MCP9808 ±0.5°C Maximum Accuracy Digital Temperature Sensor Features Description • Accuracy: - ±0.25 (typical) from -40°C to +125°C - ±0.5°C (maximum) from -20°C to 100°C - ±1°C (maximum) from -40°C to +125°C • User-Selectable Measurement Resolution: - +0.5°C, +0.25°C, +0.125°C, +0.0625°C • User-Programmable Temperature Limits: - Temperature Window Limit - Critical Temperature Limit • User-Programmable Temperature Alert Output • Operating Voltage Range: 2.7V to 5.
MCP9808 Functional Block Diagram Hysteresis Shutdown Critical Trip Lock Alarm Window Lock Clear Alert Alert Status Output Control Critical Alert only Band Gap Temperature Sensor Alert Polarity Alert Comp./Int. Configuration Temperature ΔΣ ADC TUPPER Limit TLOWER Limit +0.5°C +0.25°C +0.125°C +0.0625°C TCRITICAL Limit Manufacturer ID Device ID/Rev Resolution Register Pointer SMBus/Standard I2C™ Interface A0 DS25095A-page 2 A1 A2 Alert SDA SCL VDD GND © 2011 Microchip Technology Inc.
MCP9808 1.0 ELECTRICAL CHARACTERISTICS †Notice: Stresses above those listed under “Maximum ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings † VDD..........................................................
MCP9808 DIGITAL INPUT/OUTPUT PIN CHARACTERISTICS Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground and TA = -40°C to +125°C. Parameters Sym Min Typ Max Units V Conditions Serial Input/Output (SCL, SDA, A0, A1, A2) Input High-Level Voltage VIH 0.7 VDD — VDD Low-Level Voltage VIL GND — 0.3 VDD V Input Current IIN — — ±5 µA Low-Level Voltage VOL — — 0.4 V IOL= 3 mA High-Level Current (leakage) IOH — — 1 µA VOH = 5.
MCP9808 SENSOR SERIAL INTERFACE TIMING SPECIFICATIONS Electrical Specifications: Unless otherwise indicated, VDD = 2.7V to 5.5V, TA = -40°C to +125°C, GND = Ground and CL = 80 pF.
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MCP9808 2.0 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. Note: Unless otherwise indicated, VDD = 2.
MCP9808 Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD and TA = -40°C to +125°C. 40% 350 IDD (µA) 300 250 200 150 100 0 20 40 60 80 100 1.00 0.50 0.5 0.4 0.00 -0.50 -1.00 120 -40 -20 0 20 40 60 80 100 120 Temperature (°C) FIGURE 2-11: Supply Voltage. Supply Current vs. Temperature Accuracy vs 1000 3 0.0625°C tCONV (ms) 2.5 VPOR (V) 0.3 ∆°C/∆VDD = 0.1°C/V VDD = 2.7V VDD = 3.3V VDD = 5.5V Temperature (°C) FIGURE 2-8: Temperature.
MCP9808 0.4 35 IOL = 3 mA SMBus/I2C Bus tOUT (ms) SDA & Alert Output VOL (V) Note: Unless otherwise indicated, VDD = 2.7V to 5.5V, GND = Ground, SDA/SCL pulled-up to VDD and TA = -40°C to +125°C. 0.3 0.2 Alert VOL SDA VOL 0.1 0 30 25 20 -40 -20 0 20 40 60 80 100 120 -40 -20 0 Temperature (°C) FIGURE 2-13: vs. Temperature. 40 60 80 100 120 SDA and Alert Output VOL FIGURE 2-16: Temperature. SMBus Time-out vs. 2.00 48 VOL = 0.6V 42 1.
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MCP9808 3.0 PIN DESCRIPTION The descriptions of the pins are listed in Table 3-1. TABLE 3-1: 3.
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MCP9808 4.0 SERIAL COMMUNICATION 4.1 2-Wire Standard Mode I2C™ Protocol Compatible Interface The MCP9808 Serial Clock (SCL) input and the bidirectional Serial Data (SDA) line form a 2-wire bidirectional, Standard mode, I2C compatible communication port (refer to the Digital Input/Output Pin Characteristics and Sensor Serial Interface Timing Specifications tables).
MCP9808 4.1.4 4.1.5 ADDRESS BYTE Following the Start condition, the host must transmit an 8-bit address byte to the MCP9808. The address for the MCP9808 temperature sensor is ‘0011,A2,A1,A0’ in binary, where the A2, A1 and A0 bits are set externally by connecting the corresponding pins to VDD ‘1’ or GND ‘0’. The 7-bit address, transmitted in the serial bit stream, must match the selected address for the MCP9808 to respond with an ACK. Bit 8 in the address byte is a read/write bit.
MCP9808 5.0 FUNCTIONAL DESCRIPTION The MCP9808 temperature sensors consist of a bandgap-type temperature sensor, a Delta-Sigma Analog-toDigital Converter (ΔΣ ADC), user-programmable registers and a 2-wire SMBus/I2C protocol compatible serial interface. Figure 5-1 shows a block diagram of the register structure. Hysteresis Shutdown Critical Trip Lock Alarm Win.
