Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Op-amp Multi-purpose SOT 23 5

0.1

1 10 1k 10k

FREQUENCY (Hz)

100

1000

100

VOLTAGE NOISE (nV/

Hz)

2.5V

OUT

- R

= C

+ C

LMV793, LMV794

www.ti.com

SNOSAX6D –MARCH 2007–REVISED MARCH 2013

LMV793/LMV794 88 MHz, Low Noise, 1.8V CMOS Input, Decompensated Operational

Amplifiers

Check for Samples: LMV793, LMV794

FEATURES

DESCRIPTION

The LMV793 (single) and the LMV794 (dual) CMOS

(Typical 5V Supply, Unless Otherwise Noted)

input operational amplifiers offer a low input voltage

• Input Referred Voltage Noise 5.8 nV/√Hz

noise density of 5.8 nV/√Hz while consuming only

• Input Bias Current 100 fA

1.15 mA (LMV793) of quiescent current. The

LMV793/LMV794 are stable at a gain of 10 and have

• Gain Bandwidth Product 88 MHz

a gain bandwidth product (GBW) of 88 MHz. The

• Supply Current per Channel

LMV793/LMV794 have a supply voltage range of

– LMV793 1.15 mA

1.8V to 5.5V and can operate from a single supply.

The LMV793/LMV794 each feature a rail-to-rail

– LMV794 1.30 mA

output stage capable of driving a 600Ω load and

• Rail-to-Rail Output Swing

sourcing as much as 60 mA of current.

– @ 10 kΩ Load 25 mV from Rail

The LMV793/LMV794 provide optimal performance in

– @ 2 kΩ Load 45 mV from Rail

low voltage and low noise systems. A CMOS input

• Ensured 2.5V and 5.0V Performance

stage, with typical input bias currents in the range of

a few femto-Amperes, and an input common mode

• Total Harmonic Distortion 0.04% @1 kHz, 600Ω

voltage range, which includes ground, make the

• Temperature Range −40°C to 125°C

LMV793/LMV794 ideal for low power sensor

applications where high speeds are needed.

APPLICATIONS

The LMV793/LMV794 are manufactured using TI’s

• ADC Interface

advanced VIP50 process. The LMV793 is offered in

• Photodiode Amplifiers

either a 5-Pin SOT23 or an 8-Pin SOIC package. The

LMV794 is offered in either the 8-Pin SOIC or the 8-

• Active Filters and Buffers

Pin VSSOP.

• Low Noise Signal Processing

• Medical Instrumentation

• Sensor Interface Applications

Typical Application

Figure 1. Photodiode Transimpedance Amplifier Figure 2. Input Referred Voltage Noise vs.

Frequency

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.

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 (33 pages)

