®
150 T Series SmartStep Programmable Attenuators
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BUILT-IN SMARTSTEP DRIVER CIRCUITRY: These SmartStep attenuators feature an
internal microcontroller-based driver that provides a TTL-level digital interface for control of
the attenuator relays. This card simplifies operation and interfacing requirements, while at
the same time providing for greatly enhanced flexibility over past designs. User-selectable
modes of operation include both parallel and serial Smartstep bus. The parallel mode pro-
vides a simple, one-bit per relay on/off control with internal pullups for use primarily in
single attenuator applications. This mode allows the attenuator to be controlled via a vari-
ety of methods, such as a TTL-level digital output port, or mechanical toggle switches. The
Smartstep mode provides a two-wire serial bus structure and protocol for connecting a
number of devices to a single host control interface, suitable for use in larger system and
sub-system applications.
The SmartStep contains non-volatile configuration memory that is used to hold a wide vari-
ety of attenuator and driver-dependant parameters, including serial number, attenuator cell
dB values, relay configurations, and switching requirements, which are all accessable via
the Smartstep interface. This frees the system designer from such low-level details, allow-
ing faster integration. In either operational mode, the microcontroller enters an idle
condition during periods of inactivity, turning off all on-board clocks, reducing EMI con-
cerns, and lowering power consumption. On-board regulation for the digital circuitry allows
the SmartStep to operate from a single input supply voltage.
CELL CONFIGURATION
The table below list all the standard attenuation ranges and cell configurations for
Aeroflex / Weinschel 150T Series Smartstep Programmable Attenuators (Models
150T, 151T, 152T). Note the dash number is the attenuation value of your atten-
uator.
Cell
Range/
Data Bit-Cell Value (dB)
Model No. No.
Step Size
D7 D6
D5
D4
D3
4
D2
2
D1
4
D0
1
15XT-11
15XT-15
15XT-31
15XT-55
15XT-62
15XT-70*
152T-70
15XT-75
15XT-90
15XT-110
4
4
5
4
5
3
4
4
4
4
0-11/1
0-15/1
0-31/1
0-55/5
0-62/2
0-70/10
0-70/10
0-75/5
0-90/10
0-110/10
4
2
8
1
4
8
16
20
16
2
8
1
20
4
10
32
40
20
40
30
40
5
2
20
20
20
20
20
10
10
5
20
10
30
40
10
10
* Model 152AT-70 also!
3
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