lm2907-n 频压转换

LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 LM2907/LM2917 Frequency to Voltage Converter Check for Samples: LM2907-N, LM2917-N 1FEATURES DESCRIPTION The LM2907, LM2917 series are monolithic 2• Ground Referenced Tachometer Input frequency to voltage converters with a high gain opInterfaces Directly With Variable Reluctance amp/comparator designed to operate a relay, lamp, orMagnetic Pickups other load when the input frequency reaches or • Op Amp/Comparator Has Floating Transistor exceeds a selected rate. The tachometer uses a Output charge pump technique and offers frequency doubling for low ripple, full input protection in two• 50 mA Sink or Source to Operate Relays, versions (LM2907-8, LM2917-8) and its output swingsSolenoids, Meters, or LEDs to ground for a zero frequency input. • Frequency Doubling For Low Ripple The op amp/comparator is fully compatible with the • Tachometer Has Built-In Hysteresis With tachometer and has a floating transistor as its output.Either Differential Input or Ground Referenced This feature allows either a ground or supply referredInput load of up to 50 mA. The collector may be taken • Built-In Zener on LM2917 above VCC up to a maximum VCE of 28V. • ±0.3% Linearity Typical The two basic configurations offered include an 8-pin • Ground Referenced Tachometer is Fully device with a ground referenced tachometer input Protected From Damage Due to Swings Above and an internal connection between the tachometer output and the op amp non-inverting input. ThisVCC and Below Ground version is well suited for single speed or frequency switching or fully buffered frequency to voltageAPPLICATIONS conversion applications. • Over/Under Speed Sensing The more versatile configurations provide differential • Frequency to Voltage Conversion tachometer input and uncommitted op amp inputs.(Tachometer) With this version the tachometer input may be floated • Speedometers and the op amp becomes suitable for active filter conditioning of the tachometer output.• Breaker Point Dwell Meters • Hand-Held Tachometer Both of these configurations are available with an active shunt regulator connected across the power• Speed Governors leads. The regulator clamps the supply such that • Cruise Control stable frequency to voltage and frequency to current • Automotive Door Lock Control operations are possible with any supply voltage and a suitable resistor.• Clutch Control • Horn Control • Touch or Sound Switches ADVANTAGES • Output Swings to Ground For Zero Frequency Input • Easy to Use; VOUT = fIN × VCC × R1 × C1 • Only One RC Network provides Frequency Doubling • Zener Regulator on Chip allows Accurate and Stable Frequency to Voltage or Current Conversion (LM2917) 1 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. 2All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Copyright © 2000–2013, Texas Instruments IncorporatedProducts conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com CONNECTION DIAGRAMS PDIP and SOIC Packages, Top Views Figure 1. See Package Number D0008A or P0008E Figure 2. See Package Number D0008A or P0008E Figure 3. See Package Number D0014A or Figure 4. See Package Number D0014A or NFF0014A NFF0014A 2 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–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) Supply Voltage 28V Supply Current (Zener Options) 25 mA Collector Voltage 28V Differential Input Voltage Tachometer 28V Op Amp/Comparator 28V Input Voltage Range Tachometer LM2907-8, LM2917-8 ±28V LM2907, LM2917 0.0V to +28V Op Amp/Comparator 0.0V to +28V Power Dissipation LM2907-8, LM2917-8 1200 mW LM2907-14, LM2917-14 (1) 1580 mW Operating Temperature Range −40°C to +85°C Storage Temperature Range −65°C to +150°C Soldering Information PDIP Package Soldering (10 seconds) 260°C SOIC Package Vapor Phase (60 seconds) 215°C Infrared (15 seconds) 220°C (1) For operation in ambient temperatures above 25°C, the device must be derated based on a 150°C maximum junction temperature and a thermal resistance of 101°C/W junction to ambient for LM2907-8 and LM2917-8, and 79°C/W junction to ambient for