The ADA4938-1 / ADA4938-2 are low noise, ultralow distortion, high speed differential amplifiers. It is an ideal choice for driving high performance ADCs with resolutions up to 16 bits from dc to 27 MHz, or up to 12 bits from dc to 74 MHz. The output common-mode voltage is adjustable over a wide range, allowing the ADA4938-1/ADA4938-2 to match the input of the ADC. The internal common-mode feedback loop also provides exceptional output balance as well as suppression of even-order harmonic distortion products.
Full differential and single-ended-to-differential gain configurations are easily realized with the ADA4938-1/ADA4938-2. A simple external feedback network of four resistors determines the closed-loop gain of the amplifier.
The ADA4938-1 / ADA4938-2 are fabricated using the Analog Devices, Inc., proprietary third generation, high voltage XFCB process, enabling it to achieve very low levels of distortion with an input voltage noise of only 2.6 nV/√Hz. The low dc offset and excellent dynamic performance of the ADA4938-1/ADA4938-2 makes them well-suited for a wide variety of data acquisition and signal processing applications.
The ADA4938-1 (single amplifier) is available in a Pb-free, 3 mm × 3 mm, 16-lead LFCSP. The ADA4938-2 (dual amplifier) is available in a Pb-free, 4 mm × 4 mm, 24-lead LFCSP. The pinouts have been optimized to facilitate layout and minimize distortion. The devices are specified to operate over the extended industrial temperature range of −40°C to +85°C.
Applications
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Line drivers
### Features and Benefits
Extremely low harmonic distortion (HD)
−106 dBc HD2 at 10 MHz
−82 dBc HD2 at 50 MHz
−109 dBc HD3 at 10 MHz
−82 dBc HD3 at 50 MHz
Low input voltage noise: 2.6 nV/√Hz
High speed
−3 dB bandwidth of 1000 MHz, G = +1
Slew rate: 4700 V/μs
0.1 dB gain flatness to 150 MHz
Fast overdrive recovery of 4 ns
1 mV typical offset voltage
Externally adjustable gain
Differential-to-differential or single-ended-to-differential operation
