LM75A device highlight

The LM75A is used in general applications such as personal computers, system thermal management, electronics equipment, and industrial controllers. It is ideally suited for portable products.

The LM75A is a temperature-to-digital converter using an on-chip band-gap temperature sensor and Sigma-Delta A-to-D conversion technique. It contains a number of data registers:

1. The Configuration Register is used to store the device settings such as device operation mode, OS operation mode, OS polarity, and OS fault queue.
2. The Temperature Register is used to store programmable over-temp shutdown and hysteresis limits that can be communicated by the Host via the 2-wire serial I2C-bus interface using device pins SCL and SDA. The device also includes an open-drain output (OS), which becomes active when the temperature exceeds the programmed limits.

A bus master may be a personal computer or a microcontroller. The bus master can query the LM75A at any time to read temperature. Both the over-temperature threshold (T_OS) and the hysteresis temperature (T_HYS) contents are stored in the T_OS and T_HYS registers which are programmed via the host. Three pins (AO, A1, A3) are used to select the address; thus, eight LM75A may be used on single I2C bus. The temperature register always stores an 11-bit 2's complement data giving a temperature resolution of 0.125^oC. The device is powered up in normal operation mode with the OS in comparator mode, over-temperature threshold at 80^oC and hysteresis temperature at 75^oC. The LM75A can be configured for different conditions. It can be set in normal mode to periodically monitor the ambient temperature or in shutdown mode to minimize power consumption.

The LM75A is a pin-by-pin replacement for the industry standard National LM75. However, the LM75 has better specification than most competitive devices. The LM75A operates with equal or better temperature accuracy over the operating temperature range of -55 to +125^oC and supply voltage range of 2.8 to 5.5V than the competitive devices. With a temperature resolution of 0.125^oC, it far exceeds all competitive "LM75" devices, which specify 0.5^oC.

• Pin-for-Pin replacement of industry standard LM75 devices
• Offers improved temperature resolution of 0.125^oC via an 11-bit ADC compared to the standard 0.5^oC
• Temperature accuracy of ±2^oC from -25^oC to +100^oC T_amb
• Power supply voltage range from 2.8V to 5.5V
• 5.5V-tolerant I/Os
• Small 8-pin SO & TSSOP packages
• I2C-bus interface with up to 8 devices on the same bus
• Temperature range -55^oC to +125^oC T_amb
• Stand-alone operation as thermostat at power-up
• Low supply current of 3.5uA in shut-down mode for power conservation

• System thermal management
• Personal computers
• Electronics equipment
• Industrial controllers
• Consumer products

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	LM75A		Local-only digital temperature sensor and thermal Watchdog™

• I²C/SMBus Thermal Management Functions