Low Power Selectable Gain Differential ADC Driver, G = 1, 2, 3

The ADA4950-1/ADA4950-2 are gain-selectable versions of the ADA4932-1/ADA4932-2 with on-chip feedback and gain resistors It is an ideal choice for driving high performance ADCs as a single-ended-to-differential or differential-to-differential amplifier. The output common-mode voltage is user adjustable by means of an internal common-mode feedback loop, allowing the ADA4950-x output to match the input of the ADC. The internal feedback loop also provides exceptional output balance as well as suppression of even-order harmonic distortion products.

Differential gain configurations of 1, 2, and 3 are easily realized with internal feedback networks that are connected externally to set the closed-loop gain of the amplifier.

The ADA4950-x is fabricated using the Analog Devices, Inc., proprietary silicon-germanium (SiGe) complementary bipolar process, enabling it to achieve low levels of distortion and noise at low power consumption. The low offset and excellent dynamic performance of the ADA4950-x make it well suited for a wide variety of data acquisition and signal processing applications.

The ADA4950-x is available in a Pb-free, 3 mm × 3 mm, 16-lead LFCSP (ADA4950-1, single) or a Pb-free 4 mm × 4 mm, 24-lead LFCSP (ADA4950-2, dual). The pinout has been optimized to facilitate PCB layout and minimize distortion. The ADA4950-1/ADA4950-2 are specified to operate over the -40°C to +105°C temperature range; both operate on supplies from +3 V to ±5 V.

Applications

* ADC drivers

* Single-ended-to-differential converters

* IF and baseband gain blocks

* Differential buffers

* Line drivers

* High performance at low power * High speed

-3 dB bandwidth of 750 MHz, G = 1

0.1 dB flatness to 210 MHz, VOUT, dm = 2 V p-p, RL, dm = 200 Ω

Slew rate: 2900 V/µs, 25% to 75% Fast 0.1% settling time of 9 ns * Low power: 9.5 mA per amplifier * Low harmonic distortion 108 dB SFDR @ 10 MHz 98 dB SFDR @ 20 MHz * Low output voltage noise: 9.2 nV/√Hz, G = 1, RTO * ±0.2 mV typical input offset voltage * Selectable differential gains of 1, 2, and 3 * Differential-to-differential or single-ended-to-differential operation * Adjustable output common-mode voltage * Input common-mode range shifted down by one VBE * Wide supply range: +3 V to ±5 V * Available in 16-lead and 24-lead LFCSP packages