PCT2075

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© NXP Semiconductors N.V. 2017. All rights reserved.

Product data sheet

Rev. 9.1 — 21 April 2017

7 of 37

NXP Semiconductors

PCT2075

I2C-bus Fm+ digital temperature sensor and thermal watchdog

In both cases, comparator mode and interrupt mode, the OS output is activated only if a

number of consecutive faults, defined by the device fault queue, has been met. The fault

queue is programmable and stored in the two bits, B3 and B4, of the Configuration

register. Also, the OS output active state is selectable as HIGH or LOW by setting

accordingly the configuration register bit B2.

At power-up, the PCT2075 is put into normal operation mode in OS comparator mode, the

Tots is set to 80 C, the Thys is set to 75 C, the OS active state is selected LOW and the

fault queue is equal to 1. The temp reading data is 0

C and not updated until the first

conversion is completed in about 28 ms. The default Tots and Thys is set at the factory and

can be modified on custom part number.

The OS response to the temperature is illustrated in Figure 7.

7.2 I2C-bus serial interface

The device can be connected to a compatible 2-wire serial interface Fast-mode Plus

I2C-bus as a slave device under the control of a controller or master device, using two

device terminals, SCL and SDA. The controller must provide the SCL clock signal and

write/read data to/from the device through the SDA terminal. Notice that if the I2C-bus

common pull-up resistors have not been installed as required for I2C-bus, then an external

pull-up resistor, about 1.5 k

, is needed for each of these two terminals. The bus

communication protocols are described in Section 7.10.

(1) OS is reset by either reading register or putting the device in shutdown mode. It is assumed that

the fault queue is met at each Tots and Thys crossing point.

Fig 7.

OS response to temperature

002aah455

(1)

(1)

(1)

Tots

Thys

OS reset

OS active

OS reset

OS active

OS output in comparator mode

OS output in interrupt mode

reading temperature limits