Datasheet

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DESCRIPTION

The OPA843 provides a level of speed and dynamic range

previously unattainable in a monolithic op amp. Using a high

Gain Bandwidth (GBW), two gain-stage design, the OPA843

gives a medium gain range device with exceptional dynamic

range. The “classic” differential input complements this high

dynamic range with DC precision beyond most high-speed

amplifier products. Very low input offset voltage and current,

high Common-Mode Rejection Ratio (CMRR) and Power-

Supply Rejection Ratio (PSRR), and high open-loop gain

combine to give a high DC precision amplifier along with low

noise and high 3rd-order intercept.

12- to 16-bit converter interfaces will benefit from this combi-

nation of features. High-speed transimpedance applications

can be implemented with exceptional DC precision as well.

Differential configurations using two OPA843s can deliver

very low distortion to high output voltages, as shown below.

FEATURES

● HIGH BANDWIDTH: 260MHz (G = +5)

● GAIN BANDWIDTH PRODUCT: 800MHz

● LOW INPUT VOLTAGE NOISE: 2.0nV/

√Hz

● VERY LOW DISTORTION: –96dBc (5MHz)

● HIGH OPEN-LOOP GAIN: 110dB

● FAST 12-BIT SETTLING: 10.5ns (0.01%)

● LOW INPUT OFFSET VOLTAGE: 300µV

● OUTPUT CURRENT: ±100mA

APPLICATIONS

● ADC/DAC BUFFER AMPLIFIER

● LOW DISTORTION “IF” AMPLIFIER

● ACTIVE FILTERS

● LOW-NOISE RECEIVER

● WIDEBAND TRANSIMPEDANCE

● TEST INSTRUMENTATION

● PROFESSIONAL AUDIO

● OPA643 UPGRADE

OPA843

SBOS268C – DECEMBER 2002 – DECEMBER 2008

www.ti.com

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

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.

Wideband, Low Distortion, Medium Gain,

Voltage-Feedback OPERATIONAL AMPLIFIER

INPUT NOISE GAIN-BANDWIDTH

SINGLES VOLTAGE (nV/

√Hz

) PRODUCT (MHz)

OPA842 2.6 200

OPA846 1.2 1750

OPA847 0.85 3900

OPA843 RELATED PRODUCTS

= 10V

1:1

50Ω

132Ω

OPA843

+5V

–5V

Very Low Distortion Differential Driver

400Ω

402Ω

40.2Ω

402Ω

DIFFERENTIAL DISTORTION vs OUTPUT VOLTAGE

Output Voltage Swing (Vp-p)

Harmonic Distortion (dBc)

101

–85

–90

–95

–100

–105

–110

= 10

= 400Ω

F = 5MHz

2nd-Harmonic

3rd-Harmonic

Summary of content (29 pages)

