1 Features

• Very Low Quiescent Current: 750 μA (at 5 V)
• Rail-to-Rail Input and Output:
  • Common-Mode Input Voltage Extends
    400 mV Beyond the Rails
  • Output Swings Within 150 mV From the Rails
• Wide –3-dB Bandwidth at 5 V:
  • 90 MHz at Gain = +1, 40 MHz at Gain = +2
• High Slew Rate: 35 V/μs
• Fast Settling Time (2-V Step):
  • 78 ns to 0.1%
  • 150 ns to 0.01%
• Low Distortion at Gain = +2, V_O = 2-V_PP, 5 V:
  • –91 dBc at 100 kHz, –67 dBc at 1 MHz
• Input Offset Voltage: 2.5 mV (Max at +25°C)
• Output Current > 30 mA (10-Ω Load, 5 V)
• Low Voltage Noise of 12.5 nV/√Hz
• Supply Voltages: +2.7 V, 3 V, +5 V, ±5 V, +15 V
• Packages: SOT23, MSOP, and SOIC

2 Applications

• Portable/Battery-Powered Applications
• High Channel Count Systems
• ADC Buffer
• Active Filters
• Current Sensing

3 Description

Fabricated using the BiCom-II process, the THS4281 is a low-power, rail-to-rail input and output, voltage-feedback operational amplifier designed to operate over a wide power-supply range of 2.7-V to 15-V single supply, and ±1.35-V to ±7.5-V dual supply. Consuming only 750 μA with a unity gain bandwidth of 90 MHz and a high 35-V/μs slew rate, the THS4281 allows portable or other power-sensitive applications to realize high performance with minimal power. To ensure long battery life in portable applications, the quiescent current is trimmed to be less than 900 μA at +25°C, and 1 mA from –40°C to +85°C.

The THS4281 is a true single-supply amplifier with a specified common-mode input range of 400 mV beyond the rails. This allows for high-side current sensing applications without phase reversal concerns. Its output swings to within 40 mV from the rails with 10-kΩ loads, and 150 mV from the rails with 1-kΩ loads.

The THS4281 has a good 0.1% settling time of 78 ns, and 0.01% settling time of 150 ns. The low THD of –87 dBc at 100 kHz, coupled with a maximum offset voltage of less than 2.5 mV, makes the THS4281 a good match for high-resolution ADCs sampling less than 2 MSPS.

The THS4281 is offered in a space-saving SOT23-5 package, a small MSOP-8 package, and the industry standard SOIC-8 package.

1. For all available packages, see the orderable addendum at the end of the data sheet.

High-side, Low Power Current-Sensing system