LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 LMP90100/LMP90099/LMP90098/LMP90097 Sensor AFE System: Multi-Channel, Low Power 24-Bit Sensor AFE with True Continuous Background Calibration Check for Samples: LMP90100 FEATURES APPLICATIONS • • • • • 1 23 • • • • • • • • • • • • • • 24-Bit Low Power Sigma Delta ADC True Continuous Background Calibration at all gains In-Place System Calibration using Expected Value programming Low-Noise programmable gain (1x - 128x) Continuous background open/short and out of range sensor diagnostics 8 output data rates (ODR) with single-cycle settling 2 matched excitation current sources from 100 µA to 1000 µA (LMP90100/LMP90098) 4-DIFF / 7-SE inputs (LMP90100/LMP90099) 2-DIFF / 4-SE inputs (LMP90098/LMP90097) 7 General Purpose Input/Output pins Chopper-stabilized buffer for low offset SPI 4/3-wire with CRC data link error detection 50 Hz to 60 Hz line rejection at ODR ≤13.42 SPS Independent gain and ODR selection per channel Supported by Webench Sensor AFE Designer Automatic Channel Sequencer KEY SPECIFICATIONS • • • • • • • • • ENOB/NFR Up to 21.5/19 bits Offset Error (typ) 8.4 nV Gain Error (typ) 7 ppm Total Noise < 10 µV-rms Integral Non-Linearity (INL max) ±15 ppm of FSR Output Data Rates (ODR) 1.6775 - 214.65 SPS Analog Voltage, VA +2.85 to +5.5 V Operating Temp Range -40°C to 125 °C Package 28 Pin HTSSOP exposed pad Temperature and Pressure Transmitters Strain Gauge Interface Industrial Process Control DESCRIPTION The LMP90100/LMP90099/LMP90098/LMP90097 are highly integrated, multi-channel, low power 24-bit Sensor AFEs. The devices features a precision, 24bit Sigma Delta Analog-to-Digital Converter (ADC) with a low-noise programmable gain amplifier and a fully differential high impedance analog input multiplexer. A true continuous background calibration feature allows calibration at all gains and output data rates without interrupting the signal path. The background calibration feature essentially eliminates gain and offset errors across temperature and time, providing measurement accuracy without sacrificing speed and power consumption. Another feature of the LMP90100/LMP90099/LMP90098/LMP90097 is continuous background sensor diagnostics, allowing the detection of open and short circuit conditions and out-of-range signals, without requiring user intervention, resulting in enhanced system reliability. Two sets of independent external reference voltage pins allow multiple ratiometric measurements. In addition, two matched programmable current sources are available in the LMP90100/LMP90098 to excite external sensors such as resistive temperature detectors and bridge sensors. Furthermore, seven GPIO pins are provided for interfacing to external LEDs and switches to simplify control across an isolation barrier. Collectively, these features make the LMP90100/LMP90099/LMP90098/LMP90097 complete analog front-ends for low power, precision sensor applications such as temperature, pressure, strain gauge, and industrial process control. The LMP90100/LMP90099/LMP90098/LMP90097 are ensured over the extended temperature range of 40°C to +125°C and are available in a 28-pin HTSSOP package with an exposed pad. 1 2 3 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. TRI-STATE is a registered trademark of National Semiconductor Corporation. All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2011–2013, Texas Instruments Incorporated LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Typical Application 2 -Wire RTD 3-Wire RTD IB1 2 3 4 SCLK IB2 VIN0 ... VIN2 ... VIN4 ... VIN6/VREFP2 VIN7/ VREFN2 2 VIO CSB 1 + VREFP1 VREFN1 VA 4-Wire RTD Thermocouple VA GND SDO/DRDYB LMP90100 LM90xxx 24-bit Sensor AFE Family of Products MicroController SDI D0 ... D6/DRDYB CLK/XIN XOUT LEDs/ Switches Submit Documentation Feedback Product Channel Configuration Current Sources LMP90100 4 Differential/7 Single-Ended Yes LMP90099 4 Differential/7 Single-Ended No LMP90098 2 Differential/4 Single-Ended Yes LMP90097 2 Differential/4 Single-Ended No Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Block Diagram Chip Configurable LMP90xxx Channel Configurable Fixed EXC. CURRENT EXC. CURRENT IB1 LMP90100/LMP9 0098 only VIO VA VA IB2 POR Open/Short Sensor Diag. VIN0 VIN1 VIN3 LMP90100/LMP9 0099 only VIN4 VIN5 BACKGROUND CALIBRATION INPUT MUX VIN2 FGA 16x PGA 1x, 2x, 4x, 8x SERIAL I/F CONTROL & CALIBRATION DATA PATH SCLK SDI SDO/DRDYB CSB BUFF 24 bit SD Module VIN6/VREFP2 DIGITAL FILTER VIN7/VREFN2 CLK MUX VREF Ext. Clk Detect Internal CLK MUX GND VREFP1 GPIO VREFN1 XOUT CLK/ D6/ XIN DRDYB D0 Figure 1. Block Diagram Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 3 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com • True Continuous Background Calibration The LMP90100/LMP90099/LMP90098/LMP90097 feature a 24 bit ΣΔ core with continuous background calibration to compensate for gain and offset errors in the ADC, virtually eliminating any drift with time and temperature. The calibration is performed in the background without user or ADC input interruption, making it unique in the industry and eliminating down time associated with field calibration required with other solutions. Having this continuous calibration improves performance over the entire life span of the end product. • Continuous Background Sensor Diagnostics Sensor diagnostics are also performed in the background, without interfering with signal path performance, allowing the detection of sensor shorts, opens, and out-of-range signals, which vastly improves system reliability. In addition, the fully flexible input multiplexer described below allows any input pin to be connected to any ADC input channel providing additional sensor path diagnostic capability. • Flexible Input MUX Channels The flexible input MUX allows interfacing to a wide range of sensors such as thermocouples, RTDs, thermistors, and bridge sensors. The LMP90100/LMP90099’s multiplexer supports 4 differential channels while the LMP90098/LMP90097 supports 2. Each effective input voltage that is digitized is VIN = VINx – VINy, where x and y are any input. In addition, the input multiplexer of the LMP90100/LMP90099 also supports 7 single-ended channels (LMP90098/LMP90097 supports 4), where the common ground is any one of the inputs. • Programmable Gain Amplifiers (FGA & PGA) The LMP90100/LMP90099/LMP90098/LMP90097 contain an internal 16x fixed gain amplifier (FGA) and a 1x, 2x, 4x, or 8x programmable gain amplifier (PGA). This allows accurate gain settings of 1x, 2x, 4x, 8x, 16x, 32x, 64x, or 128x through configuration of internal registers. Having an internal amplifier eliminates the need for external amplifiers that are costly, space consuming, and difficult to calibrate. • Excitation Current Sources (IB1 & IB2) - LMP90100/LMP90098 Two matched internal excitation currents, IB1 and IB2, can be used for sourcing currents to a variety of sensors. The current range is from 100 µA to 1000 µA in steps of 100 µA. 4 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Connection Diagram LMP90100/ LMP90099 only VA 1 28 VIO VIN0 2 27 D6/DRDYB VIN1 3 26 D5 VIN2 4 25 D4 VIN3 5 24 D3 VIN4 6 23 D2 22 D1 VIN5 7 VREFP1 8 VREFN1 LMP90xxx 28-pin HTSSOP 21 D0 9 20 SDO/DRDYB SDI VIN6/VREFP2 10 19 VIN7/VREFN2 11 18 SCLK IB2 12 17 CSB IB1 13 16 GND XOUT 14 15 XIN/CLK LMP90100/ LMP90098 only Figure 2. See Package Number PWP0028A See Pin Descriptions for specific information regarding options LMP90099, LMP90098, and LMP90097. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 5 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Pin Functions PIN DESCRIPTIONS Pin # Pin Name Type 1 VA Analog Supply 2-4 VIN0 - VIN2 Analog Input Analog input pins 5-7 (LMP90100, LMP90099) VIN3 - VIN5 Analog Input Analog input pins 5-7 (LMP90098, LMP90097) VIN3 - VIN5 No Connect No connect: must be left unconnected 8 VREFP1 Analog Input Positive reference input 9 VREFN1 Analog Input Negative reference input 10 VIN6 / VREFP2 Analog Input Analog input pin or VREFP2 input 11 VIN7 / VREFN2 Analog Input Analog input pin or VREFN2 input 12 - 13 (LMP90100, LMP90098) IB2 & IB1 Analog output Excitation current sources for external RTDs 12 - 13 (LMP90099, LMP90097) IB2 & IB1 No Connect 14 XOUT Analog output External crystal oscillator connection 15 XIN / CLK Analog input External crystal oscillator connection or external clock input 16 GND Ground 17 CSB Digital Input Chip select bar 18 SCLK Digital Input Serial clock 19 SDI Digital Input Serial data input 20 SDO / DRDYB Digital Output 21 - 26 D0 - D5 Digital IO General purpose input/output (GPIO) pins 27 D6 / DRDYB Digital IO General purpose input/output pin or data ready bar 28 VIO Digital Supply Thermal Pad 6 Function Analog power supply pin No connect: must be left unconnected Power supply ground Serial data output and data ready bar Digtal input/output supply pin You can leave this thermal pad floating. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1) (2) Analog Supply Voltage, VA -0.3V to 6.0V Digital I/O Supply Voltage, VIO -0.3V to 6.0V Reference Voltage, VREF -0.3V to VA+0.3V Voltage on Any Analog Input Pin to GND (3) -0.3V to VA+0.3V Voltage on Any Digital Input PIN to GND (3) -0.3V to VIO+0.3V Voltage on SDO (3) Input Current at Any Pin -0.3V to VIO + 0.3V (3) 5mA Output Current Source or Sink by SDO 3mA Total Package Input and Output Current 20mA ESD Susceptibility Human Body Model (HBM) 2500V Machine Models (MM) 200V Charged Device Model (CDM) 1250V Junction Temperature (TJMAX) +150°C Storage Temperature Range –65°C to +150°C For soldering specifications: see product folder at www.ti.com and http://www.ti.com/lit/SNOA549. (1) (2) (3) All voltages are measured with respect to GND, unless otherwise specified Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not ensure specific performance limits. For ensured specifications and test conditions, see the Electrical Characteristics. The ensured specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. When the input voltage (VIN) exceeds the power supply (VIN < GND or VIN > VA), the current at that pin must be limited to 5mA and VIN has to be within the Absolute Maximum Rating for that pin. The 20 mA package input current rating limits the number of pins that can safely exceed the power supplies with current flow to four pins. Operating Ratings Analog Supply Voltage, VA +2.85V to 5.5V Digital I/O Supply Voltage, VIO +2.7V to 5.5V Full Scale Input Range, VIN ±VREF / PGA Reference Voltage, VREF +0.5V to VA TMIN = –40°C Temperature Range for Electrical Characteristics TMAX = +125°C –40°C ≤ TA ≤ +125°C Operating Temperature Range Junction to Ambient Thermal Resistance (θJA) (1) (1) 41°C/W The maximum power dissipation is a function of TJ(MAX) AND θJA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) - TA) / θJA. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 7 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Electrical Characteristics Unless otherwise noted, the key for the condition is (VA = VIO = VREF) / ODR (SPS) / buffer / calibration / gain . Boldface limits apply for TMIN ≤ TA ≤ TMAX; the typical values apply for TA = +25°C. Symbol n Parameter Conditions Min Typ Resolution ENOB / NFR ODR INL Effective Number of Bits and Noise Free Resolution 3V / all / ON / OFF / all. Shorted input. Table 1 Bits 5V / all / ON / OFF / all. Shorted input. Table 3 Bits Gain FGA × PGA Integral NonLinearity 3V / 214.65 / ON / ON / 1 1.6675 Table 1 1 Table 1 128 -15 ±7 +15 3V & 5V / 214.65 / ON / ON / 16 Table 2 µV 5V / all / ON / OFF / all. Shorted input. Table 4 µV Below Noise Floor (rms) µV 3V / 214.65 / ON / ON / 128 5V / 214.65 / ON / ON / 128 1.22 9.52 µV 0.00838 0.70 µV 1.79 8.25 µV 0.0112 0.63 µV 3V & 5V / 214.65 / ON or OFF / OFF / 1-8 100 nV/°C 3 nV/°C 3V & 5V / 214.65 / ON / OFF / 16 25 nV/°C 3V & 5V / 214.65 / ON / ON / 16 0.4 nV/°C 3V & 5V / 214.65 / ON / OFF / 128 6 nV/°C 3V & 5V / 214.65 / ON / ON / 128 0.125 nV/°C 5V / 214.65 / ON / OFF / 1, TA = 150°C 2360 nV / 1000 hours 5V / 214.65 / ON / ON / 1, TA = 150°C 100 nV / 1000 hours 3V & 5V / 214.65 / ON / ON / 1-8 Offset Drift over Time (1) 3V & 5V / 214.65 / ON / ON / 1 GE Gain Error Gain Drift over Temp (1) Gain Drift over Time (1) ppm 3V / all / ON / ON / all. Shorted input. 