LM50C series (LM50C, LM50-Q1)

This is an overview of the LM50C series (LM50C, LM50-Q1) and the OSS-ECAL offering for the LM50C series. The LM50C series is a temperatures sensor IC (-40 °C to +125 °C) manufactured by Texas Instruments.
MCU interface : ADC

CAUTION:Please be sure to refer to the latest version of the Datasheet prior to actual design.

LM50C series (LM50C, LM50-Q1)

General description

The LM50 and LM50-Q1 devices are precision integrated-circuit temperature sensors that can sense a –40°C to 125°C temperature range using a single positive supply. The output voltage of the device is linearly proportional to temperature (10 mV/°C) and has a DC offset of 500 mV. The offset allows reading negative temperatures without the need for a negative supply.

The ideal output voltage of the LM50 or LM50-Q1 ranges from 100 mV to 1.75 V for a –40°C to 125°C temperature range. The LM50 and LM50-Q1 do not require any external calibration or trimming to provide accuracies of ±3°C at room temperature and ±4°C over the full –40°C to 125°C temperature range. Trimming and calibration of the LM50 and LM50-Q1 at the wafer level assure low cost and high accuracy. The linear output, 500 mV offset, and factory calibration of the LM50 and LM50-Q1 simplify the circuitry requirements in a single supply environment where reading negative temperatures is necessary. Because the quiescent current of the LM50 and LM50-Q1 is less than 130 µA, self-heating is limited to a very low 0.2°C in still air.

Feature

  • LM50-Q1 is AEC-Q100 Grade 1 Qualified and is Manufactured on an Automotive Grade Flow
  • Calibrated Directly in Degrees Celsius (Centigrade)
  • Linear + 10 mV/°C Scale Factor
  • ±2°C Accuracy Specified at 25°C
  • Specified for Full –40° to 125°C Range
  • Suitable for Remote Applications
  • Low Cost Due to Wafer-Level Trimming
  • Operates From 4.5 V to 10 V
  • Less Than 130-µA Current Drain
  • Low Self-Heating: Less Than 0.2°C in Still A
  • Nonlinearity Less Than 0.8°C Over Temp
  • UL Recognized Component

Application

  • Automotive
  • Computers
  • Disk Drives
  • Battery Management
  • FAX Machines
  • Printers
  • Portable Medical Instruments
  • HVAC
  • Power Supply Modules

OSS-ECAL specification

API Function

etSTS oLM50C( etCMD cmd, float32* rlt )

The oLM50C function is an API function that executes LM50C series (LM50C, LM50-Q1) processing according to the command in the argument.

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_MINMinimum temperature error (rlt is minimum temperature)
eSTS_ERR_MAXMaximum temperature error (rlt is maximum temperature)
eSTS_ERR_HAL_ADCHAL ADC Error
eSTS_ERR_COMMAND_CODECommand selection error
eSTS_ERR_OTHERS_RUNOther components are executing the process
eSTS_ERR_HAL_OTHERS_RUNOther application is running HAL
eSTS_ERR_ADC_OBJECTAD conversion object selection error
Parameter INetCMD cmdOSS-ECAL command code
eCMD_STARTCommand to start AD conversion.
eCMD_READCommand that reads the AD conversion value, converts the AD conversion value to a characteristic Temperature, and stores the Temperature in rlt.

AD conversion value to temperature conversion equation
Voltage value = (AD conversion value × VDD) / ( 2AD bit )
Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)
eCMD_START_READCommand that starts AD conversion, waits for AD conversion to finish, reads out the AD conversion value, converts the AD conversion value to a characteristic Temperature, and stores the Temperature in rlt.

AD conversion value to temperature conversion equation
Voltage value = (AD conversion value × VDD) / ( 2AD bit )
Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)
Parameter OUTfloat32* rltTemperature -40 to 125 [°C]

Command Correspondence Table by HAL

ArduinoeCMD_START_READ
ARM MbedeCMD_START_READ
AUTOSAR–
Infineon ModusToolboxeCMD_START_READ
NXP MCUXpresso iMXRT1051B_1052BeCMD_START
eCMD_READ
eCMD_START_READ
Renesas SSPeCMD_START
eCMD_READ
eCMD_START_READ
STM STM32Cube FW_F4eCMD_START
eCMD_READ
eCMD_START_READ
etSTS oLM50C_START(void)

The oLM50C_START function is an API function to start AD conversion of the LM50C series (LM50C, LM50-Q1).

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_HAL_ADCHAL ADC Error
eSTS_ERR_OTHERS_RUNOther components are executing the process
eSTS_ERR_HAL_OTHERS_RUNOther application is running HAL
eSTS_ERR_ADC_OBJECTAD conversion object selection error

Function Correspondence Table by HAL

Arduino–
ARM Mbed–
AUTOSARX
Infineon ModusToolbox–
NXP MCUXpresso iMXRT1051B_1052BX
Renesas SSPX
STM STM32Cube FW_F4X
etSTS oLM50C_READ( float32* rlt )

The oLM50C_READ function is an API function that checks for the end of AD conversion of the LM50C series (LM50C, LM50-Q1), reads the AD conversion value, converts the AD conversion value to a characteristic temperature, and stores the temperature in rlt.

