LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 LMV7271/LMV7275/LMV7272 Single & Dual, 1.8V Low Power Comparators with Rail-to-Rail Input Check for Samples: LMV7271 FEATURES DESCRIPTION • The LMV727X are rail-to-rail input low power comparators, which are characterized at supply voltage 1.8V, 2.7V and 5.0V. They consume only 9uA supply current per channel while achieving a 800ns propagation delay. 1 2 • • • • • • • • (VS = 1.8V, TA = 25°C, Typical values unless specified). Single or Dual Supplies Ultra low supply current 9µA per channel Low input bias current 10nA Low input offset current 200pA Low guaranteed VOS 4mV Propagation delay 880ns (20mV overdrive) Input common mode voltage range 0.1V beyond rails LMV7272 is available in DSBGA package The LMV7271/LMV7275 (single) are available in SC70 and SOT-23 packages. The LMV7272 (dual) is available in DSBGA package. With these tiny packages, the PC board area can be significantly reduced. They are ideal for low voltage, low power and space critical designs. The LMV7271/LMV7272 both feature a push-pull output stage which allows operation with minimum power consumption when driving a load. The LMV7275 features an open drain output stage that allows for wired-OR configurations. The open drain output also offers the advantage of allowing the output to be pulled to any voltage up to 5.5V, regardless of the supply voltage of the LMV7275. APPLICATIONS • • • • Mobile communications Laptops and PDA's Battery powered electronics General purpose low voltage applications The LMV727X are built with Texas Instruments' advance submicron silicon-gate BiCMOS process. They all have bipolar inputs for improved noise performance and CMOS outputs for rail-to-rail output swing. Typical Circuit VIN VCC R1 C1 = 0.1µF C2 = 10µF + VOUT R2 - VREF Figure 1. Threshold Detector Part Number Single/Dual Package Output LMV7271 Single SC70, SOT-23 Push/Pull LMV7272 Dual DSBGA Push/Pull LMV7275 Single SC70, SOT-23 Open Drain 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 © 2003–2013, Texas Instruments Incorporated LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com 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) ESD Tolerance VIN Differential 2KV (3) 200V (4) ±Supply Voltage Supply Voltage (V+ - V−) 6V V+ +0.1V, V− −0.1V Voltage at Input/Output pins Soldering Information Infrared or Convection (20 sec.) 235°C Wave Soldering (10 sec.) 260°C −65°C to +150°C Storage Temperature Range Junction Temperature (1) (5) +150°C Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics. If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office / Distributors for availability and specifications. Human body model, 1.5kΩ in series with 100pF. Machine Model, 0Ω in series with 200pF. Typical values represent the most likely parametric norm. (2) (3) (4) (5) Operating Ratings (1) Supply Voltage Range Temperature Range 1.8V to 5.5V (2) −40°C to +85°C Package Thermal Resistance (2) SOT-23 325°C/W SC70 265°C/W 8-Bump DSBGA 220°C/W (1) (2) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics. The maximum power dissipation is a function of TJ(MAX), θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) - TA)/θJA. All numbers apply for packages soldered directly into a PC board. 1.8V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 1.8V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol Parameter Condition Min (1) Typ Max (1) Units 0.3 4 6 mV (2) VOS Input Offset Voltage TC VOS Input Offset Temperature Drift 20 uV/°C IB Input Bias Current 10 nA IOS Input Offset Current 200 pA IS Supply Current VCM = 0.9V (3) LMV7271/LMV7275 LMV7272 (1) (2) (3) 2 9 12 14 µA 18 25 28 µA All limits are guaranteed by testing or statistical analysis. Typical values represent the most likely parametric norm. Offset Voltage average drift determined by dividing the change in VOS at temperature extremes into the total temperature change. