ANADIGICS ARA1400

ARA1400
Reverse Amplifier with Step Attenuator
Data Sheet - Rev 2.1
FEATURES
•
Low cost integrated monolothic GaAs amplifier
with step attenuator
•
Attenuation Range: 0-56 dB, adjustable in
4 dB increments via a 4 wire parallel control
•
Meets DOCSIS distortion requirements at
+60 dBmV output signal level
•
Low distortion and low noise
•
Frequency range: 5-100 MHz
•
5 Volt operation
•
0 to +85 °C temperature range
APPLICATIONS
•
MCNS/DOCSIS Compliant Cable Modems
•
CATV Interactive Set-Top Box
•
Telephony over Cable Systems
•
OpenCable Set-Top Box
•
Residential Gateway
S12 Package
28 Pin SSOP with Heat Slug
PRODUCT DESCRIPTION
The ARA1400 is a GaAs IC designed to provide the
reverse path amplification and output level control
functions in a CATV Set-Top Box or Cable Modem. It
incorporates a digitally controlled precision step
attenuator that is preceded by an ultra low noise
amplifier stage, and followed by an ultra-linear
output driver amplifier. The device is capable of
meeting the MCNS/DOCSIS requirements for
4
harmonic performance at a +60dBmV output level
while requiring only a single polarity +5V supply.
Both the input and the output are single-ended and
matched to 75 Ohms, and a precision attenuator
provides up to 56 dB of attenuation in 4 dB
increments. The device is offered in a 28-pin SSOP
package featuring a heat slug on the bottom of the
package.
Attenuation Control
LPF
ARA1400
Balun
Upstream
QPSK/16QAM
Modulator
RAM
Clock
Data
Transmit Enable/Disable
5-42 MHz
Microcontroller
with Ethernet
MAC
MAC
Clock
ROM
Data
44 MHz
Diplexer
54-860 MHz
DoubleConversion
Tuner
SAW
Filter
QAM Receiver
with FEC
10Base-T
Transceiver
Figure 1: Cable Modem or Set Top Box Application Diagram
03/2004
RJ45
Connector
ARA1400
RFOUT1
ATT IN
ATT OUT
RFIN2
56 dB 4 dB step digital attenuator section
RFIN
ISET1
32 dB
16 dB
8 dB
ISET2
4 dB
Figure 2: Functional Block Diagram
1
GND
2
N/C
3
ATT IN
4
RFOUT1
5
VREF1
6
ATT ACG1
ATTACG2
23
7
ATT ACG1
ATTACG2
22
8
ATT ACG1
ATTACG2
21
9
ATT ACG1
ATTACG2
20
10
RFIN
RFOUT
19
11
ISET1
VREF2
18
12
VATT
VA2
17
13
32 dB
4 dB
16
14
16 dB
8 dB
15
ATTOUT
28
ISET2
27
RFIN2
26
Tx
25
ATTACG3
24
Figure 3: Pinout
2
RFOUT
AMP
AMP
Data Sheet - Rev 2.1
03/2004
Tx
ARA1400
Table 1: Pin Description
PIN
NAME
DESCRIPTION
PIN
NAME
DESCRIPTION
1
GND
Ground
15
8 dB
82 dB Attenution Control Bit
2
N/C
No Connection
(1)
16
4 dB
4 dB Attenution Control Bit
3
ATTIN
Attenuator Input (2)
17
V A2
4
RFOUT1
Amplifier A1 Output and
Supply
18
VREF2
Reference Voltage for
Amplifier A2
5
VREF1
Reference Voltage for
Amplifier A1
19
RFOUT
RF Output from Switch (2)
6
ATTACG1
Attenuator AC Ground 1
(3)
20
ATTACG2
Attenuator AC Ground 2
(3)
7
ATTACG1
Attenuator AC Ground 1
(3)
21
ATTACG2
Attenuator AC Ground 2
(3)
8
ATTACG1
Attenuator AC Ground 1
(3)
22
ATTACG2
Attenuator AC Ground 2
(3)
9
ATTACG1
Attenuator AC Ground 1
(3)
23
ATTACG2
Attenuator AC Ground 2
(3)
10
RFIN
Amplifier A1 Input (4)
24
ATTACG3
Attenuator AC Ground 3
(3)
11
ISET1
Amplifier A1 Current Adjust
25
Tx
12
VATT
Attenuator Supply
26
RFIN2
Amplifier A2 Input (4)
13
32 dB
32 dB Attenution Control Bit
27
ISET2
Amplifier A2 Current Adjust
14
16 dB
16 dB Attenution Control Bit
28
ATTOUT
Amplifier A2 Supply
Output Switch Control
Attenuator Output (2)
Notes:
(1) All N/C pins should be grounded.