LM2907-14 and LM2917-14. (2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications. ELECTRICAL CHARACTERISTICS VCC = 12 VDC, TA = 25°C, see test circuit Symbol Parameter Conditions Min Typ Max Units TACHOMETER Input Thresholds VIN = 250 mVp-p @ 1 kHz (1) ±10 ±25 ±40 mV Hysteresis VIN = 250 mVp-p @ 1 kHz (1) 30 mV Offset Voltage VIN = 250 mVp-p @ 1 kHz (1) LM2907/LM2917 3.5 10 mV LM2907-8/LM2917-8 5 15 mV Input Bias Current VIN = ±50 mVDC 0.1 1 μA VOH Pin 2 VIN = +125 mVDC(2) 8.3 V VOL Pin 2 VIN = −125 mVDC(2) 2.3 V I2, I3 Output Current V2 = V3 = 6.0V (3) 140 180 240 μA I3 Leakage Current I2 = 0, V3 = 0 0.1 μA K Gain Constant See (2) 0.9 1.0 1.1 Linearity fIN = 1 kHz, 5 kHz, 10 kHz (4) −1.0 0.3 +1.0 % OP/AMP COMPARATOR VOS VIN = 6.0V 3 10 mV IBIAS VIN = 6.0V 50 500 nA Input Common-Mode 0 VCC−1.5V V Voltage (1) Hysteresis is the sum +VTH − (−VTH), offset voltage is their difference. See test circuit.(2) VOH is equal to ¾ × VCC − 1 VBE, VOL is equal to ¼ × VCC − 1 VBE therefore VOH − VOL = VCC/2. The difference, VOH − VOL, and the mirror gain, I2/I3, are the two factors that cause the tachometer gain constant to vary from 1.0.(3) Be sure when choosing the time constant R1 × C1 that R1 is such that the maximum anticipated output voltage at pin 3 can be reached with I3 × R1. The maximum value for R1 is limited by the output resistance of pin 3 which is greater than 10 MΩ typically.(4) Nonlinearity is defined as the deviation of VOUT (@ pin 3) for fIN = 5 kHz from a straight line defined by the VOUT @ 1 kHz and VOUT @ 10 kHz. C1 = 1000 pF, R1 = 68k and C2 = 0.22 mFd. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 3 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) VCC = 12 VDC, TA = 25°C, see test circuit Symbol Parameter Conditions Min Typ Max Units Voltage Gain 200 V/mV Output Sink Current VC = 1.0 40 50 mA Output Source Current VE = VCC −2.0 10 mA Saturation Voltage ISINK = 5 mA 0.1 0.5 V ISINK = 20 mA 1.0 V ISINK = 50 mA 1.0 1.5 V ZENER REGULATOR Regulator Voltage RDROP = 470Ω 7.56 V Series Resistance 10.5 15 Ω Temperature Stability +1 mV/°C Total Supply Current 3.8 6 mA TEST CIRCUIT AND WAVEFORM Figure 5. 4 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 Tachometer Input Threshold Measurement Figure 6. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 5 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS Tachometer Linearity vs Temperature Tachometer Linearity vs Temperature Figure 7. Figure 8. Total Supply Current Zener Voltage vs Temperature Figure 9. Figure 10. Normalized Tachometer Output (K) vs Temperature Normalized Tachometer Output (K) vs Temperature Figure 11. Figure 12. 6 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Tachometer Currents I2and I3 vs Supply Voltage Tachometer Currents I2and I3 vs Temperature Figure 13. Figure 14. Tachometer Linearity vs R1 Tachometer Input Hysteresis vs Temperature Figure 15. Figure 16. Op Amp Output Transistor Characteristics Op Amp Output Transistor Characteristics Figure 17. Figure 18. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 7 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com APPLICATIONS INFORMATION The LM2907 series of tachometer circuits is designed for minimum external part count applications and maximum versatility. In order to fully exploit its features and advantages let's examine its theory of operation. The first stage of operation is a differential amplifier driving a positive feedback flip-flop circuit. The input threshold voltage is the amount of differential input voltage at which the output of this stage changes state. Two options (LM2907-8, LM2917-8) have one input internally grounded so that an input signal must swing above and below ground and exceed the input thresholds to produce an output. This is offered specifically for magnetic variable reluctance pickups which typically provide a single-ended ac output. This single input is also fully protected against voltage swings to ±28V, which are easily attained with these types of pickups. The differential input options (LM2907, LM2917) give the user the option of setting his own