Datasheet

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LMP7717, LMP7718

www.ti.com

SNOSAY7H –MARCH 2007–REVISED MARCH 2013

88 MHz, Precision, Low Noise, 1.8V CMOS Input, Decompensated Operational Amplifier

Check for Samples: LMP7717, LMP7718

FEATURES

DESCRIPTION

The LMP7717 (single) and the LMP7718 (dual) low

• (Typical 5V Supply, Unless Otherwise Noted)

noise, CMOS input operational amplifiers offer a low

• Input Offset Voltage: ±150 µV (max)

input voltage noise density of 5.8 nV/√Hz while

• Input Referred Voltage Noise: 5.8 nV/√Hz

consuming only 1.15 mA (LMP7717) of quiescent

current. The LMP7717/LMP7718 are stable at a gain

• Input Bias Current: 100 fA

of 10 and have a gain bandwidth (GBW) product of

• Gain Bandwidth Product: 88 MHz

88 MHz. The LMP7717/LMP7718 have a supply

• Supply Voltage Range: 1.8V to 5.5V

voltage range of 1.8V to 5.5V and can operate from a

single supply. The LMP7717/LMP7718 each feature a

• Supply Current Per Channel

rail-to-rail output stage. Both amplifiers are part of the

– LMP7717: 1.15 mA

LMP™ precision amplifier family and are ideal for a

– LMP7718: 1.30 mA

variety of instrumentation applications.

• Rail-to-Rail Output Swing

The LMP7717 family provides optimal performance in

– @ 10 kΩ Load: 25 mV from Rail

low voltage and low noise systems. A CMOS input

stage, with typical input bias currents in the range of

– @ 2 kΩ Load: 45 mV from Rail

a few femto-Amperes, and an input common mode

• Ensured 2.5V and 5.0V Performance

voltage range, which includes ground, make the

• Total Harmonic Distortion: 0.04% @1 kHz,

LMP7717/LMP7718 ideal for low power sensor

600Ω

applications where high speeds are needed.

• Temperature Range: −40°C to 125°C

The LMP7717/LMP7718 are manufactured using TI’s

advanced VIP50 process. The LMP7717 is offered in

APPLICATIONS

either a 5-Pin SOT-23 or an 8-Pin SOIC package.

The LMP7718 is offered in either the 8-Pin SOIC or

• ADC Interface

the 8-Pin VSSOP.

• Photodiode Amplifiers

• Active Filters and Buffers

• Low Noise Signal Processing

• Medical Instrumentation

• Sensor Interface Applications

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.

2LMP is a trademark of Texas Instruments.

3All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (36 pages)

