Rainbow Electronics MAX2036 User Manual

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 per­formance 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 differ­ential 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 fIN=
5MHz, and an ultrasound-specific* two-tone third-order
intermodulation distortion specification of -52dBc at
V

OUT

= 1.5V

P-P

and fIN= 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 inter­face wiring. The LO phase dividers can be pro­grammed 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 differen­tial 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 low­power 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

♦ 8-Channel Configuration
♦ High Integration for Ultrasound Imaging

Applications

♦ Pin Compatible with the MAX2035 Ultrasound

VGA
VGA Features
♦ 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

♦ ±0.5dB Absolute Gain Error
♦ 120mW Consumption per Channel
♦ Switchable Output VGA Clamp Eliminating ADC

Overdrive
♦ Fully Differential VGA Outputs for Direct ADC

Drive
♦ Variable Gain Range Achieves 50dB Dynamic

Range
♦ -62dBc HD2 at V

OUT

= 1.5V

P-P

and fIN= 5MHz

♦ Two-Tone Ultrasound-Specific* IMD3 of -52dBc at

V

OUT

= 1.5V

P-P

and fIN= 5MHz
CWD Mixer Features
♦ Low Mixer Noise of -155dBc/Hz at 1kHz Offset

from 1.25MHz Carrier

♦ Serial-Programmable LO Phase Generator for 4, 8,

16 LO Quadrature Phase Resolution

♦ Optional Individual Channel 4 x fLOLO Input

Drive Capability

♦ 269mW Power Consumption per Channel (Normal

Power Mode) and 226mW Power Consumption
per Channel (Low-Power Mode)

♦ CWD Implementation Is Fully Compliant with All

Patents Related to Ultrasound Imaging
Techniques

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-4420; Rev 0; 1/09

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 package.
D = Dry packing.

†

EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX2036CCQ+D 0°C to +70°C 100 TQFP-EP

†

MAX2036CCQ+TD 0°C to +70°C 100 TQFP-EP

†

Pin Configuration appears at end of data sheet.

*

See the Ultrasound-Specific IMD3 Specification in the

Applications Information section.

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS—VGA MODE

(Figure 7, V

CC

= V

REF =

4.75V to 5.25V, VCM= (3/5)V

REF

, T

A =

0°C to +70°C, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 0
or 1, TMODE = 0, PD = 0, CW_VG = 1, CW_M1 = 0, CW_M2 = 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 =

1kΩ, CW mixer outputs pulled up to +11V

through four separate ±0.1% 115Ω resistors, all CW channels programmed off. Typical values are at V

CC

= V

REF

=5V, TA= +25°C,

unless otherwise noted.) (Note 2)

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.

VCC, V

REF

to GND .................................................-0.3V to +5.5V

Any Other Pins to GND...............................-0.3V to (V

CC

+ 0.3V)

CW Mixer Output Voltage to GND (CW_IOUT+, CW_IOUT-,

CW_QOUT+, CW_QOUT-) ................................................13V

VGA Differential Input Voltage (VGIN_+, VGIN_-)............8.0V

P-P

Analog Gain Control Differential Input Voltage

(VG_CTL+, VG_CTL-) ..................................................8.0V

P-P

CW Mixer Differential Input Voltage

(CWIN_+, CWIN_-).......................................................8.0V

P-P

CW Mixer LVDS LO Differential Input Voltage..................8.0V

P-P

Continuous Power Dissipation (TA= +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

θ

JC

(Note 1) .....................................................................+2°C/W

θ

JA

(Note 1)....................................................................+22°C/W

Storage Temperature Range .............................-40°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

CONDITIONS

VGA MODE

Supply Voltage Range V

CC

5

V

VCC External Reference Voltage
Range

V

REF

(Note 3)

