1.6
95
1.4
90
1.2
TXEN = LOW
85
1.0
20 MHz
80
65 MHz
0.8
75
0.6
70
0.4
65 MHz
65
0.2
60
42 MHz
0.0
55
-0.2
0
5
Figure 3
10
15
20
25
30
35
Gain Code
40
45
50
55
28
60
30
32
34
36
38
Figure 4
-45
42 MHz
86
84
46
48
50
52
54
56
58
60
62
Vin = 34 dBmV
-50
-55
65 MHz
82
44
Input-Output Isolation vs. Gain Code
Vout = 53 dBmV / Tone
88
42
Gain Code
Gain Rolloff vs. Gain Code
90
40
-60
80
78
-65
65 MHz
76
-70
74
33 MHz
72
-75
70
68
-80
50
51
52
53
54
55
56
57
58
59
60
61
62
63
50
Gain Code
Figure 5
Third-Order Output Intercept vs. Gain
Control
51
52
53
54
55
56
57
58
59
60
61
62
63
Gain Code
Figure 6
Second-Order Harmonic Distortion vs. Gain
Code
DS-00010
Rev 1.2 — December 2000
Page 4 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
69
-40
Vin = 34 dBmV
42 MHz
68
-45
20 MHz
67
66
-50
65
-55
65 MHz
64
65 MHz
63
-60
62
30 MHz
-65
61
50
51
52
53
54
55
56
57
58
59
60
61
62
63
52
Gain Code
Figure 7
Third-Order Harmonic Distortion vs. Gain
Code
1.0E-06
53
Figure 8
54
55
56
57
58
Gain Code
59
60
61
62
63
Output 1 dB Compression Point vs. Gain
and Frequency
110
Preliminary and Proprietary
100
90
1.0E-07
80
70
60
1.0E-08
50
40
30
1.0E-09
20
0
5
10
15
20
25
30
35
40
45
50
55
60
0
Gain Code
Figure 9
Output Noise vs. Gain Code
5
10
15
20
25
30
35
Gain Code
40
45
50
55
60
Figure 10 Power Supply Current vs. Gain Code
10
Z0 = 75 Ohms
15
20
25
30
35
5
15
25
35
45
55
65
75
85
95
Frequency ( MHz )
Figure 11 Output Return Loss vs. Frequency
DS-00010
Rev 1.2 — December 2000
Page 5 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
8 DETAILED DESCRIPTION
5
6
Variable Attenuator
Vout+
16
Vcm
14
Power Amp
Input Amp
Vin+
Vcc2
Vcc1
2
19
This section describes the MT1530 functional blocks shown in Figure 12.
CEXT
Vin-
CS
SDA
SCLK
TXEN
8
10
18
DGND
7
15
PA
Control
9
SHDN
Serial
Interface
12
Preliminary and Proprietary
Vout-
Figure 12 MT1530 Amplifier Block Diagram
8.1 FUNCTIONAL MODES
The MT1530 amplifier has three functional modes controlled through the serial
interface or external pins: transmit mode, transmit-disable mode, and shutdown
mode.
8.1.1 TRANSMIT MODE
Transmit mode is the normal active mode of the MT1530. The TXEN and SHDN pins
must be held high in this mode.
8.1.2 TRANSMIT-DISABLE MODE
Transmit-disable mode is typically used between bursts in TDMA systems. This
mode shuts off the power amplifier while keeping the input amplifier and variable
attenuator powered up. Taking TXEN low while keeping SHDN high and D7 = 1 (see
Table 5) activates this mode.
DS-00010
Rev 1.2 — December 2000
Page 6 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
8.1.3 SHUTDOWN MODE
Shutdown mode minimizes current consumption while maintaining the programmed
gain state stored in the latch of the serial interface. All analog functions are disabled
in this mode and current consumption is reduced to 131 µA (typical). Shutdown
mode is enabled when either D7 = 0 or SHDN is set low. This mode overrides the
TXEN input pin, but TXEN should be held low to minimize glitching when exiting this
mode.