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 1.8V Electrical Characteristics (continued) Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 1.8V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol ISC Min Typ 3.5 6 4 6 IO = 0.5mA 1.7 1.74 IO = 1.5mA 1.47 1.63 Parameter Output Short Circuit Current Condition Sourcing, VO = 0.9V (LMV7271/LMV7272 only) Sinking, VO = 0.9V (1) (2) Max (1) Units mA VOH Output Voltage High (LMV7271/LMV7272 only) VOL Output Voltage Low VCM Input Common Mode Voltage Range CMRR > 45 dB CMRR Common Mode Rejection Ratio 0 < VCM < 1.8V 46 78 dB PSRR Power Supply Rejection Ratio V+ = 1.8V to 5V 55 80 dB ILEAKAGE Output Leakage Current VO = 1.8V (LMV7275 only) 2 pA V IO = −0.5mA 52 100 IO = −1.5mA 166 220 mV 1.9 V −0.1 V 1.8V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 1.8V, V− = 0V, VCM = 0.5V, VO = V+/2 and RL > 1MΩ to V−. Boldface limits apply at the temperature extremes. Symbol Propagation Delay (High to Low) tPHL Propagation Delay (Low to High) tPLH (1) (2) Parameter Condition Min (1) Typ (2) Max (1) Units Input Overdrive = 20mV Load = 50pF//5kΩ 880 ns Input Overdrive = 50mV Load = 50pF//5kΩ 570 ns Input Overdrive = 20mV Load = 50pF//5kΩ 1100 ns Input Overdrive = 50mV Load = 50pF//5kΩ 800 ns Machine Model, 0Ω in series with 200pF. All limits are guaranteed by testing or statistical analysis. 2.7V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 2.7V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Min (1) Typ Max (1) Units 0.3 4 6 mV (2) VOS Input Offset Voltage TC VOS Input Offset Temperature Drift 20 µV/°C IB Input Bias Current 10 nA IOS Input offset Current 200 VCM = 1.35V (3) LMV7271/LMV7275 IS Supply Current LMV7272 ISC (1) (2) (3) Output Short Circuit Current pA 9 13 15 18 25 28 Sourcing, VO = 1.35V (LMV7271/LMV7272 only) 10 15 Sinking, VO = 1.35V 10 15 µA µA mA Machine Model, 0Ω in series with 200pF. All limits are guaranteed by testing or statistical analysis. Offset Voltage average drift determined by dividing the change in VOS at temperature extremes into the total temperature change. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 3 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com 2.7V Electrical Characteristics (continued) Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 2.7V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol Min Typ IO = 0.5mA 2.63 2.66 IO = 2.0mA 2.48 2.55 Parameter Conditions (1) (2) Max (1) Units VOH Output Voltage High (LMV7271/LMV7272 only) VOL Output Voltage Low VCM Input Common Voltage Range CMRR > 45dB CMRR Common Mode Rejection Ratio 0 < VCM < 2.7V 46 78 dB PSRR Power Supply Rejection Ratio V+ = 1.8V to 5V 55 80 dB ILEAKAGE Output Leakage Current VO = 2.7V (LMV7275 only) 2 pA V IO = −0.5mA 50 70 IO = −2mA 155 220 mV 2.8 V −0.1 V 2.7V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 2.7V, V− = 0V, VCM = 0.5V, VO = V+/2 and RL > 1MΩ to V−. Boldface limits apply at the temperature extremes. Symbol Propagation Delay (High to Low) tPHL Propagation Delay (Low to High) tPLH (1) (2) Parameter Condition Min (1) Typ (2) Max (1) Units Input Overdrive = 20mV Load = 50pF//5kΩ 1200 ns Input Overdrive = 50mV Load = 50pF//5kΩ 810 ns Input Overdrive = 20mV Load = 50pF//5kΩ 1300 ns Input Overdrive = 50mV Load = 50pF//5kΩ 860 ns Machine Model, 0Ω in series with 200pF. All limits are guaranteed by testing or statistical analysis. 