W83L786NR Datasheet, PDF (15/50 Pages) Winbond – H/W Monitoring IC

W83L786NR/ W83L786NG
7.4.1 Voltage Input can not be over 2.048V
The input voltage Vcore, and Vram can be expressed as following equation:
VRAM
= V_+2.5V
×
R₂
R₁ + R₂
. V_+2.5V is +2.5V inputs.
The value of R1 and R2 can be selected to 100K Ohms and 100K Ohms, respectively, when the input
voltage is 2.5V. The node voltage of VRAM can be subject to less than 2.048V for the maximum input
range of the 8-bit ADC. The pin 5 is connected to the power supply V_CC with +3.3V. There are two
functions in this pin with 3.3V: the first function is to supply internal analog power of the
W83L786NR/NG and the second function is to connect this pin to internal serial resistors to monitor
the +3.3V voltage. The values of two serial resistors are 20K ohms and 40K ohms so that input
voltage to ADC is 1.1V which is less than 2.048V of ADC maximum input voltage. The express
equation can represent as follows.
V_in
= VCC
×
20KΩ
20KΩ + 40KΩ
≅ 1.1V
where VCC is set to 3.3V.
7.4.2 Voltage Fault (VOLTAGE_FAULT #)
W83L786NR/NG provides a good protection for voltage. Set Pin 20 (VOLTAGE_FAULT#) to monitor
voltage. When Vcore (Pin13), Vram (Pin14), or VCC (Pin5) voltage exceeds high or low voltage limit in
VR2B ~ VR34, Pin 20 VOLTAGE_FAULT# will be asserted (Figure 4).
Voltage High limit
Voltage Low lim it
VOLTAGE_FAULT#
Figure 4. Voltage Fault
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