Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Op-amp Voltage feedback SOT 23 5

APPLICATIONS

● WIDEBAND PHOTODIODE AMPLIFIERS

● SAMPLE-AND-HOLD BUFFERS

● CCD OUTPUT BUFFERS

● ADC INPUT BUFFERS

● WIDEBAND PRECISION AMPLIFIERS

● TEST AND MEASUREMENT FRONT ENDS

DESCRIPTION

The OPA656 combines a very wideband, unity-gain stable,

voltage-feedback op amp with a FET-input stage to offer an

ultra high dynamic-range amplifier for ADC (Analog-to-Digital

Converter) buffering and transimpedance applications. Extremely

low DC errors give good precision in optical applications.

The high unity-gain stable bandwidth and JFET input allows

exceptional performance in high-speed, low-noise integrators.

The high input impedance and low bias current provided by

the FET input is supported by the ultra-low 7nV/√Hz input

voltage noise to achieve a very low integrated noise in

wideband photodiode transimpedance applications.

Broad transimpedance bandwidths are achievable given the

OPA656’s high 230MHz gain bandwidth product. As shown

below, a –3dB bandwidth of 1MHz is provided even for a high

1MΩ transimpedance gain from a 47pF source capacitance.

FEATURES

● 500MHz UNITY-GAIN BANDWIDTH

● LOW INPUT BIAS CURRENT: 2pA

● LOW OFFSET AND DRIFT: ±0.25mV, ±2µV/°C

● LOW DISTORTION: 74dB SFDR at 5MHz

● HIGH OUTPUT CURRENT: 70mA

● LOW INPUT VOLTAGE NOISE: 7nV/

√Hz

Wideband, Unity-Gain Stable, FET-Input

OPERATIONAL AMPLIFIER

Frequency

1MΩ TRANSIMPEDANCE BANDWIDTH

130

120

110

100

10kHz 100kHz 1MHz 5MHz

Transimpedance Gain (dB)

1MHz Bandwidth

OPA656

Wideband Photodiode Transimpedance Amplifier

(47pF)

–V

499kΩ499kΩ

1pF

OPA656

SBOS196G – DECEMBER 2001 – REVISED NOVEMBER 2008

www.ti.com

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.

OPA656

SLEW VOLTAGE

BW RATE NOISE

DEVICE (V) (MHz) (V/

µS) (nV/√HZ) AMPLIFIER DESCRIPTION

OPA355 +5 200 300 5.8 Unity-Gain Stable CMOS

OPA655 ±5 400 290 6 Unity-Gain Stable FET-Input

OPA657 ±5 1600 700 4.8 Gain of +7 Stable FET-Input

OPA627 ±15 16 55 4.5 Unity-Gain Stable FET-Input

THS4601 ±15 180 100 5.4 Unity-Gain Stable FET-Input

RELATED OPERATIONAL AMPLIFIER PRODUCTS

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.

All trademarks are the property of their respective owners.

www.ti.com

Summary of content (25 pages)