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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 88 MHz, Precision, Low Noise, 1.8V CMOS Input, Decompensated Operational Amplifier Check for Samples: LMP7717, LMP7718 FEATURES DESCRIPTION • • • • • • • The LMP7717 (single) and the LMP7718 (dual) low noise, CMOS input operational amplifiers offer a low input voltage noise density of 5.8 nV/√Hz while consuming only 1.15 mA (LMP7717) of quiescent current.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com Typical Application CF RF IIN CCM + + VOUT CD - VB CIN = CD + CCM VOUT = - RF IIN Figure 1. Photodiode Transimpedance Amplifier VOLTAGE NOISE (nV/ Hz) 1000 5V 100 2.5V 10 1 0.1 1 10 100 1k 10k FREQUENCY (Hz) Figure 2. Input Referred Voltage Noise vs. Frequency These devices have limited built-in ESD protection.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 Absolute Maximum Ratings (1) (2) ESD Tolerance (3) Human Body Model 2000V Machine Model 200V Charge-Device Model 1000V VIN Differential ±0.3V Supply Voltage (V+ – V−) 6.0V Input/Output Pin Voltage V+ +0.3V, V− −0.3V −65°C to 150°C Storage Temperature Range Junction Temperature (4) +150°C For soldering specifications: see product folder at www.ti.com/ and http://www.ti.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com 2.5V Electrical Characteristics (1) Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbol Parameter Min (2) Conditions Typ (3) Max (2) Units ±20 ±180 ±480 µV ±4 μV/°C VOS Input Offset Voltage TC VOS Input Offset Voltage Temperature Drift (4) (5) LMP7717 −1.0 LMP7718 −1.8 Input Bias Current VCM = 1.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 2.5V Electrical Characteristics(1) (continued) Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com 5V Electrical Characteristics (1) Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbo l VOS Parameter Min (2) Conditions Input Offset Voltage Typ (3) Max (2) Units ±10 ±150 ±450 µV ±4 μV/°C TC VOS Input Offset Voltage Temperature Drift (4) (5) LMP7717 −1.0 LMP7718 −1.8 IB VCM = 2.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 5V Electrical Characteristics(1) (continued) Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbo l IS SR Typ (3) Max (2) LMP7717 1.15 1.40 1.75 LMP7718 per channel 1.30 1.70 2.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. TCVOS Distribution (LMP7717) Offset Voltage Distribution 25 25 VS = 5V -40°C d TA d 125qC VS = 2.5V, 5V PERCENTAGE (%) PERCENTAGE (%) UNITS TESTED: 10,000 15 VCM = VS/2 UNITS TESTED: 10,000 20 20 V CM = VS/2 10 5 15 10 5 0 -4 -3 -2 -1 0 1 0 -200 2 100 Figure 6. Figure 7.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. Offset Voltage vs. VCM Offset Voltage vs. VCM 200 200 VS = 2.5V VS = 5V 150 -40°C OFFSET VOLTAGE (PV) OFFSET VOLTAGE (PV) 150 100 25°C 50 0 125°C -50 -100 -150 -40°C 50 25°C 0 125°C -50 -100 -150 -200 -0.3 0 0.3 0.6 0.9 1.2 1.5 1.8 -200 -0.3 2.1 0.7 1.7 2.7 3.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. Sourcing Current vs. Supply Voltage 200 80 150 70 100 50 25°C 0 125°C -50 125°C 60 -40°C ISOURCE (mA) OFFSET VOLTAGE (PV) Offset Voltage vs. Supply Voltage -40°C 50 25°C 40 30 -100 20 -150 10 0 -200 1.5 2.5 3.5 4.5 5.5 1 6 2 3 4 5 6 + VS (V) V (V) Figure 18. Figure 19.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. Negative Output Swing vs. Supply Voltage Positive Output Swing vs. Supply Voltage 25 50 -40°C 45 20 VOUT FROM RAIL (mV) VOUT FROM RAIL (mV) 25°C 15 125°C 10 5 125°C 40 25°C 35 30 25 20 -40°C 15 10 RLOAD = 10 k: 0 1.8 2.5 3.2 5 3.9 4.6 5.3 RLOAD = 2 k: 0 1.8 2.5 3.2 6 3.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. Overshoot and Undershoot vs. CLOAD Time Domain Voltage Noise 70 OVERSHOOT AND UNDERSHOOT % VS = ±2.5V 400 nV/DIV VCM = 0.0V US% 60 50 OS% 40 30 20 10 0 1 s/DIV 20 0 40 80 60 100 120 CLOAD (pF) Figure 30. Figure 31. THD+N vs. Frequency THD+N vs. Frequency 0.04 0.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. Closed Loop Output Impedance vs. Frequency Open Loop Gain and Phase 100 1000 100 80 60 60 GAIN 40 40 20 20 + V = 5V 0 CL = 20 pF RL = 2 k:, 10 k: -20 100k 1M OUTPUT IMPEDANCE (:) 80 PHASE (°) GAIN (dB) PHASE 100 10 1 0 -20 100M 10M 0.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = 5V, VS = V+ - V−, VCM = VS/2. PSRR vs. Frequency Large Signal Transient Response, AV = +10 100 -PSRR, 5V 90 PSRR (dB) 200 mV/DIV 80 -PSRR, 2.5V +PSRR, 5V +PSRR, 2.5V 70 60 VIN = 100 mVPP 50 f = 1 MHz, AV = +10 + V = 5V, CL = 10 pF 40 100 100 ns/DIV 1k 10k 100k 1M FREQUENCY (Hz) Figure 42. Figure 43. CMRR vs.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 APPLICATION INFORMATION ADVANTAGES OF THE LMP7717/LMP7718 Wide Bandwidth at Low Supply Current The LMP7717/LMP7718 are high performance op amps that provide a GBW of 88 MHz with a gain of 10 while drawing a low supply current of 1.15 mA. This makes them ideal for providing wideband amplification in data acquisition applications.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com 100 100 100 80 80 80 80 60 60 60 60 40 40 20 20 0 0 100 20 20 0 0 -20 1k 10k 100k 1M -20 100M 10M -20 1k 10k 100k 1M 10M PHASE (°) 40 GAIN (dB) GAIN 40 PHASE (°) GAIN (dB) PHASE -20 100M FREQUENCY (Hz) FREQUENCY (Hz) Figure 46. LMP7717 AVOL vs. Frequency Figure 47. LMP7715 AVOL vs.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 Input Lead-Lag Compensation The recommended technique which allows the user to compensate the LMP7717/LMP7718 for stable operation at any gain is lead-lag compensation. The compensation components added to the circuit allow the user to shape the feedback function to make sure there is sufficient phase margin when the loop gain is as low as 0 dB and still maintain the advantages over the unity gain op amp.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 f=f © § ¨ ¨ © F = ¨¨1 + RIN || RF RF §¨ 1+ RC RIN ¨© § ¨ ¨ © § 1 www.ti.com (8) From this formula, we can see that • 1/F's zero is located at a lower frequency compared with 1/F's pole. • 1/F's value at low frequency is 1 + RF/RIN. • This method creates one additional pole and one additional zero.