5

V

PD = 0

231

Total Power-Supply Current

Refers to V

CC

supply

current plus V

REF

current

PD =1 27 33

mA

VCC Supply Current I

VCC

216 mA

V

REF

Current I

REF

12 15 mA

Current Consumption per
Amplifier Channel

Refers to V

CC

supply current 24 27 mA

Minimum gain +2

Differential Analog Control
Voltage Range

Maximum gain -2

V

P-P

Differential Analog Control
Common-Mode Voltage

V

CM

3

V

Analog Control Input Source/Sink
Current

4.5 5 mA

LOGIC INPUTS

CMOS Input High Voltage V

IH

2.3 V

CMOS Input Low Voltage V

IL

0.8 V

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

SYMBOL

MIN TYP MAX UNITS

4.75

4.75

204

192

2.85

5.25

5.25

3.15

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

_______________________________________________________________________________________ 3

DC ELECTRICAL CHARACTERISTICS—CM MIXER MODE

(Figure 7, V

CC

= V

REF =

4.75V to 5.25V, T

A =

0°C to +70°C, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 0 or 1, TMODE = 0,
PD = 0, CW_VG = 0, CW_M1 = 0, CW_M2 = 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 =

1kΩ, CW mixer outputs pulled up to +11V through four separate

±0.1% 115Ω resistors. Typical values are at V

CC

= V

REF

=5V, TA= +25°C, unless otherwise noted.) (Note 2)

PARAMETER

CONDITIONS

CW MIXER MODE

Current in Full-Power Mode
5V V

CC

Supply

I

CC_FP

265 mA

Current in Full-Power Mode
11V V

MIX

Supply

I

MIX_FP

120 mA

Current in Full-Power Mode
5V V

REF

Supply

I

REF_FP

17 21 mA

Power Dissipation in Full-Power
Mode

Total power dissipation (all 8 channels
including both 5V (V

CC

and V

REF

) and 11V
mixer pullup supply power dissipation in the
device) (Note 4)

W

Current in Low-Power Mode
5V V

CC

Supply

I

CC_LP

LOW_PWR = 1; refers to VCC supply
current (all 8 channels)

265 mA

Current in Low-Power Mode
11V V

MIX

Supply

I

MIX_LP

LOW_PWR = 1; refers to V

MIX

supply

current (all 8 channels)

53 60 mA

Current in Low-Power Mode
5V V

REF

Supply

I

REF_LP

LOW_PWR = 1; refers to V

REF

supply

current (all 8 channels)

17 21 mA

Power Dissipation in Low-Power
Mode

LOW_PWR = 1; total power dissipation (all 8
channels including both 5V (V

CC

and V

REF

)
and 11V mixer pullup supply power
dissipation in the device) (Note 4)

W

Mixer LVDS LO Input Common­Mode Voltage

Modes 1 and 2 (Note 5)

V

LVDS LO Differential Input
Voltage

Modes 1 and 2

LVDS LO Input Common-Mode
Current

Per pin

200 µA

LVDS LO Differential Input
Resistance

Modes 1 and 2 (Note 6) 30 kΩ

Mixer IF Common-Mode Output
Current

Common-mode current in each of the
differential mixer outputs (Note 7)

mA

DATA Output High Voltage

DOUT voltage when terminated in DIN
(daisy chain) (Note 8)

4.5 V

DATA Output Low Voltage

DOUT voltage when terminated in DIN
(daisy chain) (Note 8)

0.5 V

SYMBOL

P

DISS_FP

P

DISS_LP

Refer s to V

Refer s to V

Refer s to V

sup p l y cur r ent ( al l 8 channel s) 245

C C

sup p l y cur r ent ( al l 8 channel s) 106

M IX

sup p l y cur r ent ( al l 8 channel s)

R E F

MIN TYP MAX UNITS

2.15 2.41

245

1.81 2.06

1.25
±0.2

200 700 mV

150

3.25 3.75

P-P

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

4 _______________________________________________________________________________________

AC ELECTRICAL CHARACTERISTICS—VGA MODE

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, VCM= (3/5)V

REF

, TA= 0°C to +70°C, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 1,

TMODE = 0, PD = 0, CW_VG = 1, CW_M1 = 0, CW_M2 = 0, VG_CLAMP_MODE = 1, f

RF

= fLO/16 = 5MHz, capacitance to GND at

each of the VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, CW mixer outputs
pulled up to +11V through four separate ±0.1% 115Ω resistors, differential mixer inputs are driven from a low-impedance source.
Typical values are at V

CC

= V

REF

= 5V, TA= +25°C, unless otherwise noted.) (Note 2)

