
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.
General Description
The MAX2037 8-channel variable-gain amplifier (VGA)
is designed for high linearity, high dynamic range, and
low-noise performance targeting ultrasound imaging
and Doppler applications. Each amplifier features dif-
ferential inputs and outputs and a total gain range of
typically 42dB. In addition, the VGAs offer very low out-
put-referred noise performance suitable for interfacing
with 12-bit ADCs.
The MAX2037 VGA is optimized for less than ±0.25dB
absolute gain error to ensure minimal channel-to-chan-
nel ultrasound beamforming focus error. The device’s
differential outputs are designed to directly drive ultra-
sound ADCs through an external passive anti-aliasing
filter. A switchable clamp is also provided at each ampli-
fier’s outputs to limit the output signals, thereby prevent-
ing 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 -70dBc at VOUT = 1.5VP-P and fIN =
5MHz, and an ultrasound-specific* two-tone third-order
intermodulation distortion specification of -52dBc at
VOUT = 1.5VP-P and fIN = 5MHz.
The MAX2037 operates from a +5.0V power supply,
consuming only 120mW/channel. The device is avail-
able in a 100-pin TQFP package with an exposed pad.
Electrical performance is guaranteed over a 0°C to
+70°C temperature range.
Applications
Ultrasound Imaging
Sonar
Features
8-Channel Configuration
High Integration for Ultrasound Imaging
Applications
Pin Compatible with the MAX2038 Ultrasound
VGA Plus CW Doppler Beamformer
Maximum Gain, Gain Range, and Output-Referred
Noise Optimized for Interfacing with 12-Bit ADCs
Maximum Gain of 29.5dB
Total Gain Range of 42dB
22nV/
√Hz Ultra-Low Output-Referred Noise at
5MHz
Pin-for-Pin 10-Bit Compatibility Supported By
MAX2035/MAX2036
±0.25dB Absolute Gain Error
Switchable Output VGA Clamp Eliminating ADC
Overdrive
Fully Differential VGA Outputs for Direct ADC
Drive
Variable Gain Range Achieves 42dB Dynamic
Range
-70dBc HD2 at VOUT = 1.5VP-P and fIN = 5MHz
Two-Tone Ultrasound-Specific* IMD3 of -52dBc at
VOUT = 1.5VP-P and fIN = 5MHz
120mW Consumption Per Channel
*
See the Ultrasound-Specific IMD3 Specification in the
Applications Information section.
MAX2037
Ultrasound Variable-Gain Amplifier
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-0586; Rev 1; 2/09
EP = Exposed pad.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
D = Dry packing.
PART
TEMP
RANGE
PIN-PACKAGE
MAX2037CCQ+D
0
°C to +70°C
100 TQFP-EP
MAX2037CCQ+TD
0
°C to +70°C
100 TQFP-EP
Functional Diagram
MAX2037
BIAS
CIRCUITRY
GND
EXT_RES
VCC
VREF
PD
VG_CTL+
VG_CTL-
VG_CLAMP_MODE
VGOUT1+
VGOUT1-
VGOUT8+
VGOUT8-
VGIN1+
VGIN1-
VGIN8+
VGIN8-
-12.5dB TO +29.5dB
VGA
50
Ω
50
Ω
VGA
50
Ω
50
Ω