Ultralow Distortion,

Differential ADC Driver

ADA4937-1

Rev. 0

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FEATURES

Extremely low harmonic distortion

−112 dBc HD2 @ 10 MHz

−79 dBc HD2 @ 70 MHz

−70 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%

0.1 dB gain flatness to 200 MHz

Fast overdrive recovery of 1 ns

1 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

Pb-free, 3 mm × 3 mm 16-lead LFCSP

APPLICATIONS

ADC drivers

Single-ended-to-differential converters

IF and baseband gain blocks

Differential buffers

Line drivers

FUNCTIONAL BLOCK DIAGRAM

1

–FB

2

+IN

3

–IN

4

+FB

11 –OUT

12 PD

10 +OUT

ADA4937-1

Figure 1.

–55

–60

–65

–70

–75

–80

–85

–90

–95

–100

–105

–110

–115

110

10

FREQUENCY (MHz)

0

Figure 2. Harmonic Distortion vs. Frequency

GENERAL DESCRIPTION

The ADA4937-1 is 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 ADA4937-1 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 ADA4937-1, differential gain configurations are easily

realized with a simple external feedback network of four

resistors determining the closed-loop gain of the amplifier.

The ADA4937-1 is fabricated using Analog Devices, Inc.

proprietary 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 ADA4937-1 make it

well suited for a wide variety of data acquisition and signal

processing applications.

The ADA4937-1 is available in a Pb-free, 3 mm × 3 mm 16-lead

LFCSP. The pinout has been optimized to facilitate PCB layout

and minimize distortion. The part is specified to operate over

the −40°C to +105°C temperature range for 3.3 V supplies and

the −40°C to +85°C temperature range for 5 V supplies.