Low Noise Rail-to-Rail

Differential ADC Driver

AD8139

Rev. A

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FEATURES

Fully differential

Low noise

2.25 nV/√Hz

2.1 pA/√Hz

Low harmonic distortion

98 dBc SFDR @ 1 MHz

85 dBc SFDR @ 5 MHz

72 dBc SFDR @ 20 MHz

High speed

410 MHz, 3 dB BW (G = 1)

800 V/µs slew rate

45 ns settling time to 0.01%

69 dB output balance @ 1 MHz

80 dB dc CMRR

Low offset: ±0.5 mV max

Low input offset current: 0.5 µA max

Differential input and output

Differential-to-differential or single-ended-to-differential

operation

Rail-to-rail output

Adjustable output common-mode voltage

Wide supply voltage range: 5 V to 12 V

Available in small SOIC package

APPLICATIONS

ADC drivers to 18 bits

Single-ended-to-differential converters

Differential filters

Level shifters

Differential PCB board drivers

Differential cable drivers

FUNCTIONAL BLOCK DIAGRAM

–IN

1

V+

3

+OUT

4

+IN

8

NC

7

V–

6

–OUT

5

NC = NO CONNECT

AD8139

Figure 1.

GENERAL DESCRIPTION

The AD8139 is an ultralow noise, high performance differential

amplifier with rail-to-rail output. With its low noise, high SFDR,

and wide bandwidth, it is an ideal choice for driving ADCs with

resolutions to 18 bits. The AD8139 is easy to apply, and its in-

ternal common-mode feedback architecture allows its output

common-mode voltage to be controlled by the voltage applied

to one pin. The internal feedback loop also provides out-

standing output balance as well as suppression of even-order

harmonic distortion products. Fully differential and single-

ended-to-differential gain configurations are easily realized by

the AD8139. Simple external feedback networks consisting of a

total of four resistors determine the amplifier’s closed-loop gain.

The AD8139 is manufactured on ADI’s proprietary second gen-

eration XFCB process, enabling it to achieve low levels of distor-

tion with input voltage noise of only 1.85 nV/√Hz.

The AD8139 is available in an 8-lead SOIC package with an

exposed paddle (EP) on the underside of its body and a 3 mm ×

3 mm LFCSP. It is rated to operate over the temperature range

of −40°C to +125°C.

1

10

100

1k

10k

100k

1M

10M

1G

100M

10

100

FREQUENCY (Hz)

Figure 2. Input Voltage Noise vs. Frequency