MAX2037 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – Ultrasound Variable-Gain Amplifier

19-0586; Rev 0; 10/06
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Ultrasound Variable-Gain Amplifier
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 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 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-
dle. 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 V_OUT = 1.5V_P-P and f_IN = 5MHz
♦ Two-Tone Ultrasound-Specific* IMD3 of -52dBc at
V_OUT = 1.5V_P-P and f_IN = 5MHz
♦ 120mW Consumption Per Channel
*See the Ultrasound-Specific IMD3 Specification in the
Applications Information section.
VG_CTL+
VG_CTL-
VG_IN1+
VG_IN1-
•
•
•
VG_IN8+
VG_IN8-
PD
Functional Diagram
VCC
VREF
MAX2037
-12.5dB TO +29.5dB
50Ω
VGA
50Ω
••
•
••
•
••
•
50Ω
VGA
50Ω
BIAS
CIRCUITRY
VG_CLAMP_MODE
VG_OUT1+
VG_OUT1-
•
•
•
VG_OUT8+
VG_OUT8-
GND
EXT_RES
Ordering Information
PART
TEMP
RANGE
PIN-PACKAGE ^PKG
CODE
MAX2037CCQ-D
0°C to +70°C
100 TQFP-EP^†
(14mm x 14mm)
C100E-3
MAX2037CCQ-TD 0°C to +70°C ^{100 TQFP-EPâ€}  C100E-3
(14mm x 14mm)
MAX2037CCQ+D 0°C to +70°C ^{100 TQFP-EPâ€}  C100E-3
(14mm x 14mm)
MAX2037CCQ+TD 0°C to +70°C ^{100 TQFP-EPâ€}  C100E-3
(14mm x 14mm)
†_{EP = Exposed paddle.}
+Denotes lead-free package.
T = Tape-and-reel package.
D = Dry packing.
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