PARAMETER

CONDITIONS

UNITS

Mode Select Response Time

CW_VG set from logic 1 to 0 or from 0 to 1
(Note 9)

2µs

VGA MODE

Differential output
capacitance is 10pF,
capacitance to GND at
each single-ended output
is 60pF, R

L

= 1kΩ

17

Large-Signal Bandwidth f

-3dB
gain = 20dB

No capacitive load,
RL = 1kΩ

22

MHz

Differential Input Resistance R

IN

Ω

Input Effective Capacitance C

IN

fRF = 10MHz, each input to ground 15 pF

Differential Output Resistance R

OUT

Ω

Maximum Gain

dB

Minimum Gain

dB

Gain Range 50 dB

TA = +25°C, -2.0V < VG_CTL < -1.8V,
V

REF

= 5V

TA = +25°C, -1.8V < VG_CTL < +1.2V,
V

REF

= 5V

Absolute Gain Error

T

A

= +25°C, +1.2V < VG_CTL < +2.0V,

V

REF

= 5V

dB

VGA Gain Response Time 50dB gain change to within 1dB final value 1 µs

Input-Referred Noise V G_C TL set for m axi m um g ai n, no i np ut si g nal 2

nV/√Hz

No input signal 60

Output-Referred Noise

VG_CTL set for
+20dB of gain

V

OUT

= 1.5V

P-P

,

1kHz offset

nV/√Hz

VG_CLAMP_MODE = 1,
VG_CTL set for +20dB of gain,
f

RF

= 5MHz, V

OUT

= 1.5V

P-P

-55 -62

Second Harmonic HD2

VG_CLAMP_MODE = 1,
VG_CTL set for +20dB of gain,
f

RF

= 10MHz, V

OUT

= 1.5V

P-P

-62

dBc

Third-Order Intermodulation
Distortion

IMD3

VG_CTL set for +20dB of gain,
f

RF1

= 5MHz, f

RF2

= 5.01MHz,

V

OUT

= 1.5V

P-P

, V

REF

= 5V (Note 3)

-40 -52 dBc

Channel-to-Channel Crosstalk

V

OUT

= 1V

P-P

differential, fRF = 10MHz,

VG_CTL set for +20dB of gain

-80 dB

SYMBOL

MIN TYP MAX

V

= 1.5V

OUT

3dB bandwidth,

,

P-P

170 200 230

100

39.5

-10.5

±0.6

±0.5

±1.2

120

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

_______________________________________________________________________________________ 5

AC ELECTRICAL CHARACTERISTICS—CW MIXER MODE (continued)

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, TA= 0°C to +70°C, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 1, TMODE = 0,

PD = 0, CW_VG = 0, CW_M1 = 0, CW_M2 = 0, VG_CLAMP_MODE = 1, f

RF

= fLO/16 = 5MHz, capacitance to GND at each of the

VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, CW mixer outputs pulled up to
+11V through four separate ±0.1% 115Ω resistors, differential mixer inputs are driven from a low-impedance source. Typical values
are at V

CC

= V

REF

= 5V, TA= +25°C, unless otherwise noted.) (Note 2)

PARAMETER

CONDITIONS

Maximum Output Voltage at
Clamp ON

VG_CLAMP_MODE = 0,
VG_CTL set for +20dB of gain,
350mV

P-P

differential input

2.2

V

P-P

Maximum Output Voltage at
Clamp OFF

VG_CLAMP_MODE = 1,
VG_CTL set for +20dB of gain,
350mV

P-P

differential input

3.4

V

P-P

CW MIXER MODE

Mixer RF Frequency Range 0.9 7.6 MHz

Mixer LO Frequency Range 1 7.5 MHz

Mixer IF Frequency Range

kHz

Maximum Input Voltage Range 1.8

V

P-P

CW_FILTER = 0

Differential Input Resistance

CW_FILTER = 1

Ω

M od e 3, fRF = fLO/4 = 1.25M H z, m easur ed at a
1kH z offset fr eq uency; cl utter tone at 0.9V