5V / 214.65 / ON / ON / 1 Offset Drift Over Temp (1) SPS ppm 3V / 214.65 / ON / ON / 1 Offset Error 214.6 ± 15 3V & 5V / all / ON or OFF / ON / all OE Units Bits Output Data Rates Total Noise Max 24 -80 7 3V & 5V / 13.42 / ON / ON / 16 80 ppm 50 ppm 3V & 5V / 13.42 / ON / ON / 64 50 ppm 3V & 5V / 13.42 / ON / ON / 128 100 ppm 3V & 5V / 214.65 / ON / ON / all 0.5 ppm/°C 5V / 214.65 / ON / OFF / 1, TA = 150°C 5.9 ppm / 1000 hours 5V / 214.65 / ON / ON / 1, TA = 150°C 1.6 ppm / 1000 hours CONVERTER'S CHARACTERISTIC CMRR Input Common Mode Rejection Ratio Reference Common Mode Rejection PSRR (1) 8 Power Supply Rejection Ratio DC, 3V / 214.65 / ON / ON / 1 70 117 dB DC, 5V / 214.65 / OFF / OFF / 1 90 120 dB 50/60 Hz, 5V / 214.65 / OFF / OFF / 1 117 dB VREF = 2.5V 101 dB 115 dB 112 dB DC, 3V / 214.65 / ON / ON / 1 75 DC, 5V / 214.65 / ON / ON / 1 This parameter is specified by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Electrical Characteristics (continued) Unless otherwise noted, the key for the condition is (VA = VIO = VREF) / ODR (SPS) / buffer / calibration / gain . Boldface limits apply for TMIN ≤ TA ≤ TMAX; the typical values apply for TA = +25°C. Symbol NMRR Parameter Normal Mode Rejection Ratio (2) Cross-talk Conditions Min 47 Hz to 63 Hz, 5V / 13.42 / OFF / OFF /1 Typ Max Units 78 3V / 214.65 / OFF / OFF / 1 95 136 dB 5V / 214.65 / OFF / OFF / 1 95 143 dB dB POWER SUPPLY CHARACTERISTICS VA Analog Supply Voltage 2.85 3.0 5.5 V VIO Digital Supply Voltage 2.7 3.3 5.5 V 3V / 13.42 / OFF / OFF / 1, ext. CLK 400 500 µA 5V / 13.42 / OFF / OFF / 1, ext. CLK 464 555 µA 3V / 13.42 / ON / OFF / 64, ext. CLK 600 700 µA IVA Analog Supply Current 5V / 13.42 / ON / OFF / 64, ext. CLK 690 800 µA 3V / 214.65 / ON / OFF / 64, int. CLK 1547 1700 µA 5V / 214.65 / ON / OFF / 64, int. CLK 1760 2000 µA 3V / 214.65 / OFF / OFF / 1, int. CLK 826 1000 µA 5V / 214.65 / OFF / OFF / 1, int. CLK 941 1100 µA Standby, 3V , int. CLK 3 10 µA Standby, 3V , ext. CLK 257 Standby, 5V, int. CLK 5 Standby, 3V, ext. CLK 300 Power-down, 3V, int/ext CLK 2.6 5 µA Power-down, 5V, int/ext CLK 4.6 9 µA VREFN + 0.5 VA V GND VREFP - 0.5 V 0.5 VA V µA 15 µA µA REFERENCE INPUT VREFP Positive Reference VREFN Negative Reference VREF Differential Reference VREF = VREFP - VREFN ZREF Reference Impedance 3V / 13.42 / OFF / OFF / 1 10 MOhm IREF Reference Input 3V / 13.42 / ON or OFF / ON or OFF / all ±2 µA CREFP Capacitance of the Positive Reference (2) 6 pF CREFN Capacitance of the Negative Reference (2) 6 pF 1 nA ILREF Reference Leakage Current , gain = 1 , gain = 1 Power-down ANALOG INPUT VINP VINN Positive Input Negative Input Gain = 1-8, buffer ON GND + 0.1 VA - 0.1 V Gain = 16 - 128, buffer ON GND + 0.4 VA - 1.5 V Gain = 1-8, buffer OFF GND VA V Gain = 1-8, buffer ON GND + 0.1 VA - 0.1 V Gain = 16 - 128, buffer ON GND + 0.4 VA - 1.5 V VA V Gain = 1-8, buffer OFF VIN (2) Differential Input GND VIN = VINP - VINN ±VREF / PGA This parameter is specified by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 9 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Electrical Characteristics (continued) Unless otherwise noted, the key for the condition is (VA = VIO = VREF) / ODR (SPS) / buffer / calibration / gain . Boldface limits apply for TMIN ≤ TA ≤ TMAX; the typical values apply for TA = +25°C. Symbol Parameter Differential Input Impedance ZIN Conditions Min ODR = 13.42 SPS Typ Max Units 15.4 MOhm CINP Capacitance of the 5V / 214.65 / OFF / OFF / 1 Positive Input 4 pF CINN Capacitance of the 5V / 214.65 / OFF / OFF / 1 Negative Input 4 pF 3V & 5V / 13.42 / ON / OFF / 1-8 500 pA 3V & 5V / 13.42 / ON / OFF / 16 - 128 100 pA Input Leakage Current IIN DIGITAL INPUT CHARACTERISTICS at VA = VIO = VREF = 3.0V VIH Logical "1" Input Voltage VIL Logical "0" Input Voltage IIL Digital Input Leakage Current VHYST 0.7 x VIO V -10 Digital Input Hysteresis 0.3 x VIO V +10 µA 0.1 x VIO V DIGITAL OUTPUT CHARACTERISTICS at VA = VIO = VREF = 3.0V VOH Logical "1" Output Voltage Source 300 µA VOL Logical "0" Output Voltage Sink 300 µA IOZH, IOZL TRISTATE®Leakage Current COUT TRI-STATE Capacitance 2.6 V -10 (3) 0.4 V 10 µA 5 pF 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 µA EXCITATION CURRENT SOURCES CHARACTERISTICS (LMP90100/LMP90098 only) IB1, IB2 Excitation Current Source Output IB1/IB2 Tolerance VA = VREF = 3V -7 2.5 7 % VA = VREF = 5V -3.5 0.2 3.5 % IB1/IB2 Output VA = 3.0V & 5.0V, IB1/IB2 = 100 µA to Compliance Range 1000 µA IB1/IB2 Regulation IBTC (3) 10 IB1/IB2 Drift VA - 0.8 V 0.07 %/V VA = 3.0V 95 ppm/°C VA = 5.0V 60 ppm/°C VA = 5.0V, IB1/IB2 = 100 µA to 1000 µA This parameter is specified by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Electrical Characteristics (continued) Unless otherwise noted, the key for the condition is (VA = VIO = VREF) / ODR (SPS) / buffer / calibration / gain . Boldface limits apply for TMIN ≤ TA ≤ TMAX; the typical values apply for TA = +25°C. Symbol IBMT IBMTC Parameter Conditions IB1/IB2 Matching IB1/IB2 Matching Drfit Typ Max Units 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 100 µA Min 0.34 1.53 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 200 µA 0.22 1 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 300 µA 0.2 0.85 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 400 µA 0.15 0.8 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 500 µA 0.14 0.7 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 600 µA 0.13 0.7 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 700 µA 0.075 0.65 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 800 µA 0.085 0.6 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 900 µA 0.11 0.55 % 3V & 5V / 214.65 / OFF / OFF / 1, IB1/IB2 = 1000 µA 0.11 0.45 % VA = 3.0V & 5.0V, IB1/IB2 = 100 µA to 1000 µA 2 ppm/°C 893 kHz INTERNAL/EXTERNAL CLK CLKIN Internal Clock Frequency CLKEXT External Clock Frequency External Crystal Frequency (3) 1.8 3.5717 Input Low Voltage 0 Input High Voltage 1 Frequency 1.8 MHz V V 3.5717 Start-up time SCLK 7.2 7.2 MHz 10 MHz 7 ms Serial Clock Table 1. ENOB (Noise Free Resolution) vs. Sampling Rate and Gain at VA = VIO = VREF = 3V ODR (SPS) Gain 1 2 4 8 16 32 64 128 1.6775 20.5 (18) 20.5 (18) 19.5 (17) 19 (16.5) 20.5 (18) 19.5 (17) 19 (16.5) 18 (15.5) 3.355 20 (17.5) 20 (17.5) 19 (16.5) 18.5 (16) 20 (17.5) 19 (16.5) 18.5 (16) 17 (14.5) 6.71 19.5 (17) 19.5 (17) 18.5 (16) 18 (15.5) 19.5 (17) 18.5 (16) 17.5 (15) 17 (14.5) 13.42 19 (16.5) 18.5 (16) 18 (15.5) 17.5 (15) 19 (16.5) 18 (15.5) 17.5 (15) 16.5 (14) 26.83125 20.5 (18) 20 (17.5) 19.5 (17) 19 (16.5) 20 (17.5) 19 (16.5) 18 (15.5) 17.5 (15) 53.6625 20 (17.5) 19.5 (17) 19 (16.5) 18.5 (16) 19.5 (17) 18.5 (16) 17.5 (15) 17 (14.5) 107.325 19.5 (17) 19 (16.5) 18.5 (16) 18 (15.5) 19 (16.5) 18 (15.5) 17 (14.5) 16.5 (14) 214.65 19 (16.5) 18.5 (16) 18 (15.5) 17.5 (15) 18.5 (16) 17.5 (15) 17 (14.5) 16 (13.5) Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 11 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Table 2. ENOB (Noise Free Resolution) vs. Sampling Rate and Gain at VA = VIO = VREF = 3V Gain ODR (SPS) 1 2 4 8 16 32 64 128 1.6775 20.5 (18) 20.5 (18) 19.5 (17) 19 (16.5) 20.5 (18) 19.5 (17) 19 (16.5) 18 (15.5) 3.355 20 (17.5) 20 (17.5) 19 (16.5) 18.5 (16) 20 (17.5) 19 (16.5) 18.5 (16) 17 (14.5) 6.71 19.5 (17) 19.5 (17) 18.5 (16) 18 (15.5) 19.5 (17) 18.5 (16) 17.5 (15) 17 (14.5) 13.42 19 (16.5) 18.5 (16) 18 (15.5) 17.5 (15) 19 (16.5) 18 (15.5) 17.5 (15) 16.5 (14) 26.83125 20.5 (18) 20 (17.5) 19.5 (17) 19 (16.5) 20 (17.5) 19 (16.5) 18 (15.5) 17.5 (15) 53.6625 20 (17.5) 19.5 (17) 19 (16.5) 18.5 (16) 19.5 (17) 18.5 (16) 17.5 (15) 17 (14.5) 107.325 19.5 (17) 19 (16.5) 18.5 (16) 18 (15.5) 19 (16.5) 18 (15.5) 17 (14.5) 16.5 (14) 214.65 19 (16.5) 18.5 (16) 18 (15.5) 17.5 (15) 18.5 (16) 17.5 (15) 17 (14.5) 16 (13.5) Table 3. RMS Noise (µV) vs. Sampling Rate and Gain at VA = VIO = VREF = 3V Gain of the ADC ODR (SPS) 1 2 4 8 16 32 64 128 1.6775 3.08 1.90 1.53 1.27 0.23 0.21 0.15 0.14 3.355 4.56 2.70 2.21 1.67 0.34 0.27 0.24 0.26 6.71 6.15 4.10 3.16 2.39 0.51 0.40 0.37 0.35 13.42 8.60 5.85 4.29 3.64 0.67 0.54 0.51 0.49 26.83125 3.35 2.24 1.65 1.33 0.33 0.27 0.26 0.25 53.6625 4.81 3.11 2.37 1.90 0.44 0.39 0.37 0.36 107.325 6.74 4.51 3.38 2.66 0.63 0.54 0.52 0.49 214.65 9.52 6.37 4.72 3.79 0.90 0.79 0.72 0.70 Table 4. ENOB (Noise Free Resolution) vs. Sampling Rate and Gain at VA = VIO = VREF = 5V Gain of the ADC SPS 1 2 4 8 16 32 64 128 1.6775 21.5 (19) 21.5 (19) 20.5 (18) 20 (17.5) 21 (18.5) 20.5 (18) 19.5 (17) 18.5 (16) 3.355 21 (18.5) 21 (18.5) 20 (17.5) 19.5 (17) 20.5 (18) 20 (17.5) 19 (16.5) 18 (15.5) 6.71 20.5 (18) 20 (17.5) 19.5 (17) 19 (16.5) 20 (17.5) 19.5 (17) 19 (16.5) 17.5 (15) 13.42 20 (17.5) 19.5 (17) 19 (16.5) 18.5 (16) 20 (17.5) 19 (16.5) 18 (15.5) 17.5 (15) 26.83125 21.5 (19) 21 (18.5) 20.5 (18) 20 (17.5) 21 (18.5) 20 (17.5) 19.5 (17) 18 (15.5) 53.6625 21 (18.5) 20.5 (18) 20 (17.5) 19.5 (17) 20.5 (18) 19.5 (17) 18.5 (16) 17.5 (15) 107.325 20.5 (18) 20 (17.5) 19.5 (17) 19 (16.5) 20 (17.5) 19 (16.5) 18 (15.5) 17 (14.5) 214.65 20 (17.5) 19.5 (17) 19 (16.5) 18.5 (16) 19.5 (17) 18.5 (16) 17.5 (15) 16.5 (14) Table 5. RMS Noise (µV) vs. Sampling Rate and Gain at VA = VIO = VREF = 5V Gain of the ADC SPS 1 2 4 8 16 32 64 128 1.6775 2.68 1.65 1.24 1.00 0.22 0.19 0.17 0.16 3.355 3.86 2.36 1.78 1.47 0.34 0.27 0.22 0.22 6.71 5.23 3.49 2.47 2.09 0.44 0.34 0.30 0.32 13.42 7.94 5.01 3.74 2.94 0.61 0.50 0.45 0.43 26.83125 2.90 1.86 1.34 1.08 0.29 0.24 0.23 0.23 53.6625 4.11 2.60 1.90 1.50 0.39 0.35 0.32 0.31 107.325 5.74 3.72 2.72 2.11 0.56 0.48 0.46 0.44 214.65 8.25 5.31 3.82 2.97 0.79 0.68 0.64 0.63 12 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Timing Diagrams Unless otherwise noted, specified limits apply for VA = VIO = 3.0V. Boldface limits apply for TMIN ≤ TA ≤ TMAX; the typical values apply for TA = +25°C. CSB tCH SCLK 1 2 3 1/fSCLK tCL 4 5 6 7 8 9 10 11 12 13 14 15 16 n 17 INST2 SDI MSB LSB DRDYB is driving the pin SDO is driving the pin Data Byte (s) SDO/ DRDYB MSB LSB Figure 3. Timing Diagram Symbol Parameter Conditions Min Typical fSCLK Max 10 Units MHz tCH SCLK High time 0.4 / fSCLK ns tCL SCLK Low time 0.4 / fSCLK ns CSB CSB 0.3VIO tCSHmin tCSSUmin 0.7VIO SCLK SCLK Symbol Parameter Conditions Min 0.7VIO Typical Max Units tCSSU CSB Setup time prior to an SCLK rising edge 5 ns tCSH CSB Hold time after the last rising edge of SCLK 6 ns Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 13 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com 0.9VIO 0.9VIO 0.7VIO SCLK SCLK 0.1VIO 0.1VIO t CLKR t DISU t CLKF 0.7VIO DB 0.3VIO 0.3VIO 0.7VIO SDI Symbol Parameter t DIH Conditions Min Typical Max Units tCLKR SCLK Rise time 1.15 ns tCLKF SCLK Fall time 1.15 ns tDISU SDI Setup time prior to an SCLK rising edge 5 ns tDIH SDI Hold time after an SCLK rising edge 6 ns 0.7VIO SCLK 0.3VIO CSB t DOH t DOD1 t DOA 0.9VIO 0.7VIO 0.7VIO 0.3VIO 0.3VIO Symbol Parameter 0.1VIO Conditions tDOA SDO Access time after an SCLK falling edge tDOH SDO Hold time after an SCLK falling edge tDOD1 SDO Disable time after the rising edge of CSB DB0 SDO DB DB SDO Min Typical Max Units 35 ns 5 ns 5 0.7VIO ns SCLK SCLK tDOD2 (optional, 0.3 VIO SW_OFF_TRG = 1) t DOD2 0.9 VIO 0.9VIO SDO DB0 SDO DB0 0.1 VIO 0.1VIO Symbol Parameter tDOD2 SDO Disable time after either edge of SCLK 14 Conditions Submit Documentation Feedback Min Typical Max Units 27 ns Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SCLK SNAS510P – JANUARY 2011 – REVISED MARCH 2013 8 0.9VIO 0.9VIO 9 0.3VIO SDO tDOE 0.1VIO 0.7VIO SDO 0.1VIO t DOR t DOF DB7 0.3VIO Symbol Parameter Conditions Min Typical Max Units 35 ns tDOE SDO Enable time from the falling edge of the 8th SCLK tDOR SDO Rise time (1) 7 tDOF SDO Fall time (1) 7 ns ODR ≤ 13.42 SPS 64 µs 13.42 < ODR ≤ 214.65 SPS 4 µs tDRDYB Data Ready Bar pulse at every 1/ODR second, see Figure 53 ns Specific Definitions COMMON MODE REJECTION RATIO is a measure of how well in-phase signals common to both input pins are rejected. To calculate CMRR, the change in output offset is measured while the common mode input voltage is changed. CMRR = 20 LOG(ΔCommon Input / ΔOutput Offset) EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE BITS) – says that the converter is equivalent to a perfect ADC of this (ENOB) number of bits. LMP90100’s ENOB is a DC ENOB spec, not the dynamic ENOB that is measured using FFT and SINAD. Its equation is as follows: § 2 x VREF/Gain· ENOB = log2 ¨¨ ¸¸ © RMS Noise ¹ (1) GAIN ERROR is the deviation from the ideal slope of the transfer function. INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line through the input to output transfer function. The deviation of any given code from this straight line is measured from the center of that code value. The end point fit method is used. INL for this product is specified over a limited range, per the Electrical Tables. NEGATIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output code transitions to negative full scale and (-VREF + 1LSB). NEGATIVE GAIN ERROR is the difference between the negative full-scale error and the offset error divided by (VREF / Gain). NOISE FREE RESOLUTION is a method of specifying the number of bits for a converter with noise. § 2 x VREF/Gain · NFR = log2 ¨¨ ¸¸ © Peak-to-Peak Noise¹ (2) ODR Output Data Rate. OFFSET ERROR is the difference between the differential input voltage at which the output code transitions from code 0000h to 0001h and 1 LSB. POSITIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output code transitions to positive full scale and (VREF – 1LSB). POSITIVE GAIN ERROR is the difference between the positive full-scale error and the offset error divided by (VREF / Gain). POWER SUPPLY REJECTION RATIO (PSRR) is a measure of how well a change in the analog supply voltage is rejected. PSRR is calculated from the ratio of the change in offset error for a given change in supply voltage, expressed in dB. (1) This parameter is specified by design and/or characterization and is not tested in production. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 15 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com PSRR = 20 LOG (ΔVA / ΔOutput Offset) Typical Performance Characteristics Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. Noise Measurement with Calibration at Gain = 1 250 50 230 30 VOUT ( V) VOUT ( V) Noise Measurement without Calibration at Gain = 1 210 190 170 10 -10 -30 VA = 3V VA = 3V 150 -50 0 200 400 600 TIME (ms) 800 1000 0 200 800 1000 Figure 4. Figure 5. Histogram without Calibration at Gain = 1 Histogram with Calibration at Gain = 1 1600 VA = 3V 1400 1400 1200 1200 1000 1000 COUNT COUNT 1600 800 600 400 400 200 200 170 190 210 230 VA = 3V 800 600 0 150 0 -50 250 -30 VOUT (PV) -10 10 30 50 VOUT (PV) Figure 7. Noise Measurement without Calibration at Gain = 8 Noise Measurement with Calibration at Gain = 8 40 20 35 15 30 10 VOUT ( V) VOUT ( V) Figure 6. 