Ultralow Distortion
Differential ADC Driver
Data Sheet
ADA4937-1/ADA4937-2
FEATURES FUNCTIONAL BLOCK DIAGRAMS
ADA4937-1
Extremely low harmonic distortion (HD)
112 dBc HD2 at 10 MHz
84 dBc HD2 at 70 MHz
77 dBc HD2 at 100 MHz
FB 1 12 PD
102 dBc HD3 at 10 MHz
+IN 2 11 OUT
91 dBc HD3 at 70 MHz
IN 3 10 +OUT
84 dBc HD3 at 100 MHz
4 9
+FB V
OCM
Low input voltage noise: 2.2 nV/Hz
High speed
3 dB bandwidth of 1.9 GHz, G = 1
Figure 1. ADA4937-1
Slew rate: 6000 V/s, 25% to 75%
ADA4937-2
Fast overdrive recovery of 1 ns
0.5 mV typical offset voltage
Externally adjustable gain
Differential-to-differential or single-ended-to-differential
18
IN1 1 +OUT1
operation
+FB1 2 17 V
OCM1
Adjustable output common-mode voltage
+V 3 16 V
S1 S2
Single-supply operation: 3.3 V to 5 V
15
+V 4 V
S1 S2
FB2 5 14 PD2
APPLICATIONS
+IN2 6 13 OUT2
ADC drivers
Single-ended-to-differential converters
IF and baseband gain blocks
Differential buffers
Figure 2. ADA4937-2
Line drivers 55
HD2, V =5.0V
S
60
HD3, V =5.0V
S
GENERAL DESCRIPTION
HD2, V =3.3V
S
65
HD3, V =3.3V
S
The ADA4937-1/ADA4937-2 are low noise, ultralow distortion,
70
high speed differential amplifiers. They are an ideal choice for
75
driving high performance ADCs with resolutions up to 16 bits
80
from dc to 100 MHz. The adjustable level of the output common
85
mode allows the ADA4937-1/ADA4937-2 to match the input
90
of the ADC. The internal common-mode feedback loop also
95
provides exceptional output balance as well as suppression of
100
even-order harmonic distortion products.
105
110
With the ADA4937-1/ADA4937-2, differential gain configurations
115
are easily realized with a simple external feedback network of
1 10 100
four resistors that determine the closed-loop gain of the amplifier. FREQUENCY (MHz)
Figure 3. Harmonic Distortion vs. Frequency
The ADA4937-1/ADA4937-2 are fabricated using Analog Devices,
The ADA4937-1/ADA4937-2 are available in a Pb-free, 3 mm
Inc., proprietary silicon-germanium (SiGe), complementary
3 mm, 16-lead LFCSP (ADA4937-1, single) or a Pb-free, 4 mm
bipolar process, enabling them to achieve very low levels of
4 mm, 24-lead LFCSP (ADA4937-2, dual). The pinout has been
distortion with an input voltage noise of only 2.2 nV/Hz.
optimized to facilitate PCB layout and minimize distortion.
The low dc offset and excellent dynamic performance of the
The ADA4937-1/ADA4937-2 are specified to operate over the
ADA4937-1/ADA4937-2 make them well-suited for a wide
automotive (40C to +105C) temperature range and between
variety of data acquisition and signal processing applications.
3.3 V and 5 V supplies.
Rev. F Document Feedback
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DISTORTION (dBc)
+V V
S S
+V V
S S
V
+V
S
S
+V V
S S
06591-001
06591-002
06591-003
24
IN2 7 +IN1
5 16
+FB2 8 23 FB1
6 15
+V 9 22 V
S2 S1
+V 10 21 V 7 14
S2 S1
20
V 11 PD1
OCM2 8 13
+OUT2 12 19 OUT1ADA4937-1/ADA4937-2 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1 Analyzing an Application Circuit ............................................ 18
Applications ....................................................................................... 1 Setting the Closed-Loop Gain .................................................. 18
General Description ......................................................................... 1 Estimating the Output Noise Voltage ...................................... 18
Functional Block Diagrams ............................................................. 1 Impact of Mismatches in the Feedback Networks ................. 19
Revision History ............................................................................... 2 Calculating the Input Impedance for an Application Circuit
....................................................................................................... 19
Specifications ..................................................................................... 3
Input Common-Mode Voltage Range in Single-Supply
5 V Operation ............................................................................... 3
Applications ................................................................................ 20
3.3 V Operation ............................................................................ 5
Setting the Output Common-Mode Voltage .......................... 20
Absolute Maximum Ratings ............................................................ 7
Power-Down Operation ............................................................ 20
Thermal Resistance ...................................................................... 7
Layout, Grounding, and Bypassing .............................................. 22
ESD Caution .................................................................................. 7
High Performance ADC Driving ................................................. 23
Pin Configurations and Function Descriptions ........................... 8
3.3 V Operation .......................................................................... 25
Typical Performance Characteristics ............................................. 9
Outline Dimensions ....................................................................... 26
Test Circuits ..................................................................................... 16
Ordering Guide .......................................................................... 26
Terminology .................................................................................... 17
Theory of Operation ...................................................................... 18
REVISION HISTORY
6/2016Rev. E to Rev. F Changes to Figure 5 and Figure 6 .................................................... 8
Added EP Row to Table 7 and EP Row to Table 8 ........................ 8
Updated Outline Dimensions ....................................................... 26
Changes to Ordering Guide .......................................................... 26 Added Figure 46, Figure 47, and Figure 48; Renumbered
Sequentially ..................................................................................... 15
5/2015Rev. D to Rev. E Changes to Table 9 .......................................................................... 18
Changes to Table 6 ............................................................................ 7 Changes to Input Common-Mode Voltage Range in Single-
Updated Outline Dimensions ....................................................... 26 Supply Applications Section .......................................................... 20
Changes to Ordering Guide .......................................................... 26 Changes to Ordering Guide .......................................................... 26
8/2013Rev. C to Rev. D
11/2007Rev. 0 to Rev. A
Changes to Input Bias Current Parameter, Table 1 ...................... 3
Added the ADA4937-2 ...................................................... Universal
Changes to Input Bias Current Parameter, Table 3 ...................... 5
Changes to Features .......................................................................... 1
Updated Outline Dimensions ....................................................... 26
Changes to Specifications ................................................................. 3
Changes to Figure 4 ........................................................................... 7
3/2010Rev. B to Rev. C
Changes to Typical Performance Characteristics.......................... 9
Changes to Table 2, Power Supply Parameter ............................... 4
Inserted Figure 44 ........................................................................... 15
Changes to Table 4, Power Supply Parameter ............................... 6
Added the Terminating a Single-Ended Input Section ............. 19
Changes to Figure 43 ...................................................................... 15
Changes to Table 10 and Table 11 ................................................ 21
Added the Power-Down Operation Section ............................... 20
Changes to Layout, Grounding, and Bypassing Section ........... 22
Inserted Figure 59, Figure 60, and Figure 61 .............................. 22
10/2009Rev. A to Rev. B
Updated Outline Dimensions ....................................................... 26
Changes to General Description Section ...................................... 1
Changes to Ordering Guide .......................................................... 26
Changes to Table 1 ............................................................................ 3
Changes to Operating Temperature Range Parameter, Table 2 .. 4
5/2007Revision 0: Initial Version
Changes to Table 3 ............................................................................ 5
Changes to Figure 4 .......................................................................... 7
Rev. F | Page 2 of 28