LT1993-4

1

19934fa

900MHz Low Distortion, Low

Noise Differential Amplifier/

Amplifier/ADC driver for use in applications from DC to

900MHz. The LT1993-4 has been designed for ease of

use, with minimal support circuitry required. Exception-

ally low input-referred noise and low distortion products

(with either single-ended or differential inputs) make the

LT1993-4 an excellent solution for driving high speed 12-

bit and 14-bit ADCs. In addition to the normal unfiltered

outputs (+OUT and –OUT), the LT1993-4 has a built-in

175MHz differential lowpass filter and an additional pair

of filtered outputs (+OUTFILTERED, –OUTFILTERED) to

reduce external filtering components when driving high

speed ADCs. The output common mode voltage is easily set

or AC-coupling capacitors in many applications.

The LT1993-4 is designed to meet the demanding require-

ments of communications transceiver applications. It can

be used as a differential ADC driver, a general-purpose

differential gain block, or in any other application requir-

ing differential drive. The LT1993-4 can be used in data

acquisition systems required to function at frequencies

down to DC.

The LT1993-4 operates on a 5V supply and consumes

100mA. It comes in a compact 16-lead 3

× 3 QFN package

and operates over a –40°C to 85°C temperature range.

■

Differential ADC Driver for:

Imaging

Communications

■

Differential Driver/Receiver

■

Single Ended to Differential Conversion

■

Differential to Single Ended Conversion

■

Level Shifting

■

IF Sampling Receivers

■

SAW Filter Interfacing/Buffering

■

900MHz –3dB Bandwidth

■

Fixed Gain of 4V/V (12dB)

■

Low Distortion:

■

■

Differential Inputs and Outputs

■

Additional Filtered Outputs

■

Adjustable Output Common Mode Voltage

■

DC- or AC-Coupled Operation

■

Minimal Support Circuitry Required

■

Small 0.75mm Tall 16-Lead 3

× 3 QFN Package

ADC Driver with Single-Ended to Differential Conversion

2.2V

12dB GAIN

19934 TA01

MA/COM

ETC1-1-13

1:1

Z-RATIO

LTC2255 125Msps

14-BIT ADC SAMPLING

AT 92.16Msps

70MHz

IF IN

52.3pF

82nH

LT1993-4

–INA

–INB

–OUTFILTERED

–OUT

+OUTFILTERED

+OUT

+INB

+INA

ENABLE

LTC2255

ADC

AIN–

AIN+

0.1

µF

12.2

Ω

12.2

Ω

100

Ω

0.1

µF

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

, LTC and LT are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

FREQUENCY (MHz)

0

–120

–100

–80

–60

–40

0

5

10

15

20

LT19934 TA02

30

45

40

25

35

–20

–110

–90

–70

–50

–30

–10

32768 POINT FFT

TONE CENTER FREQUENCIES

AT 62.5MHz, 67.5MHz,

72.5MHz, 77.5MHz

4-Tone WCDMA Waveform,

LT1993-4 Driving LTC2255

14-Bit ADC at 92.16Msps