LM9044VX

LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 LM9044 Lambda Sensor Interface Amplifier Check for Samples: LM9044 FEATURES DESCRIPTION • The LM9044 is a precision differential amplifier specifically designed for operation in the automotive environment. Gain accuracy is specified over the entire automotive temperature range (−40°C to +125°C) and is factory trimmed after package assembly. The input circuitry has been specifically designed to reject common-mode signals as much as 3V below ground without the need for a negative voltage supply. This facilitates the use of sensors which are grounded at the engine block while the LM9044 itself is grounded at chassis potential. An external capacitor on the RF pin sets the maximum operating frequency of the amplifier, thereby filtering high frequency transients. Both inputs are protected against accidental shorting to the battery and against load dump transients. The input impedance is typically 1.2 MΩ. 1 2 • • • • • Normal Circuit Operation Specified with Inputs up to 3V Below Ground on a Single Supply. Gain Factory Trimmed and Specified over Temperature (±3% of Full-scale from −40°C to +125°C) Low Power Consumption (Typically 1 mA) Fully Protected Inputs Input Open Circuit Detection Operation Specified over the Entire Automotive Temperature Range (−40°C to +125°C) The output op amp is capable of driving capacitive loads and is fully protected. Also, internal circuitry has been provided to detect open circuit conditions on either or both inputs and force the output to a “home” position (a ratio of the external reference voltage). Typical Application +9.0V to +16.0V +4.75V to +5.50V 10 k: 0.01 PF VCC 800 mV 450 mV 100 mV - LEAN 100: VREF +VIN AV = 1 7 VS 20 17 RICH RDIFF 0.01 PF AV = 4.5 175 k: VOUT 200: 12 5 100: 0.01 PF -VIN 0.01 PF 15 LM9044V 2 GND RF 0.01 PF 1 2 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. All 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 © 1995–2013, Texas Instruments Incorporated LM9044 SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 www.ti.com Connection Diagram *Pins 1, 3, 4, 6, 8, 9, 10, 11, 13, 14, 16, 18, 19 are trim pins and should be left floating. Figure 1. Top View PLCC Package See Package Number FN0020A 2 Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – 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) VCC Supply Voltage (RVCC = 15 kΩ) ±60V VREF Supply Voltage −0.3V to +6V DC Input Voltage (Either input) (3) −3V to +16V Input Transients (4) Power Dissipation see ±60V (5) 1350 mW Output Short Circuit Duration Indefinite Operating Temperature Range −40°C to +125°C Storage Temperature Range −65°C to +150°C Soldering Information PLCC Package Vapor Phase (60 seconds) 215°C Infrared (15 seconds) 220°C See http://www.ti.com for other methods of soldering surface mount devices. (1) (2) (3) (4) (5) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications. With a 100Ω series resistor on each input pin. This test is performed with a 1000Ω source impedance. For operation in ambient temperatures above 25°C the device must be derated based on a maximum junction temperature of 150°C and a thermal resistance of 93°C/W junction to ambient. ELECTRICAL CHARACTERISTICS VCC = 12V, VREF = 5V, −40°C ≤ TA ≤ 125°C unless otherwise noted (1) Parameter Conditions VDIFF = 0.5, −1V ≤ VCM ≤ +1V Differential Voltage Gain Gain Error VDIFF = 0.5, −3V ≤ VCM ≤ +1V 0 ≤ VDIFF ≤ 1V, −1V ≤ VCM ≤ +1V (3) 0 ≤ VDIFF ≤ 1V, −3 ≤ VCM ≤ +1V 0 ≤ VDIFF ≤ 1V, −1V ≤ VCM ≤ +1V Differential Input Resistance Non-Inverting Input Bias Current Inverting Input Bias Current VCC Supply Current Common-Mode Voltage Range Typ Max Min Typ Max 4.41 4.50 4.59 - - - Units V/V - - - 4.36 4.50 4.64 V/V −2 0 2 - - - %/FS - - - −3 0 3 %/FS 0.95 1.20 3.00 - - - MΩ - - - 0.70 1.20 4.00 MΩ 0 ≤ VDIFF ≤ 1V, −1 ≤ VCM ≤ +1V - ±0.38 ±0.65 - - - µA 0 ≤ VDIFF ≤ 1V, −3 ≤ VCM ≤ +1V - - - - ±0.38 ±1.5 µA 0 ≤ VDIFF ≤ 1V, −1 ≤ VCM ≤ +1V −25 −65 −100 - - - µA 0 ≤ VDIFF ≤ 1V, −3 ≤ VCM ≤ +1V - - - - −45 −150 µA VCC = 12V, RVCC = 15k - 300 500 - - - µA - 0.5 1.0 - - - mA −1 - 1 −3 - 1 V 50 60 - - - - dB −1V ≤ VCM ≤ +1V 0.371 0.397 0.423 - - - xVREF −3V ≤ VCM ≤ +1V - - - 0.365 0.397 0.439 xVREF Output Grounded 1.0 2.7 5.0 - - - mA (4) DC Common-Mode Rejection Ratio Min 0 ≤ VDIFF ≤ 1V, −3 ≤ VCM ≤ +1V 4.75V ≤ VREF ≤ 5.5V VREF Supply Current (2) Input Referred −1V ≤ VCM ≤ +1V, VDIFF = 0.5V One or Both Inputs Open Open Circuit Output Voltage Short Circuit Output Current (1) (2) (3) (4) These parameters are specified and 100% production tested. These parameters will be specified but not 100% production tested. Gain error is given as a percent of full-scale. Full-scale is defined as 1V at the input and 4.5V at the output. The LM9044 has been designed to common-mode to −3V, but production testing is only performed at ±1V. Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 3 LM9044 SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) VCC = 12V, VREF = 5V, −40°C ≤ TA ≤ 125°C unless otherwise noted (1) Parameter Conditions (2) Min Typ Max Min Typ Max Units VCC Power Supply Rejection Ratio VCC = 12V, RVCC = 15k VDIFF = 0.5V 50 65 - - - - dB VREF Power Supply Rejection Ratio VREF = 5 VDC VDIFF = 0.5V 60 74 - - - - dB 4 Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS Non-Inverting Input Bias Current vs Temperature Inverting Input Bias Current vs Temperature Figure 2. Figure 3. VREF Supply Current vs Temperature VCC Supply Current vs Temperature Figure 4. Figure 5. Short Circuit Output Current vs Temperature Differential Gain vs Temperature Figure 6. Figure 7. Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 5 LM9044 SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 6 Voltage Gain vs Frequency CMRR vs Frequency Figure 8. Figure 9. VREF Power Supply Rejection VCC Power Supply Rejection Figure 10. Figure 11. Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 TEST CIRCUIT Block Diagram 65 PA VCC VREF 17 20 380 nA 7.5V +VIN 7 12 AV=1 5 200: 175 k: RDIFF 1.2 M: -VIN 26.5 k: AV=4.5 VOUT 14 k: 220 k: 1.5V 4 k: Open -VIN Detector 15 LM9044V RF 2 GND Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 7 LM9044 SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 www.ti.com APPLICATION INFORMATION CIRCUIT DESCRIPTION The LM9044 is a single channel device intended to act as a linear interface between a zirconium dioxide oxygen sensor and an A-to-D convertor. The LM9044 is fabricated in Bipolar technology and requires two supplies: a nominal 12V automotive supply (i.e. VBATTERY), and a well regulated 5V supply. The IC consists of a single channel differential input amplifier with a nominal DC gain of 4.5 V/V. The differential inputs have a specified common mode voltage operating range of 1V above and below ground. The circuitry also contains provisions for default output voltage in the cases of cold sensor and open sensor wiring. Additional support circuitry includes one pin for an optional user programmed low pass filter. COLD SENSOR Typically, a Lambda sensor will have an impedance of less than 10 kΩ when operating at temperatures between 300°C, and 500°C. When a Lambda sensor is not at operating temperature, its impedance can be more than 10 MegΩ. Any voltage signal that may be developed is seriously attenuated. During this high impedance condition the LM9044 will provide a default output voltage. While the Lambda sensor is high impedance the internal non-inverting input bias current (380 nA typical) will flow through the differential input resistance (1.2 MΩ typical) and out the inverting input pin to ground. This will cause a voltage to be developed across the differential inputs: VIN(DIFF) = 380 nA x 1.2 MΩ VIN(DIFF) = 456 mV The 456 mV across differential input resistance will be the dominant input signal, and the typical VOUT will be: VOUT = VIN(DIFF) x 4.50 VOUT = 456 mV x 4.50 VOUT = 2.0V As the Lambda sensor is heated, and the sensor impedance begins to drop, the voltage signal from the sensor will become the dominate signal. The non-inverting input bias current is scaled to the VREF voltage. As the VREF voltage increases, or decreases, this bias current will change proportionally. OPEN INPUT PINS DEFAULTS In any remote sensor application it is desirable to be able to deal with the possibility of open connections between the sensor and the control module. The LM9044 is capable of providing a default output voltage should either, or both, of the wires to the Lambda sensor open. The two inputs handle the open circuit condition differently. For the case of an open connection at the non-inverting input, the device would react exactly the same as for the Cold Sensor condition. The internal non-inverting input bias current (380 nA typical) flowing through the differential input resistance (1.2 MΩ typical) would cause the typical output voltage to be at a value defined by: VOUT = ((380 nA x 1.2MΩ) x 4.50 ) VOUT = 2.0V The inverting input would still be connected to the Lambda sensor ground, so common mode signals would still need to be considered in this condition. For the case of an open connection of the inverting input, the device output stage switches from the amplifier output to a resistive voltage divider. The LM9044 has a comparator to monitor the voltage on the inverting input pin, and a 65 μA (typical) current source that will force the pin high if the pin is open. When the voltage on the inverting pin goes above typically 1.5V, the comparator will switch the output pin from the amplifier output to the resistive voltage divider stage. In this case, the default VOUT is not dependent on the gain stage, and any signal on the non-inverting input will be ignored. 