THS4508 - Wideband Fully Differential Amplifier

The THS4508 is a wideband, fully-differential operational amplifier designed for single-supply 5-V data acquisition systems. It has very low noise at 2.3 nV/√Hz, and extremely low harmonic distortion of -72 dBc HD₂ and -79 dBc HD₃ at 100 MHz with 2 V_PP, G = 10 dB, and 1-Ω load. Slew rate is very high at 6400 Vµs, and with settling time of 2 ns to 1% (2 V step), it is ideal for pulsed applications. It is designed for minimum gain of 6 dB, but is optimized for gain of 10 dB.

To allow for dc coupling to analog-to-digital converters (ADCs), its unique output common-mode control circuit maintains the output common-mode voltage within 5-mV offset (typical) from the set voltage, when set within 0.5 V of mid-supply. The common-mode set point is set to mid-supply by internal circuitry, which may be over-driven from an external source.

The THS4508 is a high-performance amplifier that has been optimized for use in high performance, 5-V single-supply data acquisition systems. The output has been optimized for best performance with its common-mode voltages set to mid-supply, and the input has been optimized for best performance with its common-mode voltage set to 0.7 V. High performance at a low power-supply voltage is ideal for high-performance, single-supply 5-V data-acquisition systems with a minimum parts count. The combined performance of the THS4508 in a gain of 10-dB driving the ADS5500 ADC, sampling at 125 MSPS, is 82-dBc SFDR, and 68.3-dBc SNR with a -1-dBFS signal at 70 MHz.

The THS4508 is offered in a quad 16-pin leadless QFN package (RGT), and is characterized for operation over the full industrial temperature range from -40°C to +85°C.

• Fully Differential Architecture
• Common-Mode Input Range Includes the
  Negative Rail
• Minimum Gain of 2 V/V (6 dB)
• Bandwidth: 2 GHz
• Slew Rate: 6400 V/µs
• 1% Settling Time: 2 ns
• HD₂: -72 dBc at 100 MHz
• HD₃: -79 dBc at 100 MHz
• OIP₂: 78 dBm at 70 MHz
• OIP₃: 42 dBm at 70 MHz
• Input Voltage Noise: 2.3 nV/√Hz (f > 10 MHz)
• Noise Figure: 19.2 dB (G = 10 dB)
• Output Common-Mode Control
• 5-V Power Supply Current: 39.2 mA
• Power-Down Capability: 0.65 mA
• APPLICATIONS
  • 5-V Data-Acquisition Systems
  • High Linearity ADC Amplifier
  • Wireless Communication
  • Medical Imaging
  • Test and Measurement