ADA4937-2_15 Datasheet, PDF (1/29 Pages) Analog Devices – Ultralow Distortion Differential ADC Driver

Data Sheet
FEATURES
Extremely low harmonic distortion (HD)
−112 dBc HD2 @ 10 MHz
−84 dBc HD2 @ 70 MHz
−77 dBc HD2 @ 100 MHz
−102 dBc HD3 @ 10 MHz
−91 dBc HD3 @ 70 MHz
−84 dBc HD3 @ 100 MHz
Low input voltage noise: 2.2 nV/√Hz
High speed
−3 dB bandwidth of 1.9 GHz, G = 1
Slew rate: 6000 V/µs, 25% to 75%
Fast overdrive recovery of 1 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 to 5 V
APPLICATIONS
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Line drivers
GENERAL DESCRIPTION
The ADA4937-xis a low noise, ultralow distortion, high speed
differential amplifier. It is an ideal choice for driving high
performance ADCs with resolutions up to 16 bits from dc to
100 MHz. The adjustable level of the output common mode
allows the ADA4937-x to match the input of the ADC. The
internal common-mode feedback loop also provides exceptional
output balance as well as suppression of even-order harmonic
distortion products.
With the ADA4937-x, differential gain configurations are easily
realized with a simple external feedback network of four resis-
tors that determine the closed-loop gain of the amplifier.
The ADA4937-x is fabricated using Analog Devices, Inc., proprie-
tary silicon-germanium (SiGe), complementary bipolar process,
enabling it to achieve very low levels of distortion with an input
voltage noise of only 2.2 nV/√Hz. The low dc offset and excellent
dynamic performance of the ADA4937-x make it well-suited
for a wide variety of data acquisition and signal processing appli-
cations.
Rev. D
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Ultralow Distortion
Differential ADC Driver
ADA4937-1/ADA4937-2
FUNCTIONAL BLOCK DIAGRAMS
–FB 1
+IN 2
–IN 3
+FB 4
ADA4937-1
12 PD
11 –OUT
10 +OUT
9 V_OCM
Figure 1. ADA4937-1
–IN1 1
+FB1 2
+V_S1 3
+V_S1 4
–FB2 5
+IN2 6
ADA4937-2
18 +OUT1
17 V_OCM1
16 –V_S2
15 –VS2
14 PD2
13 –OUT2
Figure 2. ADA4937-2
–55
–60
–65
–70
–75
–80
–85
–90
–95
–100
–105
–110
–115
1
HD2, V_S = 5.0V
HD3, V_S = 5.0V
HD2, V_S = 3.3V
HD3, V_S = 3.3V
10
100
FREQUENCY (MHz)
Figure 3. Harmonic Distortion vs. Frequency
The ADA4937-x is available in a Pb-free, 3 mm × 3 mm, 16-lead
LFCSP (ADA4937-1, single) or a Pb-free, 4 mm × 4 mm, 24-lead
LFCSP (ADA4937-2, dual). The pinout has been optimized to
facilitate PCB layout and minimize distortion. The ADA4937-x
is specified to operate over the automotive (−40°C to +105°C)
temperature range and between 3.3 V and 5 V supplies.
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