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High-speed op amps (GBW ≥ 50 MHz)

THS3491

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900-MHz high-power-output current-feedback amplifier

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Data sheet

THS3491

ACTIVE
Data sheet Order now

Product details

Architecture Current FB Number of channels 1 Total supply voltage (+5 V = 5, ±5 V = 10) (min) (V) 14 Total supply voltage (+5 V = 5, ±5 V = 10) (max) (V) 32 GBW (typ) (MHz) 900 BW at Acl (MHz) 900 Acl, min spec gain (V/V) 1 Slew rate (typ) (V/µs) 8000 Vn at flatband (typ) (nV√Hz) 1.85 Vn at 1 kHz (typ) (nV√Hz) 3 Iq per channel (typ) (mA) 17.1 Vos (offset voltage at 25°C) (max) (mV) 2 Rail-to-rail No Features Shutdown Rating Catalog Operating temperature range (°C) -40 to 85 CMRR (typ) (dB) 75 Input bias current (max) (pA) 5000000 Offset drift (typ) (µV/°C) 3 Iout (typ) (mA) 420 2nd harmonic (dBc) 76 3rd harmonic (dBc) 69 Frequency of harmonic distortion measurement (MHz) 50
Architecture Current FB Number of channels 1 Total supply voltage (+5 V = 5, ±5 V = 10) (min) (V) 14 Total supply voltage (+5 V = 5, ±5 V = 10) (max) (V) 32 GBW (typ) (MHz) 900 BW at Acl (MHz) 900 Acl, min spec gain (V/V) 1 Slew rate (typ) (V/µs) 8000 Vn at flatband (typ) (nV√Hz) 1.85 Vn at 1 kHz (typ) (nV√Hz) 3 Iq per channel (typ) (mA) 17.1 Vos (offset voltage at 25°C) (max) (mV) 2 Rail-to-rail No Features Shutdown Rating Catalog Operating temperature range (°C) -40 to 85 CMRR (typ) (dB) 75 Input bias current (max) (pA) 5000000 Offset drift (typ) (µV/°C) 3 Iout (typ) (mA) 420 2nd harmonic (dBc) 76 3rd harmonic (dBc) 69 Frequency of harmonic distortion measurement (MHz) 50
DIESALE (Y) — See data sheet HSOIC (DDA) 8 29.4 mm² 4.9 x 6 VQFN (RGT) 16 9 mm² 3 x 3
  • Bandwidth:
    • 900 MHz (VO = 2 VPP, AV = 5 V/V)
    • 320 MHz (VO = 10 VPP, AV = 5 V/V)
  • Slew rate: 8000 V/µs (VO = 20 VPP)
  • Input voltage noise: 1.7 nV/√ Hz
  • Bipolar supply range: ±7 V to ±16 V
  • Single-supply range: 14 V to 32 V
  • Output swing: 28 VPP (±16-V supplies, 100-Ω load)
  • Linear output current: ±420 mA (typical)
  • 16.8-mA trimmed supply current (low temperature coefficient)
  • HD2 and HD3: less than –75 dBc (50 MHz, VO = 10 VPP, 100-Ω load)
  • Rise and fall time: 1.3 ns (10-V step)
  • Overshoot: 1.5% (10-V step, AV = 5 V/V)
  • Current limit and thermal shutdown protection
  • Power down feature
  • Bandwidth:
    • 900 MHz (VO = 2 VPP, AV = 5 V/V)
    • 320 MHz (VO = 10 VPP, AV = 5 V/V)
  • Slew rate: 8000 V/µs (VO = 20 VPP)
  • Input voltage noise: 1.7 nV/√ Hz
  • Bipolar supply range: ±7 V to ±16 V
  • Single-supply range: 14 V to 32 V
  • Output swing: 28 VPP (±16-V supplies, 100-Ω load)
  • Linear output current: ±420 mA (typical)
  • 16.8-mA trimmed supply current (low temperature coefficient)
  • HD2 and HD3: less than –75 dBc (50 MHz, VO = 10 VPP, 100-Ω load)
  • Rise and fall time: 1.3 ns (10-V step)
  • Overshoot: 1.5% (10-V step, AV = 5 V/V)
  • Current limit and thermal shutdown protection
  • Power down feature

The THS3491 current feedback amplifier (CFA) provides a new level of performance for applications requiring the lowest distortion at high output power levels from DC through values greater than 100 MHz at 100-Ω loads. Although specified at a gain of 5 V/V, this current feedback design holds near constant bandwidth and distortion over a wide range of gains.

The 8000 V/µs of slew rate delivers an output of 10 VPP into demanding loads with low distortion through 100 MHz. The 900-MHz, small-signal bandwidth delivers a low overshoot of less than 1.5% for a 10-V step, and rise and fall times of less than 1.3 ns. Peak output current drive values greater than 500 mA enable driving heavy capacitive loads with fast signals.

New designs benefit from the lowest distortion using the VQFN-16 (RGT) package, whereas the 8-pin HSOIC (DDA) package (with PowerPAD™) upgrades existing THS3091 or THS3095 designs. Lower output headroom for the THS3491 provides more output swing on the same ±15-V supplies versus legacy THS3091 or THS3095 options.

