Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Custom amplification Ultrasound receiver TQFN 68 EP

General Description

The MAX2078 octal-channel ultrasound front-end is a

fully integrated bipolar, high-density octal-channel ultra-

sound receiver optimized for low cost, high-channel

count, high-performance portable and cart-based ultra-

sound systems. The easy-to-use IC allows the user to

achieve high-end 2D, PW, and CW Doppler (CWD)

imaging capability using substantially less space and

power. The highly compact imaging receiver lineup,

including low-noise amplifier (LNA), variable-gain

amplifier (VGA), and anti-alias filter (AAF), achieves an

ultra-low 2.4dB noise figure at R

= R

= 200Ω at a

very low 64.8mW per channel power dissipation. The

full imaging receiver channel has been optimized for

second-harmonic imaging with -64dBFS second-har-

monic distortion performance with a 1V

P-P

5MHz output

signal. The bipolar front-end has also been optimized

for excellent low-velocity PW and color-flow Doppler

sensitivity with an exceptional near-carrier SNR of

140dBc/Hz at 1kHz offset from a 5MHz 1V

P-P

output

clutter signal.

A fully integrated high-performance, programmable

CWD beamformer is also included. Separate I/Q mixers

for each channel are available for optimal CWD sensi-

tivity in high-clutter environments, yielding an impres-

sive near-carrier SNR of 154dBc/Hz at 1kHz offset from

a 1.25MHz 200mV

P-P

input clutter signal.

The MAX2078 octal-channel ultrasound front-end is

available in a small 10mm x 10mm, 68-pin thin QFN

package with an exposed pad and is specified over a

0°C to +70°C temperature range.

Applications

Medical Ultrasound Imaging

Sonar

Features

o 8 Full Channels of LNA, VGA, AAF, and CWD

Mixers in a Small, 10mm x 10mm TQFN Package

o Pin Compatible with MAX2077 with LNA, VGA,

and AAF in 10mm x 10mm TQFN Variant

o Ultra-Low Full-Channel Noise Figure of 2.4dB at

= R

= 200Ω

o Low Output-Referred Noise of 23nV/√

at 5MHz,

20dB Gain, Yielding a Broadband SNR of 68dB**

for Excellent Second-Harmonic Imaging

o High Near-Carrier SNR of 140dBc/Hz at 1kHz

Offset from a 5MHz, 1V

P-P

Output Signal, and

20dB of Gain for Excellent Low-Velocity PW and

Color-Flow Doppler Sensitivity in a High-Clutter

Environment

o Ultra-Low-Power 64.8mW per Full-Channel (LNA,

VGA, and AAF) Normal Imaging Mode (234mW per

Channel in CWD Mode)

o Selectable Active Input-Impedance Matching of

50Ω, 100Ω, 200Ω, and 1kΩ

o Wide Input-Voltage Range of 330mV

P-P

in High LNA

Gain Mode and 550mV

P-P

in Low LNA Gain Mode

o Integrated Selectable 3-Pole 9MHz, 10MHz,

15MHz, and 18MHz Butterworth AAF

o Fast-Recovery, Low-Power Modes (< 2µs)

o Fully Integrated, High Dynamic Range CWD

Beamformer with Near-Carrier SNR of 154dBc/Hz

at 1kHz Offset from a 1.25MHz, 200mV

P-P

Input

Clutter Signal

MAX2078

Octal-Channel Ultrasound Front-End

with CW Doppler Mixers

________________________________________________________________

Maxim Integrated Products

5859606162 5455565763

ZF5

INC7

CC1

THIN QFN

TOP VIEW

CI+

CI-

CQ+

CQ-

V/C

DIN

CLK

5253

CC2

OUT1+

IN7

IN8

ZF8

CC2

INC8

CC1

REF

VG-

VG+

CLP

GND

DOUT

OUT3-

OUT4+

OUT4-

CC1

LO+

LO-

OUT5+

OUT5-

OUT6+

OUT6-

OUT7+

OUT7-

OUT8+

*EP

*EP = EXPOSED PAD.

GND

INC4

IN4

ZF4

INC6

IN6

ZF6

INC5

IN5

INC3

IN3

ZF3

INC2

OUT3+

IN2

CC2

656667

INC1

IN1

ZF1

ZF2

2322212019 2726252418 2928 323130

CC2

OUT8-

3433

OUT2+

OUT2-

OUT1-

ZF7

MAX2078

Pin Configuration

Ordering Information

19-4570; Rev 2; 9/11

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.

EP = Exposed pad.

PART TEMP RANGE

PIN-PACKAGE

MAX2078CTK+ 0°C to +70°C

68 Thin QFN-EP*

When coupled with the MAX1437B ADC.

