30 MHz Dual Programmable Filters

and Variable Gain Amplifiers

ADRF6510

Rev. 0

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FEATURES

Matched pair of programmable filters and VGAs

Continuous gain control range: −5 dB to +45 dB

6-pole filter

1 MHz to 30 MHz in 1 MHz steps, 0.5 dB corner frequency

SPI programmable

6 dB front-end gain step

IMD3: >55 dBc for 1.5 V p-p composite output

HD2, HD3: >60 dBc for 1.5 V p-p output

Differential input and output

Adjustable output common-mode voltage

Optional dc output offset correction

Power-down feature

Single 5 V supply operation

APPLICATIONS

Baseband I/Q receivers

Diversity receivers

ADC drivers

FUNCTIONAL BLOCK DIAGRAM

ENBL

VPSD

COMD

LE

CLK

DATA

SDO

COM

VPS

OPP1

OPM1

COM

GAIN

VOCM

COM

OPM2

OPP2

INP1

INM1

VPS

ADRF6510

COM GNSW OFS1

VPS

COM

INP2

INM2

VPS

COM OFDS OFS2

VPS

SPI

Figure 1.

GENERAL DESCRIPTION

The ADRF6510 is a matched pair of fully differential low noise

and low distortion programmable filters and variable gain ampli-

fiers (VGAs). Each channel is capable of rejecting large out-of-

band interferers while reliably boosting the wanted signal, thus

reducing the bandwidth and resolution requirements on the

analog-to-digital converters (ADCs). The excellent matching

between channels and their high spurious-free dynamic range

over all gain and bandwidth settings make the ADRF6510 ideal

for quadrature-based (IQ) communication systems with dense

constellations, multiple carriers, and nearby interferers.

The filters provide a six-pole Butterworth response with 0.5 dB

corner frequencies programmable through the SPI port from

1 MHz to 30 MHz in 1 MHz steps. The preamplifier that precedes

the filters offers a pin-programmable option of either 6 dB or

12 dB of gain. The preamplifier sets a differential input imped-

ance of 400 Ω and has a common-mode voltage that defaults

to 2.1 V but can be driven from 1.5 V to 2.5 V.

The variable gain amplifiers that follow the filters provide 50 dB

of continuous gain control with a slope of 30 mV/dB. The output

buffers provide a differential output impedance of 20 Ω that is

capable of driving 1.5 V p-p into 1 kΩ loads. The output common-

mode voltage defaults to VPS/2, but it can be programmed via the

VOCM pin. The built-in dc offset correction loop can be disabled

if dc-coupled operation is desired. The high-pass corner frequency

is defined by external capacitors on the OFS1 and OFS2 pins.

The ADRF6510 operates from a 4.75 V to 5.25 V supply and

consumes a maximum supply current of 258 mA when pro-

grammed to the highest bandwidth setting. When disabled, it

consumes 2 mA. The ADRF6510 is fabricated in an advanced

silicon-germanium BiCMOS process and is available in a

32-lead, exposed paddle LFCSP. Performance is specified over

the −40°C to +85°C temperature range.