ADG904/ADG904-R

Rev. 0 | Page 11 of 16

APPLICATIONS

The ADG904/ADG904-R are ideal solutions for low power,

high frequency applications. The low insertion loss, high

isolation between ports, low distortion, and low current

consumption of these parts make them excellent solutions for

many high frequency switching applications. They may be used

in applications such as switchable filters, transmitters and

receivers for radar systems, and communication systems from

base stations to cell phones.

The ADG9xx wideband switches are designed to meet the

demands of devices transmitting at ISM band frequencies to

1 GHz and higher. The low insertion loss, high isolation

between ports, single pin control interface, no requirement for

dc blocking capacitors, and TTL interface compatibility make

them cost effective and easy to integrate switching solutions for

many high frequency switching applications and low power

applications where the parts can handle up to 16 dBm of power.

ABSORPTIVE VS. REFLECTIVE

The ADG904 is an absorptive (matched) switch with 50 Ω

terminated shunt legs; the ADG904-R is a reflective switch with

0 Ω terminated shunts to ground. The ADG904 absorptive

switch has a good VSWR on each port, regardless of the switch

mode. An absorptive switch should be used when there is a

need for a good VSWR that is looking into the port but not

passing the through signal to the common port. The ADG904 is

therefore ideal for applications that require minimum

reflections back to the RF source. It also ensures that the

maximum power is transferred to the load.

The ADG904-R reflective switch is suitable for applications

where high off port VSWR does not matter and the switch has

some other desired performance feature. It can be used in many

applications, including high speed filter selection. In most cases,

an absorptive switch can be used instead of a reflective switch,

but not vice versa.

ANTENNA DIVERSITY SWITCH

The ADG904 is ideal for use as an antenna diversity switch,

switching in different antennas to the tuner. The low insertion

loss ensures minimum signal loss and high isolation between

channels, making these SP4T switches suitable for switching

applications in tuner modules and set-top boxes.

TUNER

ADG904

CABLE

RF1

RF2

RF3

RF4

VGA

ANTENNA

Figure 26. Tuner Modules

FILTER SELECTION

The ADG904 can be used to switch high frequency signals

between different filters, and to multiplex the signal to the

output. These SP4T switches are also ideal for high speed signal

routing.

RFC

ADG904

ADG904

RF1

RF2

RF3

RF4

RF1

RF2

RF3

RF4

RFC

Figure 27. Filter Selection

Tx/Rx SWITCHING

The low insertion loss and high isolation between ports ensures

that the ADG904/ADG904-R is a suitable transmit/receive

switch for all ISM band and WirelessLAN, providing the

required isolation between the transmit and receive signals.

ADG904

Tx

Rx

Rx

Rx

Rx

ANTENNA

Figure 28. Tx/Rx Switching