Summary of content (26 pages)

PAGE 1
9-4570; Rev 2; 9/11 Octal-Channel Ultrasound Front-End with CW Doppler Mixers Features The MAX2078 octal-channel ultrasound front-end is a fully integrated bipolar, high-density octal-channel ultrasound receiver optimized for low cost, high-channel count, high-performance portable and cart-based ultrasound systems. The easy-to-use IC allows the user to achieve high-end 2D, PW, and CW Doppler (CWD) imaging capability using substantially less space and power.
PAGE 2
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers ABSOLUTE MAXIMUM RATINGS VCC_ to GND .........................................................-0.3V to +5.5V VCC2 - VCC1 ......................................................................> -0.3V CI_, CQ_ to GND ....................................................-0.3V to +13V ZF_, IN_, AG to GND ................................-0.3V to (VCC_ + 0.3V) INC_ ..............................................................................
PAGE 3
Octal-Channel Ultrasound Front-End with CW Doppler Mixers (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, NP = 0, V/C = 1, CLP = 0, PD = 0, no RF signals applied. Typical values are at VCC1 = 3.3V, VCC2 = 4.75V, TA = +25°C, unless otherwise noted.
PAGE 4
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers AC ELECTRICAL CHARACTERISTICS (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, NP = 0, PD = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 5
Octal-Channel Ultrasound Front-End with CW Doppler Mixers (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, V/C = 1, NP = 0, PD = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 6
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers AC ELECTRICAL CHARACTERISTICS—VGA MODE (continued) (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, V/C = 1, NP = 0, PD = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 7
Octal-Channel Ultrasound Front-End with CW Doppler Mixers (Typical Application Circuit, V/C = 0, PD = 0, NP = 0, CLP = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.5dB), fRF = fLO/16 = 5MHz, RS = 200Ω, CI_, CQ_ pulled up to 11V through four separate 0.1% 162Ω resistors, the rise/fall time of the LVDS clock driving the LO_ is required to be 0.5ns, reference noise less than 10nV/√Hz from 1kHz to 20MHz (Note 12). Typical values are at VCC1 = 3.3V, VCC2 = 4.75V, TA = +25°C, unless otherwise noted.
PAGE 8
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers AC ELECTRICAL CHARACTERISTICS—SERIAL PERIPHERAL INTERFACE (DOUT loaded with 60pF and 10MΩ, 2ns rise and fall edges on CLK.
PAGE 9
Octal-Channel Ultrasound Front-End with CW Doppler Mixers COMPLEX INPUT IMPEDANCE MAGNITUDE vs. FREQUENCY 600 400 100Ω 200Ω 5 15 20 FREQUENCY (MHz) CONTROL VOLTAGE (V) 0.275 10 0.225 5 0.175 0 0 3 0.125 2 0.075 1 0.025 0 -0.025 -1 -0.175 -2 15 10 50Ω 0 -3 MAX2078 toc03 20 200 5 GAIN = 20dB -0.075 15 1kΩ % UNITS 25 GAIN ERROR HISTOGRAM 25 MAX2078 toc02 800 INPUT IMPEDANCE (Ω) 35 GAIN (dB) 1000 MAX2078 toc01 45 -0.125 GAIN vs.
PAGE 10
Typical Operating Characteristics (continued) (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, NP = 0, PD = 0, CLP = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 11
Octal-Channel Ultrasound Front-End with CW Doppler Mixers MAX2078 Typical Operating Characteristics (continued) (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, NP = 0, PD = 0, CLP = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 12
Octal-Channel Ultrasound Front-End with CW Doppler Mixers MAX2078 Typical Operating Characteristics (continued) (Typical Application Circuit, VREF = 2.475V to 2.525V, VCC1 = 3.13V to 3.47V, VCC2 = 4.5V to 5.25V, TA = 0°C to +70°C, VGND = 0V, NP = 0, PD = 0, CLP = 0, D43/D42/D41/D40 = 1/0/1/0 (RIN = 200Ω, LNA gain = 18.
PAGE 13
Octal-Channel Ultrasound Front-End with CW Doppler Mixers PIN NAME 1 IN2 FUNCTION 2 INC2 Channel 2 Clamp Input. Connect to a coupling capacitor. See the Typical Application Circuit for details. 3 ZF3 Channel 3 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor. 4 IN3 Channel 3 Input 5 INC3 Channel 3 Clamp Input. Connect to a coupling capacitor. See the Typical Application Circuit for details. 6 ZF4 Channel 4 Active Impedance Matching Line.
PAGE 14
Octal-Channel Ultrasound Front-End with CW Doppler Mixers MAX2078 Pin Description (continued) PIN NAME 37 OUT7+ Channel 7 Positive Differential Output 38 OUT6- Channel 6 Negative Differential Output 39 OUT6+ Channel 6 Positive Differential Output 40 OUT5- Channel 5 Negative Differential Output 41 OUT5+ Channel 5 Positive Differential Output 42 LO- 43 LO+ Differential Local Oscillator Input. LO is divided in the beamformer.
PAGE 15
