Single-Supply, Differential

18-Bit ADC Driver

ADA4941-1

Rev. C

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FEATURES

Single-ended-to-differential converter

Excellent linearity

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 max, 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.SOIC/LSCSP Pinout

–60

–140

0.1

10

1

1000

FREQUENCY (kHz)

100

–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

GENERAL DESCRIPTION

The ADA4941-1 is a low power, low noise differential driver for

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 ADI’s proprietary second-

generation 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.