LT5516

1

5516f

The LT

quadrature demodulator optimized for high linearity re-

ceiver applications. It is suitable for communications

receivers where an RF or IF signal is directly converted into

I and Q baseband signals with bandwidth up to 260MHz.

The LT5516 incorporates balanced I and Q mixers, LO

buffer amplifiers and a precision, high frequency quadra-

ture generator.

In an RF receiver, the high linearity of the LT5516 provides

excellent spur-free dynamic range, even with fixed gain

front end amplification. This direct conversion receiver

can eliminate the need for intermediate frequency (IF)

signal processing, as well as the corresponding require-

ments for image filtering and IF filtering. Channel filtering

can be performed directly at the outputs of the I and Q

channels. These outputs can interface directly to channel-

select filters (LPFs) or to a baseband amplifier.

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Cellular/PCS/UMTS Infrastructure

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High Linearity Direct Conversion I/Q Receiver

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High Linearity I/Q Demodulator

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

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Frequency Range: 800MHz to 1.5GHz

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High IIP3: 21.5dBm at 900MHz

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High IIP2: 52dBm

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Noise Figure: 12.8dB at 900MHz

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Conversion Gain: 4.3dB at 900MHz

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I/Q Gain Mismatch: 0.2dB

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Shutdown Mode

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16-Lead QFN 4mm

× 4mm Package

with Exposed Pad

800MHz to 1.5GHz Direct

Conversion Quadrature Demodulator

Figure 1. High Signal-Level I/Q Demodulator for Wireless Infrastructure

BPF

5V

BPF

LPF

LT5516

+

–

0

°

LO INPUT

EN

ENABLE

LPF

DSP

+

–

90

°

0

°/90°

5516 F01

LNA

VGA

VGA

20

0

–20

–40

–60

–80

–100

RF INPUT POWER (dBm)

–18

–14

–10

–6

–2

26

5516 TA01

IM3

I/Q Output Power, IM3 vs

RF Input Power

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO