Datasheet

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Wideband, Current Feedback

OPERATIONAL AMPLIFIER With Disable

DESCRIPTION

The OPA691 sets a new level of performance for broadband

current feedback op amps. Operating on a very low 5.1mA

supply current, the OPA691 offers a slew rate and output

power normally associated with a much higher supply cur-

rent. A new output stage architecture delivers a high output

current with minimal voltage headroom and crossover distor-

tion. This gives exceptional single-supply operation. Using a

single +5V supply, the OPA691 can deliver a 1V to 4V output

swing with over 150mA drive current and 190MHz band-

width. This combination of features makes the OPA691 an

ideal RGB line driver or single-supply Analog-to-Digital Con-

verter (ADC) input driver.

The OPA691’s low 5.1mA supply current is precisely trimmed

at 25°C. This trim, along with low drift over-temperature,

FEATURES

●

FLEXIBLE SUPPLY RANGE:

+5V to +12V Single-Supply

2.5V to

6V Dual-Supply

●

UNITY-GAIN STABLE: 280MHz (G = 1)

● HIGH OUTPUT CURRENT: 190mA

● OUTPUT VOLTAGE SWING: ±4.0V

● HIGH SLEW RATE: 2100V/µs

● LOW dG/d

: 0.07%/0.02°

● LOW SUPPLY CURRENT: 5.1mA

● LOW DISABLED CURRENT: 150µA

●

WIDEBAND +5V OPERATION: 190MHz (G = +2)

APPLICATIONS

● xDSL LINE DRIVER

● BROADBAND VIDEO BUFFERS

● HIGH-SPEED IMAGING CHANNELS

● PORTABLE INSTRUMENTS

● ADC BUFFERS

● ACTIVE FILTERS

● WIDEBAND INVERTING SUMMING

● HIGH SFDR IF AMPLIFIER

ensures lower maximum supply current than competing

products. System power may be further reduced by using the

optional disable control pin. Leaving this disable pin open, or

holding it HIGH, gives normal operation. If pulled LOW, the

OPA691 supply current drops to less than 150µA while the

output goes into a high impedance state. This feature may be

used for power savings.

OPA691

SBOS226D – DECEMBER 2001– REVISED JULY 2008

OPA691 RELATED PRODUCTS

SINGLES DUALS TRIPLES

Voltage Feedback OPA690 OPA2690 OPA3690

Current Feedback OPA681 OPA2691 OPA3691

Fixed Gain OPA692 OPA3692

100Ω

50Ω

OPA691

+5V

DIS

–5V

–(V

+ V

)

100MHz, –1dB Compression = 15dBm

50Ω

RG-58

50Ω

30Ω

200MHz RF Summing Amplifier

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.

www.ti.com

Summary of content (31 pages)

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OPA OPA691 691 OPA6 91 www.ti.com SBOS226D – DECEMBER 2001– REVISED JULY 2008 Wideband, Current Feedback OPERATIONAL AMPLIFIER With Disable FEATURES APPLICATIONS ● FLEXIBLE SUPPLY RANGE: +5V to +12V Single-Supply ±2.5V to ±6V Dual-Supply ● UNITY-GAIN STABLE: 280MHz (G = 1) ● HIGH OUTPUT CURRENT: 190mA ● OUTPUT VOLTAGE SWING: ±4.0V ● HIGH SLEW RATE: 2100V/µs ● LOW dG/dφ: 0.07% /0.02° ● LOW SUPPLY CURRENT: 5.
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ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY Power Supply .............................................................................. ±6.5VDC Internal Power Dissipation(2) ............................ See Thermal Information Differential Input Voltage .................................................................. ±1.2V Input Voltage Range ............................................................................ ±VS Storage Temperature Range: ID, IDBV .........................
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ELECTRICAL CHARACTERISTICS: VS = ±5V Boldface limits are tested at +25°C. RF = 402Ω, RL = 100Ω, and G = +2, (see Figure 1 for AC performance only), unless otherwise noted. OPA691ID, IDBV TYP CONDITIONS +25°C G = +1, RF = 453Ω G = +2, RF = 402Ω G = +5, RF = 261Ω G = +10, RF = 180Ω G = +2, VO = 0.5VPP RF = 453, VO = 0.5VPP G = +2, VO = 5VPP G = +2, 4V Step G = +2, VO = 0.
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ELECTRICAL CHARACTERISTICS: VS = +5V Bolace limits are tested at +25°C. RF = 453Ω, RL = 100Ω to VS/2, and G = +2, (see Figure 2 for AC performance only), unless otherwise noted. OPA691ID, IDBV TYP PARAMETER AC PERFORMANCE (see Figure 2) Small-Signal Bandwidth (VO = 0.5VPP) Bandwidth for 0.1dB Gain Flatness Peaking at a Gain of +1 Large-Signal Bandwidth Slew Rate Rise-and-Fall Time Settling Time to 0.02% 0.
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TYPICAL CHARACTERISTICS: VS = ±5V G = +2, RF = 402Ω, and RL = 100Ω, unless otherwise noted (see Figure 1). SMALL-SIGNAL FREQUENCY RESPONSE 1 0 –1 –3 G = +5, RF = 261Ω –5 G = +10, RF = 180Ω –6 2Vp-p 5.5 5.0 4.5 4.0 3.5 4Vp-p 3.0 –7 7Vp-p 2.5 VO = 0.5Vp-p –8 2.0 0 125MHz 250MHz 0 125MHz Frequency (25MHz/div) SMALL-SIGNAL PULSE RESPONSE LARGE-SIGNAL PULSE RESPONSE +4 G = +2 VO = 0.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) G = +2, RF = 402Ω, and RL = 100Ω, unless otherwise noted (see Figure 1). HARMONIC DISTORTION vs LOAD RESISTANCE HARMONIC DISTORTION vs SUPPLY VOLTAGE –60 –60 Harmonic Distortion (dBc) Harmonic Distortion (dBc) VO = 2Vp-p f = 5MHz –65 –70 2nd-Harmonic –75 –80 –85 3rd-Harmonic –90 –65 VO = 2Vp-p RL = 100Ω f = 5MHz 2nd-Harmonic –70 –75 3rd-Harmonic –80 –95 –100 100 –85 1000 2.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) G = +2, RF = 402Ω, and RL = 100Ω, unless otherwise noted (see Figure 1). 2-TONE, 3RD-ORDER INTERMODULATION SPURIOUS INPUT VOLTAGE AND CURRENT NOISE DENSITY –30 3rd-Order Spurious Level (dBc) Inverting Input Current Noise (15pA/√Hz) 10 Noninverting Input Current Noise (12pA/√Hz) Voltage Noise (1.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) G = +2, RF = 402Ω, and RL = 100Ω, unless otherwise noted (see Figure 1).
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TYPICAL CHARACTERISTICS: VS = +5V G = +2, RF = 453Ω, and RL = 100Ω to +2.5V, unless otherwise noted (see Figure 2). LARGE-SIGNAL FREQUENCY RESPONSE SMALL-SIGNAL FREQUENCY RESPONSE 1 7.0 G = +1, RF = 499Ω 6.0 –1 G = +2, RF = 453Ω –2 G = +5, RF = 340Ω –3 –4 –5 –6 –7 –8 0 5.5 5.0 VO = 2Vp-p 4.5 4.0 3.5 3.0 G = +10, RF = 180Ω VO = 0.5Vp-p VO = 0.5Vp-p 6.5 Gain (0.5dB/div) Normalized Gain (1dB/div) 0 2.0 125MHz 0 250MHz 125MHz SMALL-SIGNAL PULSE RESPONSE LARGE-SIGNAL PULSE RESPONSE 4.1 2.
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TYPICAL CHARACTERISTICS: VS = +5V (Cont.) G = +2, RF = 453Ω, and RL = 100Ω to +2.5V, unless otherwise noted (see Figure 2). HARMONIC DISTORTION vs FREQUENCY HARMONIC DISTORTION vs LOAD RESISTANCE –50 –60 Harmonic Distortion (dBc) Harmonic Distortion (dBc) VO = 2Vp-p f = 5MHz –65 2nd-Harmonic –70 3rd-Harmonic –75 100 2nd-Harmonic –70 3rd-Harmonic –80 0.
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APPLICATIONS INFORMATION WIDEBAND CURRENT FEEDBACK OPERATION The OPA691 gives the exceptional AC performance of a wideband current feedback op amp with a highly linear, high power output stage. Requiring only 5.1mA quiescent current, the OPA691 will swing to within 1V of either supply rail and deliver in excess of 160mA at room temperature. This low output headroom requirement, along with supply voltage independent biasing, gives remarkable single (+5V) supply operation.
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SINGLE-SUPPLY ADC INTERFACE Most modern, high performance ADCs (such as the Texas Instruments ADS8xx and ADS9xx series) operate on a single +5V (or lower) power supply. It has been a considerable challenge for single-supply op amps to deliver a low distortion input signal at the ADC input for signal frequencies exceeding 5MHz. The high slew rate, exceptional output swing, and high linearity of the OPA691 make it an ideal single-supply ADC driver.