Preliminary and Proprietary
8.2 IC ARCHITECTURE
The MT1530’s signal path consists of an input amplifier, a variable attenuator, and a
power amplifier as shown in Figure 12. The input amplifier is a fixed-gain, low-noise,
differential amplifier with a nominal input impedance of 1.85 kΩ. The variable
attenuator is capable of a 51-dB attenuation range in 1-dB steps. The output power
amplifier has 12 dB of gain range in 6 dB steps.
8.2.1 INPUT AMPLIFIER
The input amplifier (IA) is a fully differential, low-noise amplifier with no gain
adjustment. Its bias may be disabled either by the external SHDN pin, or D7 of the
serial control register.
For best second-order performance, the IA should be driven differentially. However,
the device may be driven in a single-ended mode, with the other unused input
bypassed to ground with a 10 nF capacitor. The IA’s inputs are self-biasing and
must be AC coupled.
8.2.2 VARIABLE ATTENUATOR
The variable attenuator (VA) provides up to 51 dB attenuation of the input signal in
nominal 1-dB increments. The architecture is fully differential to minimize glitching
and even-order harmonics. This attenuator acts together with the output power
amplifier to achieve a nominal 63 dB of gain range, as described in section 8.2.3.
8.2.3 OUTPUT POWER AMPLIFIER
The output power amplifier (PA) is a fully differential amplifier capable of driving +64
dBmV into a 75Ω load. An off-chip transformer must be used to convert from a
differential to a single-ended output. The PA’s output impedance is nominally 300Ω,
which is transformed to 75Ω by the 4:1 impedance ratio transformer. This impedance
is maintained when the amplifier is powered down by setting TXEN = low. The
amplifier’s outputs are powered by +5V connected to the center tap of the
transformer’s secondary.
The differential nature of the PA provides superior second-order harmonic
performance. Additionally, any single-ended transients on the amplifier’s outputs that
are generated during transmit enable/disable switching are cancelled by this
architecture.
DS-00010
Rev 1.2 — December 2000
Page 7 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
In addition to providing output power, the PA also plays a role in the gainprogrammability of the IC. The output amplifier has attenuation settings of 0, 6, and
12 dB. Higher attenuations reduce output power and noise. The programmed gain
control code automatically sets the PA’s attenuation. Gain control codes of 52
through 63 set the PA’s attenuation to 0 dB, putting the PA at maximum power. Gain
control codes of 46 to 51 set the PA’s attenuation to 6 dB, lowering its power by half.
Gain control codes of less than 46 set the PA’s attenuation to 12 dB, lowering its
power to one quarter of the maximum value. Transmit-disable and shutdown modes
turn off power to the PA for maximum isolation and minimum output noise.
8.2.4 PA CONTROL
Preliminary and Proprietary
The PA Control (PAC) both adjusts the output amp’s gain, and manages power-up
and power-down transients. The PAC uses internal timing circuits to control the
ramp-up and ramp-down of the PA’s bias block. This orderly ramp keeps the PA’s
output glitch to very low levels.
The PAC begins a bias ramp-down on the falling edge of TXEN. A rising TXEN
produces a bias ramp-up. Note that for a minimum glitch on the output, the rest of
the IC must already be powered up by having disabled shutdown mode.
8.3 SERIAL INTERFACE
The serial interface (SI) programs the gain of the MT1530 using an 8-bit control
word. The SI uses the gain control word to set the VA’s and PA’s gains individually
using an internal decoder. It has an active-low chip-select ( CS ) to synchronize to
the incoming word. Data is clocked MSB first on the rising edge of SCLK. Data is
latched on the rising edge of CS . Table 4 and Table 5 show the register format.
Figure 13 illustrates serial interface timing.