(2) Pins should be AC-coupled. No external DC bias should be applied.
(3) Pins should be AC-grounded. No external DC bias should be applied.
(4) Pins should be AC-coupled from the RF path, and should be pulled to ground through a resistor.
Data Sheet - Rev 2.1
03/2004
3
ARA1400
ELECTRICAL CHARACTERISTICS
Table 2: Absolute Minimum and Maximum Ratings
PARAMETER
MIN
MAX
UNIT
0
9
VD C
Amplifier Reference Voltages (pins 5, 18)
-2.5
VSUP
2
VD C
RF Power at Amplifier Inputs (pins 10, 26)
-
+60
dBmV
Attenuator Controls (pins 13, 14, 15, 16)
0
6
V
Output Switch Control (pin 25)
0
6
V
-55
+200
°C
Soldering Temperature
-
260
°C
Soldering Time
-
5
S ec
Analog Supply: VSUP (pins 4, 12, 17)
Storage Temperature
Stresses in excess of the absolute ratings may cause permanent damage.
Functional operation is not implied under these conditions. Exposure to absolute
ratings for extended periods of time may adversely affect reliability.
Notes:
1. Pins 3, 19, and 28 should be AC-coupled. No external DC bias should be applied.
2. Pins 11 and 27 should be grounded or pulled to ground through a resistor. No external
DC bias should be applied.
3. Pins 6, 7, 8, 9, 20, 21, 22, 23 and 24 should be AC-grounded. No external DC bias
should be applied.
4. Pins 10 and 26 should be AC-coupled from the RF path, and should be pulled to
ground through a resistor.
Table 3: Operating Ranges
PARAMETER
MIN
TYP
MAX
UNIT
Amplifier Supply: VDD (pins 4, 17)
4.5
5
7
VD C
Attenuator Supply: VATTN (pin 12)
VDD-0.5
5
7
VD C
Attenuator Controls (pins 13, 14, 15, 16)
0
-
5.5
V
Amplifier Reference Voltages (pins 5, 18)
-
1.75
-
VD C
Output Switch Control (pin 25)
0
-
5.5
V
Case Temperature
0
25
85
°C
The device may be operated safely over these conditions; however, parametric
performance is guaranteed only over the conditions defined in the electrical specifications.
4
Data Sheet - Rev 2.1
03/2004
ARA1400
Table 4: DC Electrical Specifications
(TA = 25 °C; VDD,VATTN = +5.0 VDC)
PARAMETER
MIN
TYP
MAX
UNIT
Amplifier A1 Current (pin 4)
-
74
95
mA
Amplifier A2 Current (pin 17)
-
108
130
mA
Attenuator Current (pin 12)
-
12
20
mA
Total Power Consumption
-
0.97
1.23
W
COMMENTS
Table 5: AC Electrical Specifications
(TA = 25 °C; VDD, VATTN = +5.0 VDC; Tx = 0 V (switch closed), Tx = +5 V (switch open))
PARAMETER
MIN
TYP
MAX
UNIT
COMMENTS
Gain (10 MHz)
30
32
33
dB
0 dB attenuation setting
Gain Flatness
-
0.75
-
dB
5 to 100 MHz
Gain Variation over Temperature
-
-0.006
-
dB/°C
3.6
7.7
15.3
31.0
3.9
8.0
15.7
31.5
4.2
8.3
16.1
32.0
Switch Isolation at 45 MHz
-
35
Harmonics (fo = 10MHz)
2fo
3fo
-
3rd Order Output Intercept
Attenuation Steps
4 dB
8 dB
16 dB
32 dB
dB
Monotonic
30
dB
Difference in output
signal level between
active and standby
-57
-64
-52
-56
dB c
fo power = +60 dBmV
into 75 Ohms
78
-
-
dBmV
1 dB Gain Compression Point
-
70
-
dBmV
Noise Figure
-
1.7
2.5
dB
Output Noise Power
Active / No Signal / Min. Atten. Set.
