ADA4927-1 Datasheet, PDF (1/24 Pages) Analog Devices – Ultralow Distortion Current Feedback Differential ADC Driver

Ultralow Distortion
Current Feedback Differential ADC Driver
ADA4927-1/ADA4927-2
FEATURES
Extremely low harmonic distortion
−105 dBc HD2 @ 10 MHz
−91 dBc HD2 @ 70 MHz
−87 dBc HD2 @ 100 MHz
−103 dBc HD3 @ 10 MHz
−98 dBc HD3 @ 70 MHz
−89 dBc HD3 @ 100 MHz
Better distortion at higher gains than VF amplifiers
Low input voltage noise: 1.4 nV/√Hz
High speed
−3 dB bandwidth of 2.3 GHz
0.1 dB gain flatness: 150 MHz
Slew rate: 5000 V/μs, 25% to 75%
Fast 0.1% settling time: 10 ns
Low input offset voltage: 0.3 mV typical
Externally adjustable gain
Stability and bandwidth controlled by feedback resistor
Differential-to-differential or single-ended-to-differential
operation
Adjustable output common-mode voltage
Wide supply operation: +5 V to ±5 V
APPLICATIONS
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Differential line drivers
GENERAL DESCRIPTION
The ADA4927 is a low noise, ultralow distortion, high speed,
current feedback differential amplifier that is an ideal choice for
driving high performance ADCs with resolutions up to 16 bits
from dc to 100 MHz. The output common-mode level can easily be
matched to the required ADC input common-mode levels. The
internal common-mode feedback loop provides exceptional output
balance and suppression of even-order distortion products.
Differential gain configurations are easily realized using an
external feedback network comprising four resistors. The
current feedback architecture provides loop gain that is nearly
independent of closed-loop gain, achieving wide bandwidth,
low distortion, and low noise at higher gains and lower power
consumption than comparable voltage feedback amplifiers.
The ADA4927 is fabricated using the Analog Devices, Inc., silicon-
germanium complementary bipolar process, enabling very low
levels of distortion with an input voltage noise of only 1.3 nV/√Hz.
Rev. 0
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FUNCTIONAL BLOCK DIAGRAMS
–FB 1
+IN 2
–IN 3
+FB 4
ADA4927-1
12 PD
11 –OUT
10 +OUT
9 V_OCM
Figure 1.
–IN1 1
+FB1 2
+V_S1 3
+V_S1 4
–FB2 5
+IN2 6
ADA4927-2
18 +OUT1
17 V_OCM1
16 –V_S2
15 –VS2
14 PD2
13 –OUT2
–40
V_OUT, _dm = 2V p-p
–50
Figure 2.
–60
–70
–80
–90
–100
–110
–120
G=1
G = 10
G = 20
–130
1
10
100
1k
FREQUENCY (MHz)
Figure 3. Spurious-Free Dynamic Range vs. Frequency at Various Gains
The low dc offset and excellent dynamic performance of the
ADA4927 make it well suited for a wide variety of data acquisition
and signal processing applications.
The ADA4927-1 is available in a Pb-free, 3 mm × 3 mm 16-lead
LFCSP, and the ADA4927-2 is available in a Pb-free, 4 mm × 4 mm
24-lead LFCSP. The pinouts are optimized to facilitate printed
circuit board (PCB) layout and to minimize distortion. They are
specified to operate over the −40°C to +105°C temperature range.
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