Table 4
Serial Interface Control Word
BIT
MNEMONIC
7 (MSB)
D7
Software shutdown (active low)
6
D6
Unused (Don’t Care)
5
D5
Gain control, Bit 5
4
D4
Gain control, Bit 4
3
D3
Gain control, Bit 3
2
D2
Gain control, Bit 2
DESCRIPTION
1
D1
Gain control, Bit 1
0 (LSB)
D0
Gain control, Bit 0
DS-00010
Rev 1.2 — December 2000
Page 8 of 14
MT1530 UPSTREAM AMPLIFIER
ADVANCE DATA SHEET
CATV APPLICATIONS
Preliminary and Proprietary
Table 5
Chip State Control Bits
STATE
SHDN
TXEN
D7
D6
D5
D4
D3
D2
D1
D0
GAIN STATE
(DECIMAL)
0
0
X
X
X
X
X
X
X
X
X
Shutdown mode
X
0
0
X
X
X
X
X
X
X
X
Software
shutdown mode
1
0
1
X
X
X
X
X
X
X
X
Transmit-disable
mode
1
1
1
X
X
X
X
X
X
X
X
Transmit mode
1
1
1
X
0
0
0
0
0
0
0
Gain = -32 dB1
1
1
1
X
0
0
0
0
0
1
1
Gain = -31 dB1
1
1
1
X
1
0
0
0
0
0
32
Gain = 0 dB1
1
1
1
X
1
1
1
1
1
0
62
Gain = 30 dB1
1
1
1
X
1
1
1
1
1
1
63
Gain = 31 dB1
1
Typical gain at +25°C, VCC = +5V, Fin = 20 MHz
DS-00010
Rev 1.2 — December 2000
Page 9 of 14
MT1530 UPSTREAM AMPLIFIER
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Table 6
CATV APPLICATIONS
Timing Characteristics
Preliminary and Proprietary
PARAMETER
SYMBOL
MIN
CS to SCK rise setup time
tSENS
10
ns
CS to SCK rise hold time
tSENH
20
ns
SDA to SCK setup time
tSDAS
10
ns
SDA to SCK hold time
tSDAH
20
ns
SDA pulse width high
tDATAH
50
ns
SDA pulse width low
tDATAL
50
ns
SCK pulse width high
tSCKH
50
ns
SCK pulse width low
tSCKL
50
ns
tSENS
tDATAH/
tDATAL
tSDAS
TYP
tSDAH
MAX
UNITS
tSCKL tSCKH
tSENH
CS
SCLK
SDA
D7
D6
D5
D4
D3
D2
D1
D0
Figure 13 Serial Interface Timing Diagram
DS-00010
Rev 1.2 — December 2000
Page 10 of 14
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CATV APPLICATIONS
9 TERMINAL CONNECTIONS
Terminal connections for the MT1530 are described in Table 7.
Preliminary and Proprietary
Table 7
Terminal Connections
PIN
FUNCTION/
SYMBOL
1
GND
Ground connection
2
VCC1
+5V Power supply for the input amplifier, variable attenuator, and serial
interface. Bypass to GND1 with a 0.1 µF decoupling capacitor as close to
the part as possible.
3
NC
4
GND1
Ground connection for the input amplifier and variable attenuator
5
VIN+
Positive input to the input amplifier
VIN-
Negative input to the input amplifier. Bypass with capacitor if driving
amplifier single-ended.
6
7
DGND
8
CS
DESCRIPTION
No connect
Ground connection to serial interface
Chip select input to serial interface (active low)
9
SDA
Data input to serial interface (active high)
10
SCLK
Clock input to serial interface (positive-edge triggered)
11
NC
12
SHDN
13
NC
14
VCM
No connect
Shutdown mode input (active low)
No connect
Output common-mode bypass. Bypass to GND2 with 0.1 µF capacitor.
15
VOUT-
PA negative output
16
VOUT+
PA positive output
17
NC
18
TXEN
PA output enable input (active high)
No connect
19
VCC2
+5V Power supply for PA bias and control circuitry. Bypass to GND2 with a
0.1 µF decoupling capacitor as close to the part as possible.
