© 2005 California Micro Devices Corp. All rights reserved.

6

430 N. McCarthy Blvd., Milpitas, CA 95035-5112

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Tel: 408.263.3214

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Fax: 408.263.7846

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www.calmicro.com

03/25/05

CM1214

PRELIMINARY

Application Information

The CM1214-01ST/SO and the CM1214-01DF/DE

protect a single bipolar signal line, such as is found in

RF circuits. One I/O pin (pin 1 for example) is con-

nected to the signal line to be protected, and the other

I/O pin is tied to GND. It is important to have a solid

ground connection in order to reduce the clamping volt-

age. Pin 3 of the 3-lead SOT23 (Pin 1 of the 3-lead

DFN) must be left open (not connected on the PCB).

The CM1214-02MS/MR protects two bipolar lines,

such as for Gbit Ethernet. The PCB traces underneath

the package connect across to the corresponding pins,

i.e., pin 1 to pin 8 etc.

Any disturbance on the line above or below the stand-

off voltage is clamped.

Figure 6. Typical Application - RF Switch and Amplifier Protection,

CM1214-01ST/SO/DF/DE in 3-lead DFN or SOT23

Figure 7. Typical Application - Ethernet Protection, CM1214-02MS/MR in 8-lead MSOP

3-Lead DFN or SOT23-3

C

L

SIGNAL LINE

GND

SWITCH

LNA

PA

RF ANTENNA

ESD

ESD

N.C.

I/O1

I/O2

I/O3

I/O4

TX+

TX-

RX+

RX-

CM1214-02MS