input switching level and still have the hysteresis around that level for excellent noise rejection in any application. Of course in order to allow the inputs to attain common-mode voltages above ground, input protection is removed and neither input should be taken outside the limits of the supply voltage being used. It is very important that an input not go below ground without some resistance in its lead to limit the current that will then flow in the epi-substrate diode. Following the input stage is the charge pump where the input frequency is converted to a dc voltage. To do this requires one timing capacitor, one output resistor, and an integrating or filter capacitor. When the input stage changes state (due to a suitable zero crossing or differential voltage on the input) the timing capacitor is either charged or discharged linearly between two voltages whose difference is VCC/2. Then in one half cycle of the input frequency or a time equal to 1/2 fIN the change in charge on the timing capacitor is equal to VCC/2 × C1. The average amount of current pumped into or out of the capacitor then is: (1) The output circuit mirrors this current very accurately into the load resistor R1, connected to ground, such that if the pulses of current are integrated with a filter capacitor, then VO = ic × R1, and the total conversion equation becomes: VO = VCC × fIN × C1 × R1 × K where • K is the gain constant—typically 1.0 (2) The size of C2 is dependent only on the amount of ripple voltage allowable and the required response time. CHOOSING R1 AND C1 There are some limitations on the choice of R1 and C1 which should be considered for optimum performance. The timing capacitor also provides internal compensation for the charge pump and should be kept larger than 500 pF for very accurate operation. Smaller values can cause an error current on R1, especially at low temperatures. Several considerations must be met when choosing R1. The output current at pin 3 is internally fixed and therefore VO/R1 must be less than or equal to this value. If R1 is too large, it can become a significant fraction of the output impedance at pin 3 which degrades linearity. Also output ripple voltage must be considered and the size of C2 is affected by R1. An expression that describes the ripple content on pin 3 for a single R1C2 combination is: (3) It appears R1 can be chosen independent of ripple, however response time, or the time it takes VOUT to stabilize at a new voltage increases as the size of C2 increases, so a compromise between ripple, response time, and linearity must be chosen carefully. As a final consideration, the maximum attainable input frequency is determined by VCC, C1 and I2: (4) 8 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 USING ZENER REGULATED OPTIONS (LM2917) For those applications where an output voltage or current must be obtained independent of supply voltage variations, the LM2917 is offered. The most important consideration in choosing a dropping resistor from the unregulated supply to the device is that the tachometer and op amp circuitry alone require about 3 mA at the voltage level provided by the zener. At low supply voltages there must be some current flowing in the resistor above the 3 mA circuit current to operate the regulator. As an example, if the raw supply varies from 9V to 16V, a resistance of 470Ω will minimize the zener voltage variation to 160 mV. If the resistance goes under 400Ω or over 600Ω the zener variation quickly rises above 200 mV for the same input variation. TYPICAL APPLICATIONS Figure 19. Minimum Component Tachometer Figure 20. ”Speed Switch”, Load is Energized when fIN ≥ (1 / ( 2RC)) Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 9 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com Figure 21. Zener Regulated Frequency to Voltage Converter Figure 22. Breaker Point Dwell Meter 10 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 Figure 23. Voltage Driven Meter Indicating Engine RPM VO = 6V @ 400 Hz or 6000 ERPM (8 Cylinder Engine) Figure 24. Current Driven Meter Indicating Engine RPM IO = 10 mA @ 300 Hz or 6000 ERPM (6 Cylinder Engine) Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com Figure 25. Capacitance Meter VOUT = 1V–10V for CX = 0.01 to 0.1 mFd (R = 111k) Figure 26. Two-Wire Remote Speed Switch 12 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 Figure 27. 