25 20 15 10 5 0 -5 -10 5 -15 VA = 3V 0 0 200 VA = 3V -20 400 600 TIME (ms) 800 1000 Figure 8. 16 400 600 TIME (ms) 0 200 400 600 TIME (ms) 800 1000 Figure 9. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. Histogram without Calibration at Gain = 8 2000 Histogram with Calibration at Gain = 8 2000 VA = 3V 1500 COUNT COUNT 1500 VA = 3V 1000 500 1000 500 0 -25 -15 -5 5 15 25 0 -25 35 -15 -5 5 15 25 35 VOUT (#V) Figure 11. Noise Measurement without Calibration at Gain = 128 Noise Measurement without Calibration at Gain = 128 4 4 3 3 2 2 VOUT ( V) VOUT ( V) VOUT (PV) Figure 10. 1 0 -1 -2 1 0 -1 -2 -3 -3 VA = 3V -4 0 200 VA = 3V -4 400 600 TIME (ms) 800 1000 0 200 400 600 TIME (ms) 800 1000 Figure 12. Figure 13. Histogram without Calibration at Gain = 128 Histogram with Calibration at Gain = 128 3000 VA = 3V 2500 2500 2000 2000 COUNT COUNT 3000 1500 1500 1000 1000 500 500 0 -5 -3 -1 1 3 5 VA = 3V 0 -5 -3 -1 1 VOUT (PV) VOUT (PV) Figure 14. Figure 15. 3 5 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 17 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. ENOB vs. Gain without Calibration at ODR = 13.42 SPS ENOB vs. Gain with Calibration at ODR = 13.42 SPS 21 21 VA = 3V VA = 5V 20 20 19 19 ENOB (bits) ENOB (bits) VA = 3V VA = 5V 18 17 18 17 16 16 15 1 2 4 8 16 32 15 64 128 1 2 4 8 16 32 Figure 16. Figure 17. Noise vs. Gain without Calibration at ODR = 13.42 SPS Noise vs. Gain with Calibration at ODR = 13.42 SPS 12 12 VA = 3V VA = 5V VA = 3V VA = 5V 10 RMS NOISE (#V) RMS NOISE (#V) 10 8 6 4 2 0 8 6 4 2 1 2 4 8 16 32 0 64 128 1 2 4 GAIN 8 16 32 64 128 GAIN Figure 18. Figure 19. ENOB vs. Gain without Calibration at ODR = 214.65 SPS ENOB vs. Gain with Calibration at ODR = 214.65 SPS 21 21 VA = 3V VA = 5V 20 20 19 19 ENOB (bits) ENOB (bits) VA = 3V VA = 5V 18 17 16 15 18 17 16 1 2 4 8 16 32 64 128 GAIN 15 1 2 4 8 16 32 64 128 GAIN Figure 20. 18 64 128 GAIN GAIN Figure 21. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. Noise vs. Gain without Calibration at ODR = 214.65 SPS Noise vs. Gain with Calibration at ODR = 214.65 SPS 12 12 VA = 3V VA = 5V VA = 3V VA = 5V 10 RMS NOISE (#V) RMS NOISE (#V) 10 8 6 4 2 8 6 4 2 0 0 1 2 4 8 16 32 64 128 1 2 4 GAIN 8 16 32 64 128 GAIN Figure 22. Figure 23. Offset Error vs. Temperature without Calibration at Gain = 1 Offset Error vs. Temperature with Calibration at Gain = 1 2.0 VA = 3V 250 OFFSET VOLTAGE ( V) OFFSET VOLTAGE ( V) 300 200 VA = 5V 150 VA = 3V 100 50 0 1.5 1.0 0.5 VA = 5V 0.0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 24. Figure 25. Offset Error vs. Temperature without Calibration at Gain = 8 Offset Error vs. Temperature with Calibration at Gain = 8 0.4 20 OFFSET VOLTAGE (uV) OFFSET VOLTAGE ( V) 25 VA = 5V 15 10 VA = 3V 5 0 0.2 VA = 3V 0.0 -0.2 VA = 5V -0.4 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 26. -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 27. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 19 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. Gain Error vs. Temperature without Calibration at Gain = 1 Gain Error vs. Temperature with Calibration at Gain = 1 40 160 VA = 5V GAIN ERROR (ppm) GAIN ERROR (ppm) 150 140 130 VA = 3V 120 20 VA = 5V 0 -20 VA = 3V 110 -40 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) -40 -20 Figure 28. Figure 29. Gain Error vs. Temperature without Calibration at Gain = 8 Gain Error vs. Temperature with Calibration at Gain = 8 -100 -20 -120 VA = 3V -130 -140 VA = 5V -60 -80 VA = 5V -100 -150 -160 -120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Figure 30. Figure 31. Digital Filter Frequency Response Digital Filter Frequency Response 0 0 -20 -20 -40 -40 GAIN (dB) GAIN (dB) VA = 3V -40 GAIN ERROR (ppm) GAIN ERROR (ppm) -110 -60 -80 -60 -80 1.7 SPS 3.4 SPS 6.7 SPS 13.4 SPS -100 -100 -120 26.83 SPS 53.66 SPS 107.33 SPS 214.65 SPS -120 1 10 FREQUENCY (Hz) 100 Figure 32. 20 0 20 40 60 80 100 120 TEMPERATURE (°C) 10 100 FREQUENCY (Hz) 1k Figure 33. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise noted, specified limits apply for VA = VIO = VREF = 3.0V. The maximum and minimum values apply for TA = TMIN to TMAX; the typical values apply for TA = +25°C. INL at Gain = 1 INL (ppm of FSR) 10 5 0 -5 VA = 5V, 13.4 SPS -10 -5 -4 -3 -2 -1 0 1 VIN (V) 2 3 4 5 Figure 34. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 21 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com FUNCTIONAL DESCRIPTION Throughout this datasheet, the LMP90100/LMP90099/LMP90098/LMP90097 will be referred to as the LMP90xxx. The LMP90xxx is a low-power 24-Bit ΣΔ ADC with 4 fully differential / 7 single-ended analog channels for the LMP90100/LMP90099 and 2 full differential / 4 single-ended for the LMP90098/LMP90097. Its serial data output is two’s complement format. The output data rate (ODR) ranges from 1.6775 SPS to 214.65 SPS. The serial communication for LMP90xxx is SPI, a synchronous serial interface that operates using 4 pins: chip select bar (CSB), serial clock (SCLK), serial data in (SDI), and serial data out / data ready bar (SDO/DRYDYB). True continuous built-in offset and gain background calibration is also available to improve measurement accuracy. Unlike other ADCs, the LMP90xxx’s background calibration can run without heavily impacting the input signal. This unique technique allows for positive as well as negative gain calibration and is available at all gain settings. The registers can be found in Registers, and a detailed description of the LMP90xxx are provided in the following sections. SIGNAL PATH Reference Input (VREF) The differential reference voltage VREF (VREFP – VREFN) sets the range for VIN. The muxed VREF allows the user to choose between VREF1 or VREF2 for each channel. This selection can be made by programming the VREF_SEL bit in the CHx_INPUTCN registers (CHx_INPUTCN: VREF_SEL). The default mode is VREF1. If VREF2 is used, then VIN6 and VIN7 cannot be used as inputs because they share the same pin. Refer to VREF for VREF applications information. Flexible Input MUX (VIN) LMP90xxx provides a flexible input MUX as shown in Figure 35. The input that is digitized is VIN = VINP – VINN; where VINP and VINN can be any availablie input. The digitized input is also known as a channel, where CH = VIN = VINP – VINN. Thus, there are a maximum of 4 differential channels: CH0, CH1, CH2, and CH3 for the LMP90100/LMP90099. The LMP90098/LMP90097 has a maximum of 2 differential channels: CH0 and CH1 because it does not have access to the VIN3, VIN4, and VIN5 pins. LMP90xxx can also be configured single-endedly, where the common ground is any one of the inputs. There are a maximum of 7 single-ended channels: CH0, CH1, CH2, CH3, CH4, CH5, and CH6 for the LMP90100/LMP90099 and 4: CH0, CH1, CH2, CH3 for the LMP90098/LMP90097. The input MUX can be programmed in the CHx_INPUTCN registers. For example on the LMP90100, to program CH0 = VIN = VIN4 – VIN1, go to the CH0_INPUTCN register and set: 1. VINP = 0x4 2. VINN = 0x1 22 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 VREFP1 VIN0 VIN1 VIN2 VIN3* VINP + + - ADC BUFF FGA VINN + - - VIN4* VIN5* VIN6/VREFP2 VIN7/VREFN2 VREFN1 * VIN3, VIN4, VIN5 are only available for LMP90100 and LMP90099 Figure 35. Simplified VIN Circuitry Selectable Gains (FGA & PGA) LMP90xxx provides two types of gain amplifiers: a fixed gain amplifier (FGA) and a programmable gain amplifier (PGA). FGA has a fixed gain of 16x or it can be bypassed, while the PGA has programmable gain settings of 1x, 2x, 4x, or 8x. Total gain is defined as FGA x PGA. Thus, LMP90xxx provides gain settings of 1x, 2x, 4x, 8x, 16x, 32x, 64x, or 128x with true continuous background calibration. The gain is channel specific, which means that one channel can have one gain, while another channel can have the same or a different gain. The gain can be selected by programming the CHx_CONFIG: GAIN_SEL bits. Buffer (BUFF) There is an internal unity gain buffer that can be included or excluded from the signal path. Including the buffer provides a high input impedance but increases the power consumption. When gain ≥ 16, the buffer is automatically included in the signal path. When gain < 16, including or excluding the buffer from the signal path can be done by programming the CHX_CONFIG: BUF_EN bit. Internal/External CLK Selection LMP90xxx allows two clock options: internal CLK or external CLK (crystal (XTAL) or clock source). There is an “External Clock Detection” mode, which detects the external XTAL if it is connected to XOUT and XIN. When operating in this mode, the LMP90xxx shuts off the internal clock to reduce power consumption. Below is a flow chart to help set the appropriate clock registers. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 23 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Clock Options Internal CLK External CLK Source External XTAL LMP90100 will use the internal clock No Is there a XTAL connected to XIN and XOUT? Connect a XTAL to XIN and XOUT Connect an external CLK source to the XIN/CLK pin LMP90100 will automatically detect and use the XTAL if CLK_EXT_DET = 0 (default) LMP90100 will automatically use the external CLK source Yes Set CLK_EXT_DET = 1 to E\SDVV WKH ³([WHUQDO-Clock 'HWHFWLRQ´ PRGH Set CLK_SEL = 0 to select the internal clock Figure 36. CLK Register Settings The recommended value for the external CLK is discussed in the next sections. Programmable ODRs If using the internal CLK or external CLK of 3.5717 MHz, then the output date rates (ODR) can be selected (using the ODR_SEL bit) as: 1. 13.42/8 = 1.6775 SPS 2. 13.42/4 = 3.355 SPS 3. 13.42/2 = 6.71SPS 4. 13.42 SPS 5. 214.65/8 = 26.83125 SPS 6. 214.65/4 = 53.6625 SPS 7. 214.65/2 = 107.325 SPS 8. 214.65 SPS (default) If the internal CLK is not being used and the external CLK is not 3.5717 MHz, then the ODR will be different. If this is the case, use the equation below to calculate the new ODR values. ODR_Base1 = (CLKEXT) / (266,240) ODR_Base2 = (CLKEXT) / (16,640) ODR1 = (ODR_Base1) / n, where n = 1,2,4,8 ODR2 = (ODR_Base2) / n, where n = 1,2,4,8 (3) (4) (5) (6) For example, a 3.6864 MHz XTAL or external clock has the following ODR values: ODR_Base1 = (3.6864 MHz) / (266,240) = 13.85 SPS ODR_Base2 = (3.6864 MHz) / (16,640) = 221.54 SPS ODR1 = (13.85 SPS) / n = 13.85, 6.92, 3.46, 1.73 SPS ODR2 = (221.54 SPS) / n = 221.54, 110.77, 55.38, 27.69 SPS (7) (8) (9) (10) The ODR is channel specific, which means that one channel can have one ODR, while another channel can have the same or a different ODR. 24 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Note that these ODRs are meant for a single channel conversion; the ODR needs to be divided by n for n channels scanning. For example, if the ADC were running at 214.65 SPS and four channels are being scanned, then the ODR per channel would be 214.65/4 = 53.6625 SPS. Digital Filter The LMP90xxx has a fourth order rotated sinc filter that is used to configure various ODRs and to reject power supply frequencies of 50Hz and 60Hz. The 50/60 Hz rejection is only effective when the device is operating at ODR ≤ 13.42 SPS. If the internal CLK or the external CLK of 3.5717 MHz is used, then the LMP90xxx will have the frequency response shown in Figure 37 to Figure 41. 0 1.6775 SPS 3.355 SPS -20 GAIN (dB) -40 -60 -80 -100 -120 0 12 24 36 48 60 72 84 96 108 120 FREQUENCY (Hz) Figure 37. Digital Filter Response, 1.6775 SPS and 3.355 SPS 0 6.71 SPS 13.42 SPS -20 GAIN (dB) -40 -60 -80 -100 -120 0 12 24 36 48 60 72 84 96 108 120 FREQUENCY (Hz) Figure 38. Digital Filter Response, 6.71 SPS and 13.42 SPS Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 25 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 -60 www.ti.com 13.42 SPS -70 GAIN (dB) -80 -90 -100 -110 -120 45 47 49 51 53 55 57 59 61 63 65 1800 2000 FREQUENCY (Hz) Figure 39. Digital Filter Response at 13.42 SPS 0 26.83125 SPS 53.6625 SPS GAIN (dB) -40 -80 -120 0 200 400 600 800 1000 1200 1400 1600 FREQUENCY (Hz) Figure 40. Digital Filter Response, 26.83125 SPS and 53.6625 SPS 26 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 0 107.325 SPS 214.65 SPS GAIN (dB) -40 -80 -120 0 200 400 600 800 1000 1200 1400 1600 1800 2000 FREQUENCY (Hz) Figure 41. Digital Filter Response 107.325 SPS and 214.65 SPS If the internal CLK is not being used and the external CLK is not 3.5717 MHz, then the filter response would be the same as the response shown above, but the frequency will change according to the equation: fNEW = [(CLKEXT) / 256 ] x (fOLD / 13.952k) (11) Using the equation above, an example of the filter response for a 3.5717 MHz XTAL versus a 3.6864 MHz XTAL can be seen in Figure 42. 0 Crystal = 3.5717 MHz Crystal = 3.6864 MHz -20 GAIN (dB) -40 -60 -80 -100 -120 -140 40 45 50 55 60 FREQUENCY (Hz) 65 70 Figure 42. Digital Filter Response for a 3.5717MHz versus 3.6864 MHz XTAL GPIO (D0–D6) Pins D0-D6 are general purpose input/output (GPIO) pins that can be used to control external LEDs or switches. Only a high or low value can be sourced to or read from each pin. Figure 43 shows a flowchart how these GPIOs can be programmed. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 27 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com inputs outputs Pins D0 ± D6 = Set GPIO_DIRCNx = 0 Set GPIO_DIRCNx = 1 Read the GPIO_DAT: Dx bit to determine if Dx is high or low, where 0 ” [ ” 6. Write to GPIO_DAT: Dx bit to drive Dx high or low, where 0 ” [ ” 6. Figure 43. GPIO Register Settings CALIBRATION As seen in Figure 44, there are two types of calibration: background calibration and system calibration. These calibrations are further described in the next sections. Calibration Background calibration Correction System calibration Estimation Offset Gain Figure 44. Types of Calibration Background Calibration Background calibration is the process of continuously determining and applying the offset and gain calibration coefficients to the output codes to minimize the LMP90xxx’s offset and gain errors. Background calibration is a feature built into the LMP90xxx and is automatically done by the hardware without interrupting the input signal. Four differential channels, CH0-CH3, each with its own gain and ODRs, can be calibrated to improve the accuracy. Types of Background Calibration: Figure 44 also shows that there are two types of background calibration: 1. Type 1: Correction - the process of continuously determining and applying the offset and gain calibration coefficients to the output codes to minimize the LMP90xxx’s offset and gain errors. – This method keeps track of changes in the LMP90xxx's gain and offset errors due to changes in the operating condition such as voltage, temperature, or time. 2. Type 2: Estimation - the process of determining and continuously applying the last known offset and gain calibration coefficients to the output codes to minimize the LMP90xxx’s offset and gain errors. – The last known offset or gain calibration coefficients can come from two sources. The first source is the default coefficient which is pre-determined and burnt in the device’s non-volatile memory. The second source is from a previous calibration run of Type 1: Correction. 28 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 The benefits of using type 2 calibration is a higher throughput, lower power consumption, and slightly better noise. The exact savings would depend on the number of channels being scanned, and the ODR and gain of each channel. Using Background Calibration: There are four modes of background calibration, which can be programmed using the BGCALCN bits. They are as follows: 1. BgcalMode0: Background Calibration OFF 2. BgcalMode1: Offset Correction / Gain Estimation 3. BgcalMode2: Offset Correction / Gain Correction – Follow Figure 45 to set other appropriate registers when using this mode. 4. BgcalMode3: Offset Estimation / Gain Estimation Is the channel JDLQ • 16x? No Set BGCALCN = 10b to operate the device in BgcalMode2 Yes Set CH_SCAN_SEL = 10b to operate the device in ScanMode2. Set FIRST_CH & LAST_CH accordingly. Correct FGA error? No Set FGA_BGCAL = 1 to correct for FGA error using the last known coefficients. Yes Set FGA_BGCAL = 0 (default) Figure 45. BgcalMode2 Register Settings If operating in BgcalMode2, four channels (with the same ODR) are being converted, and FGA_BGCAL = 0 (default), then the ODR is reduced by: 1. 0.19% of 1.6775 SPS 2. 0.39% of 3.355 SPS 3. 0.78% of 6.71 SPS 4. 1.54% of 13.42 SPS 5. 3.03% of 26.83125 SPS 6. 5.88% of 53.6625 SPS 7. 11.11% of 107.325 SPS 8. 20% of 214.65 SPS System Calibration The LMP90xxx provides some unique features to support easy system offset and system gain calibrations. The System Calibration Offset Registers (CHx_SCAL_OFFSET) hold the System Calibration Offset Coefficients in 24-bit, two's complement binary format. The System Calibration Gain Registers (CHx_SCAL_GAIN) hold the System Calibration Gain Coefficient in 24-bit, 1.23, unsigned, fixed-point binary format. For each channel, the System Calibration Offset coefficient is subtracted from the conversion result prior to the division by the System Calibration Gain Coefficient. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 29 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com A data-flow diagram of these coefficients can be seen in Figure 46. Uncalibrated VIN ± OFFSET [CHx_SCAL_ OFFSET] y Calibrated ADC_DOUT GAIN [CHx_SCAL_ GAIN] Figure 46. System Calibration Data-Flow Diagram There are four distinct sets of System Calibration Offset and System Calibration Gain Registers for use with CH0-CH3. CH4-CH6 reuse the registers of CH0-CH2, respectively. The LMP90xxx provides two system calibration modes that automatically fill the Offset and Gain coefficients for each channel. These modes are the System Calibration Offset Coefficient Determination mode and the System Calibration Gain Coefficient Determination mode. The System Calibration Offset Coefficient Determination mode must be entered prior to the System Calibration Gain Coefficient Determination mode, for each channel. The system zero-scale condition is a system input condition (sensor loading) for which zero (0x00_0000) systemcalibrated output code is desired. It may not, however, cause a zero input voltage at the input of the ADC. The system reference-scale condition is usually the system full-scale condition in which the system's input (or sensor's loading) would be full-scale and the desired system-calibrated output code would be 0x80_0000 (unsigned 24-bit binary). However, system full-scale condition need not cause full-scale input voltage at the input of the ADC. The system reference-scale condition is not restricted to just the system full-scale condition. In fact, it can be any arbitrary fraction of full-scale (up to 1.25 times) and the desired system-calibrated output code can be any appropriate value (up to 0xA00000). The CHx_SCAL_GAIN register must be written with the desired systemcalibrated output code (default:0x800000) before entering the System Calibration Gain Coefficient Determination mode. This helps in in-place system calibration. Below are the detailed procedures for using the System Calibration Offset Coefficient Determination and System Calibration Gain Coefficient Determination modes. System Calibration Offset Coefficient Determination mode 1. Apply system zero-scale condition to the channel (CH0/CH1/CH2/CH3). 2. Enter the System Calibration Offset Coefficient Determination mode by programming 0x1 in the SCALCN register. 3. LMP90xxx starts a fresh conversion at the selected output data rate for the selected channel. At the end of the conversion, the CHx_SCAL_OFFSET register is filled-in with the System Calibration Offset coefficient. 4. The System Calibration Offset Coefficient Determination mode is automatically exited. 5. The computed calibration coefficient is accurate only to the effective resolution of the device and will probably contain some noise. The noise factor can be minimized by computing over many times, averaging (externally) and putting the resultant value back into the register. Alternatively, select the output data rate to be 26.83 sps or 1.67 sps. System Calibration Gain Coefficient Determination mode 1. Repeat the System Calibration Offset Coefficient Determination mode to calibrate for the channel's system offset. 2. Apply the system reference-scale condition to the channel CH0/CH1/CH2/CH3. 3. In the CHx_SCAL_GAIN Register, program the expected (desired) system-calibrated output code for this condition in 24-bit unsigned format. 30 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 4. Enter the System Calibration Gain Coefficient Determination mode by programming 0x3 in the SCALCN register. 5. LMP90xxx starts a fresh conversion at the selected output data rate for the channel. At the end of the conversion, the CHx_SCAL_GAIN is filled-in (or overwritten) with the System Calibration Gain coefficient. 6. The System Calibration Gain Coefficient Determination mode is automatically exited. 7. The computed calibration coefficient is accurate only to the effective resolution of the device and will probably contain some noise. The noise factor can be minimized by computing over many times, averaging (externally) and putting the resultant value back into the register. Alternatively, select the output data rate to be 26.83 sps or 1.67 sps. Post-calibration Scaling LMP90xxx allows scaling (multiplication and shifting) for the System Calibrated result. This eases downstream processing, if any. Multiplication is done using the System Calibration Scaling Coefficient in the CHx_SCAL_SCALING register and shifting is done using the System Calibration Bits Selector in the CHx_SCAL_BITS_SELECTOR register. The System Calibration Bits Selector value should ideally be the logarithm (to the base 2) of the System Calibration Scaling Coefficient value. There are four distinct sets of System Calibration Scaling and System Calibration Bits Selector Registers for use with Channels 0-3. Channels 4-6 reuse the registers of Channels 0-2, respectively. A data-flow diagram of these coefficients can be seen in Figure 47 1/ODR D6 = drdyb 1/ODR ADC Data 1 ADC Data 2 Valid ADC_DOUT (ADC Data 2) Valid ADC_DOUT (ADC Data 1) MSB SDO LSB LSB MSB Figure 47. Post-calibration Scaling Data-Flow Diagram CHANNELS SCAN MODE There are four scan modes. These scan modes are selected using the CH_SCAN: CH_SCAN_SEL bit. The first scanned channel is FIRST_CH, and the last scanned channel is LAST_CH; they are both located in the CH_SCAN register. The CH_SCAN register is double buffered. That is, user inputs are stored in a slave buffer until the start of the next conversion during which time they are transferred to the master buffer. Once the slave buffer is written, subsequent updates are disregarded until a transfer to the master buffer happens. Hence, it may be appropriate to check the CH_SCAN_NRDY bit before programming the CH_SCAN register. ScanMode0: Single-Channel Continuous Conversion LMP90xxx continuously converts the selected FIRST_CH. Do not operate in this scan mode if gain ≥ 16 and the LMP90xxx is running in background calibration modes BgcalMode1 or BgcalMode2. If this is the case, then it is more suitable to operate the device in ScanMode2 instead. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 31 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com ScanMode1: Multiple-Channels Single Scan LMP90xxx converts one or more channels starting from FIRST_CH to LAST_CH, and then enters the stand-by state. ScanMode2: Multiple-Channels Continuous Scan LMP90xxx continuously converts one or more channels starting from FIRST_CH to LAST_CH, and then it repeats this process. ScanMode3: Multiple-Channels Continuous Scan with Burnout Currents This mode is the same as ScanMode2 except that the burnout current is provided in a serially scanned fashion (injected in a channel after it has undergone a conversion). Thus it avoids burnout current injection from interfering with the conversion result for the channel. The sensor diagnostic burnout currents are available for all four scan modes. The burnout current is further gated by the BURNOUT_EN bit for each channel. ScanMode3 is the only mode that scans multiple channels while injecting burnout currents without interfering with the signal. This is described in details in Burnout Currents. SENSOR INTERFACE LMP90100/LMP90098 contain two types of current sources: excitation currents (IB1 & IB2) and burnout currents. They are described in the next sections. IB1 & IB2 - Excitation Currents IB1 and IB2 can be used for providing currents to external sensors, such as RTDs or bridge sensors. 100µA to 1000µA, in steps of 100µA, can be sourced by programming the ADC_AUXCN: RTD_CUR_SEL bits. Refer to 3–Wire RTD to see how IB1 and IB2 can be used to source a 3-wire RTD. Burnout Currents As shown in Figure 48, the LMP90xxx contains two internal 10 µA burnout current sources, one sourcing current from VA to VINP, and the other sinking current from VINN to ground. These currents are used for sensor diagnostics and can be enabled for each channel using the CHx_INPUTCN: BURNOUT_EN bit. 32 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Burnout Current = 10 PA VIN0 VIN1 VIN2 VIN3* VINP VINN VIN4* VIN5* VIN6/VREFP2 VIN7/VREFN2 Burnout Current = 10 PA * VIN3, VIN4, VIN5 are only available for LMP90100 and LMP90099 Figure 48. Burnout Currents Burnout Current Injection: Burnout currents are injected differently depending on the channel scan mode selected. When BURNOUT_EN = 1 and the device is operating in ScanMode0, 1, or 2, the burnout currents are injected into all the channels for which the BURNOUT_EN bit is selected. This will cause problems and hence in this mode, more than one channel should not have its BURNOUT_EN bit selected. Also, the burnout current will interfere with the signal and introduce a fixed error depending on the particular external sensor. When BURNOUT_EN = 1 and the device is operating in ScanMode3, burnout currents are injected into the last sampled channel on a cyclical basis (Figure 49). In this mode, burnout currents injection is truly done in the background without affecting the accuracy of the on-going conversion. Operating in this mode is recommended. