Sample & Buy Product Folder Support & Community Tools & Software Technical Documents LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 LMP91000 Sensor AFE System: Configurable AFE Potentiostat for Low-Power ChemicalSensing Applications 1 Features 3 Description * * * * * The LMP91000 is a programmable analog front-end (AFE) for use in micro-power electrochemical sensing applications. It provides a complete signal path solution between a sensor and a microcontroller that generates an output voltage proportional to the cell current. The LMP91000's programmability enables it to support multiple electrochemical sensors such as 3-lead toxic gas sensors and 2-lead galvanic cell sensors with a single design as opposed to the multiple discrete solutions. The LMP91000 supports gas sensitivities over a range of 0.5 nA/ppm to 9500 nA/ppm. It also allows for an easy conversion of current ranges from 5 A to 750 A full scale. 1 * * * * * * * * * * Typical Values, TA = 25C Supply Voltage 2.7 V to 5.25 V Supply Current (Average Over Time) <10 A Cell Conditioning Current Up to 10 mA Reference Electrode Bias Current (85C) 900pA (max) Output Drive Current 750 A Complete Potentiostat Circuit-to-Interface to Most Chemical Cells Programmable Cell Bias Voltage Low-Bias Voltage Drift Programmable TIA gain 2.75 k to 350 k Sink and Source Capability I2C Compatible Digital Interface Ambient Operating Temperature -40C to 85C Package 14-Pin WSON Supported by WEBENCH(R) Sensor AFE Designer The LMP91000's adjustable cell bias and transimpedance amplifier (TIA) gain are programmable through the I2C interface. The I2C interface can also be used for sensor diagnostics. An integrated temperature sensor can be read by the user through the VOUT pin and used to provide additional signal correction in the C or monitored to verify temperature conditions at the sensor. The LMP91000 is optimized for micro-power applications and operates over a voltage range of 2.7 to 5.25 V. The total current consumption can be less than 10 A. Further power savings are possible by switching off the TIA amplifier and shorting the reference electrode to the working electrode with an internal switch. 2 Applications * * * Chemical Species Identification Amperometric Applications Electrochemical Blood Glucose Meter Device Information(1) PART NUMBER LMP91000 PACKAGE WSON (14) BODY SIZE (NOM) 4.00 mm x 4.00 mm (1) For all available packages, see the orderable addendum at the end of the datasheet. Simplified Application Schematic VDD VREF SCL LMP91000 3-Lead Electrochemical Cell CE + A1 VARIABLE BIAS VREF DIVIDER I2C INTERFACE AND CONTROL REGISTERS SDA CONTROLLER MENB - CE RE RE TEMP SENSOR WE WE VOUT + - DGND TIA RLoad RTIA C1 C2 AGND 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 4 4 4 4 5 7 8 9 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics .......................................... I2C Interface .............................................................. Timing Requirements ............................................... Typical Characteristics .............................................. Detailed Description ............................................ 13 7.1 Overview ................................................................. 13 7.2 Functional Block Diagram ....................................... 13 7.3 7.4 7.5 7.6 8 Feature Description................................................. Device Functional Modes........................................ Programming .......................................................... Registers Maps ...................................................... 13 19 20 21 Application and Implementation ........................ 24 8.1 Application Information............................................ 24 8.2 Typical Application ................................................. 26 9 Power Supply Recommendations...................... 28 9.1 Power Consumption................................................ 28 10 Layout................................................................... 29 10.1 Layout Guidelines ................................................. 