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MAX2037CCQ-D中文资料

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/√H z 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.

MAX2037

Ultrasound Variable-Gain Amplifier

________________________________________________________________Maxim Integrated Products

Ordering Information

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/3512791731.html,.

EP = Exposed paddle.

+Denotes lead-free package.T = Tape-and-reel package.D = Dry packing.

Functional Diagram

M A X 2037

Ultrasound Variable-Gain Amplifier 2_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(Figure 2, V CC = V REF = 4.75V to 5.25V, T A = 0°C to +70°C, GND = 0V, PD = 0, no RF signals applied,capacitance to GND at each of the VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R L = 1k Ω. Typical values are at V CC = V REF = 5V, T A = +25°C, unless otherwise noted.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

V CC , V REF to GND.................................................-0.3V to +5.5V Any Other Pins to GND...............................-0.3V to (V CC + 0.3V)VGA Differential Input Voltage (VGIN_+ - VGIN_-)...........8.0V P-P Analog Gain-Control Input Differential Voltage

(VG_CTL+ - VG_CTL-)...................................................8.0V P-P Continuous Power Dissipation (T A = +70°C)100-Pin TQFP

(derated 45.5mW/°C above +70°C).........................3636.4mW

Operating Temperature Range...............................0°C to +70°C Junction Temperature......................................................+150°C θJC ...................................................................................+2°C/W θJA .................................................................................+22°C/W Storage Temperature Range.............................-40°C to +150°C Lead Temperature (soldering, 10s).................................+300°C

MAX2037

Ultrasound Variable-Gain Amplifier

_______________________________________________________________________________________3

AC ELECTRICAL CHARACTERISTICS

(Figure 2, V CC = V REF = 4.75V to 5.25V, V CM = 2.85V to 3.15V, T A = 0°C to +70°C, GND = 0V, PD = 0, VG_CLAMP_MODE = 1, f RF =5MHz, capacitance to GND at each of the VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF,R L = 1k Ω. Typical values are at V CC = V REF = 5V, T A = +25°C, unless otherwise noted.) (Note 1)

M A X 2037

Ultrasound Variable-Gain Amplifier 4_______________________________________________________________________________________

Typical Operating Characteristics

(Figure 2, V CC = V REF = 4.75V to 5.25V, GND = 0V, PD = 0, VG_CLAMP_MODE = 1, f RF = 5MHz, capacitance to GND at each of the VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R L = 1k Ω, T A = 0°C to +70°C. Typical values are at V CC = V REF = 5V, T A = +25°C, unless otherwise noted.)

01.00.52.01.53.02.53.54.54.05.0

5.0

7.52.5

10.012.515.017.520.0OVERDRIVE PHASE DELAY

vs. FREQUENCY

FREQUENCY (MHz)

O V E R D R I V E P H A S E D E L A Y (n s )

-100

-90

-80-70-60

-50-400

100125150175200POWER SUPPLY MODULATION RATIO

FREQUENCY (kHz)

P S M R (d B c )

-80

-70-60

-50-40-30

-20

-100

-15

-5

TWO-TONE ULTRASOUND-SPECIFIC

IMD3 vs. GAIN

GAIN (dB)

I M D 3 (d B c )

Note 1:Specifications at T A = +25°C and T A = +70°C are guaranteed by production test. Specifications at T A = 0°C are guaranteed

by design and characterization.

Note 2:Noise performance of the device is dependent on the noise contribution from the supply to V REF . Use a low noise supply for

V REF . V CC and V REF can be connected together to share the same supply voltage if the supply for V CC exhibits low noise.

Note 3:See the Ultrasound-Specific IMD3 Specification in the Applications Information section.