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 33 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Burnout Currents BURNOUT_EN CH0 is being sampled CH0 CH1 CH2 CH3 BURNOUT_EN CH1 is being sampled CH0 CH1 CH2 CH3 BURNOUT_EN CH2 is being sampled CH0 CH1 CH2 CH3 BURNOUT_EN CH3 is being sampled CH0 CH1 CH2 CH3 Figure 49. Burnout Currents Injection for ScanMode3 Sensor Diagnostic Flags Burnout currents can be used to verify that an external sensor is still operational before attempting to make measurements on that channel. A non-operational sensor means that there is a possibility the connection between the sensor and the LMP90xxx is open circuited, short circuited, shorted to VA or GND, overloaded, or the reference may be absent. The sensor diagnostic flags diagram can be seen in Figure 50. RAILS_FLAG Generator RAILS_FLAG Overflow detection OFLO_FLAGS VINP FGA VINN BUFF Modulator Filter RAILS_FLAG Generator ADC_DOUT RAILS_FLAG SENDIAG_THLDH and SENDIAG_THLDL SHORT_THLD_ FLAG Figure 50. Sensor Diagnostic Flags Diagram The sensor diagnostic flags are located in the SENDIAG_FLAGS register and are described in further details below. 34 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 SHORT_THLD_FLAG: The short circuit threshold flag is used to report a short-circuit condition. It is set when the output voltage (VOUT) is within the absolute Vthreshold. Vthreshold can be programmed using the 8-bit SENDIAG_THLDH register concatenated with the 8-bit SENDIAG_THLDL register. For example, assume VREF = 5V, gain = 1, SENDIAG_THLDH = 0xFA, and SENDIAG_THLDL = 0x45. In this case, Dthreshold = 0xFA45 = 64069d, and Vthreshold can be calculated as: Vthreshold = [(Dthreshold)(2)(VREF)] / [(Gain)(224)] Vthreshold = [(64069)(2)(5V)] / [(1)(224)] Vthreshold = 38.2 mV (12) (13) (14) When (-38.2mV) ≤ VOUT ≤ (38.2mV), then SHORT_THLD_FLAG = 1; otherwise, SHORT_THLD_FLAG = 0. RAILS_FLAG: The rails flag is used to detect if one of the sampled channels is within 50mV of the rails potential (VA or VSS). This can be further investigated to detect an open-circuit or short-circuit condition. If the sampled channel is near a rail, then RAILS_FLAG = 1; otherwise, RAILS_FLAG = 0. POR_AFT_LST_RD: If POR_AFT_LST_READ = 1, then there was a power-on reset since the last time the SENDIAG_FLAGS register was read. This flag's status is cleared when this bit is read, unless this bit is set again on account of another power-on-reset event in the intervening period. OFLO_FLAGS: OFLO_FLAGS is used to indicate whether the modulator is over-ranged or under-ranged. The following conditions are possible: 1. OFLO_FLAGS = 0x0: Normal Operation 2. OFLO_FLAGS = 0x1: The differential input is more than (±VREF/Gain) but is not more than ±(1.3*VREF/Gain) to cause a modulator over-range. 3. OFLO_FLAGS = 0x2: The modulator was over-ranged towards +VREF/Gain. 4. OFLO_FLAGS = 0x3: The modulator was over-ranged towards −VREF/Gain. The condition of OFLO_FLAGS = 10b or 11b can be used in conjunction with the RAILS_FLAG to determine the fault condition. SAMPLED_CH: These three bits show the channel number for which the ADC_DOUT and SENDIAG_FLAGS are available. This does not necessarily indicate the current channel under conversion because the conversion frame and computation of results from the channels are pipelined. That is, while the conversion is going on for a particular channel, the results for the previous conversion (of the same or a different channel) are available. SERIAL DIGITAL INTERFACE A synchronous 4-wire serial peripheral interface (SPI) provides access to the internal registers of LMP90xxx via CSB, SCLK, SDI, SDO/DRDYB. Register Address (ADDR) All registers are memory-mapped. A register address (ADDR) is composed of an upper register address (URA) and lower register address (LRA) as shown in Table 6. For example, ADDR 0x3A has URA=0x3 and LRA=0xA. Table 6. ADDR Map Bit [6:4] [3:0] Name URA LRA Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 35 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Register Read/Write Protocol Figure 51 shows the protocol how to write to or read from a register. Transaction 1 sets up the upper register address (URA) where the user wants to start the register-write or register-read. Transaction 2 sets the lower register address (LRA) and includes the Data Byte(s), which contains the incoming data from the master or outgoing data from the LMP90xxx. Examples of register-reads or register-writes can be found in REGISTER READ/WRITE EXAMPLES. Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Upper Address Byte (UAB) Instruction Byte 1 (INST1) [7:0] [7:3] [2:0] RA/WAB 0x0 Upper Register Address (URA) R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Instruction Byte 2 (INST2) Data Byte (s) 7 [6:5] 4 [3:0] [N:0] R/WB SZ 0 Lower Register Address (LRA) Data Byte (s) R/WB = Read/Write Data 0: Write Data 1: Read Data SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 51. Register Read/Write Protocol Streaming When writing/reading 3+ bytes, the user must operate the device in Normal Streaming mode or Controlled Streaming mode. In the Normal Streaming mode, which is the default mode, data runs continuously starting from ADDR until CSB deasserts. This mode is especially useful when programming all the configuration registers in a single transaction. See Normal Streaming Example for an example of the Normal Streaming mode. In the Controlled Streaming mode, data runs continuously starting from ADDR until the data has run through all (STRM_RANGE + 1) registers. For example, if the starting ADDR is 0x1C, STRM_RANGE = 5, then data will be written to or read from the following ADDRs: 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21. Once the data reaches ADDR 0x21, LMP90xxx will wrap back to ADDR 0x1C and repeat this process until CSB deasserts. See Controlled Streaming Example for an example of the Controlled Streaming mode. 36 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 If streaming reaches ADDR 0x7F, then it will wrap back to ADDR 0x00. Furthermore, reading back the Upper Register Address after streaming will report the Upper Register Address at the start of streaming, not the Upper Register Address at the end of streaming. To stream, write 0x3 to INST2’s SZ bits as seen in Figure 51. To select the stream type, program the SPI_STREAMCN: STRM_TYPE bit. The STRM_RANGE can also be programmed in the same register. CSB - Chip Select Bar An SPI transaction begins when the master asserts (active low) CSB and ends when the master deasserts (active high) CSB. Each transaction might be separated by a subsequent one with a CSB deassertion, but this is optional. Once CSB is asserted, it must not pulse (deassert and assert again) during a (desired) transaction. CSB can be grounded in systems where LMP90xxx is the only SPI slave. This frees the software from handling the CSB. Care has to be taken to avoid any false edge on SCLK, and while operating in this mode, the streaming transaction should not be used because exiting from this mode can only be done through a CSB deassertion. SPI Reset SPI Reset resets the SPI-Protocol State Machine by monitoring the SDI for at least 73 consecutive 1's at each SCLK rising edge. After an SPI Reset, SDI is monitored for a possible Write Instruction at each SCLK rising edge. SPI Reset will reset the Upper Address Register (URA) to 0, but the register contents are not reset. By default, SPI reset is disabled, but it can be enabled by writing 0x01 to SPI Reset Register (ADDR 0x02). DRDYB - Data Ready Bar DRDYB is a signal generated by the LMP90xxx that indicates a fresh conversion data is available in the ADC_DOUT registers. DRDYB is automatically asserted every (1/ODR) second and deasserts when ADC_DOUT is completely read out (LSB of ADC_DOUTL) (Figure 52). 1/ODR DRDYB: SDO: ... ... LSB LSB Figure 52. DRDYB Behavior for a Complete ADC_DOUT Reading If ADC_DOUT is not completely read out (Figure 53) or is not read out at all, but a new ADC_DOUT is available, then DRDYB will automatically pulse for tDRDYB second. The value for tDRDYB can be found in Timing Diagrams. 1/ODR DRDYB: tDRDYB SDO: Figure 53. DRDYB Behavior for an ADC_DOUT not Read If ADC_DOUT is being read, while the new ADC_DOUT becomes available, then the ADC_DOUT that is being read is still valid (Figure 54). DRDYB will be deasserted at the LSB of the data being read, but a consecutive read on the ADC_DOUT register will fetch the newly converted data available. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 37 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com 1/ODR D6 = drdyb 1/ODR ADC Data 1 ADC Data 2 Valid ADC_DOUT (ADC Data 2) Valid ADC_DOUT (ADC Data 1) LSB MSB SDO MSB LSB Figure 54. DRDYB Behavior for an Incomplete ADC_DOUT Reading DRDYB can also be accessed via registers using the DT_AVAIL_B bit. This bit indicates when fresh conversion data is available in the ADC_DOUT registers. If new conversion data is available, then DT_AVAIL_B = 0; otherwise, DT_AVAIL_B = 1. As opposed to the drdyb signal, a complete reading for DT_AVAIL_B occurs when the MSB of ADC_DOUTH is read out. This bit cannot be reset even if REG_AND_CNV_RST = 0xC3. DrdybCase1: Combining SDO/DRDYB with SDO_DRDYB_DRIVER = 0x00 LMP90100 uC SCLK SCLK CSB CSB SDI MOSI SDO/ DRDYB MISO INT Figure 55. DrdybCase1 Connection Diagram As shown in Figure 55, the drdyb signal and SDO can be multiplexed on the same pin as their functions are mostly complementary. In fact, this is the default mode for the SDO/DRDYB pin. Figure 56 shows a timing protocol for DrdybCase1. In this case, start by asserting CSB first to monitor a drdyb assertion. When the drdyb signal asserts, begin writing the Instruction Bytes (INST1, UAB, INST2) to read from or write to registers. Note that INST1 and UAB are omitted from the figure below because this transaction is only required if a new UAB needs to be implemented. While the CSB is asserted, DRDYB is driving the SDO/DRDYB pin unless the device is reading data, in which case, SDO will be driving the pin. If CSB is deasserted, then the SDO/DRDYB pin is High-Z. 38 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 CSB tCH SCLK 1 2 3 1/fSCLK tCL 4 5 6 7 8 9 10 11 12 13 14 15 16 n 17 INST2 SDI MSB LSB DRDYB is driving the pin SDO is driving the pin Data Byte (s) SDO/ DRDYB MSB LSB Figure 56. Timing Protocol for DrdybCase1 DrdybCase2: Combining SDO/DRDYB with SDO_DRDYB_DRIVER = 0x03 SDO/DRDYB can be made independent of CSB by setting SDO_DRDYB_DRIVER = 0x03 in the SPI Handshake Control register. In this case, DRDYB will drive the pin unless the device is reading data, independent of the state of CSB. SDO will drive the pin when CSB is asserted and the device is reading data. With this scheme, one can use SDO/DRDYB as a true interrupt source, independent of the state of CSB. But this scheme can only be used when the LMP900xx is the only device connected to the master's SPI bus because the SDO/DRDYB pin will be DRDYB even when CSB is deasserted. The timing protocol for this case can be seen in Figure 57. When drdyb asserts, assert CSB to start the SPI transaction and begin writing the Instruction Bytes (INST1, UAB, INST2) to read from or write to registers. CSB tCH SCLK 1 1/fSCLK tCL 4 5 6 7 8 9 10 11 12 13 14 15 16 n 17 INST2 SDI MSB LSB DRDYB is driving the pin SDO is driving the pin Data Byte (s) SDO/ DRDYB MSB LSB Figure 57. Timing Protocol for DrdybCase2 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 39 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com DrdybCase3: Routing DRDYB to D6 LMP90100 uC SCLK SCLK CSB CSB SDI MOSI SDO MISO Interrupt D6 = DRDYB Figure 58. DrdybCase3 Connection Diagram The drdyb signal can be routed to pin D6 by setting SPI_DRDYB_D6 high and SDO_DRDYB_DRIVER to 0x4. This is the behavior for DrdybCase3 as shown in Figure 58. The timing protocol for this case can be seen in Figure 59. Since DRDYB is separated from SDO, it can be monitored using the interrupt or polling method. If polled, the drdyb signal needs to be polled faster than tDRDYB to detect a drdyb assertion. When drdyb asserts, assert CSB to start the SPI transaction and begin writing the Instruction Bytes (INST1, UAB, INST2) to read from or write to registers. CSB SCLK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 n INST2 SDI MSB LSB Drdyb = D6 Data Byte (s) SDO High-Z MSB LSB Figure 59. Timing Protocol for DrdybCase3 Data Only Read Transaction In a data only read transaction, one can directly access the data byte(s) as soon as the CSB is asserted without having to send any instruction byte. This is useful as it brings down the latency as well as the overhead associated with the instruction byte (as well as the Upper Address Byte, if any). In order to use the data only transaction, the device must be placed in the data first mode. The following table lists transaction formats for placing the device in and out of the data first mode and reading the mode status. 