General Description
The MAX2036 8-channel variable-gain amplifier (VGA)
and programmable octal mixer array is designed for
high linearity, high dynamic range, and low-noise per-
formance targeting ultrasound imaging and Doppler
applications. Each amplifier features differential inputs
and outputs and a total gain range of 50dB (typ). In
addition, the VGAs offer very low output-referred noise
performance suitable for interfacing with 10-bit ADCs.
The MAX2036 VGA is optimized for less than ±0.5dB
absolute gain error to ensure minimal channel-to-channel
ultrasound beamforming focus error. The device’s differ-
ential outputs are designed to directly drive ultrasound
ADCs through an external passive anti-aliasing filter. A
switchable clamp is also provided at each amplifier’s
output to limit the output signals, thereby preventing
ADC overdrive or saturation.
Dynamic performance of the device is optimized to
reduce distortion to support second-harmonic imaging.
The device achieves a second-harmonic distortion
specification of -62dBc at V
OUT
= 1.5V
P-P
and f
IN
=
5MHz, and an ultrasound-specific* two-tone third-order
intermodulation distortion specification of -52dBc at
V
OUT
= 1.5V
P-P
and f
IN
= 5MHz.
The MAX2036 also integrates an octal quadrature mixer
array and programmable LO phase generators for a
complete CW beamforming solution. The LO phase
selection for each channel can be programmed using a
digital serial interface and a single high-frequency
clock or the LOs for each complex mixer pair can be
directly driven using separate 4 x LO clocks. The serial
interface is designed to allow multiple devices to be
easily daisy-chained in order to minimize program inter-
face wiring. The LO phase dividers can be pro-
grammed to allow 4, 8, or 16 quadrature phases. The
input path of each CW mixer consists of a selectable
lowpass filter for optimal CWD noise performance. The
outputs of the mixers are summed into I and Q differen-
tial current outputs. The mixers and LO generators are
designed to have exceptionally low noise performance
of -155dBc/Hz at 1kHz offset from a 1.25MHz carrier.
The MAX2036 operates from a +5.0V power supply,
consuming only 120mW/channel in VGA mode and
269mW/channel in normal power CW mode. A low-
power CW mode is also available and consumes only
226mW/channel. The device is available in a lead-free
100-pin TQFP package (14mm x 14mm) with an
exposed pad. Electrical performance is guaranteed
over a 0°C to +70°C temperature range.
Applications
Ultrasound Imaging Sonar
Features
o 8-Channel Configuration
o High Integration for Ultrasound Imaging
Applications
o Pin Compatible with the MAX2035 Ultrasound
VGA
VGA Features
o Maximum Gain, Gain Range, and Output-Referred
Noise Optimized for Interfacing with 10-Bit ADCs
Maximum Gain of 39.5dB
Total Gain Range of 50dB
60nV/
√√
Hz Ultra-Low Output-Referred Noise at
5MHz
o ±0.5dB Absolute Gain Error
o 120mW Consumption per Channel
o Switchable Output VGA Clamp Eliminating ADC
Overdrive
o Fully Differential VGA Outputs for Direct ADC
Drive
o Variable Gain Range Achieves 50dB Dynamic
Range
o -62dBc HD2 at V
OUT
= 1.5V
P-P
and f
IN
= 5MHz
o Two-Tone Ultrasound-Specific* IMD3 of -52dBc at
V
OUT
= 1.5V
P-P
and f
IN
= 5MHz
CWD Mixer Features
o Low Mixer Noise of -155dBc/Hz at 1kHz Offset
from 1.25MHz Carrier
o Serial-Programmable LO Phase Generator for 4, 8,
16 LO Quadrature Phase Resolution
o Optional Individual Channel 4 x f
LO
LO Input
Drive Capability
o 269mW Power Consumption per Channel (Normal
Power Mode) and 226mW Power Consumption
per Channel (Low-Power Mode)
MAX2036
Ultrasound VGA Integrated
with CW Octal Mixer
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-4420; Rev 1; 6/09
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
D = Dry packing.
†
EP = Exposed pad.
