Agilent 8762/3/4A,B,C
Coaxial Switches
Product Overview
High performance switches for
microwave and RF instrumentation
and systems
Agilent Technologies offers a versatile
line of multiport coaxial switches. These
50
Ω
mechanical-latching switches
come with the performance and relia-
bility that you have come to expect in
Agilent microwave accessories.
Offering excellent electrical and
mechanical performance with broad-
band operation, high isolation, low
SWR, long life, and exceptional
repeatability, these switches are
designed with your applications in
mind. Frequency ranges are available
to 4 GHz and 18 GHz for the A and B
models with SMA connectors and to
26.5 GHz for the C models with APC-
3.5 connectors.
The 8762A, 8762B, and 8762C
(Figure 1) are single-pole double-
throw switches with high isolation,
> 100 dB at 4 GHz for the A model,
> 90 dB at 18 GHz for the B model
and > 50 dB at 26.5 GHz for the C
model. All models terminate the
unused port with 50
Ω,
a key feature
for your applications where low SWR
is required on all ports.
The 8763A, 8763B, and 8763C
(Figure 2) have 4 RF ports with one
internal 50
Ω
termination designed
for applications requiring a transfer
switch or a cross switching element.
Figure 1. Agilent 8762
Figure 2. Agilent 8763
The 8764A, 8764B, and 8764C
(Figure 3) round out the family with
5 RF ports, giving you flexibility to
configure the switch for your specific
needs.
Solenoid
drive pin #1
(-)
Common
drive pin
(+)
Solenoid
drive pin #2
(-)
Transfer switching
For applications requiring a “transfer
switch,” as shown in Figure 5, an
8763A, B, or C is the ideal choice to
insert a component, such as a filter or
mixer, into a signal path. Another pop-
ular use is to switch between a device
under test and a through path for
system calibration. The 8763A,B,C’s
internal load can terminate the device
under test when in the through mode
(up to 1 watt).
Reverse signal path
Figure 6 shows how an 8762 and
8764 may be used to provide a
“transceiver” configuration. This
example illustrates how one amplifier
can be used to transmit or receive.
Any application where the signal
path direction needs to be reversed
could use this configuration.
Pivot
armature
Signal
in
2
1
Port 1
Port 2 Port 3
Port 4 Port 5
Device
4
3
Signal
out
Figure 3. Agilent 8764
Applications
Multi-source switching
The 8762A, 8762B or 8762C is an
excellent choice for applications
where you require selection of
multiple signal sources, frequency
counters, or signal control devices
such as modulators or filters, or
routing signals from multiple
sources as shown in Figure 4.
Figure 5. Agilent 8763 used as a transfer
switch (equivalent circuit action)
8762
Common
drive pin
(+)
8764
Common
drive pin
(+)
Solenoid
drive pin #1
(-)
Solenoid
drive pin #2
(-)
Solenoid
drive pin #1
(-)
Solenoid
drive pin #2
(-)
Pivot
armature
Pivot
armature
Signal
source A
1
Signal
source B
8762B
50Ω
C
2
50Ω
1
2
3
4
5
To receiver
Figure 4. Multi-source switching
Figure 6. Signal reversal
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Portable and remote applications
Due to their small package size, light
weight, low power consumption, and
high reliability, these switches are
ideal for your portable or remote
applications. The light weight and
repeatability make them well suited
for portable spectrum analyzers and
other portable microwave test equip-
ment. Their 1,000,000 cycle life make
them the ideal candidate for system
design, such as communications
repeaters or remote monitoring sta-
tions that demand minimal mainte-
nance. The switch’s automatic coil
disconnect feature and low current
drain during switching minimize the
amount of power needed for operat-
ing the switches.
Dedicated switching
For larger switching systems, where
many switches will be used to provide
complex signal routing, a switch driv-
er such as the 87130A or 70611A is
recommended. The 87130A rack-and-
stack switch driver and the MMS-
based 70611A are convenient, flexible
interface bus (GPIB) or modular sys-
tems interface bus (MS-IB) switch
controllers, providing driver circuitry,
indicator readback circuitry and
firmware that makes it easy to
integrate switch components into
a switching system. Controlling the
87130A is simple using either a PC or
workstation based GPIB controller
and Agilent Interactive Test
Generator (Agilent-ITG) or Agilent
Visual Engineering Environment
(Agilent VEE). The 70611A gives
manual control via the MMS user
interface or can also be controlled
via an GPIB equipped PC or
workstation.