40 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Table 7. Data First Mode Transactions Bit[7] Bits[6:5] Bit[4] Bits[3:0] Data Bytes Enable Data First Mode Instruction 1 11 1 1010 None Disable Data First Mode Instruction 1 11 1 1011 None Read Mode Status Transaction 1 00 1 1111 One Note that while being in the data first mode, once the data bytes in the data only read transaction are sent out, the device is ready to start on any normal (non-data-only) transaction including the Disable Data First Mode Instruction. The current status of the data first mode (enabled/disabled status) can be read back using the Read Mode Status Transaction. This transaction consists of the Read Mode Status Instruction followed by a single data byte (driven by the device). The data first mode status is available on bit [1] of this data byte. The data only read transaction allows reading up to eight consecutive registers, starting from any start address. Usually, the start address will be the address of the most significant byte of conversion data, but it could just as well be any other address. The start address and number of bytes to be read during the data only read transaction can be programmed using the DATA_ONLY_1 AND DATA_ONLY_2 registers respectively. The upper register address is unaffected by a data only read transaction. That is, it retains its setting even after encountering a data only transaction. The data only transaction uses its own address (including the upper address) from the DATA_ONLY_1 register. When in the data first mode, the SCLK must stop high before entering the Data Only Read Transaction; this transaction should be completed before the next scheduled DRDYB deassertion. Cyclic Redundancy Check (CRC) CRC can be used to ensure integrity of data read from LMP90xxx. To enable CRC, set EN_CRC high. Once CRC is enabled, the CRC value is calculated and stored in SPI_CRC_DAT so that the master device can periodically read for data comparison. Conveniently, the SPI_CRC_DAT register address is located next to the ADC_DOUT register address so that the CRC value can be easily read as part of the data set. The CRC is automatically reset when CSB or DRDYB is deasserted. The CRC polynomial is x8 + x5 + x4 + 1. The reset value of the SPI_CRC_DAT register is zero, and the final value is ones-complemented before it is sent out. Note that CRC computation only includes the bits sent out on SDO and does not include the bits of the SPI_CRC_DAT itself; thus it is okay to read SPI_CRC_DAT repeatedly. The drdyb signal normally deasserts (active high) every 1/ODR second or when the LSB of ADC_DOUTL is read. However, this behavior can be changed so that drdyb deassertion can occur after SPI_CRC_DAT is read, but not later than normal DRDYB deassertion which occurs at every 1/ODR seconds. This is done by setting bit DRDYB_AFT_CRC high. The timing protocol for CRC can be found in Figure 60. 1/ODR 1/ODR Sampling CH0 Sampling CH1 Reading SPI_CRC_DAT Reading ADC_DOUT of CH0 SDO MSB LSB MSB LSB Reading SPI_CRC_DAT Reading ADC_DOUT of CH1 MSB LSB MSB LSB Figure 60. Timing Protocol for Reading SPI_CRC_DAT If SPI_CRC_DAT read extends beyond the normal DRDYB deassertion at every 1/ODR seconds, then CRC_RST has to be set in the SPI Data Ready Bar Control Register. This is done to avoid a CRC reset at the DRDYB deassertion.Timing protocol for reading CRC with CRC_RST set is shown in Figure 61. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 41 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com 1/ODR CH0 1/ODR CH1 SDO LSB MSB MSB LSB Reading SPI_CRC_DAT Reading ADC_DOUT of CH1 Reading SPI_CRC_DAT Reading ADC_DOUT of CH0 LSB MSB MSB LSB Figure 61. Timing Protocol for Reading SPI_CRC_DAT beyond normal DRDYB deassertion at every 1/ODR seconds Follow the steps below to enable CRC: 1. Set SPI_CRC_CN = 1 (register 0x13, bit 4) to enable CRC. 2. Set DRDYB_AFT_CRC = 1 (register 0x13, bit 2) to dessert the DRDYB after CRC. 3. Compute the CRC externally, which should include CH_STS, ADC_DOUTH, ADC_DOUTM , and ADC_DOUTL. 4. Collect the data and verify the reported CRC matches with the computed CRC (step above). POWER MANAGEMENT The device can be placed in Active, Power-Down, or Stand-By state. In Power-Down, the ADC is not converting data, contents of the registers are unaffected, and there is a drastic power reduction. In Stand-By, the ADC is not converting data, but the power is only slightly reduced so that the device can quickly transition into the active state if desired. These states can be selected using the PWRCN register. When written, PWRCN brings the device into the Active, Power-Down, or Stand-By state. When read, PWRCN indicates the state of the device. The read value would confirm the write value after a small latency (approximately 15 µs with the internal CLK). It may be appropriate to wait for this latency to confirm the state change. Requests not adhering to this latency requirement may be rejected. It is not possible to make a direct transition from the power-down state to the stand-by state. This state diagram is shown below. PWRCN = 11b PWRCN = 00b Stand-by PWRCN = 01b Active PWRCN = 00b Power-down Figure 62. Active, Power-Down, Stand-by State Diagram RESET and RESTART Writing 0xC3 to the REG_AND_CNV_RST field will reset the conversion and most of the programmable registers to their default values. The only registers that will not be reset are the System Calibration Registers (CHx_SCAL_OFFSET, CHx_SCAL_GAIN) and the DT_AVAIL_B bit. 42 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 If it is desirable to reset the System Calibration Coefficient Registers, then set RESET_SYSCAL = 1 before writing 0xC3 to REG_AND_CNV_RST. If the device is operating in the “System Calibration Offset/Gain Coefficient Determination” mode (SCALCN register), then write REG_AND_CNV_RST = 0xC3 twice to get out of this mode. After a register reset, any on-going conversions will be aborted and restarted. If the device is in the power-down state, then a register reset will bring it out of the power-down state. To restart a conversion, write 1 to the RESTART bit. This bit can be used to synchronize the conversion to an external event. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 43 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com APPLICATIONS INFORMATION QUICK START This section shows step-by-step instructions to configure the LMP90xxx to perform a simple DC reading from CH0. 1. Apply VA = VIO = VREFP1 = 5V, and ground VREFN1 2. Apply VINP = ¾VREF and VINN = ¼VREF for CH0. Thus, set CH0 = VIN = VINP - VINN = ½VREF (CH0_INPUTCN register) 3. Set gain = 1 (CH0_CONFIG: GAIN_SEL = 0x0) 4. Exclude the buffer from the signal path (CH0_CONFIG: BUF_EN = 1) 5. Set the background to BgcalMode2 (BGCALCN = 0x2) 6. Select VREF1 (CH0_INPUTCN: VREF_SEL = 0) 7. To use the internal CLK, set CLK_EXT_DET = 1 and CLK_SEL = 0. 8. Follow the register read/write protocol (Figure 51) to capture ADC_DOUT from CH0. CONNECTING THE SUPPLIES VA and VIO Any ADC architecture is sensitive to spikes on the analog voltage, VA, digital input/output voltage, VIO, and ground pins. These spikes may originate from switching power supplies, digital logic, high power devices, and other sources. To diminish these spikes, the LMP90xxx’s VA and VIO pins should be clean and well bypassed. A 0.1 µF ceramic bypass capacitor and a 1 µF tantalum capacitor should be used to bypass the LMP90xxx supplies, with the 0.1 µF capacitor placed as close to the LMP90xxx as possible. Since the LMP90xxx has both external VA and VIO pins, the user has two options on how to connect these pins. The first option is to tie VA and VIO together and power them with the same power supply. This is the most cost effective way of powering the LMP90xxx but is also the least ideal because noise from VIO can couple into VA and negatively affect performance. The second option involves powering VA and VIO with separate power supplies. These supply voltages can have the same amplitude or they can be different. VREF Operation with VREF below VA is also possible with slightly diminished performance. As VREF is reduced, the range of acceptable analog input voltages is also reduced. Reducing the value of VREF also reduces the size of the LSB. When the LSB size goes below the noise floor of the LMP90xxx, the noise will span an increasing number of codes and performance will degrade. For optimal performance, VREF should be the same as VA and sourced with a clean source that is bypassed with a ceramic capacitor value of 0.1 µF and a tantalum capacitor of 10 µF. LMP90xxx also allows ratiometric connection for noise immunity reasons. A ratiometric connection is when the ADC’s VREFP and VREFN are used to excite the input device’s (i.e. a bridge sensor) voltage references. This type of connection severely attenuates any VREF ripple seen the ADC output, and is thus strongly recommended. ADC_DOUT CALCULATION The output code of the LMP90xxx can be calculated as: § (VINP - VINN) x GAIN · 23 ADC_DOUT = ± ¨ ¸ x (2 ) VREFP VREFN ¹ © Equation 1 — Output Code (15) ADC_DOUT is in 24−bit two's complement binary format. The largest positive value is 0x7F_FFFF while the largest negative value is 0x80_0000. In case of an over range the value is automatically clamped to one of these two values. Figure 63 shows the theoretical output code, ADC_DOUT, vs. analog input voltage, VIN, using the equation above. 44 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 ADC_DOUT 8,388,607d -1 LSB | | (-VREF + 1LSB) 1d | | +1LSB - 16, 777, 215d VIN (VREF - 1LSB) | | - 8,388,608d Figure 63. ADC_DOUT vs. VIN of a 24-Bit Resolution (VREF = 5.5V, Gain = 1). REGISTER READ/WRITE EXAMPLES Writing to Register Examples Using the register read/write protocol shown in Figure 51, the following example shows how to write three data bytes starting at register address (ADDR) 0x1F. After the last byte has been written to ADDR 0x21, deassert CSB to end the register-write. Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Instruction Byte 1 (INST1) Upper Address Byte (UAB) [7:0] [7:3] [2:0] 0x10 0x0 0x1 R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Data Bytes Instruction Byte 2 (INST2) 7 [6:5] 4 [3:0] [23:0] st The 1 Data Byte will be written to ADDR 0x1F, the 2 0 0x2 R/WB = Read/Write Data 0: Write Data 1: Read Data 0 0xF nd Data Byte will rd be written to ADDR 0x20, and the 3 Data Byte will be written to ADR 0x21. After this process, deassert CSB. SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 64. Register-Write Example 1 The next example shows how to write one data byte to ADDR 0x12. Since the URA for this example is the same as the last example, transaction 1 can be omitted. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 45 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Transaction 2 ± Data Access Instruction Byte 2 (INST2) Data Byte (s) 7 [6:5] 4 [3:0] [7:0] 0 0x00 0 0x2 One Data Byte will be written to ADDR 0x12. After this process, deassert CSB. R/WB = Read/Write Data 0: Write Data 1: Read Data SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 65. Register-Write Example 2 Reading from Register Example The following example shows how to read two bytes. The first byte will be read from starting ADDR 0x24, and the second byte will be read from ADDR 0x25. Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Instruction Byte 1 (INST1) Upper Address Byte (UAB) [7:0] [7:3] [2:0] 0x10 0x0 0x2 R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Instruction Byte 2 (INST2) 7 [6:5] 4 [3:0] 1 0x1 0 0x4 R/WB = Read/Write Data 0: Write Data 1: Read Data Data Bytes [15:0] 2 Data Bytes will be read from ADDR 0x24 and ADDR 0x25. After this process, deassert CSB. SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 66. Register-Read Example 46 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 STREAMING EXAMPLES Normal Streaming Example This example shows how to write six data bytes starting at ADDR 0x28 using the Normal Streaming mode. Because the default STRM_TYPE is the Normal Streaming mode, setting up the SPI_STREAMCN register can be omitted. Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Upper Address Byte (UAB) Instruction Byte 1 (INST1) [7:0] [7:3] [2:0] 0x10 0x0 0x2 R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Instruction Byte 2 (INST2) 7 [6:5] 4 Data Bytes [3:0] [47:0] st nd The 1 Data Byte will be written to ADDR 0x28, the 2 0 0x3 R/WB = Read/Write Data 0: Write Data 1: Read Data 0 0x8 Data Byte will be th written to ADDR 0x29, etc. The last and 6 Data Byte will be written to ADDR 0x2D. After this process, deassert CSB. SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 67. Normal Streaming Example Controlled Streaming Example This example shows how to read the 24-bit conversion data (ADC_DOUT) four times using the Controlled Streaming mode. The ADC_DOUT registers consist of ADC_DOUTH at ADDR 0x1A, ADC_DOUTM at ADDR 0x1B, and ADC_DOUTL at ADDR 0x1C. The first step (Figure 68) sets up the SPI_STREAMCN register. This step enters the Controlled Streaming mode by setting STRM_TYPE high in ADDR 0x03. Since three registers (ADDR 0x1A - 0x1C) need to be read, the STRM_RANGE is 2. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 47 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Instruction Byte 1 (INST1) Upper Address Byte (UAB) [7:0] [7:3] [2:0] 0x10 0x0 0x0 R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Instruction Byte 2 (INST2) Data Byte (s) 7 [6:5] 4 [3:0] [7:0] 0 0x0 0 0x3 1000_0010b R/WB = Read/Write Data 0: Write Data 1: Read Data SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 68. Setting up SPI_STREAMCN The next step shows how to perform the Controlled Streaming mode so that the master device will read ADC_DOUT from ADDR 0x1A, 0x1B, 0x1C, then wrap back to ADDR 0x1A, and repeat this process for four times. After this process, deassert CSB to end the Controlled Streaming mode. 48 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Transaction 1 ± URA Setup ± necessary only when the previous URA is different than the desired URA. Instruction Byte 1 (INST1) Upper Address Byte (UAB) [7:0] [7:3] [2:0] 0x10 0x0 0x1 R/WB = Read/Write Address 0x10: Write Address 0x90: Read Address Transaction 2 ± Data Access Instruction Byte 2 (INST2) Data Byte (s) 7 [6:5] 4 [3:0] [95:0] 1 0x3 0 0xA Read ADC_DOUTH, ADC_DOUTM, and ADC_DOUTL four times. After this process, deassert CSB. R/WB = Read/Write Data 0: Write Data 1: Read Data SZ = Size 0x0: 1 byte 0x1: 2 bytes 0x2: 3 bytes 0x3: Streaming ± 3+ bytes until CSB is de-asserted Figure 69. Controlled Streaming Example EXAMPLE APPLICATIONS 3–Wire RTD Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 49 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 + 1 PF www.ti.com 3V 3V VA VIO + 0.1 PF 0.1 PF 1 PF SCLK IB1 CSB IB1 = 1 mA SDO SDI drdyb = D6 VIN0 LMP90100 RLINE1 RTD PT-100 RCOMP = 0: D5 VIN1 RLINE2 Microcontroller IB2 = 1 mA IB2 12 pF VIN6/VREFP2 RLINE3 3.57 MHz XOUT RREF VIN7/VREFN2 XIN/CLK 12 pF Figure 70. Topology #1: 3-wire RTD Using 2 Current Sources Figure 70 shows the first topology for a 3-wire resistive temperature detector (RTD) application. Topology #1 uses two excitation current sources, IB1 and IB2, to create a differential voltage across VIN0 and VIN1. As a result of using both IB1 and IB2, only one channel (VIN0-VIN1) needs to be measured. As shown in Equation 2, the equation for this channel is IB1 x (RTD – RCOMP) assuming that RLINE1 = RLINE2. VIN0 = IB1 (RLINE1 + RTD) + (IB1 + IB2) (RLINE3 + RREF) VIN1 = IB2 (RLINE2 + RCOMP) + (IB1 + IB2) (RLINE3 + RREF) If RLINE1 = RLINE2, then: VIN = (VIN0 - VIN1) = IB1 (RTD - RCOMP) Equation 2 — VIN Equation for Topology #1 (16) The PT-100 changes linearly from 100 Ohm at 0°C to 146.07 Ohm at 120°C. If desired, choose a suitable compensating resistor (RCOMP) so that VIN can be virtually 0V at any desirable temperature. For example, if RCOMP = 100 Ohm, then at 0°C, VIN = 0V and thus a higher gain can be used. The advantage of this circuit is its ratiometric configuration, where VREF = (IB1 + IB2) x (RREF). Equation 3 shows that a ratiometric configuration eliminates IB1 and IB2 from the output equation, thus increasing the overall performance. ADC_DOUT = VIN (Gain) ( n) 2 2 VREF ADC_DOUT = [IB1( RTD - RCOMP) Gain] n (2 ) 2( IB1 + IB 2 ) RREF ADC_DOUT = >(RTD - RCOMP) Gain@ 2 (2 ) RREF ( 2 n) Equation 3 — ADC_DOUT Showing IB1 & IB2 Elimination 50 Submit Documentation Feedback (17) Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 3V 3V + + 0.1 PF 2.2 PF 0.1 PF VA 1 PF VIO SCLK IB1 IB1 = 1 mA CSB SDO/DRDYB RLINE1 SDI VIN0 Microcontroller RTD PT-100 LMP90100 D2 VIN1 RLINE2 VIN6/VREFP2 RLINE3 RREF OSC XIN/CLK VIN7/VREFN2 51: Figure 71. Topology #2: 3-wire RTD Using 1 Current Source Figure 71 shows the second topology for a 3-wire RTD application. Topology #2 shows the same connection as topology #1, but without IB2. Although this topology eliminates a current source, it requires two channel measurements as shown in Equation 4. VIN0 = IB1 (RLINE1 + RTD + RLINE3 + RREF) VIN1 = IB1 (RLINE3 + RREF) VIN6 = IB1 (RREF) CH0 = VIN0 - VIN1 = IB1 (RLINE1 + RTD) CH1 = VIN1 - VIN6 = IB1 (RLINE3) Assume RLINE1 = RLINE3, thus: CH0 - CH1 = IB1 (RTD) Equation 4 — VIN Equation for Topology #2 (18) Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 51 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Thermocouple and IC Analog Temperature 5V 2.7V VA VIO + + 0.1 PF 1 PF Thermocouple 10 nF VREFP1 SCLK + TC [ VIN4 ± VIN3] - 2.2 PF CSB SDO 2k SDI VIN3 2k 1 PF Tcold VIN4 Thot 0.1 PF D6 = DRDYB 10 nF LMP90100 Microcontroller 5V LM94022 IC Temp Sensor + 1 PF Tcold VIN5 + LM [ VIN5] - 0.1 PF XOUT VIN7 5V VREFP1 LM4140-4.1 + 1 PF 0.1 PF 0.1 PF XIN/CLK VREFN1 GND Figure 72. Thermocouple with CJC The LMP90xxx is also ideal for thermocouple temperature applications. Thermocouples have several advantages that make them popular in many industrial and medical applications. Compare to RTDs, thermistors, and IC sensors, thermocouples are the most rugged, least expensive, and can operate over the largest temperature range. A thermocouple is a sensor whose junction generates a differential voltage, VIN, that is relative to the temperature difference (Thot – Tcold). Thot is also known as the measuring junction or “hot” junction, which is placed at the measured environment. Tcold is also known as the reference or “cold” junction, which is placed at the measuring system environment. Because a thermocouple can only measure a temperature difference, it does not have the ability to measure absolute temperature. To determine the absolute temperature of the measured environment (Thot), a technique known as cold junction compensation (CJC) must be used. In a CJC technique, the “cold” junction temperature, Tcold, is sensed by using an IC temperature sensor, such as the LM94022. The temperature sensor should be placed within close proximity of the reference junction and should have an isothermal connection to the board to minimize any potential temperature gradients. Once Tcold is obtained, use a standard thermocouple look-up-table to find its equivalent voltage. Next, measure the differential thermocouple voltage and add the equivalent cold junction voltage. Lastly, convert the resulting voltage to temperature using a standard thermocouple look-up-table. For example, assume Tcold = 20°C. The equivalent voltage from a type K thermocouple look-up-table is 0.798 mV. Next, add the measured differential thermocouple voltage to the Tcold equivalent voltage. For example, if the thermocouple voltage is 4.096 mV, the total would be 0.798 mV + 4.096 mV = 4.894 mV. Referring to the type K thermocouple table gives a temperature of 119.37°C for 4.894 mV. 52 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 REGISTERS 1. If written to, RESERVED bits must be written to only 0 unless otherwise indicated. 2. Read back value of RESERVED bits and registers is unspecified and should be discarded. 3. Recommended values must be programmed and forbidden values must not be programmed where they are indicated in order to avoid unexpected results. 4. If written to, registers indicated as Reserved must have the indicated default value as shown below. Any other value can cause unexpected results. REGISTER MAP Register Name ADDR (URA & LRA) Type Default RESETCN Reset Control 0x00 WO - SPI_HANDSHAKECN SPI Handshake Control 0x01 R/W 0x00 SPI_RESET SPI Reset Control 0x02 R/W 0x00 SPI_STREAMCN SPI Stream Control 0x03 R/W 0x00 Reserved - 0x04 - 0x07 - 0x00 PWRCN Power Mode Control and Status 0x08 RO & WO 0x00 DATA_ONLY_1 Data Only Read Control 1 0x09 R/W 0x1A DATA_ONLY_2 Data Only Read Control 2 0x0A R/W 0x02 ADC_RESTART ADC Restart Conversion 0x0B WO - Reserved - 0x0C - 0x0D - 0x00 GPIO_DIRCN GPIO Direction Control 0x0E R/W 0x00 GPIO_DAT GPIO Data 0x0F RO & WO - BGCALCN Background Calibration Control 0x10 R/W 0x00 SPI_DRDYBCN SPI Data Ready Bar Control 0x11 R/W 0x03 ADC_AUXCN ADC Auxiliary Control 0x12 R/W 0x00 SPI_CRC_CN CRC Control 0x13 R/W 0x02 SENDIAG_THLD Sensor Diagnostic Threshold 1,0 0x14 - 0x15 R/W 0x0000 Reserved - 0x16 - 0x00 SCALCN System Calibration Control 0x17 R/W 0x00 ADC_DONE ADC Data Available 0x18 RO - SENDIAG_FLAGS Sensor Diagnostic Flags 0x19 RO - ADC_DOUT Conversion Data 2,1,0 0x1A - 0x1C RO - SPI_CRC_DAT CRC Data 0x1D RO & WO - CHANNEL CONFIGURATION REGISTERS (CH4 to CH6 for LMP90100/LMP9099 only) CH_STS Channel Status 0x1E RO 0x00 CH_SCAN Channel Scan Mode 0x1F R/W 0x30 CH0_INPUTCN CH0 Input Control 0x20 R/W 0x01 CH0_CONFIG CH0 Configuration 0x21 R/W 0x70 CH1_INPUTCN CH1 Input Control 0X22 R/W 0x13 CH1_CONFIG CH1 Configuration 0x23 R/W 0x70 CH2_INPUTCN CH2 Input Control 0x24 R/W 0x25 CH2_CONFIG CH2 Configuration 0x25 R/W 0x70 CH3_INPUTCN CH3 Input Control 0x26 R/W 0x37 CH3_CONFIG CH3 Configuration 0x27 R/W 0x70 CH4_INPUTCN CH4 Input Control 0x28 R/W 0x01 CH4_CONFIG CH4 Configuration 0x29 R/W 0x70 CH5_INPUTCN CH5 Input Control 0x2A R/W 0x13 CH5_CONFIG CH5 Configuration 0x2B R/W 0x70 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 53 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Register Name CH6_INPUTCN CH6 Input Control CH6_CONFIG CH6 Configuration Reserved - ADDR (URA & LRA) Type Default 0x2C R/W 0x25 0x2D R/W 0x70 0x2E - 0x2F - 0x00 SYSTEM CALIBRATION REGISTERS CH0_SCAL_OFFSET CH0 System Calibration Offset Coefficients 0x30 - 0x32 R/W 0x00_0000 CH0_SCAL_GAIN CH0 System Calibration Gain Coefficients 0x33 - 0x35 R/W 0x80_0000 CH0_SCAL_SCALING CH0 System Calibration Scaling Coefficients 0x36 R/W 0x01 CH0_SCAL_BITS_SELECT CH0 System Calibration Bits Selector OR 0x37 R/W 0x00 CH1_SCAL_OFFSET CH1 System Calibration Offset Coefficients 0x38 - 0x3A R/W 0x00_0000 CH1_SCAL_GAIN CH1 System Calibration Gain Coefficient 0x3B - 0x3D R/W 0x80_0000 CH1_SCAL_SCALING CH1 System Calibration Scaling Coefficients 0x3E R/W 0x01 0x3F R/W 0x00 CH1_SCAL_BITS_SELECT CH1 System Calibration Bits Selector OR CH2_SCAL_OFFSET CH2 System Calibration Offset Coefficients 0x40 - 0x42 R/W 0x00_0000 CH2_SCAL_GAIN CH2 System Calibration Gain Coefficient 0x43 - 0x45 R/W 0x80_0000 CH2_SCAL_SCALING CH2 System Calibration Scaling Coefficients 0x46 R/W 0x01 CH2_SCAL_BITS_SELECT CH2 System Calibration Bits Selector OR 0x47 R/W 0x00 CH3_SCAL_OFFSET CH3 System Calibration Offset Coefficients 0x48 - 0x4A R/W 0x00_0000 CH3_SCAL_GAIN CH3 System Calibration Gain Coefficient 0x4B - 0x4D R/W 0x80_0000 CH3_SCAL_SCALING CH3 System Calibration Scaling Coefficients 0x4E R/W 0x01 0x4F R/W 0x00 0x50 - 0x7F - 0x00 CH3_SCAL_BITS_SELECT CH3 System Calibration Bits Selector OR Reserved - POWER AND RESET REGISTERS Table 8. RESETCN: Reset Control (Address 0x00) Bit Bit Symbol Bit Description Register and Conversion Reset0xC3: Register and conversion reset Others: Neglected [7:0] REG_AND_CNV_ RST Table 9. SPI_RESET: SPI Reset Control (Address 0x02) Bit [0] 54 Bit Symbol Bit Description SPI_ RST SPI Reset Enable 0x0 (default): SPI Reset Disabled 0x1: SPI Reset Enabled Note:Once Written, The contents of this register are sticky. That is, the content of this register cannot be changed with subsequent write.However, a Register reset clears the register as well as the sticky status. Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Table 10. PWRCN: Power Mode Control and Status (Address 0x08) Bit Bit Symbol Bit Description [7:2] Reserved Power Control Write Only – power down mode control 0x0: Active Mode 0x1: Power-down Mode 0x3: Stand-by Mode [1:0] PWRCN Read Only – the present mode is: 0x0 (default): Active Mode 0x1: Power-down Mode 0x3: Stand-by Mode ADC REGISTERS Table 11. ADC_RESTART: ADC Restart Conversion (Address 0x0B) Bit Bit Symbol Bit Description [7:1] Reserved 0 Restart conversion 1: Restart conversion. RESTART Table 12. ADC_AUXCN: ADC Auxiliary Control (Address 0x12) Bit Bit Symbol Bit Description 7 Reserved - 6 RESET_SYSCAL The System Calibration registers (CHx_SCAL_OFFSET and CHx_SCAL_GAIN) are: 0 (default): preserved even when "REG_AND_CNV_ RST" = 0xC3. 1: reset by setting "REG_AND_CNV_ RST" = 0xC3. 5 CLK_EXT_DET External clock detection 0 (default): "External Clock Detection" is operational 1: "External-Clock Detection" is bypassed 4 CLK_SEL Clock select – only valid if CLK_EXT_DET = 1 0 (default): Selects internal clock 1: Selects external clock RTD_CUR_SEL [3:0] (LMP90100 and LMP90098 only) Selects RTD Current as follows: 0x0 (default): 0 µA 0x1: 100 µA 0x2: 200 µA 0x3: 300 µA 0x4: 400 µA 0x5: 500 µA 0x6: 600 µA 0x7: 700 µA 0x8: 800 µA 0x9: 900 µA 0xA: 1000 µA Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 55 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Table 13. ADC_DONE: ADC Data Available (Address 0x18) Bit Bit Symbol Bit Description Data Available – indicates if new conversion data is available 0x00 − 0xFE: Available 0xFF: Not available [7:0] DT_AVAIL_B Table 14. ADC_DOUT: 24-bit Conversion Data (two’s complement) (Address 0x1A - 0x1C) Address Name Register Description 0x1A ADC_DOUTH ADC Conversion Data [23:16] 0x1B ADC_DOUTM ADC Conversion Data [15:8] 0x1C ADC_DOUTL ADC Conversion Data [7:0] Note: Repeat reads of these registers are allowed as long as such reads are spaced apart by at least 72 µs. CHANNEL CONFIGURATION REGISTERS Table 15. CH_STS: Channel Status (Address 0x1E) Bit Bit Symbol Bit Description [7:2] Reserved - 1 CH_SCAN_NRDY Channel Scan Not Ready – indicates if it is okay to program CH_SCAN 0: Update not pending, CH_SCAN register is okay to program 1: Update pending, CH_SCAN register is not ready to be programmed 0 INV_OR_RPT_RD_STS Invalid or Repeated Read Status 0: ADC_DOUT just read was valid and hitherto unread 1: ADC_DOUT just read was either invalid (not ready) or there was a repeated read. Table 16. CH_SCAN: Channel Scan Mode (Address 0x1F) Bit Bit Symbol [7:6] CH_SCAN_SEL Bit Description Channel Scan Select 0x0 (default): ScanMode0: Single-Channel Continuous Conversion 0x1: ScanMode1: One or more channels Single Scan 0x2: ScanMode2: One or more channels Continuous Scan 0x3: ScanMode3: One or more channels Continuous Scan with Burnout Currents Last channel for conversion 0x0: CH0 0x1: CH1 0x2: CH2 LAST_CH 0x3: CH3 [5:3] (CH4 to CH6 for LMP90100 and 0x4: CH4 LMP90099 only) 0x5: CH5 0x6 (default): CH6 Note: LAST_CH cannot be smaller than FIRST_CH. For example, if LAST_CH = CH5, then FIRST_CH cannot be CH6. If 0x7 is written it is ignored. 