Active / No Signal / Max. Atten. Set.
-
-
-37.6
-54.6
dBmV
Input Impedance
-
75
-
Ohms
Any 160 kHz bandwidth
from 5 to 42 MHz
Note: As measured in ANADIGICS test fixture.
Data Sheet - Rev 2.1
03/2004
5
ARA1400
continued: AC Electrical Specifications
(TA = 25 °C; VDD, VATTN = +5.0 VDC; Tx = 0 V (switch closed), Tx = +5 V (switch open))
PARAMETER
MIN
TYP
MAX
UNIT
COMMENTS
Input Return Loss
(75 Ohm characteristic impedance)
-
-20
-15
dB
Output Impedance
-
-20
-12
-15
-10
Ohms
Switch closed
Switch open
Output Return Loss
(75 Ohm characteristic impedance)
-
-17
-15
-12
-10
dB
Switch closed
Switch open
Output Voltage Transient
switch closed / switch open
-
4
7
mVp-p
Note: As measured in ANADIGICS test fixture.
Table 6: Logic Interface Specifications
(TA = 25 °C; VDD, VATTN = +5.0 VDC)
PARAMETER
MIN
TYP
MAX
UNIT
Attenuator Control Logic
VIN,LOW
VIN,HIGH
0
2.7
-
0.5
5.5
V
-
5K
-
Ohms
0
2.8
-
1
5.5
V
-
10 K
-
Ohms
Attenuator Control Impedance
Output Switch Control Logic
VIN,LOW
VIN,HIGH
Output Switch Control Impedance
COMMENTS
Bypasses atten. stage
Enables atten. stage
Switch closed
Swicth open
Table 7: Attenuator Logic
ATTENUATION (dB)
0
4
8
12
16
20
24
28
32
36
40
44
48
52
56
60
4 dB Logic Input (pin 16)
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
8 dB Logic Input (pin 15)
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
16 dB Logic Input (pin 14)
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
32 dB Logic Input (pin 13)
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
Notes: “L” = logic low, “H” = logic high
6
Data Sheet - Rev 2.1
03/2004
Data Sheet - Rev 2.1
03/2004
RF Input
(75 Ohms)
3.9 Ohms
0.1uF
1uF
+5 V
1uF
620 Ohms
1.8K Ohms
1uF
3.3K Ohms
32 dB
1pF
5K Ohms
0.1uF
1uF
0.1uF
20 Ohms
0.1uF
0.1uF
10uH
16 dB
14
13
12
11
10
9
8
7
6
5
4
3
2
1
16 dB
32 dB
VATT
ISET1
RFIN
ATTACG1
ATTACG1
ATTACG1
ATTACG1
VREF1
RFOUT1
ATTIN
N/C
GND
ARA1400
28
25
26
27
8 dB
4 dB
VA2
VREF2
RFOUT
ATTACG2
ATTACG2
ATTACG2
ATTACG2
15
16
17
18
19
20
21
22
23
ATTACG3 24
Tx
RFIN2
ISET2
ATTOUT
5K Ohms
+5 V
10uH
20 Ohms
1uF
0.1uF
0.1uF
0.1uF
0.1uF
1uF
0.1uF
3.3K Ohms
1uF
1.8K Ohms
620 Ohms
1uF
0.1uF
10K Ohms
5K Ohms
RF Output
(75 Ohms)
Output
Switch
Control
(0 / +5 V)
Note:
Output Switch Closed: Output Switch Control = 0 V
Output Switch Open: Output Switch Control = +5 V
8 dB
1uF
4 dB
+5 V
ARA1400
Figure 4: Test Circuit
7
ARA1400
APPLICATION INFORMATION
Amplifier Enable / Disable
The ARA1400 includes two amplification stages that
each can be shut down through external control pins
VREF1 and VREF2 (pins 5 and 18, respectively). By
applying a typical bias of 1.75 Volts to these pins,
the amplifiers are enabled. In order to fully disable
an amplifier, its control pin requires a negative bias
of -1.5 to -2.0 Volts.
