Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Op-amp Transconductance SOT 23 6

−

Frequency (Hz)

Gain (dB)

1k 10k 100k 1M 10M 100M 1G

OUT

Low−Pass Negative Impedance Converter (NIC) Filter Frequency Response of 20kHz and 10MHz

Low−Pass NIC Filters

20kHz

Low−Pass Filter

10MHz

Low−Pass Filter

OPA861

www.ti.com

SBOS338G –AUGUST 2005–REVISED MAY 2013

Wide Bandwidth

Operational Transconductance

Amplifier (OTA)

Check for Samples: OPA861

The OTA or voltage-controlled current source can be

FEATURES

viewed as an ideal transistor. Like a transistor, it has

• Wide Bandwidth (80MHz, Open-Loop, G = +5)

three terminals—a high impedance input (base), a

• High Slew Rate (900V/µs)

low-impedance input/output (emitter), and the current

output (collector). The OPA861, however, is self-

• High Transconductance (95mA/V)

biased and bipolar. The output collector current is

• External I

-Control

zero for a zero base-emitter voltage. AC inputs

• Low Quiescent Current (5.4mA)

centered about zero produce an output current, which

is bipolar and centered about zero. The

APPLICATIONS

transconductance of the OPA861 can be adjusted

with an external resistor, allowing bandwidth,

• Video/Broadcast Equipment

quiescent current, and gain trade-offs to be

• Communications Equipment

optimized.

• High-Speed Data Acquisition

Used as a basic building block, the OPA861

• Wideband LED Drivers

simplifies the design of AGC amplifiers, LED driver

circuits for fiber optic transmission, integrators for fast

• Control Loop Amplifiers

pulses, fast control loop amplifiers and control

• Wideband Active Filters

amplifiers for capacitive sensors, and active filters.

• Line Drivers

The OPA861 is available in SO-8 and SOT23-6

surface-mount packages.

DESCRIPTION

The OPA861 is a versatile monolithic component

designed for wide-bandwidth systems, including high

performance video, RF and IF circuitry. The OPA861

is a wideband, bipolar operational transconductance

amplifier (OTA).

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.

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 (32 pages)