56 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Table 16. CH_SCAN: Channel Scan Mode (Address 0x1F) (continued) Bit Bit Symbol Bit Description Starting channel for conversion 0x0 (default): CH0 0x1: CH1 0x2: CH2 FIRST_CH 0x3: CH3 [2:0] (CH4 to CH6 for LMP90100 and 0x4: CH4 LMP90099 only) 0x5: CH5 0x6: CH6 Note: FIRST_CH cannot be greater than LAST_CH. For example, if FIRST_CH = CH1, then LAST_CH cannot be CH0. If 0x7 is written it is ignored. Note: While writing to the CH_SCAN register, if 0x7 is written to FIRST_CH or LAST_CH the write to the entire CH_SCAN register is ignored. Table 17. CHx_INPUTCN: Channel Input Control (CH4 to CH6 for LMP90100/LMP9099 only) (1) Bit Bit Symbol Bit Description 7 BURNOUT_EN Enable sensor diagnostic 0 (default): Disable Sensor Diagnostics current injection for this Channel 1: Enable Sensor Diagnostics current injection for this Channel 6 VREF_SEL Select the reference 0 (Default): Select VREFP1 and VREFN1 1: Select VREFP2 and VREFN2 VINP Positive input select 0x0: VIN0 0x1: VIN1 0x2: VIN2 0x3: VIN3 (LMP90100/LMP90099 only) 0x4: VIN4 (LMP90100/LMP90099 only) 0x5: VIN5 (LMP90100/LMP90099 only) 0x6: VIN6 0x7: VIN7 Note: to see the default values for each channel, refer to the table below. VINN Negative input select 0x0: VIN0 0x1: VIN1 0x2: VIN2 0x3: VIN3 (LMP90100/LMP90099 only) 0x4: VIN4 (LMP90100/LMP90099 only) 0x5: VIN5 (LMP90100/LMP90099 only) 0x6: VIN6 0x7: VIN7 Note: to see the default values for each channel, refer to the table below. [5:3] [2:0] (1) Register Address (hex): (a) CH0: 0x20 (b) CH1: 0X22 (c) CH2: 0x24 (d) CH3: 0x26 (e) CH4: 0x28 (f) CH5: 0x2A (g) CH6: 0x2C Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 57 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Table 18. Default VINx for CH0-CH6 VINP VINN CH0 VIN0 VIN1 CH1 VIN2 VIN3 (LMP90100/LMP90099 only) CH2 VIN4 (LMP90100/LMP90099 only) VIN5 (LMP90100/LMP90099 only) CH3 VIN6 VIN7 CH4 (LMP90100/LMP90099 only) VIN0 VIN1 CH5 (LMP90100/LMP90099 only) VIN2 VIN3 CH6 (LMP90100/LMP90099 only) VIN4 VIN5 Table 19. CHx_CONFIG: Channel Configuration (CH4 to CH6 LMP90100/LMP90099 only) (1) Bit 7 Bit Symbol Bit Description Reserved - [6:4] ODR_SEL ODR Select 0x0: 13.42 / 8 = 1.6775 SPS 0x1: 13.42 / 4 = 3.355 SPS 0x2: 13.42 / 2 = 6.71 SPS 0x3: 13.42 SPS 0x4: 214.65 / 8 = 26.83125 SPS 0x5: 214.65 / 4 = 53.6625 SPS 0x6: 214.65 / 2 = 107.325 SPS 0x7(default): 214.65 SPS [3:1] GAIN_SEL Gain Select 0x0 (default): 1 (FGA OFF) 0x1: 2 (FGA OFF) 0x2: 4 (FGA OFF) 0x3: 8 (FGA OFF) 0x4: 16 (FGA ON) 0x5: 32 (FGA ON) 0x6: 64 (FGA ON) 0x7: 128 (FGA ON) 0 (1) Enable/Disable the buffer 0 (default): Include the buffer in the signal path 1: Exclude the buffer from the signal path Note: When gain ≥ 16, the buffer is automatically included in the signal path irrespective of this bit. BUF_EN Register Address (hex): (a) CH0: 0x21 (b) CH1: 0x23 (c) CH2: 0x25 (d) CH3: 0x27 (e) CH4: 0x29 (f) CH5: 0x2B (g) CH6: 0x2D CALIBRATION REGISTERS Table 20. BGCALCN: Background Calibration Control (Address 0x10) Bit Bit Symbol Bit Description [7:2] Reserved - [1:0] BGCALN Background calibration control – selects scheme for continuous background calibration. 0x0 (default): BgcalMode0: Background Calibration OFF 0x1: BgcalMode1: Offset Correction / Gain Estimation 0x2: BgcalMode2: Offset Correction / Gain Correction 0x3: BgcalMode3: Offset Estimation / Gain Estimation 58 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Table 21. SCALCN: System Calibration Control (Address 0x17) Bit Bit Symbol Bit Description [7:2] Reserved System Calibration Control When written, set SCALCN to: 0x0 (default): Normal Mode 0x1: “System Calibration Offset Coefficient Determination” mode 0x2: “System Calibration Gain Coefficient Determination” mode 0x3: Reserved [1:0] SCALCN When read, this bit indicates the system calibration mode is in: 0x0: Normal Mode 0x1: "System Calibration Offset Coefficient Determination" mode 0x2: "System Calibration Gain Coefficient Determination" mode 0x3: Reserved Note: when read, this bit will indicate the current System Calibration status. Since this coefficient determination mode will only take 1 conversion cycle, reading this register will only return 0x00, unless this register is read within 1 conversion window. Table 22. CHx_SCAL_OFFSET: CH0-CH3 System Calibration Offset Registers (Two's-Complement) ADDR Name Description 0x48 CHx_SCAL_OFFSETH System Calibration Offset Coefficient Data [23:16] 0x49 CHx_SCAL_OFFSETM System Calibration Offset Coefficient Data [15:8] 0x4A CHx_SCAL_OFFSETL System Calibration Offset Coefficient Data[7:0] CH0 CH1 CH2 CH3 0x30 0x38 0x40 0x31 0x39 0x41 0x32 0x3A 0x42 Table 23. CHx_SCAL_GAIN: CH0-CH3 System Calibration Gain Registers (Fixed Point 1.23 Format) ADDR Name Description 0x4B CHx_SCAL_GAINH System Calibration Gain Coefficient Data [23:16] 0x44 0x4C CHx_SCAL_GAINM System Calibration Gain Coefficient Data [15:8] 0x45 0x4D CHx_SCAL_GAINL System Calibration Gain Coefficient Data[7:0] CH0 CH1 CH2 CH3 0x33 0x3B 0x43 0x34 0x3C 0x35 0x3D Table 24. CHx_SCAL_SCALING: CH0-CH3 System Calibration Scaling Coefficient Registers ADDR CH0 CH1 CH2 CH3 0x36 0x3E 0x46 0x4E Name Description CHx_SCAL_SCALING System Calibration Scaling Coefficient Data [5:0] Table 25. CHx_SCAL_BITS_SELECTOR: CH0-CH3 System Calibration Bits Selector Registers ADDR CH0 CH1 CH2 CH3 0x37 0x3F 0x47 0x4F Name Description CHx_SCAL_BITS_SELECTOR System Calibration Bits Selection Data [2:0] SENSOR DIAGNOSTIC REGISTERS Table 26. SENDIAG_THLD: Sensor Diagnostic Threshold (Address 0x14 - 0x15) Address Name Register Description 0x14 SENDIAG_THLDH Sensor Diagnostic threshold [15:8] 0x15 SENDIAG_THLDL Sensor Diagnostic threshold [7:0] Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 59 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Table 27. SENDIAG_FLAGS: Sensor Diagnostic Flags (Address 0x19) Bit Bit Symbol Bit Description 7 SHORT_THLD_ FLAG Short Circuit Threshold Flag = 1 when the absolute value of VOUT is within the absolute threshold voltage set by SENDIAG_THLDH and SENDIAG_THLDL. 6 RAILS_FLAG Rails Flag = 1 when at least one of the inputs is near rail (VA or GND). 5 POR_AFT_LST_RD Power-on-reset after last read = 1 when there was a power-on-reset event since the last time the SENDIAG_FLAGS register was read. [4:3] OFLO_FLAGS Overflow flags 0x0: Normal operation 0x1: The modulator was not overranged, but ADC_DOUT got clamped to 0x7f_ffff (positive fullscale) or 0x80_0000 (negative full scale) 0x2: The modulator was over-ranged (VIN > 1.3*VREF/GAIN) 0x3: The modulator was over-ranged (VIN < -1.3*VREF/GAIN) [2:0] SAMPLED_CH Channel Number – the sampled channel for ADC_DOUT and SENDIAG_FLAGS. SPI REGISTERS Table 28. SPI_HANDSHAKECN: SPI Handshake Control (Address 0x01) Bit Bit Symbol Bit Description [7:4] Reserved SDO/DRDYB Driver – sets who is driving the SDO/DRYB pin [3:1] SDO_DRDYB_ DRIVER Whenever CSB is Asserted and the Device is Reading ADC_DOUT Whenever CSB is Asserted and the Device is Not Reading ADC_DOUT CSB is Deasserted 0x0 (default) SDO is driving DRDYB is driving High-Z 0x3 SDO is driving DRDYB is driving DRDYB is driving 0x4 SDO is driving High-Z High-Z Others Forbidden Switch-off trigger - refers to the switching of the output drive from the slave to the master. 0 (default): SDO will be high-Z after the last (16th, 24th, 32nd, etc) rising edge of SCLK. This option allows time for the slave to transfer control back to the master at the end of the frame. 0 SW_OFF_TRG 1: SDO’s high-Z is postponed to the subsequent falling edge following the last (16th, 24th, 32nd, etc) rising edge of SCLK. This option provides additional hold time for the last bit, DB0, in nonstreaming read transfers. Table 29. SPI_STREAMCN: SPI Streaming Control (Address 0x03) Bit 7 Bit Symbol Bit Description STRM_TYPE Stream type 0 (default): Normal Streaming mode 1: Controlled Streaming mode Stream range – selects Range for Controlled Streaming mode Default: 0x00 [6:0] STRM_ RANGE Table 30. DATA_ONLY_1: Data Only Read Control 1 (Address 0x09) Bit Symbol Bit Description 7 Bit Reserved - [6:0] DATA_ONLY_ADR Start address for the Data Only Read Transaction Default: 0x1A Please refer to the description of DT_ONLY_SZ in DATA_ONLY_2 register. 60 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 Table 31. DATA_ONLY_2: Data Only Read Control 2 (Address 0x0A) Bit [7:3] Bit Symbol Bit Description Reserved - DATA_ONLY_SZ Number of bytes to be read out in Data Only mode. A value of 0x0 means read one byte and 0x7 means read 8 bytes. Default: 0x2 [2:0] Table 32. SPI_DRDYBCN: SPI Data Ready Bar Control (Address 0x11) Bit Bit Symbol Bit Description 7 SPI_DRDYB_D6 Enable DRDYB on D6 0 (default): D6 is a GPIO 1: D6 = drdyb signal 6 Reserved - 5 CRC_RST CRC Reset 0 (default): Enable CRC reset on DRDYB deassertion 1: Disbale CRC reset on DRDYB deassertion 4 Reserved - FGA_BGCAL Gain background calibration 0 (default): Correct FGA gain error. This is useful only if the device is operating in BgcalMode2 and ScanMode2 or ScanMode3. 1: Correct FGA gain error using the last known coefficients. 3 [2:0] Reserved Default - 0x3 (do not change this value) Table 33. SPI_CRC_CN: CRC Control (Address 0x13) Bit Bit Symbol [7:5] Reserved Bit Description - 4 EN_CRC Enable CRC 0 (default): Disable CRC 1: Enable CRC 3 Reserved Default - 0x0 (do not change this value) 2 DRDYB_AFT_CRC DRDYB After CRC 0 (default): DRDYB is deasserted (active high) after ADC_DOUTL is read. 1: DRDYB is deasserted after SPI_CRC_DAT (which follows ADC_DOUTL), is read. [1:0] Reserved - Table 34. SPI_CRC_DAT: CRC Data (Address 0x1D) Bit Bit Symbol Bit Description CRC Data [7:0] CRC_DAT When written, this register reset CRC: Any Value: Reset CRC When read, this register indicates the CRC data. GPIO REGISTERS Table 35. GPIO_DIRCN: GPIO Direction (Address 0x0E) Bit 7 Bit Symbol Bit Description Reserved - Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 61 LMP90100 SNAS510P – JANUARY 2011 – REVISED MARCH 2013 www.ti.com Table 35. GPIO_DIRCN: GPIO Direction (Address 0x0E) (continued) Bit x Bit Symbol Bit Description GPIO direction control – these bits are used to control the direction of each General Purpose Input/Outputs (GPIO) pins D0 - D6. 0 (default): Dx is an Input 1: Dx is an Output where 0 ≤ x ≤ 6. GPIO_DIRCNx For example, writing a 1 to bit 6 means D6 is an Output. Note: If D6 is used for DRDYB, then it cannot be used for GPIO. Table 36. GPIO_DAT: GPIO Data (Address 0x0F) Bit 7 Bit Symbol Bit Description Reserved Write Only - when GPIO_DIRCNx = 0 0: Dx is LO 1: Dx is HI x Dx Read Only - when GPIO_DIRCNx = 1 0: Dx driven LO 1: Dx driven HI where 0 ≤ x ≤ 6. For example, writing a 0 to bit 4 means D4 is LO. It is okay to Read the GPIOs that are configured as outputs and write to GPIOs that are configured as inputs. Reading the GPIOs that are outputs would return the current value on those GPIOs, and writing to the GPIOs that are inputs are neglected 62 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 LMP90100 www.ti.com SNAS510P – JANUARY 2011 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision O (March 2013) to Revision P • Page Changed layout of National Data Sheet to TI format .......................................................................................................... 62 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LMP90100 63 PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) (4) LMP90097MH/NOPB ACTIVE HTSSOP PWP 28 48 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90097 MH LMP90097MHE/NOPB ACTIVE HTSSOP PWP 28 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90097 MH LMP90097MHX/NOPB ACTIVE HTSSOP PWP 28 2500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90097 MH LMP90098MH/NOPB ACTIVE HTSSOP PWP 28 48 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90098 MH LMP90098MHE/NOPB ACTIVE HTSSOP PWP 28 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90098 MH LMP90098MHX/NOPB ACTIVE HTSSOP PWP 28 2500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90098 MH LMP90099MH/NOPB ACTIVE HTSSOP PWP 28 48 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90099 MH LMP90099MHE/NOPB ACTIVE HTSSOP PWP 28 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90099 MH LMP90099MHX/NOPB ACTIVE HTSSOP PWP 28 2500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90099 MH LMP90100MH/NOPB ACTIVE HTSSOP PWP 28 48 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90100 MH LMP90100MHE/NOPB ACTIVE HTSSOP PWP 28 250 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90100 MH LMP90100MHX/NOPB ACTIVE HTSSOP PWP 28 2500 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 LMP90100 MH (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 26-Mar-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) LMP90097MHE/NOPB HTSSOP PWP 28 250 178.0 16.4 LMP90097MHX/NOPB HTSSOP PWP 28 2500 330.0 LMP90098MHE/NOPB HTSSOP PWP 28 250 178.0 LMP90098MHX/NOPB HTSSOP PWP 28 2500 LMP90099MHE/NOPB HTSSOP PWP 28 LMP90099MHX/NOPB HTSSOP PWP LMP90100MHE/NOPB HTSSOP PWP LMP90100MHX/NOPB HTSSOP PWP 6.8 10.2 1.6 8.0 16.0 Q1 16.4 6.8 10.2 1.6 8.0 16.0 Q1 16.4 6.8 10.2 1.6 8.0 16.0 Q1 330.0 16.4 6.8 10.2 1.6 8.0 16.0 Q1 250 178.0 16.4 6.8 10.2 1.6 8.0 16.0 Q1 28 2500 330.0 16.4 6.8 10.2 1.6 8.0 16.0 Q1 28 250 178.0 16.4 6.8 10.2 1.6 8.0 16.0 Q1 28 2500 330.0 16.4 6.8 10.2 1.6 8.0 16.0 Q1 Pack Materials-Page 1 W Pin1 (mm) Quadrant PACKAGE MATERIALS INFORMATION www.ti.com 26-Mar-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMP90097MHE/NOPB HTSSOP PWP LMP90097MHX/NOPB HTSSOP PWP 28 250 213.0 191.0 55.0 28 2500 367.0 367.0 38.0 LMP90098MHE/NOPB HTSSOP PWP LMP90098MHX/NOPB HTSSOP PWP 28 250 213.0 191.0 55.0 28 2500 367.0 367.0 LMP90099MHE/NOPB HTSSOP 38.0 PWP 28 250 213.0 191.0 55.0 LMP90099MHX/NOPB LMP90100MHE/NOPB HTSSOP PWP 28 2500 367.0 367.0 38.0 HTSSOP PWP 28 250 213.0 191.0 LMP90100MHX/NOPB 55.0 HTSSOP PWP 28 2500 367.0 367.0 38.0 Pack Materials-Page 2 MECHANICAL DATA PWP0028A MXA28A (Rev D) www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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