P - P

d i ffer enti al m easur ed at the m i xer i np ut

6

Input-Referred Noise Voltage

Mode 3, RF terminated into 50Ω;
f

LO

/4 = 1.25MHz, measured at 1kHz offset

4.6

Third-Order Intermodulation
Distortion

IMD3

Mode 1, f

RF1

= 5MHz at 0.9V

P-P

differential

input, Doppler tone f

RF2

= 5.01MHz at 25dBc

from clutter tone, f

LO

/16 = 5MHz (Note 10)

-50 dBc

M i xer O utp ut V ol tag e C om p l i ance

(Note 11)

V

Channel-to-Channel Phase
Matching

Measured under zero beat conditions,
f

RF

= 5MHz, fLO/16 = 5MHz (Note 12)

±3

Channel-to-Channel Gain
Matching

Measured under zero beat conditions,
f

RF

= 5MHz, fLO/16 = 5MHz (Note 12)

±2 dB

CW_FILTER = 1

f

RF

= 1.1MHz at 1V

P - P

d i ffer enti al ,
f

LO

/16 = 1MHz

2.8

Transconductance
(Note 13)

CW_FILTER = 0
(low LPF cutoff
frequency)

f

RF

= 1.1MHz at 1V

P - P

d i ffer enti al ,
f

LO

/16 = 1MHz

2.8

mS

SYMBOL

MIN TYP MAX UNITS

4.75 12.00

633

1440

d i ffer enti al

d i ffer enti al

100

d i ffer enti al

nV/√Hz

Degrees

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

6 _______________________________________________________________________________________

AC ELECTRICAL CHARACTERISTICS—CW MIXER MODE (continued)

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, TA= 0°C to +70°C, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 1, TMODE = 0,

PD = 0, CW_VG = 0, CW_M1 = 0, CW_M2 = 0, VG_CLAMP_MODE = 1, f

RF

= fLO/16 = 5MHz, capacitance to GND at each of the VGA

differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, CW mixer outputs pulled up to +11V
through four separate ±0.1% 115Ω resistors, differential mixer inputs are driven from a low-impedance source. Typical values are at
V

CC

= V

REF

= 5V, TA= +25°C, unless otherwise noted.) (Note 2)

PARAMETER

CONDITIONS

UNITS

SERIAL SHIFT REGISTER

Serial Shift Register Programming
Rate

10 MHz

Minimum Data Set-Up Time t

DSU

30 ns

Minimum Data Hold Time t

HLD

2ns

Minimum Data Clock Time t

DCLK

ns

Minimum Data Clock Pulse Width
High

30 ns

Minimum Data Clock Pulse Width
Low

30 ns

Minimum Load Line t

LD

30 ns

Minimum Load Line High to Mixer
Clock On

30 ns

Minimum Data Clock to Load
Line High

t

CLH

30 ns

Note 2: Specifications at TA= +25°C and TA= +70°C are guaranteed by production. Specifications at TA= 0°C are guaranteed by

design and characterization.

Note 3: 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

. VCCand V

REF

can be connected together to share the same supply voltage if the supply for VCCexhibits low

noise.

Note 4: Total on-chip power dissipation is calculated as P

DISS

= VCCx ICC+ V

REF

x I

REF

+ [11V - (I

MIX

/4) x 115] x I

MIX

.

Note 5: Note that the LVDS CWD LO clocks are DC-coupled. This is to ensure immediate synchronization when the clock is first

turned on. An AC-coupled LO is problematic in that the RC time constant associated with the coupling capacitors and the
input impedance of the pin causes there to be a period of time (related to the RC time constant) when the DC level on the
chip side of the capacitor is outside the acceptable common-mode range and the LO swing does not exceed both the
logic thresholds required for proper operation. This problem associated with AC-coupling would cause an inability to
ensure synchronization among beamforming channels. The LVDS signal is terminated differentially with an external 100Ω
resistor on the board.

Note 6: External 100Ω resistor terminates the LVDS differential signal path.
Note 7: The mixer common-mode current (3.25mA/channel) is specified as the common-mode current in each of the differential

mixer outputs (CW_QOUT+, CW_QOUT-, CW_IOUT+, CW_IOUT-).

Note 8: Specification guaranteed only for DOUT driving DIN of the next device in a daisy-chain fashion.
Note 9: This response time does not include the CW output highpass filter. When switching to VGA mode, the CW outputs stop

drawing current and the output voltage goes to the rail. If a highpass filter is used, the recovery time can be excessive and
a switching network is recommended as shown in the

Applications Information

section.

