Radar Receive Path AFE: 4-Channel
LNA/PGA/AAF with ADC
Data Sheet
AD8285
FEATURES
FUNCTIONAL BLOCK DIAGRAM
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
INA+
INA–
REFERENCE
LNA
LNA
LNA
LNA
PGA
PGA
PGA
PGA
AAF
AAF
AAF
INB+
INB–
DSYNC
D[0:11]
MUX
INC+
INC–
12-BIT
ADC
DRV
IND+
IND–
AAF
Analog-to-digital converter (ADC)
INADC+
INADC–
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
SPI
AD8285
NOTES
1. AVDD18x = AVDD18, AVDD18ADC.
AVDD33x = AVDD33, AVDD33A, AVDD33B, AVDD33C, AVDD33D, AVDD33REF.
DVDD18x = DVDD18, DVDD18CLK. DVDD33x = DVDD33, DVDD33SPI, DVDD33CLK, DVDD33DRV.
Figure 1.
APPLICATIONS
Automotive radar
Adaptive cruise control
Collision avoidance
Blind spot detection
Self parking
Electronic bumper
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).
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
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.
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
Rev. B
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