PAGE 1
LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 LMV793/LMV794 88 MHz, Low Noise, 1.8V CMOS Input, Decompensated Operational Amplifiers Check for Samples: LMV793, LMV794 FEATURES DESCRIPTION 1 (Typical 5V Supply, Unless Otherwise Noted) 2 • • • • • • • • Input Referred Voltage Noise 5.8 nV/√Hz Input Bias Current 100 fA Gain Bandwidth Product 88 MHz Supply Current per Channel – LMV793 1.15 mA – LMV794 1.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 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) Human Body Model ESD Tolerance (3) 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.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 2.5V Electrical Characteristics(1) (continued) Unless otherwise specified, all limits are specified for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbol IB Parameter Input Bias Current Conditions VCM = 1.0V (5) (6) Min Typ Max −40°C ≤ TA ≤ 85°C 0.05 1 25 −40°C ≤ TA ≤ 125°C 0.05 1 100 (2) (3) IOS Input Offset Current VCM = 1.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com 5V Electrical Characteristics (1) Unless otherwise specified, all limits are specified for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes. Symbol VOS Parameter Conditions Min (2) Input Offset Voltage TC VOS IB Input Offset Voltage Temperature Drift Input Bias Current (4) Typ Max Units 0.1 ±1.35 ±1.65 mV (3) LMV793 −1.0 LMV794 −1.8 VCM = 2.0V (5) (6) 0.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 5V Electrical Characteristics(1) (continued) Unless otherwise specified, all limits are specified for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2 = VO. Boldface limits apply at the temperature extremes.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. Supply Current vs. Supply Voltage (LMV793) Supply Current vs. Supply Voltage (LMV794) 2 2 1.6 1.6 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 125°C 125°C 25°C 1.2 0.8 -40°C 0.4 0 1.5 2.5 3.5 4.5 25°C 1.2 -40°C 0.8 0.4 0 1.5 5.5 6.0 2.5 3.5 + 4.5 5.5 6 + V (V) V (V) Figure 6. Figure 7.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. Slew Rate vs. Supply Voltage Input Bias Current vs. VCM 36 1.5 34 1 + V = 5V -40°C 0.5 0 IBIAS (pA) SLEW RATE (V/Ps) RISING EDGE 32 30 28 -0.5 25°C -1 -1.5 26 FALLING EDGE -2 24 -2.5 22 1.5 -3 2.5 3.5 4.5 5.5 0 1 2 + V (V) Figure 12. 4 Figure 13. Input Bias Current vs.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. Sinking Current vs. Output Voltage Positive Output Swing vs. Supply Voltage 40 30 RLOAD = 10 k: 35 VOUT FROM RAIL (mV) 125°C 25 ISINK (mA) 20 25°C 15 10 -40°C 5 125°C 25 25°C 20 -40°C 15 10 5 0 1.8 0 0 1 2 3 4 5 2.5 3.2 VOUT (V) V (V) Figure 18. Figure 19. 5.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. Negative Output Swing vs. Supply Voltage Time Domain Voltage Noise 120 VS = ±2.5V 125°C RLOAD = 600: VCM = 0.0V 25°C 80 400 nV/DIV VOUT FROM RAIL (mV) 100 -40°C 60 40 20 0 1.8 2.5 3.2 3.9 4.6 5.3 1S/DIV 6 + V (V) Figure 24. Figure 25. Input Referred Voltage Noise vs.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. THD+N vs. Peak-to-Peak Output Voltage (VOUT) THD+N vs. Peak-to-Peak Output Voltage (VOUT) -40 -40 -50 THD+N (dB) THD+N (dB) -50 -60 RL = 600: -70 V+ = 2.5V f = 1 kHz AV = +10 -80 0.01 1 -70 -80 V+ = 5V f = 1 kHz AV = +10 -90 0.01 RL = 100 k: 0.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise specified, TA = 25°C, V– = 0, V+ = Supply Voltage = 5V, VCM = V+/2. Large Signal Transient Response, AV = +10 10 mV/DIV 200 mV/DIV Small Signal Transient Response, AV = +10 VIN = 100 mVPP VIN = 2 mVPP f = 1 MHz, AV = +10 f = 1 MHz, AV = +10 V = 2.5V, CL = 10 pF V = 5V, CL = 10 pF + + 100 ns/DIV 100 ns/DIV Figure 36. Figure 37. PSRR vs. Frequency CMRR vs.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com APPLICATION INFORMATION ADVANTAGES OF THE LMV793/LMV794 Wide Bandwidth at Low Supply Current The LMV793/LMV794 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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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 100 100 PHASE 80 80 GAIN (dB) GAIN 40 40 20 20 0 0 -20 1k 10k 100k PHASE (°) 60 60 1M 10M -20 100M FREQUENCY (Hz) 100 100 80 80 60 60 40 40 20 20 0 0 -20 1k 10k 100k 1M 10M PHASE (°) GAIN (dB) Figure 41. LMV793 AVOL vs. Frequency -20 100M FREQUENCY (Hz) Figure 42. LMV796 AVOL vs.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com Having a higher frequency for the dominate pole will result in: 1. The DC open-loop gain (AVOL) extending to a higher frequency. 2. A wider closed loop bandwidth. 3. Better slew rate due to reduced compensation capacitance within the op amp. The second open loop pole (f2) for the LMV793/LMV794 occurs at 45 MHz. The unity gain (fu’) occurs after the second pole at 51 MHz.
