SE95U: Ultra high accuracy digital temperature sensor and thermal watchdog

The SE95 is a temperature-to-digital converter using an on-chip band gap temperature sensor and Sigma Delta analog-to-digital conversion technique. The device is also a thermal detector providing an overtemperature detection output.

The SE95 contains a number of data registers accessed by a controller via the 2-wire serial I²C-bus interface:

The device includes an open-drain output (pin OS) which becomes active when the temperature exceeds the programmed limits. There are three selectable logic address pins (pins A2 to A0) so that eight devices can be connected on the same bus without address conflict.

The SE95 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 and 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 a 13-bit two's complement data giving a temperature resolution of 0.03125 Cel. This high temperature resolution is particularly useful in applications of measuring precisely the thermal drift or runaway. For normal operation and compatibility with the LM75A, only the 11 MSBs are read, with a resolution of 0.125 Cel to provide the accuracies specified. To be compatible with the LM75, read only the 9 MSBs.

The device is powered-up in normal operation mode with the OS in comparator mode, temperature threshold of 80 Cel and hysteresis of 75 Cel, so that it can be used as a stand-alone thermostat with those pre-defined temperature set points. The conversion rate is programmable, with a default of 10 conversions/s.

SE95U: Product Block Diagram
Data Sheets (1)
Name/DescriptionModified Date
Ultra high accuracy digital temperature sensor and thermal watchdog (REV 7.0) PDF (150.0 kB) SE9502 Sep 2009
Application Notes (3)
Name/DescriptionModified Date
Level shifting techniques in I2C-bus design (REV 1.0) PDF (52.0 kB) AN1044120 Jun 2007
Digital temperature sensor accuracy explained (REV 1.0) PDF (111.0 kB) AN1034909 Aug 2006
I2C manual (REV 1.0) PDF (4.2 MB) AN1021627 Mar 2003
Users Guides (3)
Name/DescriptionModified Date
I2C-bus specification and user manual (REV 6.0) PDF (1.4 MB) UM1020428 Apr 2014
I2C-bus specification and user manual (REV 5.0) PDF (1.6 MB) UM10204_JA03 Apr 2013
I2C Demonstration Board 2005-1 Quick Start Guide (REV 1.0) PDF (261.0 kB) UM1020613 Jun 2006
Brochures (2)
Name/DescriptionModified Date
NXP® I2C-bus solutions 2014: Smart, simple solutions for the 12 most common design concerns (REV 1.0) PDF (3.5 MB) 7501754001 Aug 2014
Create smarter, more efficient white goods; An industry-leading portfolio of cost-effective, power-saving solutions for... (REV 1.0) PDF (1.1 MB) 7501654301 Jun 2008
Selector Guides (1)
Name/DescriptionModified Date
I2C-bus temperature sensors; Small, accurate, low-cost sensors for advanced temperature regulation (REV 1.0) PDF (675.0 kB) 7501569301 Nov 2006
Ordering Information
ProductStatusPackage versionRemarksStandby current (uA)Operating Temperature (Cel)I2C-bus controlledPart typeAccuracy on-chip (±°C)Operating voltage (VDC)Assignable addressesSMBus clock (kHz)Accuracy remote (±°C)
SE95UEnd of LifeNAU0007-55~1252.8~5.51@-25~100?2@-55~1252.8~5.58400