AC ELECTRICAL CHARACTERISTICS (continued)

(Figure 2, V CC = V REF = 4.75V to 5.25V, V CM = 2.85V to 3.15V, T A = 0°C to +70°C, GND = 0V, PD = 0, VG_CLAMP_MODE = 1, f RF =

MAX2037

Ultrasound Variable-Gain Amplifier

_______________________________________________________________________________________

OVERLOAD RECOVERY TIME

DIFFERENTIAL OUTPUT 2.0V/div

DIFFERENTIAL INPUT 2.0V/div

400ns/div

-100

-90-95-80-85-75-65-70-60-155-5152535CHANNEL-TO-CHANNEL CROSSTALK

vs. GAIN

GAIN (dB)

C R O S S T A L K (d B )

-30

-110

110

100

CHANNEL-TO-CHANNEL CROSSTALK

vs. FREQUENCY

-90-100

FREQUENCY (MHz)

C R O S S T A L K (d B )

-70-80-60-50-40Typical Operating Characteristics (continued)

-100

-80-90-60-70-40-50-30-10-200-15

-5

SECOND HARMONIC DISTORTION

vs. GAIN

GAIN (dB)H D 2 (d B c )

-100

-80

-90-60-70-40-50-30-10-200

-15

-5

THIRD HARMONIC DISTORTION

vs. GAIN

GAIN (dB)

H D 3 (d B c )

OVERLOAD RECOVERY TIME

DIFFERENTIAL OUTPUT 1.0V/div

DIFFERENTIAL INPUT 1.0V/div

400ns/div

M A X 2037

Ultrasound Variable-Gain Amplifier 6_______________________________________________________________________________________

302520151050-5-10

0.1

100

1000

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

20151050-5-10-15-20

0.110

10011000LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

50-5-10-15-20-25-30

0.110

10011000

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

50-5-10-15-20-25-30-35

0.1

100

1000

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

0-5-10-15-20-25-30-35-40

0.110

10011000LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

-100

-80-90-60-70-40-50-30-10-200

0 1.50.5 1.0 2.0 2.5 3.0

HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT VOLTAGE

DIFFERENTIAL OUTPUT VOLTAGE (V P-P )

H A R M O N I C D I S T O R T I O N (d B c )

Typical Operating Characteristics (continued)

-15

-5

OUTPUT-REFERRED NOISE VOLTAGE

vs. GAIN

GAIN (dB)

O U T P U T -R E F E R R E D N O I S E V O L T

A G E (n V /H z )

-25

-5

-151552535

-2.5

-0.5

-1.5

0.5

1.5

2.5

GAIN vs. DIFFERENTIAL ANALOG CONTROL VOLTAGE (VG_CTL)

VG_CTL (V P-P DIFFERENTIAL)

G A I N (d B )

3530

25201510

500.1

100

1000

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

MAX2037

Ultrasound Variable-Gain Amplifier

_______________________________________________________________________________________

-70

-60-50-40-10-20-3000

155102025

TWO-TONE ULTRASOUND-SPECIFIC IMD3

vs. FREQUENCY

FREQUENCY (MHz)

I M D 3 (d B c )

201550

105

25303540450.4

-0.4-0.3-0.3-0.2-0.2-0.1-0.1-0.00.00.10.10.20.20.30.3GAIN ERROR HISTOGRAM

GAIN ERROR (dB)

% O F U N I T

-20

-10-150-51051520-15

-5

OUTPUT COMMON-MODE OFFSET VOLTAGE

vs. GAIN

M A X 2037t o c 20

GAIN (dB)

O F F S E T

V O L T A G E (m V )

0.1

100

DIFFERENTIAL OUTPUT IMPEDANCE MAGNITUDE vs. FREQUENCY

FREQUENCY (MHz)

|Z O U T |

200

6080100120140180160

-100

-90-95-80-85-70-75-65-50-60-45-55-402001100500

800140017002000HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT LOAD RESISTANCE

DIFFERENTIAL OUTPUT LOAD (Ω)H A R M O N I C D I S T O R T I O N (d B c )

-100

-90-95-80-85-70-75-65-45-50

-55-60-40565254585105HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT LOAD CAPACITANCE

DIFFERENTIAL OUTPUT LOAD (pF)H A R M O N I C D I S T O R T I O N (d B c )

-100

-80-90-60-70-40-50-30-10-200

020********

HARMONIC DISTORTION

vs. FREQUENCY

FREQUENCY (MHz)

H A R M O N I C D I S T O R T I O N (d B c )

Typical Operating Characteristics (continued)