PAGE 1
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 Wide Bandwidth Operational Transconductance Amplifier (OTA) Check for Samples: OPA861 FEATURES 1 • • • • • Wide Bandwidth (80MHz, Open-Loop, G = +5) High Slew Rate (900V/µs) High Transconductance (95mA/V) External IQ-Control Low Quiescent Current (5.
PAGE 2
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
PAGE 3
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS: VS = ±5V RL = 500Ω and RADJ = 250Ω, unless otherwise noted. OPA861ID, IDBV TYP PARAMETER MIN/MAX OVER TEMPERATURE CONDITIONS +25°C +25°C (2) 0°C to 70°C (3) –40°C to +85°C (3) UNITS MIN/ MAX TEST LEVEL (1) G = +5, VO = 200mVPP, RL = 500Ω 80 77 75 74 MHz min B G = +5, VO = 1VPP 80 MHz typ C G = +5, VO = 5VPP 80 MHz typ C G = +5, VO = 5V Step 900 V/µs min B VO = 1V Step 4.
PAGE 4
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS: VS = ±5V (continued) RL = 500Ω and RADJ = 250Ω, unless otherwise noted. OPA861ID, IDBV TYP MIN/MAX OVER TEMPERATURE +25°C (2) 0°C to 70°C (3) –40°C to +85°C (3) Maximum Operating Voltage ±6.3 ±6.3 ±6.3 Minimum Operating Voltage ±2.0 ±2.0 PARAMETER CONDITIONS +25°C MIN/ MAX TEST LEVEL (1) V typ C V max A ±2.
PAGE 5
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS: VS = +5V RL = 500Ω to VS/2 and RADJ = 250Ω, unless otherwise noted. OPA861ID, IDBV TYP MIN/MAX OVER TEMPERATURE CONDITIONS +25°C +25°C (2) 0°C to 70°C (3) –40°C to +85°C (3) UNITS MIN/ MAX TEST LEVEL (1) Bandwidth G = +5, VO = 200mVPP, RL = 500Ω 73 72 72 70 MHz min B G = +5, VO = 1VPP 73 MHz typ C Slew Rate G = +5, VO = 2.5V Step 410 395 390 390 V/µs min B VO = 1V Step 4.
PAGE 6
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com ELECTRICAL CHARACTERISTICS: VS = +5V (continued) RL = 500Ω to VS/2 and RADJ = 250Ω, unless otherwise noted. OPA861ID, IDBV TYP MIN/MAX OVER TEMPERATURE +25°C (2) 0°C to 70°C (3) –40°C to +85°C (3) Maximum Operating Voltage 12.6 12.6 12.
PAGE 7
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 TYPICAL CHARACTERISTICS: VS = ±5V At TA = +25°C, IQ = 5.4mA, and RL = 500Ω, unless otherwise noted. OTA TRANSCONDUCTANCE vs FREQUENCY OTA TRANSCONDUCTANCE vs QUIESCENT CURRENT 150 1000 IO UT VIN = 100mVPP RL = 50Ω VIN = 10mVPP 50Ω Transconductance (mA/V) Transconductance (mA/V) VI N 50Ω I Q = 5.4mA (102mA/V) IQ = 6.5mA (117mA/V) 100 IQ = 1.9mA (51mA/V) 120 2 gm = -0.8265.IQ + 24.197.IQ - 1.466 90 IOUT 60 VIN 50W 30 50W IQ = 3.
PAGE 8
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 5.4mA, and RL = 500Ω, unless otherwise noted. B-INPUT RESISTANCE vs QUIESCENT CURRENT C-OUTPUT RESISTANCE vs QUIESCENT CURRENT 120 OTA C- Output Resistance (kW ) OTA B- Input Resistance (kW ) 500 490 480 470 460 450 440 430 110 100 90 80 70 60 50 40 0 1 2 3 4 5 6 7 0 8 1 2 Figure 8.
PAGE 9
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 5.4mA, and RL = 500Ω, unless otherwise noted.
PAGE 10
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com TYPICAL CHARACTERISTICS: VS = +5V At TA = +25°C, IQ = 4.7mA, and RL = 500Ω to VS/2, unless otherwise noted. OTA TRANSCONDUCTANCE vs FREQUENCY 100 OTA TRANSCONDUCTANCE vs IQ 150 OTA Transconductance (mA/V) IQ = 5.8mA (93mA/V) Transconductance (mA/V) IQ = 4.7mA (80mA/V) IQ = 3.1mA (60mA/V) IQ = 1.
PAGE 11
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 TYPICAL CHARACTERISTICS: VS = +5V (continued) At TA = +25°C, IQ = 4.7mA, and RL = 500Ω to VS/2, unless otherwise noted. C-OUTPUT RESISTANCE vs QUIESCENT CURRENT 120 490 110 OTA C−Output Resistance (kΩ ) OTA B−Input Resistance (kΩ ) B-INPUT RESISTANCE vs QUIESCENT CURRENT 500 480 470 460 450 440 430 100 90 80 70 60 50 40 420 0 1 2 3 4 5 6 7 0 1 2 3 Figure 25. 5 6 7 Figure 26.
PAGE 12
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION The OPA861 is a versatile monolithic transconductance amplifier designed for widebandwidth systems, including high-performance video, RF, and IF circuitry. The operation of the OPA861 is discussed in the OTA (Operational Transconductance Amplifier) section of this data sheet.
PAGE 13
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 QUIESCENT CURRENT CONTROL PIN The quiescent current of the transconductance portion of the OPA861 is set with a resistor, RADJ, connected from pin 1 to –VS. The maximum quiescent current is 6mA. RADJ should be set between 50Ω and 1kΩ for optimal performance of the OTA section. This range corresponds to the 5mA quiescent current for RADJ = 50Ω, and 1mA for RADJ = 1kΩ.
PAGE 14
