The LM75BD,118 is a temperature-to-digital converter using an on-chip band gap temperaturesensor and Sigma-Delta A-to-D conversion technique with an overtemperature detectionoutput. The LM75BD,118 contains a number of data registers: Configuration register (Conf) tostore the device settings such as device operation mode, OS operation mode, OS polarityand OS fault queue; temperatureregister (Temp) to store the digital temp reading, and set-point registers (Tos and Thyst) tostore programmable overtemperature shutdown and hysteresis limits, that can becommunicated by a controller via the 2-wire serial I²C-bus interface. The device alsoincludes an open-drain output (OS) which becomes active when the temperature exceedsthe programmed limits. There are three selectable logic address pins so that eight devicescan be connected on the same bus without address conflict.
The LM75BD,118 can be configured for different operation conditions. It can be set in normalmode to periodically monitor the ambient temperature, or in shutdown mode to minimizepower 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 eitherHIGH or LOW. The fault queue that defines the number of consecutive faults in order toactivate the OS output is programmable as well as the set-point limits.
The temperature register always stores an 11-bit two’s complement data giving atemperature resolution of 0.125 °C. This high temperature resolution is particularly usefulin applications of measuring precisely the thermal drift or runaway. When the LM75BD,118 isaccessed the conversion in process is not interrupted (that is, the I²C-bus section is totallyindependent of the Sigma-Delta converter section) and accessing the LM75Bcontinuously without waiting at least one conversion time between communications willnot prevent the device from updating the Temp register with a new conversion result. Thenew conversion result will be available immediately after the Temp register is updated.
The LM75BD,118 powers up in the normal operation mode with the OS in comparator mode,temperature threshold of 80 °C and hysteresis of 75 °C, so that it can be used as astand-alone thermostat with those pre-defined temperature set points.
Feature
- Pin-for-pin replacement for industry standard LM75 and LM75A and offers improvedtemperature resolution of 0.125 °C and specification of a single part over power supplyrange from 2.8 V to 5.5 V
- 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 °C to +125 °C
- Frequency range 20 Hz to 400 kHz with bus fault time-out to prevent hanging up thebus
- 11-bit ADC that offers a temperature resolution of 0.125 °C
- Temperature accuracy of:
- ±2 °C from -25 °C to +100 °C
- ±3 °C from -55 °C to +125 °C
- Programmable temperature threshold and hysteresis set points
- Supply current of 1.0 uA in shutdown mode for power conservation
- Stand-alone operation as thermostat at power-up
- ESD protection exceeds 4500 V HBM per JESD22-A114 and 1000 V CDM perJESD22-C101
- Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
- Small 8-pin package types: SO8, TSSOP8, 3 mm x 2 mm XSON8U, and2 mm x 3 mm HWSON8
- System thermal management
- Personal computers
- Electronics equipment
- Industrial controllers
