AN1743 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'AN1743' PDF : 4 Pages View PDF
AN1743
APPLICATION NOTE
AUDIO AMPLIFIER SYSTEM USING THE
1. ABSTRACT
ANALOG SWITCH STG3699
M. Porto
This application note is an explanation of the correct use of the STG3699 Analog Switch in mobile
telecom applications.
2. E.S.D. PROTECTION CIRCUITRY DESCRIPTION
The STG Analog Switch can be used bi-directionally (one input/two outputs or two inputs/one output)
depending on the application. Both inputs and outputs are protected from the E.S.D. discharge by a
circuit that can be synthesized as four protection diodes (two versus VCC and two versus GND).
Figure 1: Generic Circuit for E.S.D. Discharge Protection
Input
Vcc
Input
GND
Output
Digital Input IN
Output
To correctly use these devices it is very important to consider the presence of the protection diodes.
For example, a possible problem area is applying a wrong input level signal (input level higher than
power supply). In fact, in this condition the diode versus VCC is forward biased, so a current will flow from
the input to VCC, damaging the device or causing incorrect function of the Analog Switch.
The values of the Human Body Model discharge for the STG3699 are very good. In fact the device was
good after a 3KV discharge.
July 2003
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