The THS3491 current feedback amplifier (CFA) provides a new level of performance for applications requiring the lowest distortion at high output power levels from DC through values greater than 100 MHz at 100-Ω loads. Although specified at a gain of 5 V/V, this current feedback design holds near constant bandwidth and distortion over a wide range of gains.

The 8000 V/µs of slew rate delivers an output of 10 VPP into demanding loads with low distortion through 100 MHz. The 900-MHz, small-signal bandwidth delivers a low overshoot of less than 1.5% for a 10-V step, and rise and fall times of less than 1.3 ns. Peak output current drive values greater than 500 mA enable driving heavy capacitive loads with fast signals.

New designs benefit from the lowest distortion using the VQFN-16 (RGT) package, whereas the 8-pin HSOIC (DDA) package (with PowerPAD™) upgrades existing THS3091 or THS3095 designs. Lower output headroom for the THS3491 provides more output swing on the same ±15-V supplies versus legacy THS3091 or THS3095 options.
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Technical documentation

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Type Title Date
* Data sheet THS3491 900-MHz, 500-mA High-Power Output Current Feedback Amplifier datasheet (Rev. C) PDF | HTML 22 Feb 2023
Technical article 3 common questions when designing with high-speed amplifiers PDF | HTML 17 Jul 2020
Technical article How to reduce distortion in high-voltage, high-frequency signal generation for AWG PDF | HTML 30 Oct 2018
EVM User's guide THS3491RGT EVM User's Guide 09 Aug 2017
EVM User's guide THS3491DDA EVM User's Guide 08 Aug 2017
Application note Load Sharing Concepts: Implementation for Large-Signal Applications 05 Oct 2011
Application note Noise Analysis for High Speed Op Amps (Rev. A) 17 Jan 2005

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

THS3491DDAEVM — THS3491 evaluation module for 900-MHz high-power-output current-feedback amplifier in DDA package

The THS3491DDA evaluation module (EVM) is used to evaluate the THS3491, which is a high-speed, high-voltage and low-distortion current-feedback amplifier in an 8-pin DDA package. The EVM is designed to quickly and easily demonstrate the functionality and performance of THS3491 in a gain of 5 V/V, (...)

User guide: PDF
Not available on TI.com
Evaluation board

THS3491RGTEVM — THS3491 evaluation module for 900-MHz high-power-output current-feedback amplifier in RGT package

The THS3491RGT evaluation module (EVM) is used to evaluate the THS3491, which is a high-speed, high-voltage and low-distortion current-feedback amplifier in a 16-pin RGT package. The EVM is designed to quickly and easily demonstrate the functionality and performance of THS3491 in a gain of 5 V/V, (...)

User guide: PDF
Not available on TI.com
Simulation model

THS3491 PSpice Model

SBOMBP9.ZIP (150 KB) - PSpice Model
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Simulation model

THS3491DDA TINA-TI Reference Design (Rev. A)

SBOMAI4A.TSC (1189 KB) - TINA-TI Reference Design
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Simulation model

THS3491DDA TINA-TI Spice Model (Rev. A)

SBOMAI5A.ZIP (11 KB) - TINA-TI Spice Model
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Simulation model

THS3491RGT TINA-TI Reference Design

SBOMAN3.TSC (344 KB) - TINA-TI Reference Design
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Simulation model

THS3491RGT TINA-TI Spice Model

SBOMAN4.ZIP (11 KB) - TINA-TI Spice Model
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Calculation tool

ANALOG-ENGINEER-CALC — Analog engineer's calculator

The analog engineer’s calculator is designed to speed up many of the repetitive calculations that analog circuit design engineers use on a regular basis. This PC-based tool provides a graphical interface with a list of various common calculations ranging from setting operational-amplifier (...)
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Calculation tool

VOLT-DIVIDER-CALC — Voltage divider calculation tool

The voltage divider calculation tool (VOLT-DIVIDER-CALC) quickly determines a set of resistors for a voltage divider. This KnowledgeBase JavaScript utility can be used to find a set of resistors for a voltage divider to achieve the desired output voltage. VOLT-DIVIDER-CALC can also be used to (...)
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Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
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Reference designs

TIDA-060033 — Bootstrap high-output voltage-extension reference design

This reference design uses three THS3491 high-speed, high-voltage current feedback amplifiers to deliver 50-Vpp output sinusoidal voltage swing at 1 MHz, while maintaining a large signal bandwidth (BW) of 100 MHz at 20-Vpp output. The high-output voltage swing is achieved by modulating the (...)
Design guide: PDF
Reference designs

TIDA-060002 — 100-MHz, 1 A Output current driver reference design for high capacitive load applications

This reference design uses the THS3491 high-speed, high-voltage current feedback amplifier to demonstrate an output current drive capability of greater than 1 A into a low-resistive or high-capacitive load while maintaining a large signal bandwidth of 100 MHz at 20 VPP. The high output (...)
Design guide: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
DIESALE (Y) —
HSOIC (DDA) 8 Ultra Librarian
VQFN (RGT) 16 Ultra Librarian
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