5.0V Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 5V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol Parameter Conditions Min (1) Typ Max (1) Units 0.3 4 6 mV (2) VOS Input Offset Voltage TC VOS Input Offset Temperature Drift 20 µV/°C IB Input Bias Current 10 nA IOS Input Offset Current 200 pA IS Supply Current VCM = 2.5V (3) LMV7271/LMV7275 LMV7272 ISC VOH (1) (2) (3) 4 Output Short Circuit Current Output Voltage High (LMV7271/LMV7272 only) 10 14 16 µA 20 27 30 µA Sourcing, VO = 2.5V (LMV7271/LMV7272 only) 18 34 Sinking, VO = 2.5V 18 34 IO = 0.5mA 4.93 4.96 IO = 4.0mA 4.675 4.77 mA V Machine Model, 0Ω in series with 200pF. All limits are guaranteed by testing or statistical analysis. Offset Voltage average drift determined by dividing the change in VOS at temperature extremes into the total temperature change. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 5.0V Electrical Characteristics (continued) Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 5V, V− = 0V. Boldface limits apply at the temperature extremes. Symbol Parameter Min Conditions Typ (1) Max (2) (1) IO = −0.5mA 27 70 IO = −4.0mA 225 315 Units VOL Output Voltage Low mV VCM Input Common Voltage Range CMRR > 45dB CMRR Common Mode Rejection Ratio 0 < VCM < 5.0V 46 78 dB PRSS Power Supply Rejection Ratio V+ = 1.8V to 5V 55 80 dB ILEAKAGE Output Leakage Current VO = 5V (LMV7275 only) 2 pA 5.1 V −0.1 5.0V AC Electrical Characteristics Unless otherwise specified, all limits guaranteed for TJ = 25°C, V+ = 5.0V, V− = 0V, VCM = 0.5V, VO = V+/2 and RL > 1MΩ to V−. Boldface limits apply at the temperature extremes. Symbol tPHL tPLH (1) (2) Parameter Min Condition Propagation Delay (High to Low) Propagation Delay (Low to High) Typ (1) Max (2) (1) Units Input Overdrive = 20mV Load = 50pF//5kΩ 2100 ns Input Overdrive = 50mV Load = 50pF//5kΩ 1380 ns Input Overdrive = 20mV Load = 50pF//5kΩ 1800 ns Input Overdrive = 50mV Load = 50pF//5kΩ 1100 ns Machine Model, 0Ω in series with 200pF. All limits are guaranteed by testing or statistical analysis. CONNECTION DIAGRAMS 1 5 +IN V + + V OUT A A1 -IN A B1 +IN A C1 A2 A3 OUT B B3 -IN B C3 + IN B 2 GND -IN 3 4 VOUT C2 V Figure 2. 5-Pin SOT-23/SC70 (LMV7271/LMV7275) (Top View) - Figure 3. 8-Bump DSBGA (LMV7272) (bump side down) Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 5 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (TA = 25°C, Unless otherwise specified). VOS vs. VCM 800 VOS vs. VCM VSUPPLY = ±0.9V 800 VSUPPLY = ±1.35V -40°C -40°C 400 400 VOS (PV) VOS (PV) 25°C 0 0 85°C -400 -400 25°C 85°C -800 -800 -0.9 -0.7 -0.5 -0.3 -0.1 0.1 0.3 0.5 0.7 0.9 -1.35 -0.9 -0.45 VCM (V) Figure 4. Figure 5. VOS vs. VCM Short Circuit vs. Supply Voltage VSUPPLY = ±2.5V 400 VOS (PV) -40°C 0 -400 25°C 85°C -800 -2.5 -2 -1 0 0.9 1.35 1 40 SOURCE 30 20 SINK 10 2 2.5 VCM (V) 0 1.8 2.44 3.08 3.72 4.36 5.0 SUPPLY VOLTAGE (V) Figure 6. 6 0.45 VCM (V) SHORT CIRCUIT OUTPUT CURRENT (mA) 800 0 Figure 7. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) (TA = 25°C, Unless otherwise specified). Supply Current vs. Supply Voltage (LMV7271) Supply Current vs. Supply Voltage (LMV7272) 25 10 9 SUPPLY CURRENT (PA) SUPPLY CURRENT (PA) 85°C 85°C 85°C 8 25°C 7 6 20 15 25°C 10 -40°C 5 -40°C VOUT = HIGH 0 5 1.8 2.44 3.08 3.72 4.36 1.5 5.0 2 2.5 3 3.5 4 5 4.5 VSUPPLY (V) SUPPLY VOLTAGE (V) Figure 8. Figure 9. Supply Current vs. Supply Voltage (LMV7272) Output Positive Swing vs. VSUPPLY 600 25 20 500 V - VOUT (mV) 15 10 25°C + SUPPLY CURRENT (PA) ISOURCE 85°C -40°C 400 4mA 300 2mA 200 1.5mA 5 100 0.5mA VOUT = LOW 0 0 1.5 2 2.5 3 3.5 4 4.5 5 1.8 2.3 2.8 3.3 3.8 4.3 4.8 VSUPPLY (V) VSUPPLY (V) Figure 10. Figure 11. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 7 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) (TA = 25°C, Unless otherwise specified). Output Negative Swing vs. VSUPPLY Output Positive Swing vs. ISOURCE 600 0.8 VSUPPLY = 1.8V ISINK 0.7 500 85°C V - VOUT (V) 400 4mA - VOUT - V (mV) 0.6 300 25°C 0.4 + 2mA 0.5 200 0.3 1.5mA 0.2 -40°C 100 0.1 0.5mA 0 0 1.8 2.3 2.8 3.3 3.8 4.3 4.8 0 0.5 1 1.5 2 2.5 3 3.5 4 ISOURCE (mA) VSUPPLY (V) Figure 12. Figure 13. Output Negative Swing vs. ISINK Output Positive Swing vs. ISOURCE 0.5 0.8 VSUPPLY = 1.8V VSUPPLY = 2.7V 0.45 0.7 85°C 85°C 0.4 0.6 V - VOUT (V) - VOUT - V (V) 0.35 0.5 25°C 0.25 0.2 + 0.4 25°C 0.3 0.3 0.15 0.2 -40° 0.1 -40°C 0.1 0.05 0 0 0 0.5 1 1.5 2 2.5 3 3.5 4 ISINK (mA) 0.5 1 1.5 2 2.5 3 3.5 4 ISOURCE (mA) Figure 14. 8 0 Figure 15. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) (TA = 25°C, Unless otherwise specified). Output Negative Swing vs. ISINK Output Negative Swing vs. ISINK 0.5 0.4 VSUPPLY = 2.7V 0.45 VSUPPLY = 5V 85°C 85°C 0.4 0.35 25°C - 0.3 VOUT - V (V) - VOUT - V (V) 0.3 25°C 0.25 0.2 0.2 0.15 0.1 0.1 -40°C -40°C 0.05 0 0 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.5 1 1.5 Figure 16. 2.5 3 3.5 4 Figure 17. Output Positive Swing vs. ISOURCE Propagation Delay (tPLH) 5 OUTPUT VOLTAGE (V) 0.4 VSUPPLY = 5V 85°C 0.3 25°C VCC = 1.8V TEMP = 25°C LOAD = 5k: 50pF 4 3 50mV 20mV 2 1 0 0.2 | INPUT VOLTAGE (mV) + V - VOUT (V) 2 ISINK (mA) ISINK (mA) 0.1 -40°C 0 0 0.5 1 1.5 2 2.5 3 3.5 | 100 0 OVERDRIVE -100 4 0 500 1000 1500 2000 2500 3000 TIME (ns) ISOURCE (mA) Figure 18. Figure 19. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 9 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) (TA = 25°C, Unless otherwise specified). Propagation Delay (tPLH) VCC = 1.8 V 4 TEMP = 25°C 3 LOAD = 5k: 50pF 2 50mV 1 5 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) Propagation Delay (tPHL) 5 20mV 3 50mV 2 20mV 1 0 | | 100 OVERDRIVE 0 -100 0 500 1000 1500 INPUT VOLTAGE (mV) 0 INPUT VOLTAGE (mV) VCC = 2.7V TEMP = 25°C LOAD = 5k: 50pF 4 | | 100 0 OVERDRIVE -100 2000 2500 3000 0 500 Figure 20. Figure 21. Propagation Delay (tPLH) VCC = 2.7 V TEMP = 25°C LOAD = 5k: 50pF 4 3 5 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) Propagation Delay (tPHL) 50mV 1 20mV VCC = 5.0V TEMP = 25°C 3 LOAD = 5k: 50pF 20mV 2 1 OUTPUT VOLTAGE (V) 100 OVERDRIVE 0 -100 500 1000 1500 INPUT VOLTAGE (mV) | | | | 100 0 OVERDRIVE -100 2000 2500 3000 0 500 1000 1500 2000 TIME (ns) TIME (ns) Figure 22. Figure 23. Propagation Delay (tPHL) tPHL vs. Overdrive 5 8 VCC = 5.0 V TEMP = 25°C 3 LOAD = 5k: 50pF 7 4 2500 3000 VS = 5V 6 2 50mV 1 0 20mV | | 100 tPHL (PS) INPUT VOLTAGE (mV) 0 0 INPUT VOLTAGE (mV) 50mV 4 0 OVERDRIVE 5 4 VS = 2.7V 3 2 0 1 -100 VS = 1.8V 0 0 500 1000 1500 2000 2500 3000 TIME (ns) 0 10 100 1000 OVERDRIVE (mV) Figure 24. 10 1500 2000 2500 3000 TIME (ns) 5 2 1000 TIME (ns) Figure 25. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) (TA = 25°C, Unless otherwise specified). tPLH vs. Overdrive 5 VS = 5V 4.5 4 tPLH (PS) 3.5 3 2.5 VS = 2.7V 2 1.5 1 VS = 1.8V 0.5 0 1 10 100 1000 OVERDRIVE (mV) Figure 26. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 11 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com APPLICATION NOTES BASIC COMPARATOR A comparator is often used to convert an analog signal to a digital signal. As shown in Figure 28, the comparator compares an input voltage (VIN) to a reference voltage (VREF). If VIN is less than VREF, the output (VO) is low. However, if VIN is greater than VREF, the output voltage (VO) is high. Figure 27. LMV7271 V VREF + VO VIN + V - VOLTS VO VREF TIME VIN Figure 28. LMV7271 Basic Comparator RAIL-TO-RAIL INPUT STAGE The LMV727X has an input common mode voltage range (VCM) of −0.1V below the V− to 0.1V above V+. This is achieved by using paralleled PNP and NPN differential input pairs. When the VCM is near V+, the NPN pair is on and the PNP pair is off. When the VCM is near V−, the NPN pair is off and the PNP pair is on. The crossover point between the NPN and PNP input stages is around 950mV from V+. Since each input stage has its own offset voltage (VOS), the VOS of the comparator becomes a function of the VCM. See curves for VOS vs. VCM in Typical Performance Characteristics section. In application design, it is recommended to keep the VCM away from the crossover point to avoid problems. The wide input voltage range makes LMV727X ideal in power supply monitoring circuits, where the comparators are used to sense signals close to ground and power supplies. OUTPUT STAGE The LMV7271 and LMV7272 have a push-pull output stage. This output stage keeps the total system power consumption to the absolute minimum. The only current consumed is the low supply current and the current going directly into the load. When the output switches, both PMOS and NMOS at the output stage are on at the same time for a very short time. This allows current to flow directly between V+ and V− through output transistors. The result is a short spike of current (shoot-through current) drawn from the supply and glitches in the supply voltages. The glitches can spread to other parts of the board as noise. To prevent the glitches in supply lines, power supply bypass capacitors must be installed. See section for supply bypassing in the Application Notes for details. 12 Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 HYSTERESIS It is a standard procedure to use hysteresis (positive feedback) around a comparator, to prevent oscillation, and to avoid excessive noise on the output because the comparator is a good amplifier of its own noise. Inverting Comparator with Hysteresis The inverting comparator with hysteresis requires a three resistor network that is referenced to the supply voltage VCC of the comparator (Figure 29). When VIN at the inverting input is less than VA, the voltage at the noninverting node of the comparator (VIN < VA), the output voltage is high (for simplicity assume VO switches as high as VCC). The three network resistors can be represented as R1||R3 in series with R2. The lower input trip voltage VA1 is defined as VA1 = VCC R2 (R1||R3) + R2 (1) When VIN is greater than VA (VIN > VA), the output voltage is low and very close to ground. In this case the three network resistors can be presented as R2//R3 in series with R1. The upper trip voltage VA2 is defined as VA2 = VCC (R2||R3) R1 + (R2||R3) (2) The total hysteresis provided by the network is defined as ΔVA = VA1 - VA2 (3) A good typical value of ΔVA would be in the range of 5 to 50mV. This is easily obtained by choosing R3 as 1000 to 100 times (R1||R2) for 5V operation, or as 300 to 30 times (R1||R2) for 1.8V operation. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 13 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com Figure 29. Inverting Comparator with Hysteresis Non-Inverting Comparator with Hysteresis A non-inverting comparator with hysteresis requires a two resistor network, and a voltage reference (VREF) at the inverting input (Figure 30). When VIN is low, the output is also low. For the output to switch from low to high, VIN must rise up to VIN1, where VIN1 is calculated by (4) When VIN is high, the output is also high. To make the comparator switch back to its low state, VIN must equal VREF before VA will again equal VREF. VIN can be calculated by: (5) The hysteresis of this circuit is the difference between VIN1 and VIN2. ΔVIN = VCCR1/R2 14 (6) Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 Figure 30. Non-Inverting Comparator with Hysteresis CIRCUIT TECHNIQUES FOR AVOIDING OSCILLATIONS IN COMPARATOR APPLICATIONS Feedback to almost any pin of a comparator can result in oscillation. In addition, when the input signal is a slow voltage ramp or sine wave, the comparator may also burst into oscillation near the crossing point. To avoid oscillation or instability, PCB layout should be