Overview
The THS3491 current feedback amplifier (CFA) from Texas Instruments is designed to provide exceptional performance for applications requiring low distortion at high output power levels. This amplifier operates effectively from DC through frequencies greater than 100 MHz at 100-Ω loads. It is particularly suited for applications where high bandwidth, low distortion, and high output power are critical. The THS3491 is available in two package options: the 8-pin HSOIC (DDA) with PowerPAD™ and the 16-pin VQFN (RGT), making it versatile for both new designs and upgrades to existing THS3091 or THS3095 designs.
Key Specifications
| Parameter | Value |
|---|---|
| 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) |
| Supply Current | 16.8 mA (trimmed, 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) |
| Operating Temperature Range | -40°C to 85°C |
| Package Options | 8-pin HSOIC (DDA) with PowerPAD™, 16-pin VQFN (RGT) |
Key Features
- High bandwidth of up to 900 MHz and high slew rate of 8000 V/µs, enabling low distortion at high output power levels.
- Low input voltage noise of 1.7 nV/√Hz.
- Broad supply voltage range: bipolar ±7 V to ±16 V and single-supply 14 V to 32 V.
- High output swing of 28 VPP with ±16-V supplies and 100-Ω load.
- High linear output current of ±420 mA (typical).
- Low supply current of 16.8 mA with a low temperature coefficient.
- Excellent harmonic distortion performance with HD2 and HD3 less than –75 dBc.
- Fast rise and fall times of less than 1.3 ns and low overshoot of 1.5%.
- Current limit and thermal shutdown protection for reliability.
- Power down feature for power management.
Applications
The THS3491 is ideal for various high-performance applications, including:
- High-frequency signal processing and amplification.
- Audio and video equipment requiring low distortion and high output power.
- Medical imaging and diagnostic equipment.
- Test and measurement instruments.
- Industrial control systems and automation.
- Communication systems and base stations.
Q & A
- What is the bandwidth of the THS3491?
The THS3491 has a bandwidth of up to 900 MHz for small-signal inputs and 320 MHz for larger signal inputs (VO = 10 VPP, AV = 5 V/V). - What is the slew rate of the THS3491?
The slew rate of the THS3491 is 8000 V/µs (VO = 20 VPP). - What is the input voltage noise of the THS3491?
The input voltage noise is 1.7 nV/√Hz. - What are the supply voltage ranges for the THS3491?
The THS3491 operates with bipolar supplies from ±7 V to ±16 V and single-supply from 14 V to 32 V. - What is the output swing of the THS3491?
The output swing is 28 VPP with ±16-V supplies and a 100-Ω load. - What is the typical linear output current of the THS3491?
The typical linear output current is ±420 mA. - Does the THS3491 have any protection features?
Yes, it includes current limit and thermal shutdown protection. - What are the package options for the THS3491?
The THS3491 is available in 8-pin HSOIC (DDA) with PowerPAD™ and 16-pin VQFN (RGT) packages. - What is the operating temperature range of the THS3491?
The operating temperature range is -40°C to 85°C. - What are some typical applications for the THS3491?
Typical applications include high-frequency signal processing, audio and video equipment, medical imaging, test and measurement instruments, industrial control systems, and communication systems.