Note 10: See the

Ultrasound-Specific IMD3 Specification

in the

Applications Information

section.

Note 11: Mixer output-voltage compliance is the range of acceptable voltages allowed on the CW mixer outputs.
Note 12: Channel-to-channel gain-and-phase matching measured on 30 pieces during engineering characterization at room temper-

ature. Each mixer is used as a phase detector and produces a DC voltage in the IQ plane. The phase is given by the angle
of the vector drawn on that plane. Multiple channels from multiple parts are compared to each other to produce the phase
variation.

Note 13: Transconductance is defined as the quadrature summing of the CW differential output current at baseband divided by the

mixer’s input voltage.

SYMBOL

MIN TYP MAX

100

t

DCLKPWH

t

DCLKPWL

t

MIXCLK

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

_______________________________________________________________________________________ 7

Typical Operating Characteristics

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, V

GND

= 0, PD = 0, VG_CLAMP_MODE = 1, fRF= 5MHz, capacitance to GND at each of the

VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, TA= 0°C to +70°C. Typical val-

ues are at V

CC

= V

REF

= 5V, VCM= 3.0V, TA= +25°C, unless otherwise noted.)

OVERDRIVE PHASE DELAY

vs. FREQUENCY

MAX2036 toc01

V

IN1

= 35mV

P-P

DIFFERENTIAL

V

IN2

= 87.5mV

P-P

DIFFERENTIAL

GAIN = 20dB

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

0 2.5 5.0 7.5 10.0 12.5 15.0

OVERDRIVE PHASE DELAY (ns)

FREQUENCY (MHz)

17.5 20.0

POWER-SUPPLY MODULATION RATIO

MAX2036 toc02

V

OUT

= 1.5V

P-P

DIFFERENTIAL

V

MOD

= 50mV

P-P

, f

CARRIER

= 5MHz,

GAIN = 20dB

-30

-40

-50

-60

-70

-80

-90
0 25 50 75 100 125 150

PSMR (dBc)

FREQUENCY (kHz)

175 200

TWO-TONE ULTRASOUND-SPECIFIC

IMD3 vs. GAIN

MAX2036 toc03

-30

-40

-50

-60

-70

-80

-20

-10

0

-15 -5 5 15 25 35 45

IMD3 (dBc)

GAIN (dB)

V

OUT

= 1V

P-P

DIFFERENTIAL

GAIN = 20dB

f = 2MHz, 5MHz

f = 10MHz

OVERLOAD RECOVERY TIME

MAX2036 toc07

OUTPUT OVERLOAD TO 100mV

P-P

f = 5MHz

DIFFERENTIAL
INPUT
200mV/div

DIFFERENTIAL
OUTPUT
500mV/div

SECOND-HARMONIC DISTORTION

vs. GAIN

MAX2036 toc04

-30

-40

-50

-60

-70

-100

-90

-80

-20

-10

0

-15 -5 5 15 25 35 45

HD2 (dBc)

GAIN (dB)

f = 2MHz

V

OUT

= 1V

P-P

DIFFERENTIAL

f = 5MHz

f = 12MHz

THIRD-HARMONIC DISTORTION

vs. GAIN

MAX2036 toc05

-30

-40

-50

-60

-70

-100

-90

-80

-20

-10

0

-15 -5 5 15 25 35 45

HD3 (dBc)

GAIN (dB)

V

OUT

= 1V

P-P

DIFFERENTIAL

f = 12MHz

f = 5MHz

f = 2MHz

OVERLOAD RECOVERY TIME

MAX2036 toc06

OUTPUT OVERLOAD TO 1V

P-P

f = 5MHz

DIFFERENTIAL
INPUT
200mV/div

DIFFERENTIAL
OUTPUT
500mV/div

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

8 _______________________________________________________________________________________

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc14

30

25

20

15

10

5

0

-5

-10

0.1 10 1001 1000
FREQUENCY (MHz)

GAIN (dB)

V

OUT

= 1.5V

P-P

DIFFERENTIAL

VG_CTL = +0.2V

P-P

DIFFERENTIAL

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc15

20

15

10

5

0

-5

-10

-15

-20

0.1 10 1001 1000

GAIN (dB)