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also ensures that the maximum differential voltage across the inputs of the unselected channel do not exceed the rated ±1.2V maximum for standard video signal levels. control of one amplifier or the other due to the “make-beforebreak” disable timing. In this case, the switching glitches for two 0V inputs drop to < 20mV. The section on Disable Operation shows the turn-on and turn-off switching glitches using a grounded input for a single channel is typically less than ±50mV.
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Each channel includes a bandpass filter. Each bandpass filter is set for a different frequency band. This allows the channelizing part of this circuit. The role of the channelizers OPA691s is to provide impedance isolation. This is done through the use of four matching resistances (59Ω in this case). These matching resistors ensure that the signals will combine during the transition between channels. They have been used to get a gain of +1 at the load.
PAGE 15
amplifier circuits where parasitic capacitance and inductance can have a major effect on circuit performance. A SPICE model for the OPA691 is available through the TI web site (www.ti.com). These models do a good job of predicting small-signal AC and transient performance under a wide variety of operating conditions. They do not do as well in predicting the harmonic distortion or dG/dφ characteristics. These models do not attempt to distinguish between the package types in their small-signal AC performance.
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As the desired signal gain increases, this equation will eventually predict a negative RF. A somewhat subjective limit to this adjustment can also be set by holding RG to a minimum value of 20Ω. Lower values will load both the buffer stage at the input and the output stage if RF gets too low— actually decreasing the bandwidth. Figure 8 shows the recommended RF versus NG for both ±5V and a single +5V operation.
PAGE 17
on the noninverting input to achieve bias current error cancellation at the output. The input bias currents for a current feedback op amp are not generally matched in either magnitude or polarity. Connecting a resistor to ground on the noninverting input of the OPA691 in the circuit of Figure 9 will actually provide additional gain for that input’s bias and noise currents, but will not decrease the output DC error since the input bias currents are not matched.
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dynamic range does not decrease significantly. For two tones centered at 20MHz, with 10dBm/tone into a matched 50Ω load (i.e., 2VPP for each tone at the load, which requires 8VPP for the overall 2-tone envelope at the output pin), the Typical Characteristics show 48dBc difference between the test-tone power and the 3rd-order intermodulation spurious levels. This exceptional performance improves further when operating at lower frequencies.
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input voltage at the inputs of the OPA237 (this is a low-cost, precision voltage feedback op amp with 1.5MHz gain bandwidth product). If these two don’t agree (due to DC offsets introduced by the OPA691), the OPA237 sums in a correction current through the 2.86kΩ inverting summing path. Several design considerations will allow this circuit to be optimized. First, the feedback to the OPA237’s noninverting input must be precisely matched to the high-speed signal gain.
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THERMAL ANALYSIS Due to the high output power capability of the OPA691, heatsinking or forced airflow may be required under extreme operating conditions. Maximum desired junction temperature will set the maximum allowed internal power dissipation, as described below. In no case should the maximum junction temperature be allowed to exceed 175°C. Operating junction temperature (TJ) is given by TA + PD • θJA.
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design handbook for microstrip and stripline layout techniques). A 50Ω environment is normally not necessary on board, and in fact, a higher impedance environment will improve distortion, as shown in the Distortion versus Load plots. With a characteristic board trace impedance defined based on board material and trace dimensions, a matching series resistor into the trace from the output of the OPA691 is used as well as a terminating shunt resistor at the input of the destination device.
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Revision History DATE REVISION 7/08 D 2/07 C PAGE SECTION 2 Abs Max Ratings 3, 4 Electrical Characteristics, Power Supply 8 Typical Characteristics DESCRIPTION Changed Storage Temperature Range from −40°C to +125C to −65°C to +125C. Added minimum supply voltage. Changed Closed-Loop Output Impedance vs Frequency plot. NOTE: Page numbers for previous revisions may differ from page numbers in the current version. 22 OPA691 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 26-Jan-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) OPA691IDBVR SOT-23 DBV 6 3000 180.0 OPA691IDBVT SOT-23 DBV 6 250 OPA691IDR 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 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) OPA691IDBVR SOT-23 DBV 6 3000 210.0 185.0 35.0 OPA691IDBVT SOT-23 DBV 6 250 210.0 185.0 35.0 OPA691IDR SOIC D 8 2500 367.0 367.0 35.
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