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LT5557

5557fa

Infrastructure

High Signal Level Downmixer for Multi-Carrier Wireless Infrastructure

400MHz to 3.8GHz

3.3V High Signal Level

Downconverting Mixer

25.6dBm at 900MHz

24.7dBm at 1950MHz

23.7dBm at 2.6GHz

2.9dB at 1950MHz

11.7dB at 1950MHz

× 4mm) QFN Package

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

The LT

wide dynamic range downconverter applications. The IC

includes a high speed differential LO buffer amplifier

driving a double-balanced mixer. Broadband, integrated

transformers on the RF and LO inputs provide single-

ended 50

Ω interfaces. The differential IF output allows

convenient interfacing to differential IF filters and amplifi-

ers, or is easily matched to drive a single-ended 50

Ω load,

with or without an external transformer.

The RF input is internally matched to 50

Ω from 1.6GHz to

2.3GHz, and the LO input is internally matched to 50

Ω

from 1GHz to 5GHz. The frequency range of both ports is

easily extended with simple external matching. The IF

output is partially matched and usable for IF frequencies

up to 600MHz.

The LT5557’s high level of integration minimizes the total

solution cost, board space and system-level variation.

Conversion Gain, IIP3, SSB NF and

LO Leakage vs RF Frequency

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

All other trademarks are the property of their respective owners.

*Operation over a wider frequency range is possible with reduced performance. Consult factory for

information and assistance.

BIAS

EN

RF

100nH

100nH

4.7pF

150nH

IF

OUTPUT

240MHz

RF

INPUT

LO INPUT

–3dBm (TYP)

1nF

1

μF

1nF

4.7pF

3.3V

5557 TA01a

LT5557

GND

RF FREQUENCY (MHz)

1700

10

22

24

26

1900

2100

5557 TA01b

6

18

14

8

20

2

4

16

12

40

20

10

0

30

60

50

1800

2000

2200

LOW-SIDE LO

IF = 240MHz

TA = 25°C

IIP3

SSB NF

LO-IF

LO-RF