THS3491 Current Feedback Amplifier (CFA)

By Texas Instruments 33

THS3491 Current Feedback Amplifier (CFA)

Texas Instruments' 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 8,000 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.

Features
  • Bandwidth:
    • 900 MHz (VO = 2 VPP, AV = 5 V/V)
    • 320 MHz (VO = 10 VPP, AV = 5 V/V)
  • Slew rate: 8,000 V/µs (VO = 20 VPP)
  • Input voltage noise: 1.7 nV/√Hz
  • Single-supply range: 14 V to 32 V
  • Output swing: 28 VPP (±16 V supplies, 100 Ω load)
  • Linear output current: ±420 mA (typ.)
  • 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
Applications
  • High-voltage, arbitrary waveform generators
  • Pattern generators for LCD testers
  • Output drivers for LCR meters
  • Power FET drivers
  • High capacitive load piezo element drivers
  • VDSL line drivers
  • Pin-compatible upgrade to THS3095 (DDA)

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