1 Features
1• High-Drive Mode:
– GBW (G = 100): 120 MHz
– Slew Rate: 115 V/μs
– 16-Bit Settling at 4-V Step: 280 ns
– Low Voltage Noise: 2.5 nV/√Hz at 10 kHz
– Low Output Impedance: 1 Ω at 1 MHz gain–
Offset Voltage: ±100 μV (max)
– Offset Voltage Drift: ±3 μV/ºC (max)
– Low Quiescent Current: 2 mA (typ)
• Low-Power Mode:
– GBW: 1 MHz
– Low Quiescent Current: 270 μA (typ)
• Power-Scalable Features:
– Ultrafast Transition from Low-Power to High-
Drive Mode: 170 ns
• High AC and DC Precision:
– Low Distortion: –122 dBc for HD2 and –140
dBc for HD3 at 100 kHz
– Input Common-Mode Range Includes Negative
Rail
– Rail-to-Rail Output
– Wide Temperature Range: Fully Specified from
–40°C to +125°C

2 Applications
• Precision SAR ADC Drivers
• Precision Voltage Reference Buffers
• Programmable Logic Controllers
• Test and Measurement Equipment
• Power-Sensitive Data Acquisition Systems

3 Description
The OPAx625 family of operational amplifiers are
excellent 16-bit and 18-bit, high-precision, SAR ADC drivers with low THD and noise that allow for a
unique power-scalable solution. This family of devices
is fully characterized and specified with a 16-bit
settling time of 280 ns that enables a true 16-bit effective number of bits (ENOB). With a high dc
precision of only 100 μV offset voltage, a wide gain–
bandwidth product of 120 MHz, and a low wideband
noise of 2.5 nV/√Hz, this family is optimized for driving high-throughput, high-resolution SAR ADCs,
such as the ADS88xx family of SAR ADCs.
The OPAx625 features two operating modes: high-
drive and low-power. In the innovative low-power
mode, the OPAx625 tracks the input signal allowing
the device to transition from low-power mode to high- drive mode at 16-bit ENOB within 170 ns.
The OPAx625 family is available in 6-pin SOT and
10-pin VSSOP packages and is specified for operation from –40°C to +125°C.