100 Cycle Delay Switch Variable Reluctance Magnetic Pickup Buffer Circuits Precision two-shot output frequency equals twice input frequency. Pulse height = VZENER Figure 28. Figure 29. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 13 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com Finger Touch or Contact Switch Figure 30. Figure 31. Flashing begins when fIN ≥ 100 Hz. Flash rate increases with input frequency increase beyond trip point. Figure 32. Flashing LED Indicates Overspeed 14 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 Figure 33. Frequency to Voltage Converter with 2 Pole Butterworth Filter to Reduce Ripple Figure 34. Overspeed Latch Figure 36. Figure 35. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 15 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com Frequency Switch Applications Some frequency switch applications may require hysteresis in the comparator function which can be implemented in several ways. Figure 37. 16 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 Figure 38. Figure 39. Figure 40. Figure 41. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 17 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com Changing the Output Voltage for an Input Frequency of Zero Figure 42. Figure 43. Changing Tachometer Gain Curve or Clamping the Minimum Output Voltage Figure 44. Figure 45. 18 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 ANTI-SKID CIRCUIT FUNCTIONS “Select-Low” Circuit VOUT Proportional to the Lower of the Two Input Wheel Speeds Figure 46. Figure 47. “Select-High” Circuit VOUT Proportional to the Higher of the Two Input Wheel Speeds Figure 48. Figure 49. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 19 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com “Select-Average” Circuit Figure 50. 20 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N www.ti.com SNAS555C –JUNE 2000–REVISED MARCH 2013 EQUIVALENT SCHEMATIC DIAGRAM *This connection made on LM2907-8 and LM2917-8 only. **This connection made on LM2917 and LM2917-8 only. Figure 51. Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 21 Product Folder Links: LM2907-N LM2917-N LM2907-N, LM2917-N SNAS555C –JUNE 2000–REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision B (March 2013) to Revision C Page • Changed layout of National Data Sheet to TI format .......................................................................................................... 21 22 Submit Documentation Feedback Copyright © 2000–2013, Texas Instruments Incorporated Product Folder Links: LM2907-N LM2917-N PACKAGE OPTION ADDENDUM www.ti.com 9-Aug-2013 Addendum-Page 1 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3) Op Temp (°C) Device Marking (4/5) Samples LM2907M ACTIVE SOIC D 14 55 TBD Call TI Call TI -40 to 85 LM2907M LM2907M-8 ACTIVE SOIC D 8 95 TBD Call TI Call TI -40 to 85 LM29 07M-8 LM2907M-8/NOPB ACTIVE SOIC D 8 95 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 LM29 07M-8 LM2907M/NOPB ACTIVE SOIC D 14 55 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 LM2907M LM2907MX ACTIVE SOIC D 14 2500 TBD Call TI Call TI -40 to 85 LM2907M LM2907MX-8 ACTIVE SOIC D 8 2500 TBD Call TI Call TI -40 to 85 LM29 07M-8 LM2907MX-8/NOPB ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 LM29 07M-8 LM2907MX/NOPB ACTIVE SOIC D 14 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 LM2907M LM2907N ACTIVE PDIP NFF 14 25 TBD Call TI Call TI -40 to 85 LM2907N LM2907N-8 ACTIVE PDIP P 8 40 TBD Call TI Call TI -40 to 85 LM 2907N-8 LM2907N-8/NOPB ACTIVE PDIP P 8 40 Green (RoHS & no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 85 LM 2907N-8 LM2907N/NOPB ACTIVE PDIP NFF 14 25 Green (RoHS & no Sb/Br) CU SN Level-1-NA-UNLIM -40 to 85 LM2907N LM2917M ACTIVE SOIC D 14 55 TBD Call TI Call TI -40 to 85 LM2917M LM2917M-8 ACTIVE SOIC D 8 95 TB