engineered thoughtfully. Several precautions are recommended: 1. Power supply bypassing is critical, and will improve stability and transient response. Resistance and inductance from power supply wires and board traces increase power supply line impedance. When supply current changes, the power supply line will move due to its impedance. Large enough supply line shift will cause the comparator to mis-operate. To avoid problems, a small bypass capacitor, such as 0.1uF ceramic, should be placed immediately adjacent to the supply pins. An additional 6.8μF or greater tantalum capacitor should be placed at the point where the power supply for the comparator is introduced onto the board. These capacitors act as an energy reservoir and keep the supply impedance low. In dual supply application, a 0.1μF capacitor is recommended to be placed across V+ and V− pins. 2. Keep all leads short to reduce stray capacitance and lead inductance. It will also minimize any unwanted coupling from any high-level signals (such as the output). The comparators can easily oscillate if the output lead is inadvertently allowed to capacitively couple to the inputs via stray capacitance. This shows up only during the output voltage transition intervals as the comparator changes states. Try to avoid a long loop which could act as an inductor (coil). 3. It is a good practice to use an unbroken ground plane on a printed circuit board to provide all components with a low inductive ground connection. Make sure ground paths are low-impedance where heavier currents are flowing to avoid ground level shift. Preferably there should be a ground plane under the component. 4. The output trace should be routed away from inputs. The ground plane should extend between the output and inputs to act as a guard. This can be achieved by running a topside ground plane between the output and inputs. A typical PCB layout is shown in Figure 31. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 15 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com V + OUT B OUT A -INA -INB +INA +INB V - Figure 31. Typical PCB Layout 5. When the signal source is applied through a resistive network to one input of the comparator, it is usually advantageous to connect the other input with a resistor with the same value, for both DC and AC consideration. Input traces should be laid out symmetrically if possible. 6. All pins of any unused comparators should be tied to the negative supply. DSBGA LIGHT SENSITIVITY Exposing the DSBGA device to direct sunlight will cause mis-operation of the device. Light sources such as Halogen lamps can also affect electrical performance if brought near to the device. The wavelengths, which have the most detrimental effect, are reds and infrareds. DSBGA MOUNTING The DSBGA package requires specific mounting techniques, which are detailed in Application Note AN-1112 (SNVA009). LMV7272 DSBGA to DIP Conversion Board To facilitate characterization and testing, a DSBGA to DIP conversion board, LMV7272TLCONV, is available. It is a 2-layer board, with the LMV7272 mounted on the bottom layer, and a capacitor (C1, between the positive and negative supplies) added to the top layer. LMV7272 + OUTB LMV7272 (DSBGA) (Bottom Layer) V -INB OUTA +INB -INA - +INA V C1 (Top Layer) Figure 32. LMV7272TLCONV Diagram Typical Applications UNIVERSAL LOGIC LEVEL SHIFTER The output of LMV7275 is an unconnected drain of an NMOS device, which can be pulled up, through a resistor, to any desired output level within the permitted power supply range. Hence, the following simple circuit works as a universal logic level shifter, pulling up the signal to the desired level. 