Octal-Channel Ultrasound Front-End with CW Doppler Mixers CQCQ+ MAX2078 CICI+ V/C NP CS DIN CLK VCC2 OUT1+ VCC1 VCC2 ZF1 IN1 OUT1- INC1 LNA VGA LNA VGA LNA VGA ANTI-ALIAS ZF2 OUT2+ IN2 OUT2- INC2 ANTI-ALIAS ZF3 OUT3+ IN3 OUT3- INC3 ANTI-ALIAS ZF4 OUT4+ IN4 OUT4- INC4 LNA VGA ANTI-ALIAS VCC1 GND LO+ LOZF5 AG OUT5+ IN5 OUT5- INC5 LNA VGA ANTI-ALIAS ZF6 OUT6+ IN6 OUT6- INC6 LNA VGA ANTI-ALIAS ZF7 OUT7+ IN7 OUT7- INC7 LNA VGA LNA VGA ANTI-ALIAS ZF8 OUT8+ I
PAGE 16
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers Detailed Description The MAX2078 also integrates an octal quadrature mixer array and programmable LO phase generators for a complete continuous-wave Doppler (CWD) beamforming solution. Separate mixers for each channel are available for optimal CWD sensitivity, yielding an impressive SNR of 154dBc/Hz at 1kHz offset from a 200mVP-P, 1.25MHz input signal.
PAGE 17
Octal-Channel Ultrasound Front-End with CW Doppler Mixers Overload Recovery The device is also optimized for quick overload recovery for operation under the large input signal conditions that are typically found in ultrasound input buffer imaging applications. See the Typical Operating Characteristics for an illustration of the rapid recovery time from a transmit-related overload. Octal Continuous-Wave (CW) Mixer The MAX2078 CW mixers are designed using an active double-balanced topology.
PAGE 18
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers Each mixer can be programmed to 1 of 16 phases; therefore, 4 bits are required for each channel for programming. Each CW channel can be programmed to an off state by setting bit Di to 1. The power-down mode (PD) line overrides this soft shutdown. After the serial shift registers have been programmed, the CS signal, when going high, loads the phase information in the form of 5 bits per channel into the I/Q phase divider/selectors.
PAGE 19
Octal-Channel Ultrasound Front-End with CW Doppler Mixers 162Ω 162Ω 1μF CI50Ω Applications Information Mode Select Response Time The mode select response time is the time that the device takes to switch between CW and VGA modes. Figure 2 depicts one possible approach to interfacing the CW outputs to an instrumentation amplifier, which is used to drive an ADC.
PAGE 20
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers If drawn, the simplified dominant highpass network would look like Figure 3. The highpass pole in this case is at fP = 1/(2 x pi x RC) ~ 5Hz. Note that this low highpass corner frequency is required to filter the downconverted clutter tone, which appears at DC, but not interfere with CWD imaging at frequencies as low as 400Hz.
PAGE 21
Octal-Channel Ultrasound Front-End with CW Doppler Mixers 47 REGISTER BITS MSB LSB … CHANNEL 1 (i = 1) D46 D45 D44 D43 D42 D41 D40 D39 D38 D46 D45 D44 D43 D42 D41 D40 Di + 4 Di + 3 tCS D37 D36 Di + 2 Di + 1 CHANNEL 8 (i = 8) D35 … D4 D3 D2 D1 D0 Di … Di + 4 Di + 3 Di + 2 Di + 1 Di tCH tCW tCLH DIN CLK tCWS CS tMIXCS MIXER CLOCK ON LO+ MIXER CLOCK OFF MIXER CLOCK ON MIXER CLOCK OFF LO- MIXER CLOCK ON LO+ MIXER CLOCK OFF MIXER CLOCK ON LO- Figure 5.
PAGE 22
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers Ultrasound Front-End CWD Beamformer The user provides an LO frequency of 16MHz to 120MHz. This high clock frequency requires a differential LVDS input. Note that the LVDS CWD LO clocks are DCcoupled. This is to ensure immediate synchronization when the clock is first turned on.
PAGE 23
Octal-Channel Ultrasound Front-End with CW Doppler Mixers MAX2078 Ultrasound-Specific IMD3 Specification Unlike typical communications applications, the two input tones are not equal in magnitude for the ultrasound-specific IMD3 two-tone specification. In this measurement, f1 represents reflections from tissue and f2 represents 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.
PAGE 24
Octal-Channel Ultrasound Front-End with CW Doppler Mixers MAX2078 Typical Application Circuit 11V VCC2 R4 162Ω 68 C8 22nF ZF5 IN5 IN5 INC5 C9 10nF C10 22nF IN6 ZF6 IN6 INC6 C11 10nF C12 22nF IN7 ZF7 DIN CSB CLK OUT1+ CLK DIN CS NP V/C CQ- CQ+ CI- CI+ VCC1 VCC2 ZF1 IN1 VCC2 53 52 + 50 2 49 3 48 4 47 5 46 6 45 7 8 44 MAX2078 9 43 10 42 11 41 12 40 13 39 14 38 15 37 16 36 *EP 35 17 18 19 20 21 C13 10nF 22 23 25 26 27 28 29 30 31 32
PAGE 25
Octal-Channel Ultrasound Front-End with CW Doppler Mixers PROCESS: Complementary BiCMOS For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 26
MAX2078 Octal-Channel Ultrasound Front-End with CW Doppler Mixers Revision History REVISION NUMBER REVISION DATE 0 6/09 Initial release 1 10/09 Corrected two minor errors 2 9/11 Updated input impedance value in AC Electrical Characteristics—VGA Mode DESCRIPTION PAGES CHANGED — 16, 24 4 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.