M A X 2037

Ultrasound Variable-Gain Amplifier

Pin Description

MAX2037

Ultrasound Variable-Gain Amplifier

_______________________________________________________________________________________9

Pin Description (continued)

Detailed Description

The MAX2037’s VGAs are optimized for high linearity,

high dynamic range, and low output noise perfor-mance, making this component ideal for ultrasound-imaging applications. The VGA paths also exhibit a channel-to-channel crosstalk of -80dB at 10MHz and an absolute gain error of less than ±0.25dB for minimal channel-to-channel focusing error in an ultrasound sys-tem. Each VGA path includes circuitry for adjusting analog gain, an output buffer with differential output ports (VGOUT_+, VGOUT_-) for driving ADCs, and dif-ferential input ports (VGIN_+, VGIN_-) that are ideal for directly interfacing to the MAX2034 quad LNA. See the Functional Diagram for details.

The VGA has an adjustable gain range from -12.5dB to +29.5dB, achieving a total dynamic range of typically 42dB. The VGA gain can be adjusted with the differen-tial gain-control input VG_CTL+ and VG_CTL-. Set the differential gain-control input voltage at -2V for maxi-mum gain and +2V for minimum gain. The differential analog control common-mode voltage is typically 3.0V.

VGA Clamp

A clamp is provided to limit the VGA output signals to avoid overdriving the ADC or to prevent ADC satura-tion. Set VG_CLAMP_MODE low to clamp the VGA dif-ferential outputs at 2.4V P-P . Set the VG_CLAMP_MODE high to disable the clamp.

Power Down

The device can also be powered down with PD. Set PD to logic-high for power-down mode. I n power-down mode, the device draws a total supply current of 27mA.Set PD to a logic-low for normal operation

Overload Recovery

The device is also optimized for quick overload recov-ery for operation under the large input signal conditions that are typically found in ultrasound input buffer imag-ing applications. See the Typical Operating Characteristics for an illustration of the rapid recovery time from a transmit-related overload.

Applications Information

External Compensation

External compensation is required for bypassing inter-nal biasing circuitry. Connect, as close as possible,individual 4.7μF capacitors from each pin EXT_C1,EXT_C2, and EXT_C3 (pin 13, 14, 15) to ground.

External Bias Resistor

An external resistor at EXT_RES is required to set the bias for the internal biasing circuitry. Connect, as close as possible, a 7.5k Ωresistor from EXT_RES (pin 38) to ground.

Analog Input and Output Coupling

I n typical applications, the MAX2037 is being driven from a low-noise amplifier (such as the MAX2034) and is typically driving a discrete differential anti-alias filter into an ADC (such as the MAX1436 octal ADC). The differential input impedance of the MAX2037 is typically 200Ω. The differential outputs are capable of driving a differential load resistance of 1000Ω. The output impedance is 100Ωdifferential. The differential outputs have a common-mode bias of approximately 3.0V. AC-couple these differential outputs if the next stage has a different common-mode input range.

Ultrasound-Specific IMD3 Specification

Unlike typical communications specs, the two input tones are not equal in magnitude for the ultrasound-specific I MD3 two-tone specification. I n this measure-ment, f 1represents reflections from tissue and f 2represents reflections from blood. The latter reflections are typically 25dB lower in magnitude, and hence the measurement is defined with one input tone 25dB lower than the other. The IMD3 product of interest (f 1- (f 2 - f 1))presents itself as an undesired Doppler error signal in ultrasound applications. See Figure 1.

Board Layout

The pin configuration of the MAX2037 is optimized to facilitate a very compact physical layout of the device and its associated discrete components. A typical application for this device might incorporate several devices in close proximity to handle multiple channels

M A X 2037

Ultrasound Variable-Gain Amplifier 10______________________________________________________________________________________

MAX2037

Ultrasound Variable-Gain Amplifier

Pin Configuration

M A X 2037

Ultrasound Variable-Gain Amplifier Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

12____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600?2006 Maxim Integrated Products

is a registered trademark of Maxim Integrated Products, Inc.

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to https://www.wendangku.net/doc/3512791731.html,/packages .)