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
04679-0-001
–IN 1
V
OCM
2
V+ 3
+OUT 4
+IN8
NC7
V–6
–OUT5
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 1G100M
10
100
04679-0-078
FREQUENCY (Hz)
IN
PU
T VOLTA
G
E N
O
ISE (
n
V/ H
z
)

Figure 2. Input Voltage Noise vs. Frequency