29 10.2 Layout Example .................................................... 29 11 Device and Documentation Support ................. 30 11.1 Trademarks ........................................................... 30 11.2 Electrostatic Discharge Caution ............................ 30 11.3 Glossary ................................................................ 30 12 Mechanical, Packaging, and Orderable Information ........................................................... 30 4 Revision History Changes from Revision H (March 2013) to Revision I * Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ................................................................................................. 3 Changes from Revision G (March 2013) to Revision H * 2 Page Page Changed layout of National Data Sheet to TI format ........................................................................................................... 27 Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 5 Pin Configuration and Functions 14-Pin WSON Top View DGND 1 14 CE MENB RE SCL WE SDA VREF DAP NC C1 VDD C2 AGND 7 8 VOUT Pin Functions PIN I/O DESCRIPTION NAME NO. DGND 1 G Connect to ground MENB 2 I Module Enable, Active-Low SCL 3 I Clock signal for I2C compatible interface SDA 4 I/O Data for I2C compatible interface NC 5 N/A Not Internally Connected VDD 6 P Supply Voltage AGND 7 G Ground VOUT 8 O Analog Output C2 9 N/A External filter connector (Filter between C1 and C2) C1 10 N/A External filter connector (Filter between C1 and C2) VREF 11 I Voltage Reference input WE 12 I Working Electrode. Output to drive the Working Electrode of the chemical sensor RE 13 I Reference Electrode. Input to drive Counter Electrode of the chemical sensor CE 14 I Counter Electrode. Output to drive Counter Electrode of the chemical sensor DAP -- N/C Connect to AGND Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 3 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature (unless otherwise noted) (1) MAX UNIT Voltage between any two pins MIN 6.0 V Current through VDD or VSS 50 mA Current sunk and sourced by CE pin 10 mA Current out of other pins (2) 5 mA 150 C 150 C Junction Temperature (3) Storage temperature (1) (2) (3) -65 Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. All non-power pins of this device are protected against ESD by snapback devices. Voltage at such pins will rise beyond absmax if current is forced into pin. The maximum power dissipation is a function of TJ(MAX), RJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is PDMAX = (TJ(MAX) - TA)/ JA All numbers apply for packages soldered directly onto a PCB. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) 2000 Charged-device model (CDM), per JEDEC specification JESD22C101 (2) 1000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions MIX MAX Supply Voltage VS= (VDD - AGND) 2.7 5.25 V Temperature Range (1) -40 85 C (1) UNIT The maximum power dissipation is a function of TJ(MAX), RJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is PDMAX = (TJ(MAX) - TA)/ JA All numbers apply for packages soldered directly onto a PCB. 6.4 Thermal Information LMP91000 THERMAL METRIC (1) WSON UNIT 14 PINS RJA (1) 4 Package Thermal Resistance 44 C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 6.5 Electrical Characteristics Unless otherwise specified, TA = 25C, VS=(VDD - AGND), VS = 3.3 V and AGND = DGND = 0 V, VREF = 2.5 V, Internal Zero = 20% VREF. (1) PARAMETER TEST CONDITIONS MIN (2) TYP (3) MAX (2) 10 13.5 UNIT POWER SUPPLY SPECIFICATION 3-lead amperometric cell mode MODECN = 0x03 -40 to 80C (please verify that the degree is correct) 15 Standby mode MODECN = 0x02 6.5 -40 to 80C 8 10 Temperature Measurement mode with TIA OFF MODECN = 0x06 11.4 -40 to 80C IS Supply Current 13.5 15 A Temperature Measurement mode with TIA ON MODECN = 0x07 14.9 -40 to 80C 18 20 2-lead ground-referred galvanic cell mode VREF=1.5 V 6.2 MODECN = 0x01 8 -40 to 80C 9 Deep Sleep mode MODECN = 0x00 0.6 -40 to 80C 0.85 1 POTENTIOSTAT Bias_RW Bias Programming range (differential voltage between RE pin and WE pin) Bias Programming Resolution Percentage of voltage referred to VREF or VDD 24% First two