Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Op-amp Transconductance SOIC 8

OTA FEATURES DESCRIPTION

BUFFER FEATURES

OPA860 FEATURES

APPLICATIONS

OPA860

www.ti.com

....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008

Wide Bandwidth

OPERATIONAL TRANSCONDUCTANCE

AMPLIFIER (OTA) and BUFFER

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

The OPA860 is a versatile monolithic component

designed for wide-bandwidth systems, including high

• High Slew Rate (900V/ µ s)

performance video, RF and IF circuitry. It includes a

• High Transconductance (95mA/V)

wideband, bipolar operational transconductance

• External I

-Control

amplifier (OTA), and voltage buffer amplifier.

The OTA or voltage-controlled current source can be

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

• Closed-Loop Buffer

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

• Wide Bandwidth (1600MHz, V

= 1V

)

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

• High Slew Rate (4000V/ µ s)

output (collector). The OTA, however, is self-biased

and bipolar. The output collector current is zero for a

• 60mA Output Current

zero base-emitter voltage. AC inputs centered about

zero produce an output current, which is bipolar and

centered about zero. The transconductance of the

• Low Quiescent Current (11.2mA)

OTA can be adjusted with an external resistor,

• Versatile Circuit Function

allowing bandwidth, quiescent current, and gain

trade-offs to be optimized.

Also included in the OPA860 is an uncommited

• Baseline Restore Circuits

closed-loop, unity-gain buffer. This provides

• Video/Broadcast Equipment

1600MHz bandwidth and 4000V/ µ s slew rate.

• Communications Equipment

Used as a basic building block, the OPA860

• High-Speed Data Acquisition

simplifies the design of AGC amplifiers, LED driver

• Wideband LED Driver circuits for fiber optic transmission, integrators for fast

pulses, fast control loop amplifiers and control

• AGC-Multiplier

amplifiers for capacitive sensors and active filters.

• ns-Pulse Integrator

The OPA860 is available in an SO-8 surface-mount

• Control Loop Amplifier

package.

• OPA660 Upgrade

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.