V

OUT

= 1.5V

P-P

DIFFERENTIAL

VG_CTL = +1.2V

P-P

DIFFERENTIAL

FREQUENCY (MHz)

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc16

10

5

0

-5

-10

-15

-20

-25

-30

0.1 10 1001 1000

GAIN (dB)

V

OUT

= 1.5V

P-P

DIFFERENTIAL

VG_CTL = +1.7V

P-P

DIFFERENTIAL

FREQUENCY (MHz)

GAIN vs. DIFFERENTIAL ANALOG

CONTROL VOLTAGE (VG_CTL)

MAX2036 toc11

-15

5

-5

25

15

35

45

-2.5 2.5

VG_CTL (V

P-P

DIFFERENTIAL)

GAIN (dB)

-0.5-1.5 0.5 1.5

f = 5MHz

50

45

40

35

30

25

20

15

10

0.1 10 1001 1000
FREQUENCY (MHz)

GAIN (dB)

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc12

V

OUT

= 1.5V

P-P

DIFFERENTIAL

VG_CTL = -2V

P-P

DIFFERENTIAL

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc13

40

35

30

25

20

15

10

5

0

0.1 10 1001 1000
FREQUENCY (MHz)

GAIN (dB)

V

OUT

= 1.5V

P-P

DIFFERENTIAL

VG_CTL = -0.8V

P-P

DIFFERENTIAL

CHANNEL-TO-CHANNEL CROSSTALK

vs. GAIN

MAX2036 toc08

-65

-70

-75

-80

-85

-100

-95

-90

-60

-15 -5 5 15 25 35 45

CROSSTALK (dB)

GAIN (dB)

V

OUT

= 1.5V

P-P

DIFFERENTIAL

f = 10MHz, ADJACENT CHANNELS

-30

-110
1 10 100

CHANNEL-TO-CHANNEL CROSSTALK

vs. FREQUENCY

-90

-100

MAX2036 toc09

FREQUENCY (MHz)

CROSSTALK (dB)

-70

-80

-60

-50

-40

V

OUT

= 1V

P-P

DIFFERENTIAL

GAIN = 20dB, ADJACENT CHANNELS

OUTPUT-REFERRED NOISE VOLTAGE

vs. GAIN

MAX2036 toc10

80

70

60

50

40

30

-15 -5 5 15 25 35 45

OUTPUT-REFERRED NOISE VOLTAGE (nV/√Hz)

GAIN (dB)

f = 5MHz

Typical Operating Characteristics (continued)

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, V

GND

= 0, PD = 0, VG_CLAMP_MODE = 1, fRF= 5MHz, capacitance to GND at each of the

VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, TA= 0°C to +70°C. Typical val-

ues are at V

CC

= V

REF

= 5V, VCM= 3.0V, TA= +25°C, unless otherwise noted.)

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

_______________________________________________________________________________________ 9

LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

MAX2036 toc17

0

-5

-10

-15

-20

-25

-30

-35

-40

0.1 10 1001 1000

GAIN (dB)

V

OUT

= 1V

P-P

DIFFERENTIAL

VG_CTL = +2V

P-P

DIFFERENTIAL

FREQUENCY (MHz)

HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT VOLTAGE

MAX2036 toc18

-100

-70

-80

-90

-60

-50

-40

-30

-20

-10

0

01.00.5 1.5 2.0 2.5 3.0
DIFFERENTIAL OUTPUT VOLTAGE (V

P-P

)

HARMONIC DISTORTION (dBc)

f = 5MHz, GAIN = 20dB

THIRD HARMONIC

SECOND HARMONIC

HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT LOAD RESISTANCE

MAX2036 toc19

-100

-75

-80

-85

-90

-95

-70

-65

-60

-55

-50

-45

-40

200 800500 1100 1400 1700 2000

DIFFERENTIAL OUTPUT LOAD (Ω)

HARMONIC DISTORTION (dBc)

V

OUT

= 1V

P-P

DIFFERENTIAL

f = 5MHz, GAIN = 20dB

THIRD HARMONIC

SECOND HARMONIC

Typical Operating Characteristics (continued)

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, V

GND

= 0, PD = 0, VG_CLAMP_MODE = 1, fRF= 5MHz, capacitance to GND at each of the

VGA differential outputs is 60pF, differential capacitance across the VGA outputs is 10pF, R

L

= 1kΩ, TA= 0°C to +70°C. Typical val-

ues are at V

CC

= V

REF

= 5V, VCM= 3.0V, TA= +25°C, unless otherwise noted.)

