AT75A

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Description

The AT75A is a temperature-to-digital converter using an on-chip band gap temperature sensor and Sigma-delta A-to-D conversion technique. The device is also a thermal detector providing an overtemperature detection output. The AT75A contains a number of data registers: Configuration register (Conf) to store the device settings such as device operation mode, OS operation mode, temperature register (Temp) to store the digital temp reading, and set-point registers (Tos and Thyst) to store programmable overtemperature shutdown and hysteresis limits, that can be communicated by a controller via the 2-wire serial I2C-bus interface. The device also includes an open-drain output (OS) which becomes active when the temperature exceeds the programmed limits. There are three selectable logic address pins so that eight devices can be connected on the same bus without address conflict.

The AT75A can be configured for different operation conditions. It can be set in normal mode to periodically monitor the ambient temperature, or in shutdown mode to minimize power consumption. The OS output operates in either of two selectable modes:OS comparator mode or OS interrupt mode. Its active state can be selected as either HIGH or LOW. The fault queue that defines the number of consecutive faults in order to activate the OS output is programmable as well as the set-point limits.

The temperature register always stores an 11-bit 2's complement data giving a temperature resolution of 0.125℃ This high temperature resolution is particularly useful in applications of measuring precisely the thermal drift or runaway.

The device is powered-up in normal operation mode with the OS in comparator mode, temperature threshold of 80℃ and hysteresis of 75℃, so that it can be used as a stand-alone thermostat with those pre-defined temperature set points.

Features

Pin-for-pin replacement for industry standard AT75 and offers improved temperature resolution of 0.125 ℃ and specification of a single part over power supply range from 2.8 V to 5.5 V

Small 8-pin package types: SO8 and MSOP8

I2C-bus interface with up to 8 devices on the same bus

Power supply range from 2.8 V to 5.5 V

Temperatures range from -55 ℃ to +125℃

11-bit ADC that offers a temperature resolution of 0.125℃

Temperature accuracy of:

±2 ℃ from-25 ℃ to +100℃

±3 ℃ from-55℃ to +125℃

Programmable temperature threshold and hysteresis set points

Supply current of 3.5 μA in shutdown mode for power conservation

Stand-alone operation as thermostat at power-up

ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD22-A115 and 1000 V CDM per JESD22-C101

Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA

Applications

System thermal management

Personal computers

Electronics equipment

Industrial controllers

Typical application