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OPA843 OPA 843 www.ti.com SBOS268C – DECEMBER 2002 – DECEMBER 2008 Wideband, Low Distortion, Medium Gain, Voltage-Feedback OPERATIONAL AMPLIFIER FEATURES DESCRIPTION ● HIGH BANDWIDTH: 260MHz (G = +5) The OPA843 provides a level of speed and dynamic range previously unattainable in a monolithic op amp. Using a high Gain Bandwidth (GBW), two gain-stage design, the OPA843 gives a medium gain range device with exceptional dynamic range.
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ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS(1) Power Supply ............................................................................... ±6.5VDC Internal Power Dissipation ...................................... See Thermal Analysis Differential Input Voltage .................................................................. ±1.2V Input Voltage Range ............................................................................ ±VS Storage Voltage Range: D, DBV ............................
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ELECTRICAL CHARACTERISTICS: VS = ±5V Boldface limits are tested at +25°C. At TA = +25°C, VS = ±5V, RF = 402Ω, RL = 100Ω, and G = +5, unless otherwise noted. See Figure 1 for AC performance. OPA843ID, OPA843IDBV TYP PARAMETER AC PERFORMANCE (see Figure 1) Small-Signal Bandwidth (VO = 200mVPP) Gain-Bandwidth Product Bandwidth for 0.
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TYPICAL CHARACTERISTICS: VS = ±5V TA = +25°C, G = +5, RF = 402Ω, RG = 100Ω, and RL = 100Ω, unless otherwise noted. NONINVERTING SMALL-SIGNAL FREQUENCY RESPONSE 6 VO = 0.2Vp-p INVERTING SMALL-SIGNAL FREQUENCY RESPONSE 3 G = +3 3 Normalized Gain (dB) Normalized Gain (dB) G = +5 0 –3 G = +10 –6 G = +20 –9 –12 –3 RG = RS = 50Ω VO = 0.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +5, RF = 402Ω, RG = 100Ω, and RL = 100Ω, unless otherwise noted.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +5, RF = 402Ω, RG = 100Ω, and RL = 100Ω, unless otherwise noted. 2-TONE, 3RD-ORDER INTERMODULATION INTERCEPT INPUT VOLTAGE AND CURRENT NOISE DENSITY 10 55 PI G = +5 Current Noise Intercept Point (+dBm) Voltage Noise nV/√Hz Current Noise pA/√Hz 50 2.8pA/√Hz Voltage Noise 2.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +5, RF = 402Ω, RG = 100Ω, and RL = 100Ω, unless otherwise noted. OPEN-LOOP GAIN AND PHASE CMRR AND PSRR vs FREQUENCY 120 CMRR 80 –PSRR 60 40 –30 20log (AOL) 80 –60 ∠AOL 60 20 40 –120 20 –150 0 –180 –20 102 103 104 105 106 107 103 104 107 108 CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY 109 10 1 1W Internal Power Limit Output Impedance (Ω) RL = 100 RL = 50 0 RL = 25 –1 1W Internal Power Limit –2 OPA843 ZO 0.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +5, RF = 402Ω, RG = 100Ω, and RL = 100Ω, unless otherwise noted. SETTLING TIME VIDEO DIFFERENTIAL GAIN/DIFFERENTIAL PHASE 0.20 Differential Gain (%) 0.15 0.1 G = +4 0.10 0.05 0 –0.05 –0.10 –0.15 0.015 0.075 dP, Negative Video 0.01 0.05 dP, Positive Video 0.005 0.025 dG, Positive Video –0.20 See Figure 1 –0.25 0 0 5 10 15 20 0 25 1 2 Time (ns) TYPICAL DC DRIFT OVER TEMPERATURE VIO 0 0 100 x IOS –0.5 –12.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, GD = 10, RF = 1kΩ, RG = 100Ω, and RL = 100Ω, unless otherwise noted.
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APPLICATIONS INFORMATION +5V WIDEBAND NONINVERTING OPERATION The OPA843’s combination of speed and dynamic range is useful in a wide variety of application circuits, as long as simple guidelines common to all high-speed amplifiers are observed. For example, good power-supply decoupling, as shown in Figure 1, is essential to achieve the lowest possible harmonic distortion and smooth frequency response.
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the 3rd-harmonic much lower. 2-tone 3rd-order intermodulation terms will be much lower than most other solutions using the circuit shown on the front page. The differential typical characteristic curves also show that a 4VPP output will have > 80dBc SFDR through 20MHz using this differential approach. 1dB through 50MHz. For narrowband IF’s in the 44MHz region, this configuration of the OPA843 will show a 3rd-order intercept of 33dBm while dissipating only 200mW (23dBm) power from ±5V supplies.
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WIDEBAND INVERTING SUMMING AMPLIFIER 100pF One common application for a wideband op amp like the OPA843 is to sum a number of signal sources together. Figure 5 shows the inverting summing configuration that is most often used. This circuit offers the benefit that each input sees an input impedance set only by its individual input resistor, since the summing junction (inverting op amp node) is a virtual ground. Each input is non-interactive with every other.