AD conversion value to temperature conversion equation
Voltage value = (AD conversion value × VDD) / ( 2AD bit )
Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_MINMinimum temperature error (rlt is minimum temperature)
eSTS_ERR_MAXMaximum temperature error (rlt is maximum temperature)
eSTS_ERR_HAL_ADCHAL ADC Error
eSTS_ERR_TIMEOUTADC Timeout error (AUTOSAR only)
eSTS_ERR_OTHERS_RUNOther components are executing the process
eSTS_ERR_ADC_OBJECTAD conversion object selection error
Parameter OUTfloat32* rltTemperature -40 to 125 [°C]

Function Correspondence Table by HAL

Arduino–
ARM Mbed–
AUTOSARXTime-out time ADC_TIMEOUT [us] setting
Infineon ModusToolbox–
NXP MCUXpresso iMXRT1051B_1052BX
Renesas SSPX
STM STM32Cube FW_F4XTime-out time HAL_MAX_DELAY
etSTS oLM50C_START_READ( float32* rlt )

The oLM50C_START_READ function is an API function that starts an AD conversion of the LM50C series (LM50C, LM50-Q1), waits for the AD conversion to finish, reads the AD conversion value, converts the AD conversion value to a temperature characteristic, and stores the temperature in rlt.

AD conversion value to temperature conversion equation
Voltage value = (AD conversion value × VDD) / ( 2AD bit )
Temperature = ((voltage value – voltage offset value) / gain) + Temperature offset value (Min, Max Limit)

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_MINMinimum temperature error (rlt is minimum temperature)
eSTS_ERR_MAXMaximum temperature error (rlt is maximum temperature)
eSTS_ERR_HAL_ADCHAL ADC Error
eSTS_ERR_OTHERS_RUNOther components are executing the process
eSTS_ERR_HAL_OTHERS_RUNOther application is running HAL
eSTS_ERR_ADC_OBJECTAD conversion object selection error
Parameter OUTfloat32* rltTemperature -40 to 125 [°C]

Function Correspondence Table by HAL

ArduinoX
ARM MbedX
AUTOSAR–
Infineon ModusToolboxX
NXP MCUXpresso iMXRT1051B_1052BX
Renesas SSPX
STM STM32Cube FW_F4XTime-out time HAL_MAX_DELAY
API functions for AUTOSAR

In AUTOSAR, the ADC group and channels of the MCU may be registered to the MCAL ADC channel group for AD conversion. In such a case, use the following API functions.

etSTS oMCAL_ADC_GR_START( Adc_GroupType gr )

The oMCAL_ADC_GR_START function is an API function that initiates conversion of a ADC channel group.

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_HAL_BUSYHAL running
Parameter INAdc_GroupType grID value of ADC channel group
etSTS oMCAL_ADC_GR_READ( Adc_GroupType gr, Adc_ValueGroupType* buf )

The oMCAL_ADC_GR_READ function is an API function that checks the end of ADC conversion for the ADC channel group, reads each AD conversion value, and stores each AD conversion value in buf. This function has a Timeout function and should be used with the ADC_TIMEOUT value set.

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_HAL_ADCHAL ADC Error
eSTS_ERR_TIMEOUTADC Timeout error (AUTOSAR only)
sSTS_ERR_PROCESSThe return value of the Adc_GetGroupStatus function is other than the following value.
ADC_STREAM_COMPLETED
ADC_BUSY
Parameter INAdc_GroupType grID value of ADC channel group
Parameter OUTAdc_ValueGroupType* bufFirst address of buffer of ADC channel group
etSTS oPRC_CHAR_CONV_L_FF( sint32 before, const stCOEF_L_FF coef, float32* rlt )

The oPRC_CHAR_CONV_L_FF function is a common process function. This function converts the value of the argument before (AD conversion value) to a voltage, converts the voltage linearly by the constant coef, and limits the converted value by the maximum minimum value.