2 All 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
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 Wide Bandwidth OPERATIONAL TRANSCONDUCTANCE AMPLIFIER (OTA) and BUFFER OTA FEATURES DESCRIPTION • • • • The OPA860 is a versatile monolithic component designed for wide-bandwidth systems, including high performance video, RF and IF circuitry.
PAGE 2
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... 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.
PAGE 3
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ELECTRICAL CHARACTERISTICS: VS = ±5V RL = 500Ω and RADJ = 250Ω, unless otherwise noted.
PAGE 4
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com ELECTRICAL CHARACTERISTICS: VS = ±5V (continued) RL = 500Ω and RADJ = 250Ω, unless otherwise noted. OPA860ID 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) IE = ±1mA ±4.2 ±3.7 ±3.
PAGE 5
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 TYPICAL CHARACTERISTICS: VS = ±5V At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted. (See Figure 53.) OTA + BUF Performance SMALL-SIGNAL FREQUENCY RESPONSE 9 LARGE-SIGNAL FREQUENCY RESPONSE 9 G = +2V/V RL = 500Ω 6 6 3 0 Gain (dB) 3 Gain (dB) G = +2V/V RL = 500Ω VOUT = 0.
PAGE 6
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted. (See Figure 53.
PAGE 7
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 TYPICAL CHARACTERISTICS: VS = ±5V At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted. OTA Performance OTA TRANSCONDUCTANCE vs FREQUENCY 1000 OTA TRANSCONDUCTANCE vs QUIESCENT CURRENT 150 IQ = 12.
PAGE 8
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted.
PAGE 9
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 TYPICAL CHARACTERISTICS: VS = ±5V At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted. BUF Performance BUFFER BANDWIDTH vs OUTPUT VOLTAGE BUFFER BANDWIDTH vs LOAD RESISTANCE 6 6 RL = 500Ω 3 Gain (dB) 3 Gain (dB) RL = 1kΩ VO = 0.2VPP VO = 0.6VPP 0 VO = 5VPP −3 VO = 2.
PAGE 10
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted.
PAGE 11
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted. BUFFER GROUP DELAY TIME vs FREQUENCY BUFFER OUTPUT VOLTAGE AND CURRENT LIMITATIONS 1.2 5 3 0.8 Output Voltage (V) 0.6 0.4 0.
PAGE 12
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS: VS = ±5V (continued) At TA = +25°C, IQ = 11.2mA, and RL = 500Ω, unless otherwise noted.
PAGE 13
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 APPLICATION INFORMATION The OPA860 combines a high-performance buffer with a transconductance section. This transconductance section is discussed in the OTA (Operational Transconductance Amplifier) section of this data sheet.
PAGE 14
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com BASIC CONNECTIONS Figure 46 shows basic connections required for operation. These connections are not shown in subsequent circuit diagrams. Power-supply bypass capacitors should be located as close as possible to the device pins. Solid tantalum capacitors are generally best.
PAGE 15
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 RQ = 250Ω, roughly sets IQ = 11.2mA. RS (25Ωto 200Ω) RADJ 250Ω +5V(1) 1 8 2 7 + +1 3 −VS −5V(1) 0.1µF +VS 2.2µF 6 Solid Tantalum 4 5 49.9Ω 0.1µF + VO RS (25Ωto 200Ω) 2.2µF VI Solid Tantalum 49.9Ω NOTE: (1) VS = ±6.5V absolute maximum. Figure 46.
PAGE 16
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com The forward amplifier shown in Figure 48 and Figure 49 corresponds to one of the basic circuits used to characterize the OPA860. Extended characterization of this topology appears in the Typical Characteristics section of this data sheet.
PAGE 17
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 Common-C Amplifier Figure 50b shows the OTA connected as an E-follower—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 OTA section is to be used as a buffer, use RE ≥ 500Ω for best results.
PAGE 18
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com Direct Feedback Amplifier The gain for this topology is given by Equation 5: R3 The direct feedback amplifier (shown in Figure 53) topology has been used to characterize the OPA860. Extended characterization of this topology appears in the Typical Characteristics section of this data sheet.
PAGE 19
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 Current-Feedback Amplifier loop amplifiers show an integrator behavior from DC to the frequency, represented by the RC time constant of the network from the C-output to GND. Above this frequency, they operate as an amp with constant gain.
PAGE 20
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com OPA860 R2 50Ω VOUT +1 200Ω VIN C1 R1 C2 500Ω 50Ω rE RF 259Ω RG 249Ω Figure 54. OPA860 Used in a Noninverting Current-Feedback Architecture 8 5 6 +1 VOUT 3 8 180Ω 2 10pF VREF 10pF 3 2 10Ω 180Ω VIN 5 33Ω 10Ω 33Ω 6 +1 Figure 55.
PAGE 21
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 DC-Restore Circuit Comparator The OPA860 can be used advantageously with an operational amplifier, here the OPA820, as a DC-restore circuit. Figure 56 illustrates this design.
PAGE 22
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com C3 2.2pF Offset Trim 0.5pF …2.5pF +5V R5 47kΩ R2 10kΩ R8 27kΩ +5V −5V R1 100kΩ RC5 150Ω VIN 5 +1 R2 100kΩ 6 RC5 150Ω 3 2 +5V C3 2.2µF RC5 150Ω 7 OTA 8 RS 47Ω 1 4 1 VOUT BUF602 5 4 RQ 250Ω C3 2.2µF C3 2.2µF C3 2.2µF −5V −5V D1 D2 DMF3068A Figure 57.
PAGE 23
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 Video Luminance Matrix The inverting amplifier in Figure 59 amplifies the three input voltages that correspond to the luminance section of the RGB color signal.
PAGE 24
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com DESIGN-IN TOOLS DEMONSTRATION BOARDS A printed circuit board (PCB) is available to assist in the initial evaluation of circuit performance using the OPA860. This module is available free, as an unpopulated PCB delivered with descriptive documentation.
PAGE 25
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 As a worst-case example, compute the maximum TJ using an OPA860ID in the circuit of Figure 53 operating at the maximum specified ambient temperature of +85°C and driving a grounded 20Ω load. PD = 10V × 11.2mA + 52/(4 × 20Ω) = 424mW Maximum TJ = +85°C + (0.43W × 125°C/W) = 139°C.
PAGE 26
OPA860 SBOS331C – JUNE 2005 – REVISED AUGUST 2008 ....................................................................................................................................................... www.ti.com INPUT AND ESD PROTECTION The OPA860 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.
PAGE 27
OPA860 www.ti.com ....................................................................................................................................................... SBOS331C – JUNE 2005 – REVISED AUGUST 2008 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (June 2006) to Revision C ....................................................................................................
PAGE 28
PACKAGE OPTION ADDENDUM www.ti.
PAGE 29
PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device OPA860IDR Package Package Pins Type Drawing SOIC D 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 Pack Materials-Page 1 6.4 B0 (mm) K0 (mm) P1 (mm) 5.2 2.1 8.0 W Pin1 (mm) Quadrant 12.
PAGE 30
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) OPA860IDR SOIC D 8 2500 367.0 367.0 35.
PAGE 31
PAGE 32
PAGE 33
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.