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ST6215C Datasheet, PDF (81/105 Pages) STMicroelectronics – 8-BIT MCUs WITH A/D CONVERTER, TWO TIMERS, OSCILLATOR SAFEGUARD & SAFE RESET
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ST6215C/ST6225C
EMC CHARACTERISTICS (Cont’d)
11.7.3 ESD Pin Protection Strategy
To protect an integrated circuit against Electro-
Static Discharge the stress must be controlled to
prevent degradation or destruction of the circuit el-
ements. The stress generally affects the circuit el-
ements which are connected to the pads but can
also affect the internal devices when the supply
pads receive the stress. The elements to be pro-
tected must not receive excessive current, voltage
or heating within their structure.
An ESD network combines the different input and
output ESD protections. This network works, by al-
lowing safe discharge paths for the pins subjected
to ESD stress. Two critical ESD stress cases are
presented in Figure 59 and Figure 60 for standard
pins.
Standard Pin Protection
To protect the output structure the following ele-
ments are added:
– A diode to VDD (3a) and a diode from VSS (3b)
– A protection device between VDD and VSS (4)
To protect the input structure the following ele-
ments are added:
– A resistor in series with the pad (1)
– A diode to VDD (2a) and a diode from VSS (2b)
– A protection device between VDD and VSS (4)
Figure 59. Positive Stress on a Standard Pad vs. VSS
VDD
VDD
(3a)
(2a)
Main path
Path to avoid
(1)
OUT
(4)
IN
(3b)
(2b)
VSS
VSS
Figure 60. Negative Stress on a Standard Pad vs. VDD
VDD
VDD
Main path
(3a)
(2a)
(1)
OUT
(4)
IN
(3b)
(2b)
VSS
VSS
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