EMC1428 datasheet(17/53 Pages) MICROCHIP

17 / 53 page

1°C Multiple Temperature Sensor with HW Thermal Shutdown & Hottest of Thermal Zones

Data Sheet

 2014 Microchip Technology Inc.

DS20005275A-page 17

The External Diode 1 channel and any software enabled channels are subject to the fault queue such

that the error must exceed the threshold for one to four consecutive measurements before the

SYS_SHDN pin is asserted.

Figure 4.2 shows a block diagram of the interaction between the input channels and the SYS_SHDN

pin.

4.3

TRIP_SET Pin

The EMC1428’s TRIP_SET pin is an input to the Critical / Thermal Shutdown logic block which sets

the Critical / Thermal shutdown temperature. The system designer creates a voltage level at this input

through a simple resistor connected to GND as shown in Figure 4.3. The value of this resistor is used

to create an input voltage on the TRIP_SET pin which is translated into a temperature ranging from

65°C to 127°C as enumerated in Table 4.1.

APPLICATION NOTE: Current only flows when the TRIP_SET pin is being monitored. At all other times, the internal

reference voltage is removed and the TRIP_SET pin will be pulled down to ground.

APPLICATION NOTE: The TRIP_SET pin circuitry is designed to use a 1% resistor externally. Using a 1% resistor

will result in the Thermal / Critical Shutdown temperature being decoded correctly. If a 5%

resistor is used, then the Thermal / Critical Shutdown temperature may be decoded with as

much as ±1°C error.

APPLICATION NOTE: Note that an open condition on the TRIP_SET pin will be decoded as a minimum

temperature threshold level.

Figure 4.2 Block Diagram of Hardware Thermal Shutdown

EMC1428 Datasheet(PDF) 17 Page - Microchip Technology