ADA4930-1_17 Datasheet, PDF (1/25 Pages) Analog Devices – Ultralow Noise Drivers for Low Voltage ADCs

Data Sheet
FEATURES
Low input voltage noise: 1.2 nV/√Hz
Low common-mode output: 0.9 V on single supply
Extremely low harmonic distortion
−104 dBc HD2 at 10 MHz
−79 dBc HD2 at 70 MHz
−73 dBc HD2 at 100 MHz
−101 dBc HD3 at 10 MHz
−82 dBc HD3 at 70 MHz
−75 dBc HD3 at 100 MHz
High speed
−3 dB bandwidth of 1.35 GHz, G = 1
Slew rate: 3400 V/μs, 25% to 75%
0.1 dB gain flatness to 380 MHz
Fast overdrive recovery of 1.5 ns
0.5 mV typical offset voltage
Externally adjustable gain
Differential-to-differential or single-ended-to-differential
operation
Adjustable output common-mode voltage
Single-supply operation: 3.3 V or 5 V
APPLICATIONS
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Line drivers
GENERAL DESCRIPTION
The ADA4930-1/ADA4930-2 are very low noise, low distortion,
high speed differential amplifiers. They are an ideal choice for
driving 1.8 V high performance ADCs with resolutions up to
14 bits from dc to 70 MHz. The adjustable output common
mode allows the ADA4930-1/ADA4930-2 to match the input of
the ADC. The internal common-mode feedback loop provides
exceptional output balance, suppression of even-order harmonic
distortion products, and dc level translation.
With the ADA4930-1/ADA4930-2, differential gain configurations
are easily realized with a simple external feedback network of
four resistors determining the closed-loop gain of the amplifier.
The ADA4930-1/ADA4930-2 are fabricated using Analog Devices,
Inc., proprietary silicon-germanium (SiGe), complementary
bipolar process, enabling them to achieve very low levels of
distortion with an input voltage noise of only 1.2 nV/√Hz.
Rev. C
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Ultralow Noise
Drivers for Low Voltage ADCs
ADA4930-1/ADA4930-2
FUNCTIONAL BLOCK DIAGRAMS
–FB 1
+IN 2
–IN 3
+FB 4
ADA4930-1
12 PD
11 –OUT
10 +OUT
9 VOCM
Figure 1.
–IN1 1
+FB1 2
+V_S1 3
+V_S1 4
–FB2 5
+IN2 6
ADA4930-2
18 +OUT1
17 VOCM1
16 –VS2
15 –VS2
14 PD2
13 ^–OUT2
Figure 2.
100
10
1
0
10
100
1k
10k 100k
1M
10M 100M
FREQUENCY (Hz)
Figure 3. Voltage Noise Spectral Density
The low dc offset and excellent dynamic performance of the
ADA4930-1/ADA4930-2 make them well suited for a wide
variety of data acquisition and signal processing applications.
The ADA4930-1 is available in a Pb-free, 3 mm × 3 mm 16-lead
LFCSP, and the ADA4930-2 is available in a Pb-free, 4 mm × 4 mm
24-lead LFCSP. The pinout has been optimized to facilitate printed
circuit board (PCB) layout and minimize distortion. The
ADA4930-1 is specified to operate over the −40°C to +105°C
temperature range, and the ADA4930-2 is specified to operate over
the −40°C to +105°C temperature range for 3.3 V or 5 V supply
voltages.
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