5305 Spectrum Drive, Frederick, MD 21703-7362 TEL: 301-846-9222, 800-638-2048 Fax: 301-846-9116
web: www.weinschel.com email: sales@weinschel.com
144
10/23/01
Model 3250 & 3250T dc to 1.0 GHz
RF Programmable Attenuators 1 Watt/75 ΩΩ
Ideal for Wireless/Cellular Modem Applications.
Features
oCost Effective design for Wireless/Cellular
Applications
oOptional TTL or SmartStep Interface
oCustom Configurations including bus controlled
attenuator subsystems
Specifications
NOMINAL IMPEDANCE: 75 Ω
FREQUENCY RANGE: dc to 1.0 GHz:
CELL CONFIGURATIONS:
Model NO. Attenuation Cell
Number Cells Range/Steps Increments
(dB) (dB)
3250-63 6 63/1 1, 2, 4, 8, 16, 32
INCREMENTAL ATTENUATION ACCURACY:
Frequency Accuracy
Range (GHz)
dc - 0.5 + 0.3 dB or 2.0%
0.5 - 1.0 + 0.4 dB or 2.0%
MAXIMUM SWR:
Frequency Range (GHz) SWR
dc - 0.5 1.20
0.5 - 1.0 1.30
Frequency Range (GHz) Loss (dB)
dc - 0.5 2.25
0.5 - 1.0 4.75
RATED SWITCH LIFE: 5 million operations per cell (typ)
SWITCHING TIME: 8 msec. maximum @ nominal rated
voltage.
CYCLING RATE: 5 Hz maximum
OPERATING VOLTAGE: +11V to +16V
+12V to +17V (TTL opt -1)
OPERATING CURRENT: 16 mA maximum per cell
TEMPERATURE RANGE (Operating): -40 to +70°C
POWER RATING: 1 watt average, 50 watts peak (5 µsec
pulse width; 1% duty cycle)
CONNECTORS: BNC female connectors per MIL-STD-
348 interface dimensions - mate nondestructively with
MIL-C-39012 connectors.
CONTROL TERMINALS: 0.040 inch. (1 mm) diameter
solderable leads
CONSTRUCTION:
Housing: Aluminum
Connectors: Nickel plated brass body and
beryllium copper contacts.
WEIGHT: 3250 140 g (4.5 oz)
3250T 189 g (4.9 oz)
ACCESSORIES
SmartStep Interface: The Model 8210A SmartStep
Interface provides a flexible, low cost solution for the oper-
ation of programmable step attenuators and other
electromechanical devices under computer control.
Designed to interface to Weinschel's new line of SmartStep
programmable attenuators, the 8210A represents a new
concept in device control applications for bench test and
subsystem designs. The 8210A provides a high-level inter-
face from various industry standard communications
interfaces, including IEEE-488 and RS232/RS422/RS485,
to the SmartStep's serial Driver Interface Bus.
MAXIMUM CHARACTERISTIC ZERO LOSS (dB):
8/5/99
MODEL NUMBER DESCRIPTION:
Example:
3250* - XX - X
*Add T to Basic Model Number when ordering SmartStep
Control Circuitry.
Basic
Model
Number
Attenuation
Value (dB)
TTL Option
(Add -1)
Example: 3250-63-1
5305 Spectrum Drive, Frederick, MD 21703-7362 TEL: 301-846-9222, 800-638-2048 Fax: 301-846-9116
web: www.weinschel.com email: sales@weinschel.com
145
10/23/01
Figure 1. SmartStep Driver Circuitry
CONTROL CONFIGURATION:
Standard Unit: One terminal is connected to case ground
and the remaining terminals are provided for activation of
individual cells. Attenuation is fail-safe to "0" setting in the
absence of a control voltage. Application of a voltage (+) to
a particular cell causes it to switch to the attenuate position.
Units with TTL Option: Units with this options are supplied
with a very low profile connectorized TTL interface board
mounted directly to the control terminals. This TTL interface
option is available with a 10 pin ribbon cable connector and
is supplied with a mating connector. Refer to Physical
Dimensions for mating connector pin/wiring details. Two
wires are specified for supply voltage and ground. The
remaining wires will accept TTL control signals to activate or
de-activate a particular attenuation cell. A TTL high will
energize a cell to the high attenuation state, whereas a TTL
low will maintain a cell in its zero attenuation state.