smallest step 1 All other steps 2% VDD = 2.7 V Internal Zero 50% VDD IRE Input bias current at RE pin -40 to 80C -40 to 80C AOL_A1 (2) (3) (4) -90 90 -900 sink 750 source 750 Minimum charging capability (4) sink 10 source 10 Open-loop voltage gain of control loop op amp (A1) pA 900 Minimum operating current capability A mA 300 mV VCE Vs-300 mV; -750 A ICE 750 A -40 to 80C (1) 90 800 VDD = 5.25 V Internal Zero 50% VDD ICE -90 -800 dB 104 120 Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. Limits are 100% production tested at 25C. Limits over the operating temperature range are specified through correlations using statistical quality control (SQC) method. Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will also depend on the application and configuration. The typical values are not tested and are not specified on shipped production material. At such currents no accuracy of the output voltage can be expected. Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 5 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com Electrical Characteristics (continued) Unless otherwise specified, TA = 25C, VS=(VDD - AGND), VS = 3.3 V and AGND = DGND = 0 V, VREF = 2.5 V, Internal Zero = 20% VREF.(1) PARAMETER en_RW Low Frequency integrated noise between RE pin and WE pin MIN (2) TEST CONDITIONS 0.1 Hz to 10 Hz, Zero Bias TYP (3) MAX (2) UNIT 3.4 (5) Vpp 0.1 Hz to 10 Hz, with Bias 5.1 (5) (6) 0% VREF Internal Zero=20% VREF 0% VREF Internal Zero=50% VREF -550 550 1% VREF -575 575 2% VREF -610 610 0% VREF Internal Zero=67% VREF VOS_RW WE Voltage Offset referred to RE 4% VREF -750 750 BIAS polarity (7) 6% VREF -840 840 -40 to 80C 8% VREF -930 930 10% VREF -1090 1090 12% VREF -1235 1235 14% VREF -1430 1430 16% VREF -1510 1510 18% VREF -1575 1575 20% VREF -1650 1650 22% VREF -1700 1700 24% VREF -1750 1750 -4 4 1% VREF -4 4 2% VREF -4 4 4% VREF -5 5 6% VREF -5 5 8% VREF -5 5 10% VREF -6 6 12% VREF -6 6 14% VREF -7 7 16% VREF -7 7 18% VREF -8 8 20% VREF -8 8 22% VREF -8 8 24% VREF -8 8 V 0% VREF Internal Zero=20% VREF 0% VREF Internal Zero=50% VREF 0% VREF Internal Zero=67% VREF TcVOS_RW (5) (6) (7) (8) 6 WE Voltage Offset Drift referred to RE from -40C to 85C (8) BIAS polarity (7) V/C This parameter includes both A1 and TIA's noise contribution. In case of external reference connected, the noise of the reference has to be added. For negative bias polarity the Internal Zero is set at 67% VREF. Offset voltage temperature drift is determined by dividing the change in VOS at the temperature extremes by the total temperature change. Starting from the measured voltage offset at temperature T1 (VOS_RW(T1)), the voltage offset at temperature T2 (VOS_RW(T2)) is calculated according the following formula: VOS_RW(T2)=VOS_RW(T1)+ABS(T2-T1)* TcVOS_RW. Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 Electrical Characteristics (continued) Unless otherwise specified, TA = 25C, VS=(VDD - AGND), VS = 3.3 V and AGND = DGND = 0 V, VREF = 2.5 V, Internal Zero = 20% VREF.(1) PARAMETER MIN (2) TEST CONDITIONS TYP (3) Transimpedance gain accuracy 0.05% 7 programmable gain resistors 2.75 3.5 7 14 35 120 350 TIA_GAIN Programmable TIA Gains Maximum external gain resistor Internal zero voltage TIA_ZV Programmable Load 20% 50% 67% 3 programmable percentages of VDD 20% 50% 67% 0.04% 4 programmable resistive loads 10 33 50 100 Load accuracy Power Supply Rejection Ratio at RE pin k 350 3 programmable percentages of VREF Internal zero voltage Accuracy PSRR UNIT 5% Linearity RL MAX (2) 5% 2.7 V VDD 5.25 V Internal zero 20% VREF Internal zero 50% VREF 80 110 dB Internal zero 67% VREF TEMPERATURE SENSOR SPECIFICATION (Refer to Table 1 in the Feature Description for details) Temperature Error TA= -40C to 85C Sensitivity TA= -40C to 85C -3 3 -8.2 Power on time C mV/C 1.9 ms EXTERNAL REFERENCE SPECIFICATION VREF External Voltage reference range 1.5 VDD Input impedance 10 V M 6.6 I2C Interface Unless otherwise specified, TA = 25C, VS = (VDD - AGND), 2.7 V 0V BIAS selection (Percentage of the source reference) 0000 0% (default) 0001 1% 0010 2% 0011 4% 0100 6% 0101 8% 0110 10% 0111 12% 1000 14% 1001 16% 1010 18% 1011 20% 1100 22% 1101 24% Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 7.6.5 MODECN -- Mode Control Register (Address 0x12) The Parameters in the Mode register allow the configuration of the Operation Mode of the LMP91000. Bit Name 7 FET_SHORT [6:3] RESERVED [2:0] OP_MODE Function Shorting FET feature 0 Disabled (default) 1 Enabled Mode of Operation selection 000 Deep Sleep (default) 001 2-lead ground referred galvanic cell 010 Standby 011 3-lead amperometric cell 110 Temperature measurement (TIA OFF) 111 Temperature measurement (TIA ON) When the LMP91000 is in Temperature measurement (TIA ON) mode, the output of the temperature sensor is present at the VOUT pin, while the output of the potentiostat circuit is available at pin C2. Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 23 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information 8.1.1 Connection of More Than One LMP91000 to the I2C BUS The LMP91000 comes out with a unique and fixed I2C slave address. It is still possible to connect more than one LMP91000 to an I2C bus and select each device using the MENB pin. The MENB simply enables/disables the I2C communication of the LMP91000. When the MENB is at logic level low all the I2C communication is enabled, it is disabled when MENB is at high logic level. In a system based on a controller and more than one LMP91000 connected to the I2C bus, the I2C lines (SDA and SCL) are shared, while the MENB of each LMP91000 is connected to a dedicate GPIO port of the controller. The controller starts communication asserting one out of N MENB signals where N is the total number of LMP91000s connected to the I2C bus. Only the enabled device will acknowledge the I2C commands. After finishing communicating with this particular LMP91000, the microcontroller de-asserts the corresponding MENB and repeats the procedure for other LMP91000s. Figure 30 shows the typical connection when more than one LMP91000 is connected to the I2C bus. SCL GPIO N C SDA LMP91000 MENB SCL GPIO 3 GPIO 2 SDA MENB LMP91000 SDA MENB SCL SDA MENB GPIO 1 SCL LMP91000 LMP91000 SCL SDA Figure 30. More Than One LMP91000 on I2C Bus 8.1.2 Smart Gas Sensor Analog Front-End The LMP91000 together with an external EEPROM represents the core of a SMART GAS SENSOR AFE. In the EEPROM it is possible to store the information related to the GAS sensor type, calibration and LMP91000's configuration (content of registers 10h, 11h, 12h). At startup the microcontroller reads the EEPROM's content and configures the LMP91000. A typical smart gas sensor AFE is shown in Figure 31. The connection of MENB to the hardware address pin A0 of the EEPROM allows the microcontroller to select the LMP91000 and its corresponding EEPROM when more than one smart gas sensor AFE is present on the I2C bus. Note: only EEPROM I2C addresses with A0=0 should be used in this configuration. 24 Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 Application Information (continued) SCL A0 SDA SCL MENB MENB SCL SDA I2C EEPROM LMP91000 SDA Figure 31. Smart Gas Sensor AFE 8.1.3 Smart Gas Sensor AFES on I2C BUS The connection of Smart gas sensor AFEs on the I2C bus is the natural extension of the previous concepts. Also in this case the microcontroller starts communication asserting 1 out of N MENB signals where N is the total number of smart gas sensor AFE connected to the I2C bus. Only one of the devices (either LMP91000 or its corresponding EEPROM) in the smart gas sensor AFE enabled will acknowledge the I2C commands. When the communication with this particular module ends, the microcontroller de-asserts the corresponding MENB and repeats the procedure for other modules. Figure 32 shows the typical connection when several smart gas sensor AFEs are connected to the I2C bus. SMART SENSOR AFE SMART SENSOR AFE GPIO 1 SCL SDA I2C EEPROM A0 SCL SDA LMP91000 MENB SCL SDA I2C EEPROM A0 SDA SCL MENB LMP91000 SDA A0 I2C EEPROM SCL SCL SDA MENB LMP91000 SMART SENSOR AFE GPIO 2 C GPIO N SCL SDA Figure 32. I2C Bus Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 25 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com 8.2 Typical Application The LMP91000 can be used in conjunction with environment sensors to build a battery power environment monitors such as an air quality data-loggers, or wirless sensors. In this application due to the monitored phenomena the micro-controller and the LMP9100 spend most of the time in idle state. In order to save power and enlarge the battery life, the LMP91000 can be put in deep sleep mode with Internal FET feature enabled. To optimize the current consumption of the entire system, the acquisitions and in general the activities of the micro can operate at set intervals with the TPL5000. The TPL5000 is a programmable timer with watch-dog feature. VOLTAGE REFERENCE VIN VOUT GND TPL5000 VOUT VBAT_OK VIN + Lithium ion battery C Rp 100k D0 PGOOD D1 RSTn RST D2 WAKE GPIO LMP91000 Rp 100k VDD Rp 100k VDD VREF SDA SCL CE SCL SDA RE CE POWER MANAGEMENT GND VDD TCAL GPIO ADC VOUT GND DONE GPIO GND GND GPIO GPIO GPIO GPIO Button Button WE MENB RE WE GAS SENSOR Temp 29C CO 0PPM TIME xx:xx Date xx/xx/xxxx Button DISPLAY KEYBOARD Figure 33. Data-Logger 8.2.1 Design Requirements The Design is driven by the low-current consumption constraint. The data are usually acquired on a rate that ranges between 1s to 10s. The highest necessity it the maximization of the battery life. The TPL5000 helps achieving that goal because it allows putting the micro-controller in its lowest power mode. Moreover the deep slep mode of the LMP91000 allows burning only some hundreds of nA. 8.2.2 Detailed Design Procedure When the focal constraint is the battery, the selection of a low power voltage reference, a micro-controller and display is mandatory. The first step in the design is the calculation of the power consumption of each device in the different mode of operations. An example is the LMP91000; the device has gas measurement mode, sleep mode and micro-controller in low power mode which is normal operation. The different modes offer the possibility to select the appropriate timer interval which respect the application constraint and maximize the life of the battery. 8.2.2.1 Sensor Test Procedure The LMP91000 has all the hardware and programmability features to implement some test procedures. The purpose of the test procedure is to: a. test proper function of the sensor (status of health) b. test proper connection of the sensor to the LMP91000 The test procedure is very easy. The variable bias block is user programmable through the digital interface. A step voltage can be applied by the end user to the positive input of A1. As a consequence a transient current will start flowing into the sensor (to charge its internal capacitance) and it will be detected by the TIA. If the current transient is not detected, either a sensor fault or a connection problem is present. The slope and the aspect of the transient response can also be used to detect sensor aging (for example, a cell that is drying and no longer 26 Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 Typical Application (continued) efficiently conducts the current). After it is verified that the sensor is working properly, the LMP91000 needs to be reset to its original configuration. It is not required to observe the full transient in order to contain the testing time. All the needed information are included in the transient slopes (both edges). Figure 34 shows an example of the test procedure, a Carbon Monoxide sensor is connected to the LMP91000, two pulses are then sequentially applied to the bias voltage: 1. from 0 mV to 40 mV 2. from 40 mV to -40 mV and finally the bias is set again at 0mV since this is the normal operation condition for this sensor. 