Radar Receive Path AFE: 4-Channel

LNA/PGA/AAF with ADC

Data Sheet

AD8285

Rev. B

Document Feedback

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityisassumedbyAnalogDevicesforitsuse,norforanyinfringementsofpatentsorother

rights of thirdparties that may result from its use. Specifications subject to changewithout notice.

No license is granted by implication or otherwise under any patent or patent rights of Analog

Devices.Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700 ©2014–2015 Analog Devices, Inc. All rights reserved.

Technical Support

www.analog.com

FEATURES

4-channel LNA, PGA, and AAF

1 direct to ADC channel

Programmable gain amplifier (PGA)

Includes low noise preamplifier (LNA)

Serial peripheral interface (SPI) programmable gain

16 dB to 34 dB in 6 dB steps

Antialiasing filter (AAF)

Programmable third order, low-pass elliptic filter (LPF)

from 1.0 MHz to 12.0 MHz

Analog-to-digital converter (ADC)

12 bits of accuracy up to 72 MSPS

Signal-to-noise ratio (SNR): 68.5 dB

Spurious-free dynamic range (SFDR): 68 dB at gain = 16 dB

Low power: 185 mW per channel at 12 bits and 72 MSPS

Low noise: 3.5 nV/√Hz maximum of input referred voltage noise

Power-down mode

72-lead, 10 mm × 10 mm LFCSP package

Specified from −40°C to +105°C

Qualified for automotive applications

APPLICATIONS

Automotive radar

Adaptive cruise control

Collision avoidance

Blind spot detection

Self parking

Electronic bumper

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The AD8285 is designed for low cost, low power, compact size,

flexibility, and ease of use. It contains four channels of a low noise

preamplifier (LNA) with a programmable gain amplifier (PGA)

and an antialiasing filter (AAF) plus one direct to ADC channel, all

integrated with a single 12-bit analog-to-digital converter (ADC).

Each channel features a gain range of 16 dB to 34 dB in 6 dB

increments and an ADC with a conversion rate of up to 72 MSPS.

The combined input referred noise voltage of the entire channel

is 3.5 nV/√Hz at maximum gain. The channel is optimized for

dynamic performance and low power in applications where a

small package size is critical.

Fabricated in an advanced complementary metal oxide

semiconductor (CMOS) process, the AD8285 is available in a

10 mm × 10 mm, RoHS compliant, 72-lead LFCSP that is specified

over the automotive temperature range of −40°C to +105°C.

Table 1. Related Devices

Part No.

Description

AD8283

6-channel LNA/PGA/AAF, pseudo simultaneous

channel sampling with ADC

AD8284

4-channel LNA/PGA/AAF, sequential channel

sampling with ADC

ADA8282

4-channel LNA/PGA

REFERENCE

SPI

INA+

INA–

INB+

INC+

INC–

INB–

IND+

IND–

12-BIT

ADC

DSYNC

D[0:11]

AAF

AD8285

AAF

AAF

AAF

DRV

PGA

LNA

PGA

LNA

PGA

LNA

PGA

LNA

INADC+

INADC–

NOTES

1. AVDD18x = AVDD18, AVDD18ADC.

AVDD33x = AVDD33, AVDD33A, AVDD33B, AVDD33C, AVDD33D, AVDD33REF.

DVDD18x = DVDD18, DVDD18CLK. DVDD33x = DVDD33, DVDD33SPI, DVDD33CLK, DVDD33DRV.

MUX