To order 3250 Series Attenuators with this option add -1 to
basic model number for ribbon cable connector. Example:
Model 3250-63 with a TTL interface would be 3250-63-1.
Note: Control is non-latching and requires a continuous
control signal for the period of time in which attenuation is
required.
TTL DRIVER SPECIFICATIONS:
INTERFACE CONNECTOR: Option -1: 10 pin .025 square
post header on .1 center, mates with Amp connector
746285-1 or equivalent
INPUT VOLTAGE: VIN High= +2.0V minimum
+5.0V typical
Vcc maximum
VIN Low = 0 minimum
0.8 maximum
INPUT CURRENT: IIN (VIN=2.4 V) = 55 µA
IIN (VIN=3.85 V) = 280 µA
SUPPLY CURRENT: ICC=25 mA maximum per cell
SUPPLY VOLTAGE: VCC=+12.0 to +15 V
TEMPERATURE RANGE (Operating): -40 to +70 °C
Units with SmartStep driver Circuitry (Figure 1): The
SmartStep attenuators feature an internal microcontroller-
based driver that provides a TTL-level digital interface for
control of the attenuator relays. This card simplifies oper-
ation 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 I2C bus. The parallel mode provides 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 variety of methods,
such as a TTL-level digital output port, or mechanical toggle
switches. The I2C 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 sys-
tem and sub-system applications. The SmartStep contains
non-volatile configuration memory that is used to hold a
Non-Volatile
Configuration
Memory
Single-Chip
Microcontroller
Relay
Drivers
TTL/CMOS
Compatible
Digital Interface
+12 to
+15 V
Input
To
Attenuator
Relays
EMI
Filters
+5 V
Regulator
wide variety of attenuator and driver-dependant parame-
ters, including serial number, attenuator cell dB values,
relay configurations, and switching requirements, which are
all accessable via the I2C interface.
SmartStep Driver Interface Specifications:
Input Supply Voltage: +12.0 to +15.0V
Control Signals: TTL/CMOS compatible
Interface Modes: parallel/ I2C serial
DC Characteristics (at 25°C):
Digital Interface:
Parameter Specification
VILLow Level input: -0.5 min, 0.8V max
VIH High Level input: 2.0 min, 5.25V max
IPU Pullup Current 50 µA min, 400 µA max
Power Supply:
VIN Supply Voltage: +12.0 to +15.0V
IIN Supply current: 25 mA
ICELL Supply Current: 150 mA (per cell, switching)
TEMPERATURE: -20° to +70°C operating
-55° to +85°C nonoperating
INTERFACE CONNECTOR: 14 pin .025 square post
header on .1 center. Mates with Amp connector 746285-2 or
equivalent (one mating connector included with each unit).
5305 Spectrum Drive, Frederick, MD 21703-7362 TEL: 301-846-9222, 800-638-2048 Fax: 301-846-9116
web: www.weinschel.com email: sales@weinschel.com
146
10/23/01
BNC CONNECTORS
BOTH ENDS
PHYSICAL DIMENSIONS:
Model 3250:
Model 3250 w/TTL Option -1:
TTL Conn 3250-63-1
PIN No. (J3) dB (Cell)
1NC
2NC
332
41
52
64
78
816
9 COM
10 +Vcc
NC = Not Connected
Control Connector J3 Pin Locations:
NOTE: All dimensions are given in mm (inches) and are maximum, unless otherwise specified.
5305 Spectrum Drive, Frederick, MD 21703-7362 TEL: 301-846-9222, 800-638-2048 Fax: 301-846-9116
web: www.weinschel.com email: sales@weinschel.com
147
10/23/01
BNC CONNECTORS
BOTH ENDS
PHYSICAL DIMENSIONS:
Model 3250T:
NOTE: All dimensions are given in mm (inches) and are maximum, unless otherwise specified.