8.2.3 Application Curve INPUT PULSE (100mV/DIV) OUTPUTT VOLTTAGE (1V/DIV) LMP91000 OUTPUT TEST PULSE TIME (25ms/DIV) Figure 34. Test Procedure Example Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 27 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com 9 Power Supply Recommendations 9.1 Power Consumption The LMP91000 is intended for use in portable devices, so the power consumption is as low as possible in order to ensure a long battery life. The total power consumption for the LMP91000 is below 10 A at 3.3 v average over time, (this excludes any current drawn from any pin). A typical usage of the LMP91000 is in a portable gas detector and its power consumption is summarized in Table 3. This has the following assumptions: * Power On only happens a few times over life, so its power consumption can be ignored. * Deep Sleep mode is not used. * The system is used about 8 hours a day, and 16 hours a day it is in Standby mode. * Temperature Measurement is done about once per minute. This results in an average power consumption of approximately 7.95 A. This can potentially be further reduced, by using the Standby mode between gas measurements. It may even be possible, depending on the sensor used, to go into deep sleep for some time between measurements, further reducing the average power consumption. Table 3. Power Consumption Scenario Current consumption (A) typical value Deep Sleep StandBy 3-Lead Amperometric Cell Temperature Measurement TIA OFF Temperature Measurement TIA ON 0.6 6.5 10 11.4 14.9 Time ON (%) 0 60 39 0 1 Average (A) 0 3.9 3.9 0 0.15 Total 7.95 Notes A1 OFF ON ON ON ON TIA OFF OFF ON OFF ON TEMP SENSOR OFF OFF OFF ON ON I2C interface ON ON ON ON ON 28 Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 LMP91000 www.ti.com SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 10 Layout 10.1 Layout Guidelines The most critical point when designing with electrocemical gas sensors and the LMP91000 is the connection of the sensor to the LMP91000. Particular attention is required in the layout of the RE, CE and WE traces which connect the sensor to the front-end. The traces needs to be short and far from hifh freqency signals, such as clock. A way to reduce the lenght of the traces is positioning the LMP91000 below the gas sensor, this is possible with cyclindrical electrochemical gas sensor or on the oppoite layer in case of solid gas sensor or low profile gas sensor. In case of uasge of external transimpeance gain resistance it needs to be placed close to the LMP91000, the terminal of the resistance conencted to C1 needs to be far from high frequency signals. 10.2 Layout Example TOP LAYER BOTTOM LAYER Figure 35. Layout Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 29 LMP91000 SNAS506I - JANUARY 2011 - REVISED DECEMBER 2014 www.ti.com 11 Device and Documentation Support 11.1 Trademarks WEBENCH is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.2 Electrostatic Discharge Caution 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. 11.3 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 30 Submit Documentation Feedback Copyright (c) 2011-2014, Texas Instruments Incorporated Product Folder Links: LMP91000 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (C) Device Marking (3) (4/5) (6) LMP91000SD/NOPB ACTIVE WSON NHL 14 1000 RoHS & Green SN Level-3-260C-168 HR -40 to 85 L91000 LMP91000SDE/NOPB ACTIVE WSON NHL 14 250 RoHS & Green SN Level-3-260C-168 HR -40 to 85 L91000 LMP91000SDX/NOPB ACTIVE WSON NHL 14 4500 RoHS & Green SN Level-3-260C-168 HR -40 to 85 L91000 (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device 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 Device Marking for that device. (6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. 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Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 20-Sep-2016 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LMP91000SD/NOPB WSON NHL 14 LMP91000SDE/NOPB WSON NHL LMP91000SDX/NOPB WSON NHL SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 14 250 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 14 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 20-Sep-2016 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMP91000SD/NOPB WSON NHL 14 1000 210.0 185.0 35.0 LMP91000SDE/NOPB WSON NHL 14 250 210.0 185.0 35.0 LMP91000SDX/NOPB WSON NHL 14 4500 367.0 367.0 35.0 Pack Materials-Page 2 MECHANICAL DATA NHL0014B SDA14B (Rev A) www.ti.com IMPORTANT NOTICE AND DISCLAIMER TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES "AS IS" AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. 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