In addition, the built-in firmware
makes it possible to define often used
switch paths. With the path com-
mand, macros can be designed which
open and close the right solenoids to
select the desired switch port, and
the path may be given a meaningful
name. Remember that only one select
pin should be activated at one time to
prevent rapid cycling of the switch.
Both the 87130A and 70611A provide
position monitoring and reporting,
which make it possible for a program
to determine if all the switches are in
their proper state (position) before the
program continues with testing. A
programmable wake up condition
makes it possible to ensure that the
matrix or switching system starts up
in a predetermined state, to prevent
damage to delicate equipment from
excessive power. This would also be
the state that the system returns to
after a power interruption.
Accessory cables and adapters make
it easy to quickly get the 8762/3/4
working with the 87130A or 70611A.
Reference literature number 5963-
2038E,
Switch Attenuator Driver
Configuration Guide.
For smaller switching needs, the
11713A attenuator/switch controller
provides simple GPIB control for up
to ten 8762/3/4 switches. Connecting
cables can be ordered which make it
easy to connect the switches to the
11713A.
3
Operation and use
How the switch works
All the switches are “break before
make;” the switched ports are not
connected to each other preventing
possible damage to sensitive circuits.
The standard configuration switch
uses 24 Vdc for the switching voltage,
Option 876xx-011
1
specifies a voltage
of 5 Vdc, and Option 876xx-015 speci-
fies 15 Vdc. Options 876xx-T15 and
876xx-T24 are TTL/5V CMOS compati-
ble with 15 Vdc and 24 Vdc drive
respectively.
Driving the switch
For standard, Options 876xx-011 and
876xx-015 switches, switching is
accomplished by applying the supply
voltage to pin “C” and grounding the
appropriate pin to actuate the switch-
ing mechanism.
Avoid grounding both RF
path select pins as rapid cycling may
occur.
After the switch is fully latched
(30 ms), the drive current is automat-
ically disconnected. If the drive cir-
cuit is pulsed, the pulse duration
must be at least 30 ms to ensure that
the switch will fully latch. For TTL/5
volt CMOS compatible drive (Options
876xx-T24 and 876xx-T15), apply the
supply voltage to pin “C,” and ground
to pin #1. Switch positions by apply-
ing a TTL “high” or TTL “low” to pin
#2 as needed. See Table 1.
Remote indication (TTL options excluded)
The position of the switch may be
determined by utilizing the open and
closed states of the internal coil con-
tacts. Figure 7 displays two indicator
circuits, one to provide a TTL output
and one that directly activates an
LED. The circuits will output a TTL
“HI” and LED “on” if the switch is in
the state shown in Figure 7. When
drive pin 1 contact is closed (as
shown), RF port 2 is connected to
common port. For the Agilent 8763/4,
see Figures 2, 3, and Table 1 for cor-
responding RF port connections. The
circuits shown are designed to oper-
ate with coil voltage of 24 V. If other
voltage switches are used, the circuit
components must be modified to
accommodate that voltage.
Since current is drawn through the
solenoid for these indicator circuits,
inadvertent switching is prevented by
limiting the current to 5 mA. Additional
design information may be required
from the component manufacturer for
the circuits described in Figure 7,
depending upon specific applications.
Agilent Technologies assumes no
responsibility for use of any circuits
described herein, and makes no repre-
sentations or warranties, expressed or
implied, that such circuits are free
from patent infringements.
Figure 7. TTL and LED remote indicator circuits
1. Where xx = 2A, 3A, 4A, 2B, 3B, 4B, 2C, 3C, or 4C.
4
Standard drive
Model number
8762A/B/C
Pin 1
Ground
Open
8763A/B/C
Ground
Open
Pin 2
Open
Ground
Open
Ground
Pin 2
2
TTL high
TTL low
TTL high
TTL low
TTL drive
1
RF path
1 to C closed
2 terminated
2 to C closed
1 terminated
1 to 2 closed
3 to 4 closed
1 terminated
2 to 3 closed
4 open
1 open
2 to 3 closed
4 to 5 closed
1 to 2 closed
3 to 4 closed
5 open
8764A/B/C
Ground
Open
TTL high
Open
Ground
TTL low
Table 1. Switching logic table
7.0V
HIGH
3.0V
0.4V
0.0V
LOW
Absolute max input
Minimum
on
state
Maximum
off
state
Figure 8. Control voltage states
1. Pin 1 is always at ground.
2. See Figure 8 for control voltage states.
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