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LMV793, LMV794 www.ti.com © § ¨ ¨ © F § = ¨¨1 + RF §¨1 + s(Rc + RIN || RF) C 1 + sRcC RIN ¨ © § ¨ ¨ © 1 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 (4) where 1/F's pole is located at 1 fp = 2SRcC (5) 1/F's zero is located at 1 fz = 2S Rc + RIN || RF)C (6) 1 F =1+ f=0 RF RIN (7) The circuit gain for Figure 44 at low frequencies is −RF/RIN, but F, the feedback factor is not equal to the circuit gain.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com 100 PHASE ADDITIONAL COMPENSATION GAIN (dB) and PHASE (°C) 80 AVOL 60 45° PHASE MARGIN 40 20 1 with ADDITIONAL F COMPENSATION 1 F 0 -20 1k 2nd POLE f2 10k 100k 1M GBP 10M 100M FREQUENCY (Hz) Figure 45.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Figure 47. C Increased to 2.2 nF, Gain = −1 Some over-compensation appears to be needed for the desired overshoot characteristics. Instead of intersecting the AVOL curve at 18 dB, 2 dB of over-compensation will be used, and the AVOL curve will be intersected at 20 dB. Using Equation 8 for 20 dB, or 10 V/V, the closest standard value of RC is 240Ω. The following two waveforms show the new resistor value with C = 390 pF and 2.2 nF.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com To summarize, the following steps were taken to compensate the LMV793 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 2.2 nF which moved the pole of F, the feedback factor, farther away from the AVOL curve. 3.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Figure 52. LMV796 Response Gain = +2 The response shown in Figure 51 is close to the response shown in Figure 49. The part is actually slightly faster in the non-inverting configuration. Decreasing the value of RC to around 200Ω can decrease the negative overshoot but will have slightly longer rise and fall times. The other option is to add a small resistor in series with the input signal.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com Figure 54. RC = 330Ω and C = 10 nF, Gain = +1 Figure 55. LMV796 Response Gain = +1 With no increase in power consumption the decompensated op amp offers faster speed over the compensated equivalent part. These examples used RF = 2 kΩ. This value is high enough to be easily driven by the LMV793/LMV794, yet small enough to minimize the effects from the parasitic capacitance of both the PCB and the op amp.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 CF 2.5V 2.5V RF DPHOTO CD LMV793 CCM VOUT + -2.5V Figure 56. Transimpedance Amplifier Figure 56 is the complete schematic for a transimpedance amplifier. Only the supply bypass capacitors are not shown. CD represents the photo diode capacitance which is given on its datasheet.
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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 A= ZGBW Z = www.ti.com ´ ¶GBW ´ ¶ (15) The expression fGBW is the gain bandwidth product of the part. For a unity gain stable part this is the frequency where A = 1. For the LMV793 fGBW = 88 MHz. Multiplying A and F results in the following equation: ´ ¶ GBW ´ ¶ ´ ¶ x 1 + sCFRF 1 + sRF (CF + CIN) § CFRF ¨ ¨ © CFRF 1+ x 1+ § ¨ ¨ © = 2 =1 RF (CF + CIN) CFRF § ¨ ¨ © P ´ ¶ GBW § ¨ ¨ © AF ´ = ¶ 2 (16) For the above equation s = jω.
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LMV793, LMV794 www.ti.com SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 Figure 59. Rise Time In Figure 58 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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LMV793, LMV794 SNOSAX6D – MARCH 2007 – REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision C (March 2013) to Revision D • 24 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 (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.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-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) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LMV793MAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMV793MF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMV793MFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Mar-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMV793MAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LMV793MF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMV793MFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 LMV794MAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LMV794MM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LMV794MMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.
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