ADG3242BRJ-R2 Analog Devices Inc, ADG3242BRJ-R2 Datasheet - Page 13

• Manufacturer Part Number: ADG3242BRJ-R2
• Description: IC SW BUS CTRL 2.5/3.3V SOT23-8
• Manufacturer: Analog Devices Inc
• Type: Bus Switchr

Specifications of ADG3242BRJ-R2

• Rohs Status: RoHS non-compliant
• Circuit: 2 x 1:1
• Independent Circuits: 1
• Voltage Supply Source: Single Supply
• Voltage - Supply: 2.5V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: SOT-23-8
• Operating Temperature: -
• Current - Output High, Low: -
• Other names: ADG3242BRJ-R2CT

BUS ISOLATION
A common requirement of bus architectures is low capacitance
loading of the bus. Such systems require bus bridge devices that
extend the number of loads on the bus without exceeding the spec-
ifications. Because the ADG3242 is designed specifically for
applications that do not need drive, yet require simple logic func-
tions, it solves this requirement. The device isolates access to
the bus, thus minimizing capacitance loading.
HOT PLUG AND HOT SWAP ISOLATION
The ADG3242 is suitable for hot swap and hot plug applications.
The output signal of the ADG3242 is limited to a voltage that
is below the V
Figure 34. Thus, the switch acts like a buffer to take the impact
from the hot insertion, protecting vital and expensive chipsets
from damage.
In hot plug applications, the system cannot be shut down when
new hardware is being added. To overcome this, a bus switch can
be positioned on the backplane between the bus devices and the
hot plug connectors. The bus switch is turned off during hot plug.
Figure 36 shows a typical example of this type of application.
BUS SWITCH
LOCATION
Figure 35. Location of Bus Switched in a Bus Isolation Application
LOAD A
CC
supply, as shown in Figure 30, Figure 32, and
LOAD B
LOAD C
LOAD D
BUS/
BACKPLANE
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There are many systems, such as docking stations, PCI boards for
servers, and line cards for telecommunications switches, that
require the ability to handle hot swapping. If the bus can be isolated
prior to insertion or removal, there is more control over the hot
swap event. This isolation can be achieved using bus switches. The
bus switches are positioned on the hot swap card between the con-
nector and the devices. During hot swap, the ground pin of the
hot swap card must connect to the ground pin of the backplane
before connecting to any other signal or power pins.
ANALOG SWITCHING
Bus switches are used in many analog switching applications,
for example, video graphics. Bus switches can have lower on
resistance, smaller on and off channel capacitance, and better
frequency performance than their analog counterparts. The
bus switch channel itself, consisting solely of an NMOS switch,
limits the operating voltage (see Figure 4 for a typical plot), but
in many cases, this does not present an issue.
HIGH IMPEDANCE DURING POWER-UP/POWER-
DOWN
To ensure the high impedance state during power-up or power-
down, BE must be tied to V
minimum value of the resistor is determined by the current sink-
ing capability of the driver.
RAM
CPU
BUS
Figure 36. ADG3242 in a Hot Plug Application
CC
through a pull-up resistor. The
CARD (1)
CARD (2)
PLUG-IN
PLUG-IN
ADG3242
CARD I/O
CARD I/O