8 Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 In this condition VOUT is: VOUT = VREF x ((14k + 4k) / (26.5k + 14k + 4k)) VOUT = VREF x 0.4045 When VREF is at 5.0V, VOUT is defined as: VOUT = 5.0V x 0.4045 VOUT = 2.0V In the cases where both the inverting and non-inverting pins are open, the open inverting pin condition (i.e.: a voltage divider across the output) will be the dominant condition. Any common mode voltage transient on the inverting input pin which goes above the comparator threshold will immediately cause the output to switch to the resistive voltage divider mode. The output will return to normal operation when the voltage on the inverting input falls below the 1.5V threshold. OUTPUT RESISTANCE Under normal operating conditions the output pin resistance is typically 200Ω. If the LM9044 is operating in a default output mode due an open connection on the inverting input, the output resistance will typically appear to be close to 11 kΩ. An external output filter capacitor value of no more than 0.01 μF is generally recommended. Since the output pin voltage drive is basically a simple NPN emitter follower, the output pin pull-down is done by the internal feedback resistor string. With larger value capacitors on the output pin the effect will be somewhat similar to a voltage peak detector where the output capacitor is charged through the 200Ω resistor, and discharged back through the 200Ω resistor and the 18 kΩ feedback resistor string to ground. The output resistance provides current limiting for the output stage should it become shorted to Ground. Any DC loading of the output will cause an error in the output voltage. SUPPLY BYPASSING For best performance the LM9044 requires a VREF supply which is stable and noise free. The same 5V reference supply used for the A/D converter is the recommended LM9044 VREF supply. The LM9044 VCC pin has an internal zener shunt voltage regulator, typically 7.5V, and requires a series resistor to limit the current. The VCC pin should be bypassed with a minimum 0.01 μF capacitor to the Ground pin, and should be located as close to the device as possible. Some applications may require an additional bypass capacitance if the system voltage is unusually noisy. SETTING THE BANDWIDTH The LM9044 bandwidth is limited by an external capacitor (CF) on the RF pin. This pin has an internal 175 kΩ resistor. The external capacitor and the internal resistor form a simple RC lowpass filter with a corner frequency (fC) defined as: fC = 1/ (2 x π x 175 kΩ x CF) With a CF capacitor value of 0.001 μF, the corner frequency is: fC = 1/ (2 x π x 175 kΩ x 0.001 μF) fC = 909 Hz INPUT FILTERING Filtering at the differential inputs is strongly recommended. Both the differential voltage signal and the common mode voltage signal should have low pass filters. Input filtering is accomplished with series resistors on the input pins, and appropriate bypass capacitors. Typical input pin series resistance values are in the 100Ω to 1kΩ range. Series resistance values larger than 1kΩ will generate offset voltages that affect the accuracy of the signal voltage seen at the differential input pins. Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 9 LM9044 SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 www.ti.com Simplified Internal Schematic 10 Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 LM9044 www.ti.com SNOSBP4D – FEBRUARY 1995 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision C (March 2013) to Revision D • Page Changed layout of National Data Sheet to TI format .......................................................................................................... 10 Submit Documentation Feedback Copyright © 1995–2013, Texas Instruments Incorporated Product Folder Links: LM9044 11 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) LM9044V/NOPB ACTIVE PLCC FN 20 40 RoHS & Green SN Level-2A-250C-4 WEEK -40 to 125 LM9044V LM9044VX/NOPB ACTIVE PLCC FN 20 1000 RoHS & Green SN Level-2A-250C-4 WEEK -40 to 125 LM9044V (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