16 Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 VB VA LOGIC IN REXT - 1k: LOGIC OUT LMV7275 + 1k: Figure 33. Logic Level Shifter POSITIVE PEAK DETECTOR A positive peak detect circuit is basically a comparator operated in a unity gain follower configuration, with a capacitor as a load to maintain the highest voltage. A diode is added at the output to prevent the capacitor from discharging through the pull-up resistor, and a 1MΩ resistor added in parallel to the capacitor to provide a high impedance discharge path. When the input VIN increases, the inverting input of the comparator follows it, thus charging the capacitor. When it decreases, the cap discharges through the 1MΩ resistor. The decay time can be modified by changing the resistor. The output should be accessed through a follower circuit to prevent loading. +VCC VIN R1 1k: + - VOUT C1 10PF + R2 1M: Figure 34. Positive Peak Detector OR'ING THE OUTPUT Since the output is an unconnected NMOS drain, many drains can be tied together, pulled up to VDD by a single resistor to provide an output OR'ing function. If any of the comparator outputs is pulled low the output VO goes down. Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 17 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com Figure 35. OR’ing the Outputs NEGATIVE PEAK DETECTOR For the negative detector, the output transistor of the comparator acts as a low impedance current sink. Since there is no pull-up resistor, the only discharge path will be the 1MΩ resistor and any load impedance used. Decay time is changed by varying the 1MΩ resistor. +VCC VIN + VOUT - R1 1M: + C1 10PF -VCC Figure 36. Negative Peak Detector SQUARE WAVE GENERATOR A typical application for a comparator is as a square wave oscillator. The circuit below generates a square wave whose period is set by the RC time constant of the capacitor C1and resistor R4. The maximum frequency is limited by the large signal propagation delay of the comparator, and by the capacitive loading at the output, which limits the output slew rate. 18 Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 LMV7271 www.ti.com SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 + V 4.3k: R4 = 100k: C1 = 750pF VC VO + R1 = 100k: VA R3 = 100k: + R2 = 100k: V 0 f | 10KHz Figure 37. Squarewave Oscillator To analyze the circuit, consider it when the output is high. That implies that the inverted input (VC) is lower than the non-inverting input (VA). This causes the C1 to get charged through R4, and the voltage VC increases till it is equal to the non-inverting input. The value of VA at this point is VCC.R2 VA1 = R2 + R1||R3 (7) If R1 = R2 = R3, then VA1 = 2VCC/3 At this point the comparator switches pulling down the output to the negative rail. The value of VA at this point is VCC (R2||R3) VA2 = R1 + (R2||R3) (8) If R1 = R2 = R3, then VA2 = VCC/3 The capacitor C1 now discharges through R4, and the voltage VC decreases till it is equal to VA2, at which point the comparator switches again, bringing it back to the initial stage. The time period is equal to twice the time it takes to discharge C1 from 2VCC/3 to VCC/3, which is given by R4C1.ln2. Hence the formula for the frequency is: F = 1/(2·R4·C1·ln2) Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 19 LMV7271 SNOSA56H – FEBRUARY 2003 – REVISED FEBRUARY 2013 www.ti.com REVISION HISTORY Changes from Revision G (February 2013) to Revision H • 20 Page Changed layout of National Data Sheet to TI format .......................................................................................................... 