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com The forward amplifier shown in Figure 33 and Figure 34 corresponds to one of the basic circuits used to characterize the OPA861. Extended characterization of this topology appears in the Typical Characteristics section of this datasheet. V+ RL RS VO VO VI Inverting Gain VOS = Several Volts R1 160Ω RE RS VI 8 C 3 B OPA861 E 2 V− VI 8 C 3 B VO OPA861 Figure 33.
PAGE 15
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 Common-C Amplifier Figure 35b shows the OPA861 connected as an Efollower—a voltage buffer. It is interesting to notice that the larger the RE resistor, the closer to unity gain the buffer will be. If the OPA861 is to be used as a buffer, use RE ≥ 500Ω for best results.
PAGE 16
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com Table 1.
PAGE 17
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 6 5 8 BUF602 VOUT 3 8 180Ω 2 10pF VREF 10pF 3 2 10Ω 180Ω 33Ω 10Ω 33Ω 6 VIN Figure 37. Control-Loop Amplifier Using Three OPA861s C1 100pF 20Ω JFET−Input, Wideband VIN D 1, D2 = 1N4148 RQ = 1kΩ OPA656 R2 100kΩ D1 VOUT 20Ω D2 CCII 8 C The OTA amplifier works as a current conveyor (CCII) in this circuit, with a current gain of 1. R1 and C1 set the DC restoration time constant.
PAGE 18
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com Differential Line Driver/Receiver The input impedance is shown in Equation 6: Z IN + 1 ) R 1 ) sRC 2sC 1 ) 2sRC (6) Figure 40 shows the frequency responses for lowpass, Butterworth filters set at 20kHz and 10MHz. For the 20kHz filter, set R to 1kΩ and C 1 + 1 C 2 + 5.6mF 2 . For the 10MHz filter, the parasitic capacitance at the output pin needs to be taken into consideration.
PAGE 19
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 ACTIVE FILTERS USING THE OPA861 IN CURRENT CONVEYOR STRUCTURE One further example of the versatility of the Diamond Transistor and Buffer is the construction of highfrequency (> 10MHz) active filters. Here, the Current Conveyor structure, shown in Figure 43, is used with the Diamond Transistor as a Current Conveyor.
PAGE 20
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com A few designs for a low-pass filter are shown in Figure 47 and Table 2. Gain (dB) Table 2. Component Values for Filters Shown In Figure 47 fO R RO CO 1MHz 150 100 2nF 20MHz 150 100 112.5pF 50MHz 150 100 25pF 3 0 -3 -6 -9 -12 -15 -18 -21 -24 -27 -30 -33 -36 -39 -42 -45 -48 50MHz Filter High-CMRR, Moderate Precision, Differential I/O ADC Driver The circuit shown in Figure 48 depicts an ADC driver implemented with two OPA861s.
PAGE 21
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 NOISE PERFORMANCE Common−Mode Rejection Ratio(dB) 75 Input−Referred 70 65 60 55 50 45 The OTA noise model consists of three elements: a voltage noise on the B-input; a current noise on the B-input; and a current noise on the E-input. Figure 51 shows the OTA noise analysis model with all the noise terms included. In this model, all noise terms are taken to be noise voltage or current density terms in either nV/√Hz or pA/√Hz.
PAGE 22
OPA861 SBOS338G – AUGUST 2005 – REVISED MAY 2013 www.ti.com As a worst-case example, compute the maximum TJ using an OPA861IDBV in the circuit of Figure 32b operating at the maximum specified ambient temperature of +85°C and driving a –1V voltage reference. PD = 10V × 5.4mA + (15mA × 9V) = 185mW Maximum TJ = +85°C + (0.19W × 150°C/W) = 114°C. Although this is still well below the specified maximum junction temperature, system reliability considerations may require lower tested junction temperatures.
PAGE 23
OPA861 www.ti.com SBOS338G – AUGUST 2005 – REVISED MAY 2013 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision F (May 2011) to Revision G • Page Changed transfer function equations in Negative Impedance Converter Filter: Low-Pass Filter section .......................... 17 Changes from Revision E (August 2008) to Revision F Page • Updated Figure 30 .....................................................................
PAGE 24
PACKAGE OPTION ADDENDUM www.ti.
PAGE 25
PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
PAGE 26
PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device OPA861IDBVT Package Package Pins Type Drawing SPQ SOT-23 250 DBV 6 Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 180.0 8.4 Pack Materials-Page 1 3.2 B0 (mm) K0 (mm) P1 (mm) 3.1 1.39 4.0 W Pin1 (mm) Quadrant 8.
PAGE 27
PACKAGE MATERIALS INFORMATION www.ti.com 13-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) OPA861IDBVT SOT-23 DBV 6 250 210.0 185.0 35.
PAGE 28
PAGE 29
PAGE 30
PAGE 31
PAGE 32
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.