Single-Supply, Differential,

18-Bit ADC Driver

Data Sheet

ADA4941-1

Rev. D

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FEATURES

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

APPLICATIONS

Single-supply data acquisition systems

Instrumentation

Process control

Battery-power systems

Medical instrumentation

FUNCTIONAL BLOCK DIAGRAM

DIS

4

3

2

1

IN

OUT–

OUT+

V+

REF

FB

V–

7

8

5

6

Figure 1.

GENERAL DESCRIPTION

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 single-

supply 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.

–60

–140

0.1

10

1

1000

FREQUENCY (kHz)

100

VO = 2V p-p

VO = 6V p-p

–65

–70

–75

–80

–85

–90

–95

–100

–105

–110

–115

–120

–125

–130

–135

HD3

HD2

HD3

HD2

Figure 2. Distortion vs. Frequency at Various Output Amplitudes