19 Submit Documentation Feedback Copyright © 2003–2013, Texas Instruments Incorporated Product Folder Links: LMV7271 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) LMV7271MF ACTIVE SOT-23 DBV 5 1000 TBD Call TI Call TI -40 to 85 C25A LMV7271MF/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C25A LMV7271MFX/NOPB ACTIVE SOT-23 DBV 5 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C25A LMV7271MG ACTIVE SC70 DCK 5 1000 TBD Call TI Call TI -40 to 85 C34 LMV7271MG/NOPB ACTIVE SC70 DCK 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C34 LMV7271MGX ACTIVE SC70 DCK 5 3000 TBD Call TI Call TI -40 to 85 C34 LMV7271MGX/NOPB ACTIVE SC70 DCK 5 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C34 LMV7272TL/NOPB ACTIVE DSBGA YZR 8 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 C 01 LMV7272TLX/NOPB ACTIVE DSBGA YZR 8 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM -40 to 85 C 01 LMV7275MF ACTIVE SOT-23 DBV 5 1000 TBD Call TI Call TI -40 to 85 C26A LMV7275MF/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C26A LMV7275MFX ACTIVE SOT-23 DBV 5 3000 TBD Call TI Call TI -40 to 85 C26A LMV7275MFX/NOPB ACTIVE SOT-23 DBV 5 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C26A LMV7275MG ACTIVE SC70 DCK 5 1000 TBD Call TI Call TI -40 to 85 C35 LMV7275MG/NOPB ACTIVE SC70 DCK 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C35 LMV7275MGX ACTIVE SC70 DCK 5 3000 TBD Call TI Call TI -40 to 85 C35 LMV7275MGX/NOPB ACTIVE SC70 DCK 5 3000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 C35 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 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. 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 14-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) LMV7271MF SOT-23 DBV 5 1000 178.0 8.4 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3.2 3.2 1.4 4.0 8.0 Q3 LMV7271MF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7271MFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7271MG SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7271MG/NOPB SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7271MGX SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7271MGX/NOPB SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7272TL/NOPB DSBGA YZR 8 250 178.0 8.4 1.7 1.7 0.76 4.0 8.0 Q1 LMV7272TLX/NOPB DSBGA YZR 8 3000 178.0 8.4 1.7 1.7 0.76 4.0 8.0 Q1 LMV7275MF SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7275MF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7275MFX SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7275MFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV7275MG SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7275MG/NOPB SC70 DCK 5 1000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7275MGX SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 LMV7275MGX/NOPB SC70 DCK 5 3000 178.0 8.4 2.25 2.45 1.2 4.0 8.0 Q3 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 14-Mar-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMV7271MF SOT-23 DBV 5 1000 210.0 185.0 35.0 LMV7271MF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMV7271MFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 LMV7271MG SC70 DCK 5 1000 210.0 185.0 35.0 LMV7271MG/NOPB SC70 DCK 5 1000 210.0 185.0 35.0 LMV7271MGX SC70 DCK 5 3000 210.0 185.0 35.0 LMV7271MGX/NOPB SC70 DCK 5 3000 210.0 185.0 35.0 LMV7272TL/NOPB DSBGA YZR 8 250 210.0 185.0 35.0 LMV7272TLX/NOPB DSBGA YZR 8 3000 210.0 185.0 35.0 LMV7275MF SOT-23 DBV 5 1000 210.0 185.0 35.0 LMV7275MF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMV7275MFX SOT-23 DBV 5 3000 210.0 185.0 35.0 LMV7275MFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 LMV7275MG SC70 DCK 5 1000 210.0 185.0 35.0 LMV7275MG/NOPB SC70 DCK 5 1000 210.0 185.0 35.0 LMV7275MGX SC70 DCK 5 3000 210.0 185.0 35.0 LMV7275MGX/NOPB SC70 DCK 5 3000 210.0 185.0 35.0 Pack Materials-Page 2 MECHANICAL DATA YZR0008xxx D 0.600±0.075 E TLA08XXX (Rev C) D: Max = 1.55 mm, Min = 1.489 mm E: Max = 1.55 mm, Min = 1.489 mm 4215045/A NOTES: A. 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