MCP9808 5.1 Registers The MCP9808 has several registers that are user-accessible. These registers include the Temperature register, Configuration register, Temperature Alert Upper Boundary and Lower Boundary Limit registers, Critical Temperature Limit register, Manufacturer Identification register and Device Identification register. The Temperature register is read-only, used to access the ambient temperature data. This register is doublebuffered and it is updated every tCONV.
MCP9808 TABLE 5-1: BIT ASSIGNMENT SUMMARY FOR ALL REGISTERS (See Section 5.
MCP9808 5.1.1 SENSOR CONFIGURATION REGISTER (CONFIG) user-specified temperature boundary (see Section 5.2.2 “Temperature Hysteresis (THYST)”. The Continuous Conversion or Shutdown mode is selected using bit 8. In Shutdown mode, the band gap temperature sensor circuit stops converting temperature and the Ambient Temperature register (TA) holds the previous temperature data (see Section 5.2.1 “Shutdown Mode”).
MCP9808 REGISTER 5-2: bit 7 CONFIG: CONFIGURATION REGISTER (→ ADDRESS ‘0000 0001’b) Crit. Lock: TCRIT Lock bit 0 = Unlocked. TCRIT register can be written (power-up default) 1 = Locked. TCRIT register can not be written When enabled, this bit remains set to ‘1’ or locked until cleared by an internal Reset (Section 5.3 “Summary of Power-on Default”). This bit can be programmed in Shutdown mode. bit 6 Win.
MCP9808 Writing to the CONFIG Register to Enable the Event Output Pin <0000 0000 0000 1000>b: 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A 0 W C 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 1 SCL SDA S A K Address Byte A C K Configuration Pointer MCP9808 MCP9808 1 2 3 4 5 6 7 8 0 0 0 0 0 0 0 0 A C K 1 2 3 4 5 6 7 8 0 0 0 0 1 0 0 0 MSB Data A C K P LSB Data MCP9808 MCP9808 Note: This is an example routine (see Appendix A: “Source Code”).
MCP9808 Reading the CONFIG Register: 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA 0 S 0 1 A 2 1 A 1 A A 0 W C K 0 Address Byte 0 0 0 0 0 0 It is not necessary to select the Register Pointer if it was set from the previous read/write.
MCP9808 5.1.2 UPPER/LOWER/CRITICAL TEMPERATURE LIMIT REGISTERS (TUPPER/TLOWER/TCRIT) The MCP9808 has a 16-bit read/write Alert Output Temperature Upper Boundary register (TUPPER), a 16-bit Lower Boundary register (TLOWER) and a 16-bit Critical Boundary register (TCRIT) that contain 11-bit data in two’s complement format (0.25°C). This data represents REGISTER 5-3: the maximum and minimum temperature boundary or temperature window that can be used to monitor ambient temperature.
MCP9808 Writing +90°C to the TUPPER Register <0000 0101 1010 0000>b: 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 0 0 1 1 A 2 A 1 A A W C 0 K 0 0 0 0 0 0 1 0 SCL SDA S Address Byte A C K TUPPER Pointer MCP9808 MCP9808 1 2 3 4 5 6 7 8 0 0 0 0 0 1 0 1 A C K 1 2 3 4 5 6 7 8 1 0 1 0 0 0 0 0 MSB Data A C K P LSB Data MCP9808 MCP9808 Reading from the TUPPER Register: 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA S 0 0 1 1 A 2
MCP9808 5.1.3 AMBIENT TEMPERATURE REGISTER (TA) In addition, the TA register uses three bits (TA<15:13>) to reflect the Alert pin state. This allows the user to identify the cause of the Alert output trigger (see Section 5.2.3 “Alert Output Configuration”); bit 15 is set to ‘1’ if TA is greater than or equal to TCRIT, bit 14 is set to ‘1’ if TA is greater than TUPPER and bit 13 is set to ‘1’ if TA is less than TLOWER.
MCP9808 5.1.3.1 TA Bits to Temperature Conversion To convert the TA bits to decimal temperature, the upper three boundary bits (TA<15:13>) must be masked out. Then, determine the SIGN bit (bit 12) to check positive or negative temperature, shift the bits accordingly, and combine the upper and lower bytes of the 16-bit register. The upper byte contains data for temperatures greater than +32°C while the lower byte contains data for temperature less than +32°C, including fractional data.
MCP9808 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Note: SCL SDA S 0 0 1 1 A 2 A 1 A 0 A W C K 0 0 Address Byte 0 0 0 1 0 1 It is not necessary to select the Register Pointer if it was set from the previous read/write.
MCP9808 5.1.4 MANUFACTURER ID REGISTER This register is used to identify the manufacturer of the device in order to perform manufacturer-specific operation. The Manufacturer ID for the MCP9808 is 0x0054 (hexadecimal).
