Digital Attenuator, 1 Bit, Variable Step, 10 - 20 dB, DC - 3000 MHz
AT-246
M/A-COM Division of AMP Incorporated
3
North America: Tel. (800) 366-2266, Fax (800) 618-8883
3
Asia/Pacific: Tel.+85 2 2111 8088, Fax +85 2 2111 8087
3
Europe: Tel. +44 (1344) 869 595, Fax+44 (1344) 300 020
www.macom.com
AMP and Connecting at a Higher Level are trademarks.
Specifications subject to change without notice.
V2.00
Features
Variable Step (10 - 20 dB) with an External Resistor
Matched Input and Output
Low Intermodulation Product: +53 dBm IP
3
Low DC Power Consumption: 50 W
Low Cost, Low Profile MSOP 8 Plastic Package
Tape and Reel Packaging Available
MSOP-8
1
Electrical Specifications: T
A
= +25C
1, 2
Digital Attenuator, 1 Bit, Variable Step
10 - 20 dB, DC - 3000 MHz
AT-246
Parameter
Test Conditions
Units
Min.
Typ.
Max.
Reference Insertion Loss
DC - 3.0 GHz
dB
0.8
1.0
Attenuation Flatness
DC - 1.5 GHz
dB
0.5
1.0
1.5 - 3.0 GHz
dB
1.5
2.0
VSWR
DC - 3.0 GHz
1.3:1
1 dB Compression
Input Power 50 MHz
dBm
24
Input Power 500 MHz
dBm
30
T
rise
, T
fall
10% to 90% RF, 90% to 10% RF
S
20
T
on
, T
off
50% Control to 90% RF, Control to 10% RF
S
23
Transients
In-band
mV
25
IP
2
Measured Relative 50 MHz
dBm
54
to Input Power
2
500 MHz
dBm
73
IP
3
Measured Relative 50 MHz
dBm
45
to Input Power
2
500 MHz
dBm
55
Description
M/A-COM's AT-246 is a GaAs MMIC matched 1 bit attenuator
in a low cost plastic MSOP-8 package. It is designed to be a
building block for a single step attenuator by placing a resistor
across RF1-RF2. Attenuation levels of 10 to 20 dB with flat
response are achievable from DC to 3 GHz. The AT-246 is
ideally suited for circuits where fast switching, very low power
consumption and low intermodulation products are required.
Typical applications include gain/level and sensitivity control in
radio and cellular equipment, wireless LAN's, GPS equipment
and other gain/level control circuits.
The AT-246 is fabricated using a mature 1-micron gate length
GaAs MESFET process. The process features full chip passiva-
tion for increased performance and reliability.
Ordering Information
Part Number
Package
AT-246 PIN
MSOP-8 Lead Plastic
AT-246TR
Forward Tape and Reel
1
1. If specific reel size is required, consult factory for part number
assignment.
1.
All measurements in a 50
system unless otherwise specified. Loss varies at 0.003 dB/C.
2.
For two-tone Input Power up to +5 dBm.
I D P I N
0 .1 9 3
.0 1 0
R
0 .1 1 8
.0 2 0
.0 2 0
0 .0 2 5 6
0 .1 1 8
1 2
4 X
0 .0 3 4
0 .0 4 0
0 .0 0 8
0 .0 1 3
1 2
4 X
0 .0 0 7
0 .0 2 1 5
3
1.
Dimensions are in inches.
Digital Attenuator, 1 Bit, Variable Step, 10 - 20 dB, DC - 3000 MHz
AT-246
M/A-COM Division of AMP Incorporated
3
North America: Tel. (800) 366-2266, Fax (800) 618-8883
3
Asia/Pacific: Tel.+85 2 2111 8088, Fax +85 2 2111 8087
3
Europe: Tel. +44 (1344) 869 595, Fax+44 (1344) 300 020
www.macom.com
AMP and Connecting at a Higher Level are trademarks.
Specifications subject to change without notice.
V2.00
1
1.1
1.2
1.3
1.4
1.5
0
1
2
3
4
FREQUENCY (GHz)
VSWR
Worst Case
0
5
10
15
20
25
0
1
2
3
4
FREQUENCY (GHz)
Attenuation (dB)
ATTENUATION vs FREQUENCY
RStep= 820
RStep=180
RStep=51
RStep=OPEN
0
0.2
0.4
0.6
0.8
1
1.2
0
0.5
1
1.5
2
2.5
3
FREQUENCY (GHz)
Insertion Loss (dB)
-40 C
+25 C
+85 C
Parameter
Absolute Maximum
Input Power
50 MHz
+27 dBm
500 - 2000 MHz
+33 dBm
Control Voltage
+5V, -8.5V
Operating Temperature
-40C to +85C
Storage Temperature
-65C to +150C
Absolute Maximum Ratings
1
1.
Exceeding any one or a combination of these limits may cause
permanent damage.
Typical Performance Curves
Insertion Loss vs. Frequency
Attenuation vs. Frequency
VSWR vs Frequency
Functional Schematic
Note:
Rstep value is selected for desired attenuation level. The usable
range is 50
to OPEN to achieve 10 - 20 dB attenuation with >15 dB
Return Loss.
V1
V2
Attenuation (dB)
0
1
Reference I.L.
1
0
Step
Truth Table
"0" = 0 0.2V
"1" = -5 0.2V
PIN Configuration
PIN No.
Function
Description
1
GND
RF Ground
2
V1
Bit Control
3
V2
Bit Control
4
GND
RF Ground
5
RF2
RF in/out
6
GND
RF Ground
7
GND
RF Ground
8
RF1
RF in/out
20dB
PIN 1
GND
V1
V2
GND
RF1
GND
GND
RF2
Rstep
Step Set Resistor
PIN 1
Recommended Layout
PDF 
ZIP