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+5V +5V VCC VCC OPA843 OPA843 Power-supply decoupling not shown. VEE VEE –5V R4 600Ω C2 41.125pF –5V RF 1.2kΩ R1 120Ω VOUT RLOAD 1kΩ R2 1.2kΩ VIN C1 5.2pF RG R5 1.2kΩ FIGURE 8. Adjustable Equalizer. value should be between 200Ω and 1kΩ. Below 200Ω, the feedback network will present additional output loading that can degrade the harmonic distortion performance of the OPA843. Above 1kΩ, the typical parasitic capacitance (approximately 0.
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the phase margin approaches 90°, as it does in high-gain configurations. At low signal gains, most amplifiers will exhibit a more complex response with lower phase margin. The OPA843 is optimized to give a maximally flat 2nd-order Butterworth response in a gain of 5. In this configuration, the OPA843 has approximately 60° of phase margin and will show a typical –3dB bandwidth of 260MHz.
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occurs at NG1 • Z0 and the pole in the noise gain occurs at NG2 • Z0. Since GBP is expressed in Hz, multiply Z0 by 2π and use this to get CF by solving: CF = 1 2πRF Z0 NG2 (12) Finally, since CS and CF set the high-frequency noise gain, determine CS by: CS = (NG2 – 1)CF (13) The resulting closed-loop bandwidth will be approximately equal to: f −3dB ≅ Z 0 GBP (14) For the values shown in Figure 10, the f–3dB will be approximately 105MHz.
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the 2nd-harmonic 12dB and the 3rd-harmonic 18dB. Increasing the signal gain will also increase the 2nd-harmonic distortion. Again, a 6dB increase in gain will increase the 2nd- and 3rd-harmonic by 6dB even with a constant output power and frequency. Finally, the distortion increases as the fundamental frequency increases due to the roll off in the loop gain with frequency. Conversely, the distortion will improve going to lower frequencies down to the dominant open-loop pole at approximately 3kHz.
PAGE 17
1600 1400 +5V VCC Mean = 0.04µA Standard Deviation = 0.17µA Total Count = 5572 Power-supply decoupling not shown. 1200 Count 200Ω 0.1µF 1000 OPA843 800 VEE –5V 600 +5V RG 250Ω 400 RF 1kΩ VIN 200 5kΩ 0 < –1.00 < –0.90 < –0.80 < –0.70 < –0.60 < –0.50 < –0.40 < –0.30 < –0.20 < –0.10 < –0.00 <0.10 <0.20 <0.30 <0.40 <0.50 <0.60 <0.70 <0.80 <1.90 <1.00 >1.00 20kΩ ±125mV Output Adjustment 10kΩ 0.1µF mV 5kΩ FIGURE 14.
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BOARD LAYOUT Achieving optimum performance with a high-frequency amplifier such as the OPA843 requires careful attention to board layout parasitics and external component types. Recommendations that will optimize performance include: a) Minimize parasitic capacitance to any AC ground for all of the signal I/O pins. Parasitic capacitance on the output and inverting input pins can cause instability: on the noninverting input, it can react with the source impedance to cause unintentional bandlimiting.
PAGE 19
INPUT AND ESD PROTECTION The OPA843 is built using a very high-speed complementary bipolar process. The internal junction breakdown voltages are relatively low for these very small geometry devices. These breakdowns are reflected in the Absolute Maximum Ratings table. All device pins are protected with internal ESD protection diodes to the power supplies, as shown in Figure 16. These diodes provide moderate protection to input overdrive voltages above the supplies as well.
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Revision History DATE REVISION PAGE 12/08 C 2 3/06 B 13 SECTION DESCRIPTION Absolute Maximum Ratings Changed minimum Storage Temperature Range from −40°C to −65°C. Design-In Tools Board part number changed. NOTE: Page numbers for previous revisions may differ from page numbers in the current version. 20 OPA843 www.ti.
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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 14-Jul-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) OPA843IDBVR SOT-23 DBV 5 3000 180.0 OPA843IDBVT SOT-23 DBV 5 250 OPA843IDR SOIC D 8 2500 B0 (mm) K0 (mm) P1 (mm) 8.4 3.2 3.1 1.39 4.0 180.0 8.4 3.2 3.1 1.39 330.0 12.4 6.4 5.2 2.1 Pack Materials-Page 1 W Pin1 (mm) Quadrant 8.0 Q3 4.0 8.0 Q3 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) OPA843IDBVR SOT-23 DBV 5 3000 210.0 185.0 35.0 OPA843IDBVT SOT-23 DBV 5 250 210.0 185.0 35.0 OPA843IDR SOIC D 8 2500 367.0 367.0 35.
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