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LMP7717, LMP7718 www.ti.com RF RIN § ¨ ¨ © + § ¨ ¨1 © + RIN || RF RC § ¨ ¨ © § ¨1 ¨ © SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 = 18 dB = 7.9 (9) Now set RF = RIN = R. With these values and solving for RC we have RC = R/5.9. Note that the value of C does not affect the ratio between the resistors. Once the value of the resistors is set, then the position of the pole in F must be set. A 2 kΩ resistor is used for RF and RIN in this design.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com Figure 53. RC = 240Ω and C = 390 pF, Gain = −1 Figure 54. RC = 240Ω and C = 2.2 nF, Gain = −1 To summarize, the following steps were taken to compensate the LMP7717 for a gain of −1: 1. Values for Rc and C were calculated from the Bode plot to give an expected phase margin of 45°. The values were based on RIN = RF = 2 kΩ. These calculations gave Rc = 330Ω and C = 390 pF. 2. To reduce the ringing C was increased to 2.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 For large signal response the rise and fall times are dominated by the slew rate of the op amps. Even though both parts are quite similar the LMP7717 will give rise and fall times about 2.5 times faster than the LMP7715. This is possible because the LMP7717 is a decompensated op amp and even though it is being used at a gain of −1, the speed is preserved by using a good technique for external compensation.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com RF RC RP LMP7717 C + Figure 58. LMP7717 with Lead-Lag Compensation for Non-Inverting Configuration Figure 58 is the result of using Equation 5 and additional experimentation in the lab. RP is not part of Equation 5, but it is necessary to introduce another pole at the input stage for good performance at gain = +1. Equation 5 is shown below with RIN = ∞. + RF Rc § ¨ ¨ © § ¨1 ¨ © = 18 dB = 7.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 Figure 60. LMP7715 Response Gain = +1 With no increase in power consumption the decompensated op amp offers faster speed than the compensated equivalent part . These examples used RF = 2 kΩ. This value is high enough to be easily driven by the LMP7717/LMP7718, yet small enough to minimize the effects from the parasitic capacitance of both the PCB and the op amp.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com Figure 61 is the complete schematic for a transimpedance amplifier. Only the supply bypass capacitors are not shown. CD represents the photodiode capacitance which is given on its datasheet. CCM is the input common mode capacitance of the op amp and, for the LMP7717 it is shown in the last graph of the TYPICAL PERFORMANCE CHARACTERISTICS section of this datasheet.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 For the above equation s = jω. To find the actual amplitude of the equation the square root of the square of the real and imaginary parts are calculated. At the intersection of F and A, we have: Z= 1 CFRF (17) After a bit of algebraic manipulation the above equation reduces to: §C + C IN ¨ F ¨ CF © § ¨ ¨ © 1+ 2 2 = 8S2 ´ ¶GBW RF CF 2 2 (18) In the above equation the only unknown is CF.
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LMP7717, LMP7718 SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 www.ti.com Figure 64. Rise Time In Figure 63 the ringing and the hump during the on time is from the laser. The higher drive levels for the laser gave ringing in the light source as well as light changing from the thermal characteristics. The hump is due to the thermal characteristics. Solving for CF using a 100 kΩ feedback resistor, the calculated value is 0.54 pF. One of the problems with more gain is the very small value for CF. A 0.
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LMP7717, LMP7718 www.ti.com SNOSAY7H – MARCH 2007 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision G (March 2013) to Revision H • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LMP7717MAE/NOPB Package Package Pins Type Drawing SOIC SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant D 8 250 178.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP7717MAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP7717MF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMP7717MAE/NOPB SOIC D LMP7717MAX/NOPB SOIC D 8 250 210.0 185.0 35.0 8 2500 367.0 367.0 35.0 LMP7717MF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMP7717MFE/NOPB SOT-23 DBV 5 250 210.0 185.0 35.0 LMP7717MFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 LMP7718MAE/NOPB SOIC D 8 250 210.0 185.0 35.
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