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OPA656 OPA 656 www.ti.com SBOS196G – DECEMBER 2001 – REVISED NOVEMBER 2008 Wideband, Unity-Gain Stable, FET-Input OPERATIONAL AMPLIFIER FEATURES DESCRIPTION ● ● ● ● ● ● The OPA656 combines a very wideband, unity-gain stable, voltage-feedback op amp with a FET-input stage to offer an ultra high dynamic-range amplifier for ADC (Analog-to-Digital Converter) buffering and transimpedance applications. Extremely low DC errors give good precision in optical applications.
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ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS(1) Supply Voltage ................................................................................. ±6.5V Internal Power Dissipation ........................... See Thermal Characteristics Differential Input Voltage ..................................................................... ±VS Input Voltage Range ............................................................................ ±VS Storage Temperature Range .................................
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ELECTRICAL CHARACTERISTICS: VS = ±5V RF = 250Ω, RL = 100Ω, and G = +2, unless otherwise noted. Figure 1 for AC performance. OPA656U, N (Standard-Grade) TYP PARAMETER AC PERFORMANCE (Figure 1) Small-Signal Bandwidth Gain-Bandwidth Product Bandwidth for 0.1dB flatness Peaking at a Gain of +1 Large-Signal Bandwidth Slew Rate Rise-and-Fall Time Settling Time to 0.
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ELECTRICAL CHARACTERISTICS: VS = ±5V: High Grade DC Specifications(1) RF = 250Ω, RL = 100Ω, and G = +2, unless otherwise noted. OPA656UB, NB (High-Grade) TYP PARAMETER Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Offset Current Common-Mode Rejection Ratio (CMRR) Power-Supply Rejection Ratio (+PSRR) (–PSRR) MIN/MAX OVER TEMPERATURE CONDITIONS +25°C +25°C(2) VCM = 0V VCM = 0V VCM = 0V VCM = 0V VCM = ±0.5V +VS = 4.5V to 5.5V –VS = –4.5V to –5.5V ±0.1 ±2 ±1 ±0.5 95 78 68 ±0.
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TYPICAL CHARACTERISTICS: VS = ±5V TA = +25°C, G = +2, RF = 250Ω, RL = 100Ω, unless otherwise noted. NONINVERTING SMALL-SIGNAL FREQUENCY RESPONSE INVERTING SMALL-SIGNAL FREQUENCY RESPONSE 6 9 3 0 G = +2 –3 –6 G = +5 –9 –12 G = +10 See Figure 1 VO = 200mVp-p RF = 402Ω 6 Normalized Gain (dB) 3 0 –6 G = –5 –9 –12 G = –10 –15 See Figure 2 –21 –18 –24 0.5 1 10 Frequency (MHz) 100 500 0.5 1 10 Frequency (MHz) NONINVERTING LARGE-SIGNAL FREQUENCY RESPONSE 9 500 3 VO = 0.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +2, RF = 250Ω, RL = 100Ω, unless otherwise noted. HARMONIC DISTORTION vs OUTPUT VOLTAGE (5MHz) HARMONIC DISTORTION vs LOAD RESISTANCE –60 –60 VO = 2Vp-p f = 5MHz –70 –75 2nd Harmonic –80 –85 –90 3rd Harmonic –95 –100 See Figure 1 –105 f = 5MHz RL = 200Ω –65 Harmonic Distortion (dBc) Harmonic Distortion (dBc) –65 –70 –75 –80 –85 3rd Harmonic –90 –95 –100 –110 –105 100 1k 0.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +2, RF = 250Ω, RL = 100Ω, unless otherwise noted. 2-TONE, 3RD-ORDER INTERMODULATION SPURIOUS INPUT CURRENT AND VOLTAGE NOISE DENSITY –30 3rd-Order Spurious Level (dBc) 10 Input Voltage Noise 7nV/√Hz Input Current Noise 1.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +2, RF = 250Ω, RL = 100Ω, unless otherwise noted. TYPICAL INPUT OFFSET VOLTAGE DRIFT OVER TEMPERATURE TYPICAL INPUT BIAS CURRENT vs COMMON-MODE INPUT VOLTAGE 1.0 2.0 Input Bias Current (pA) Input Offset Voltage (mV) 1.5 0.5 0 –0.5 1.0 0.5 0 –0.5 –1.0 –1.5 –1.0 –2.
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TYPICAL CHARACTERISTICS: VS = ±5V (Cont.) TA = +25°C, G = +2, RF = 250Ω, RL = 100Ω, unless otherwise noted. CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY OUTPUT VOLTAGE AND CURRENT LIMITATIONS 10 5 4 1W Internal Power VO (V) 2 1 Output Impedance (Ω) 3 RL = 100Ω RL = 50Ω 0 RL = 25Ω –1 –2 1 0.1 –3 –4 –5 –100 –80 1W Internal Power –60 –40 –20 0 20 40 60 80 0.
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APPLICATIONS INFORMATION WIDEBAND, NONINVERTING OPERATION The OPA656 provides a unique combination of a broadband, unity gain stable, voltage-feedback amplifier with the DC precision of a trimmed JFET-input stage. Its very high Gain Bandwidth Product (GBP) of 230MHz can be used to either deliver high signal bandwidths for low-gain buffers, or to deliver broadband, low-noise transimpedance bandwidth to photodiode-detector applications.
PAGE 11
is peaked up over frequency by the diode source capacitance, and can, in many cases, become the limiting factor to input sensitivity. The key elements to the design are the expected diode capacitance (CD) with the reverse bias voltage (–VB) applied, the desired transimpedance gain, RF, and the GBP for the OPA656 (230MHz). Figure 3 shows a design from a 25pF source capacitance diode through a 50kΩ transimpedance gain.
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OPERATING SUGGESTIONS FREQUENCY RESPONSE CONTROL SETTING RESISTOR VALUES TO MINIMIZE NOISE The OPA656 provides a very low input noise voltage while requiring a low 14mA quiescent supply current. To take full advantage of this low input noise, careful attention to the other possible noise contributors is required. Figure 4 shows the op amp noise analysis model with all the noise terms included.
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the amplifier output and the capacitive load. This does not eliminate the pole from the loop response, but rather shifts it and adds a zero at a higher frequency. The additional zero acts to cancel the phase lag from the capacitive load pole, thus increasing the phase margin and improving stability. The Typical Characteristics show the recommended RS versus Capacitive Load and the resulting frequency response at the load. In this case, a design target of a maximally flat frequency response was used.
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a careful control of the negative supply voltage is required. The +PSRR is tested to a minimum value of 74dB. This translates into 10(–74/20) = 0.2mV/V sensitivity for the input offset voltage to positive power supply changes. As an example, compute the worst-case output DC error for the transimpedance circuit of Figure 1 at 25°C and then the shift over the 0°C to 70°C range given the following assumptions. Negative Power Supply = –5V ±0.2V with a ±5mV/°C worst-case shift Positive Power Supply = +5V ±0.
PAGE 15
c) Careful selection and placement of external components will preserve the high frequency performance of the OPA656. Resistors should be a very low reactance type. Surface-mount resistors work best and allow a tighter overall layout. Metal film and carbon composition axially leaded resistors can also provide good high frequency performance. Again, keep their leads and PCB trace length as short as possible. Never use wirewound type resistors in a high frequency application.
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Revision History DATE REVISION 11/08 G 3/06 F PAGE SECTION 2 Abs Max Ratings 3 Electrical Characteristics 11 Design-In Tools DESCRIPTION Changed Storage Temperature Range from −40°C to +125C to −65°C to +125C. DC Performance section; deleted Drift from Input Offset Current specifications. Added Design-In Tools paragraph and table. NOTE: Page numbers for previous revisions may differ from page numbers in the current version. 16 OPA656 www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 (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.
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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) OPA656N/250 SOT-23 DBV 5 250 180.0 OPA656NB/250 SOT-23 DBV 5 250 OPA656U/2K5 SOIC D 8 2500 OPA656UB/2K5 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 2.1 330.0 12.4 6.4 5.2 2.
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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) OPA656N/250 SOT-23 DBV 5 250 210.0 185.0 35.0 OPA656NB/250 SOT-23 DBV 5 250 210.0 185.0 35.0 OPA656U/2K5 SOIC D 8 2500 367.0 367.0 35.0 OPA656UB/2K5 SOIC D 8 2500 367.0 367.0 35.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.