Functional Schematic

V 1.00

Features

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•

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Low Power Consumption, < 10 µA @ +3 V

•

Low Cost Plastic SOT-363 Package

1.

For best results at 2.4 GHz, use 8 pF 0402 profile SMT capaci-

tors on RF ports and 100 pF bypassing on pins 4 and 6.

Description

The SW-438 is a GaAs MMIC SPDT switch in a low cost

SOT-363 surface mount plastic package.

Typical applica-

tions include transmit/receive switching for Bluetooth and

WLAN equipment. The SW-438 can also be used in applica-

tions up to 500 mW in systems such as cellular, PCS,

DCS1800, GSM, CDMA and other analog and digital wire-

less communications systems.

M/A -COM fabricates the SW-438 using a 0.5 micron gate

length GaAs p-HEMT process. The process features full pas-

sivation for increased performance and reliability.

GaAs SPDT Switch

DC– 3.0 GHz

RF1

GND

RF2

V1

RFC

V2

PIN 1

C≥39pF

C≥39pF

C≥39pF

C=100pF

C=100pF

Broad Band Applications

RF1

GND

RF2

V1

RFC

V2

PIN 1

C=8pF

C=8pF

C=8pF

C=100pF

C=100pF

2.4GHz Application

External Component Requirements

Please note the values of the external capacitors. The ca-

pacitors at each of the RF ports are used as for achieving

optimum insertion loss. They also provide DC blocking for

positive control.

The 8 pF (0402) capacitor is recom-

mended for 2 - 3 GHz operation. If this value is changed or

the capacitor placed too far from the switch, the perform-

ance will be affected. We also recommend 100 pF bypass

capacitors on pins 4 and 6.

For broadband applications with positive control voltages,

use DC blocking capacitors with value of 39 pF or more

.

Pin Configuration

Pin No.

Function

Description

1

RF1

RF Input/Output

2

GND

RF Ground

3

RF2

RF Input/Output

4

V2

Control 2 Input

5

RFC

RF Common Port

6

V1

Control 1 Input

Ordering Information

Part Number

Package

SW-438TR-3000

SW-438 on 13 Inch, 3000 piece Reel

SW-438SMB

SW-438 sample test board

Mode

(Control)

V1

V2

RFC-RF1

RFC-RF2

0 + 0.2V

+2.3 to +5V

+2.3 to +5V

0 + 0.2V

Off

On

On

Off

0 + 0.2V

-2.3 to +5V

-2.3 to +5V

0 + 0.2V

On

Off

Off

On

Truth Table

1.

External DC blocking capacitors are required on all RF ports.

2.

If negative control is used, DC blocking capacitors are not required on RF ports.