Single-Supply, Differential 18-Bit ADC Driver

The ADA4941-1 is a low power, low noise differential driver for analog-to-digital converters (ADCs) up to 18 bits in systems that are sensitive to power. The ADA4941-1 is configured in an easy-to-use, single-ended-to-differential configuration and requires no external components for a gain of 2 configuration. A resistive feedback network can be added to achieve gains greater than 2. The ADA4941-1 provides essential benefits, such as low distortion and high SNR that are required for driving high resolution ADCs.

With a wide input voltage range (0 V to 3.9 V on a single 5 V supply), rail-to-rail output, high input impedance, and a user-adjustable gain, the ADA4941-1 is designed to drive single-supply ADCs with differential inputs found in a variety of low power applications, including battery-operated devices and singlesupply data acquisition systems.

The ADA4941-1 is ideal for driving the 16-bit and 18-bit PulSAR® ADCs, such as the AD7687, AD7690, and AD7691. The ADA4941-1 is manufactured on Analog Devices, Inc., proprietary, second-generation, eXtra fast complementary bipolar (XFCB) process, which enables the amplifier to achieve 18-bit performance on low supply currents.

The ADA4941-1 is available in a small 8-lead LFCSP as well as a standard 8-lead SOIC and is rated to work over the extended industrial temperature range, −40°C to +125°C.

Applications

* Single-supply data acquisition systems

* Instrumentation

* Process control

* Battery-power systems

* Medical instrumentation

* Single-ended-to-differential converter

* Excellent linearity

* Distortion −110 dBc at 100 kHz for VO, dm = 2 V p-p

* Low noise: 10.2 nV/√Hz, output-referred, G = 2

* Extremely low power: 2.2 mA (3 V supply)

* High input impedance: 24 MΩ

* User-adjustable gain

* High speed: 31 MHz, −3 dB bandwidth (G = +2)

* Fast settling time: 300 ns to 0.005% for a 2 V step

* Low offset: 0.8 mV maximum, output-referred, G = 2

* Rail-to-rail output

* Disable feature

* Wide supply voltage range: 2.7 V to 12 V

* Available in space-saving, 3 mm × 3 mm LFCSP