20
GND2
Ground connection for the PA
DS-00010
Rev 1.2 — December 2000
Page 11 of 14
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CATV APPLICATIONS
10 PIN CONFIGURATION
Preliminary and Proprietary
Top View
GND
1
20
GND2
VCC1
2
19
VCC2
NC
3
18
TXEN
GND1
4
17
NC
VIN+
5
16
VOUT+
VIN-
6
15
VOUT-
DGND
7
14
VCM
CS
8
13
NC
SDA
9
12
SHDN
SCLK
10
11
NC
MT1530
Figure 14 Pin Diagram
DS-00010
Rev 1.2 — December 2000
Page 12 of 14
MT1530 UPSTREAM AMPLIFIER
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CATV APPLICATIONS
11 PACKAGE DRAWING
SEE:V.T"D"
AA ONLY
SEE: V.T"S"
0.045" DIA
AB/AC/AD ONLY
C
L
3
2
1
0.118
0.016 X 45°
0.010
0.157 MAX
0.150 MIN
C
L
CL
C
L
0.035 MAX
0.016 MIN
0.244 MAX
0.228 MIN
2X
0.003
2X
0.010
N
C
L
0.010
Preliminary and Proprietary
D/2
END VIEW
TOP VIEW
0.061 MAX
0.055 MIN
8° MAX
0 MIN
0.012 MAX
0.008 MIN
0.068 MAX
0.061 MIN
0.025
C
L CL
0.005
H
0.010 MAX
0.007 MIN
0.009 MAX
0.007 MIN
PARTING LINE
SEATING PLANE
0.004
0.0098 MAX
0.004 MIN
SEE DETAIL "C"
WITH PLATING
SIDE VIEW
0.011 MAX
0.008 MIN
BASE METAL
DETAIL "C"
CONTROLLING DIMENSION: INCHES
VARIATIONS
AA
AB
AC
AD
MIN.
0.189
0.337
0.337
0.386
V.T."D"
MAX.
NOM.
0.196
0.194
0.344
0.342
0.342
0.344
0.391
0.393
MIN.
0.002
0.050
0.025
0.025
V.T."S"
NOM.
MAX.
0.005
0.007
0.053
0.055
0.028
0.030
0.028
0.030
N
16
20
24
28
THIS PACKAGE MEETS JEDEC REGISTRATION MO-137AA-AF
EXCEPT FOR THE PKG THICKNESS, DIM 0.061 MAX.
Figure 15 MT1530 Package Drawing
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Rev 1.2 — December 2000
Page 13 of 14
MT1530 UPSTREAM AMPLIFIER
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CATV APPLICATIONS
NOTICES
Preliminary and Proprietary
NOTICE - The information in this document is believed to be accurate and reliable. Microtune assumes no
responsibility for any consequences arising from the use of this information, nor from any infringement of patents
or the rights of third parties which may result from its use. No license is granted by implication or otherwise under
any patent or other rights of Microtune. The information in this publication replaces and supersedes all
information previously supplied, and is subject to change without notice. The customer is responsible for
assuring that proper design and operating safeguards are observed to minimize inherent and procedural
hazards. Microtune assumes no responsibility for applications assistance or customer product design.
NOTICE - The devices described in this document are not authorized for use in medical, life-support equipment,
or any other application involving a potential risk of severe property or environmental damage, personal injury, or
death without prior express written approval of Microtune. Any such use is understood to be entirely at the user’s
risk.
TRADEMARKS - Microtune, MicroTuner, and the Microtune logo are trademarks of Microtune, Inc. All other
trademarks belong to their respective companies.
PATENTS - This product is manufactured and protected by the following U.S. patents: 5,805,988; 5,739,730;
5,625,325; 5,737,035; 5,648,744; 5,717,730; 5,847,612; 6,104,242; 6,100,761; 6,144,402; and additional patents
pending or filed.
COPYRIGHT - Entire contents Copyright © 2000 Microtune, Inc.
World Headquarters
Microtune, Inc.
2201 Tenth Street
Plano, TX 75074
European Headquarters
Microtune GmbH and Co. KG
Marie Curie Strasse 1
85055 Ingolstadt / Germany
Pan-Asian Headquarters
Microtune, Inc. - Hong Kong
Silvercord Tower 1, Room 503
30 Canton Road
Kowloon, Hong Kong
Telephone: 972-673-1600
Fax: 972-673-1602
Email: [email protected]
Website: www.microtune.com
Telephone: +49-841-9378-011
Fax: +49-841-9378-010
Sales Telephone: +49-841-9378-020
Sales Fax: +49-841-9378-024
Telephone: +852-2378-8128
Fax: +852-2302-0756
For a detailed list of current sales representatives, visit our Web site at www.microtune.com.
DS-00010
Rev 1.2 — December 2000
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