Return valueetSTSOSS-ECAL status code
eSTS_FINCompleted successfully
eSTS_ERR_MINMinimum temperature error (rlt is minimum temperature)
eSTS_ERR_MAXMaximum temperature error (rlt is maximum temperature)
Parameter OUTfloat32* rltTemperature -40 to 125 [°C]
Sample program
etSTS oss_ecal( void )
{
        /*********************************************************************/
        /* ADC Gr is registered with multiple Ch and AD conversion is        */
        /* performed to convert LM50C temperature.                           */
        /*********************************************************************/
        Adc_ValueGroupType val = 0;
        sint32 wk = 0;
        float32 phy = 0.0F;
        
        /* ADC Gr(Multi-Ch) start */
        sts = oMCAL_ADC_GR_START( ADC_LM50C_GR );
        if( sts == eSTS_FIN )
        {
                /* ADC Gr(Multi-Ch) value read */
                sts = oMCAL_ADC_GR_READ( ADC_LM50C_GR, GR_BUF );
                if( sts == eSTS_FIN )
                {
                        /* LM50C Temperature conversion */
                        /* Get A/D value */
                        val = *(GR_BUF+ADC_LM50C_CH);
                        /* Linear characteristic conversion */
                        wk = (sint32)mac_max_u16( val );
                        sts = oPRC_CHAR_CONV_L_FF( wk, cCOEF_LM50C, &phy );
                        if( sts == eSTS_FIN )
                        {
                                vgPHY = phy;
                        }
                        else
                        {
                                /* nothing to do */
                        }
                }
                else
                {
                        /* nothing to do */
                }
        }
        else
        {
                /* nothing to do */
        }
}

HAL Support List

OSS-ECAL’s HAL support is as follows. Please note that even if the same HAL is used, different versions, MCUs, and development environments may not work together. The list is being expanded sequentially.

ManufacturerSDK/IDE ToolHAL NameVerHALNAMESupport
ArduinoArduino IDEArduino1.8.6ARDUINOX
ArmKeil MDK v6Mbed OS6.17.0MBEDX
Debian–GNU/Linux10.3Linux–
InfineonModusToolboxmtb-hal-cat12.4.3ModusToolboxX
NXPMCUXpresso SDKSDK_2.x_EVKB-IMXRT10502.16iMXRT1051B1052BX
NXPPlatformSDK_S32K1_2022_02AUTOSAR MCAL4.4MCALX
RenesasSynergy Software PackageHAL2.6.0SSPX
STMicroelectronicsSTM32CubeSTM32CubeF4V1.28.1STM32F4X
Development environment

The MCU and development environment during OSS-ECAL development are as follows.

HALNAMEManufacturerBoardMCUIDE
ARDUINOArduino1.Mega 2560 Rev3
2.Arduino Pro Mini 3.3V		ATmega2560
ATmega328P		Arduino IDE 2.3.3
MBEDSTMicroelectronicsSTM32 Nucleo-64 boardsSTM32F401RETxArm Keil Studio Cloud
LinuxBeagleBoardBeagleBone BlackTI AM335x–
ModusToolboxInfineonCY8CPROTO-063-BLE PSoC 6 BLE Prototyping KitCYBLE-416045-02ModusToolbox
iMXRT1051B1052BNXPIMXRT1050-EVKBi.MX RT1050MCUXpresso IDE
MCALSTMicroelectronicsS32K144EVB-Q100S32K144S32 Design Studio for S32 Platform
SSPRenesasS7G2 SKR7FS7G27H3A01CFCe² studio for Renesas Synergy
STM32F4STMicroelectronicsSTM32 Nucleo-64 boardsSTM32F401RETxSTM32CubeIDE

Files

Folder*FileSummary
LM50C_HALNAME_VERSION/samplesample.c (.cpp)Sample Application Program
sample.hSample Application Header
LM50C_HALNAME_VERSIONoLM50C.c (.cpp)OSS-ECAL Program for LM50C series (LM50C, LM50-Q1)
oLM50C.hOSS-ECAL Header for LM50C series (LM50C, LM50-Q1)
LM50C_ARDUINO.inoSample application programs for Arduino
oss_ecal.hOSS-ECAL Common Header (Ver 01.00.00 or later, AUTOSAR is Ver 01.01.07 or later)
oTypes.hTypedef header file for AUTOSAR
user_setting.c (.cpp)Const and Table of User setting
user_setting.hHeader of User setting
readme.mdReadme
OSS-ECAL Terms of Use.txtOSS-ECAL Terms of Use

* For HALNAME, please refer to HAL Support.

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Built-in How to

How to incorporate OSS-ECAL into user programs

How to incorporate multiple OSS-ECALs in a user program (same MCU function)

How to incorporate multiple OSS-ECALs in a user program (different MCU function)

How to incorporate multiple identical electronic components into a user program

How to reduce the impact on user programs by replacing electronic components

CAUTION

The sample version of OSS-ECAL is not intended to be used with Threads (Tasks) or interrupts of different priority. Please do not use it as in the example below.

Example: If each sensor is assigned to the same ADC group and the OSS-ECAL API is executed in processes with different priorities, correct values may not be obtained.
ADC Gr0 Ch0　Temperature sensor AD22100A　100ms cycle Thread (low priority) to take in temperature
ADC Gr0 Ch1　Pressure sensor　　 MPX5999D　Event interrupts (high priority) to take pressure

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