MCP9808 5.1.5 DEVICE ID AND REVISION REGISTER The upper byte of this register is used to specify the device identification and the lower byte is used to specify the device revision. The Device ID for the MCP9808 is 0x04 (hex). The revision begins with 0x00 (hex) for the first release, with the number being incremented as revised versions are released.
MCP9808 5.1.6 RESOLUTION REGISTER This register allows the user to change the sensor resolution (see Section 5.2.4 “Temperature Resolution”). The POR default resolution is +0.0625°C. The selected resolution is also reflected in the Capability register (see Register 5-2).
MCP9808 5.2 5.2.1 SENSOR FEATURE DESCRIPTION Shutdown mode disables all power consuming activities (including temperature sampling operations) while leaving the serial interface active. This mode is selected by setting bit 8 of CONFIG to ‘1’. In this mode, the device consumes ISHDN. It remains in this mode until bit 8 is cleared to ‘0’ to enable Continuous Conversion mode or until power is recycled. The Shutdown bit (bit 8) cannot be set to ‘1’ while the CONFIG<7:6> bits (Lock bits) are set to ‘1’.
MCP9808 5.2.3.2 Interrupt Mode In Interrupt mode, the Alert output is asserted as activehigh or active-low (depending on the polarity configuration) when TA drifts above or below TUPPER and TLOWER limits. The output is deasserted by setting bit 5 (Interrupt Clear bit) of CONFIG. Shutting down the device will not reset or deassert the Alert output. This mode can not be selected when the Alert output is used as a critical temperature output only, using bit 2 of CONFIG.
MCP9808 TCRIT – THYST TCRIT TUPPER – THYST TUPPER TUPPER – THYST TA TLOWER – THYST TLOWER TLOWER – THYST Alert Output (Active-Low) Comparator Interrupt S/w Int. Clear Critical Only Alert Output (Active-High) Comparator Interrupt S/w Int.
MCP9808 5.3 Summary of Power-on Default The MCP9808 has an internal Power-on Reset (POR) circuit. If the power supply voltage, VDD, glitches below the VPOR threshold, the device resets the registers to the power-on default settings. Table 5-3 shows the power-on default summary for the Temperature Sensor registers.
MCP9808 NOTES: DS25095A-page 34 © 2011 Microchip Technology Inc.
MCP9808 6.0 APPLICATIONS INFORMATION 6.1 Layout Considerations ature accuracy error of approximately +0.5°C could result from self-heating if the communication pins sink/source the maximum current specified. For example, if the event output is loaded to maximum IOL, Equation 6-1 can be used to determine the effect of self-heating. The MCP9808 does not require any additional components besides the master controller in order to measure temperature.
MCP9808 NOTES: DS25095A-page 36 © 2011 Microchip Technology Inc.
MCP9808 7.0 PACKAGING INFORMATION 7.1 Package Marking Information 8-Lead DFN (2x3x0.9 mm) Example ALP 141 25 8-Lead MSOP (3x3 mm) Example 9808E 141256 Legend: XX...X Y YY WW NNN e3 * Note: Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free.
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MCP9808 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging © 2011 Microchip Technology Inc.
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MCP9808 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging © 2011 Microchip Technology Inc.
MCP9808 NOTES: DS25095A-page 42 © 2011 Microchip Technology Inc.
MCP9808 Software License Agreement The software supplied herewith by Microchip Technology Incorporated (the “Company”) is intended and supplied to you, the Company’s customer, for use solely and exclusively with products manufactured by the Company. The software is owned by the Company and/or its supplier, and is protected under applicable copyright laws. All rights are reserved.
MCP9808 /******************************************************************** * Function Name: i2c_start * Return Value: void * Parameters: void * Description: Send I2C Start Command ********************************************************************/ void i2c_start(void) { PIR1bits.SSPIF = 0; //clear flag while (SSPSTATbits.BF ); // wait for idle condition SSPCON2bits.SEN = 1; // initiate START condition while (!PIR1bits.SSPIF) ; // wait for a flag to be set PIR1bits.
MCP9808 /******************************************************************** * Function Name: i2c_write * Return Value: Status byte for WCOL detection. * Parameters: Single data byte for I2C2 bus. * Description: This routine writes a single byte to the * I2C2 bus. ********************************************************************/ unsigned char i2c_write( unsigned char i2cWriteData ) { PIR1bits.SSPIF = 0; // clear interrupt while ( SSPSTATbits.
MCP9808 NOTES: DS25095A-page 48 © 2011 Microchip Technology Inc.
MCP9808 APPENDIX B: REVISION HISTORY Revision A (October 2011) • Original Release of this Document. © 2011 Microchip Technology Inc.
MCP9808 NOTES: DS25095A-page 50 © 2011 Microchip Technology Inc.
MCP9808 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO.
MCP9808 NOTES: DS25095A-page 52 © 2011 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature.
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