Thermal Layout Considerations
The device package for the ARA1400 features a heat
slug on the bottom of the package body. Use of the
heat slug is an integral part of the device design.
Soldering it to the ground plane of the PC board will
ensure the lowest possible thermal resistance for
the device, and will result in the longest MTF (mean
time to failure.)
Output Switch Control
A switch located at the output of Amplifier A2 in the
ARA1400 provides isolation without having to
disable the amplifiers. The switch is controled by
the Tx logic input (pin 25).
A PC board layout that optimizes the benefits of the
heat slug is shown in Figure 5. The via holes located
under the body of the device must be plated through
to a ground plane layer of metal, in order to provide
sufficient thermal conductivity. The recommended
solder mask outline is shown in Figure 6.
Amplifier Bias Current
The ISET pins (11 and 27) set the bias current for the
amplification stages. Grounding these pins results
in the maximum possible current. By placing a
resistor from the pin to ground, the current can be
reduced. The recommended bias conditions use
the configuration shown in the test circuit schematic
in Figure 4.
0.025 BSC
ESD Sensitivity
Electrostatic discharges can cause permanent
damage to these devices. Electrostatic charges
accumulate on test equipment and the human body,
and can discharge without detection. Proper
precautions and handling are strongly
recommended. Refer to the ANADIGICS application
note on ESD precautions.
0.089
0.014 TYP
BODY OUTLINE
(NOMINAL)
0.025 MIN.
0.163
0.099
0.070
0.197
0.060 TYP.
0.400
Figure 5: PC Board Layout
8
Data Sheet - Rev 2.1
03/2004
0.150
(12X)0.020 TO 0.060 DIA.P
PLATED THRU HOLES.
DIMENSIONS IN INCHES
ARA1400
0.016 TYP.
0.091
0.0535
0.025 TYP.
0.163
0.242
0.085
0.098
0.025 BSC
0.145
DIMENSIONS IN INCHES
Figure 6: Solder Mask Outline
Data Sheet - Rev 2.1
03/2004
9
ARA1400
PACKAGE OUTLINE
Figure 7: S12 Package Outline - 28 Pin SSOP with Heat Slug
10
Data Sheet - Rev 2.1
03/2004
ARA1400
COMPONENT PACKAGING
Volume quantities of the ARA1400 are supplied on
tape and reel. Each reel holds 3,500 pieces. Smaller
quantities are available in plastic tubes of 50 pieces.
Figure 8: Reel Dimensions
Figure 9: Tape Dimensions
Data Sheet - Rev 2.1
03/2004
11
ARA1400
ORDERING INFORMATION
ORDER NUMBER
TEMPERATURE
RANGE
PACKAGE
DESCRIPTION
ARA1400S12CTR
0 to 85 °C
28 Pin SSOP
with Heat Slug
3,500 piece tape and reel
ARA1400S12C
0 to 85 °C
28 Pin SSOP
with Heat Slug
Plastic tubes (50 pieces per tube)
COMPONENT PACKAGING
ANADIGICS, Inc.
141 Mount Bethel Road
Warren, New Jersey 07059, U.S.A.
Tel: +1 (908) 668-5000
Fax: +1 (908) 668-5132
URL: http://www.anadigics.com
E-mail: Mktg@anadigics.com
IMPORTANT NOTICE
ANADIGICS, Inc. reserves the right to make changes to its products or to discontinue any product at any time without
notice. The product specifications contained in Advanced Product Information sheets and Preliminary Data Sheets are
subject to change prior to a product’s formal introduction. Information in Data Sheets have been carefully checked and are
assumed to be reliable; however, ANADIGICS assumes no responsibilities for inaccuracies. ANADIGICS strongly urges
customers to verify that the information they are using is current before placing orders.
WARNING
ANADIGICS products are not intended for use in life support appliances, devices or systems. Use of an ANADIGICS
product in any such application without written consent is prohibited.
12
Data Sheet - Rev 2.1
03/2004