HARMONIC DISTORTION

vs. DIFFERENTIAL OUTPUT LOAD CAPACITANCE

MAX2036 toc20

-100

-75

-80

-85

-90

-95

-70

-65

-60

-55

-50

-45

-40

54525 65 85 105

DIFFERENTIAL OUTPUT LOAD (pF)

HARMONIC DISTORTION (dBc)

V

OUT

= 1V

P-P

DIFFERENTIAL

f = 5MHz, GAIN = 20dB

THIRD HARMONIC

SECOND HARMONIC

HARMONIC DISTORTION

vs. FREQUENCY

MAX2036 toc21

-100

-50

-60

-70

-80

-90

-40

-30

-20

-10

0

02010 30 40 50

FREQUENCY (MHz)

HARMONIC DISTORTION (dBc)

V

OUT

= 1V

P-P

DIFFERENTIAL

GAIN = 20dB

THIRD HARMONIC

SECOND HARMONIC

TWO-TONE ULTRASOUND-SPECIFIC IMD3

vs. FREQUENCY

MAX2036 toc22

-70

-20

-30

-40

-50

-60

-10

0

0105152025

FREQUENCY (MHz)

IMD3 (dBc)

V

OUT

= 1V

P-P

DIFFERENTIAL

GAIN = 20dB

0

10

5

25

20

15

30

35

45

40

50

-4.50 -3.00

-2.25-3.75

-1.50

-0.75

0.75

1.50

2.25

3.00

3.75

4.50

GAIN ERROR (dB)

% OF UNITS

GAIN ERROR HISTOGRAM

MAX2036 toc23

SAMPLE SIZE = 188 UNITS

f

IN_

= 5MHz, GAIN = 20dB

-100

-75

-50

-25

0

25

50

75

100

-15 5-5 15 25 35 45
GAIN (dB)

OFFSET VOLTAGE (mV)

OUTPUT COMMON-MODE OFFSET VOLTAGE

vs. GAIN

MAX2036 toc24

DIFFERENTIAL OUTPUT IMPEDANCE

MAGNITUDE vs. FREQUENCY

MAX2036 toc25

0.1 10 100
FREQUENCY (MHz)

Z

OUT

(Ω)

1

200

60

80

100

120

140

180

160

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

10 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(Figure 7, VCC= V

REF

= 4.75V to 5.25V, V

GND

= 0, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 1, TMODE = 0, PD = 0, CW_VG = 0,
CW_M1 = 0, CW_M2 = 0, CW mixer outputs pulled up to +11V through four separate ±0.1% 115Ω resistors, differential mixer inputs
are driven from a low impedance source.)

CW FILTER RESPONSE

(CW_FILTER = 1)

MAX2036 toc26

FREQUENCY (MHz)

LOSS (dB)

15105

-12

-10

-8

-6

-4

-2

0

2

4

-14
020

CW FILTER RESPONSE

(CW_FILTER = 0)

MAX2036 toc27

FREQUENCY (MHz)

LOSS (dB)

15105

-25

-20

-15

-10

-5

0

5

-30
020

CW IMD3 vs. FREQUENCY

(MODE 1, V

RF

= 900mV

P-P

DIFFERENTIAL

V

CC

= V

REF

)

MAX2036 toc28

FRF (MHz)

IMD3 (dBc)

642

-53

-52

-50

-51

-49

-48

-47

-46

-54
0 8

4.75

5.00

5.25

INPUT-REFERRED NOISE vs. CLUTTER

VOLTAGE (MODE 4, F_CLUTTER = 1.25MHz

AT 1kHz OFFSET)

MAX2036 toc29

CLUTTER VOLTAGE (V

)

INPUT-REFERRED NOISE (nV√Hz)

1.51.00.5

2

4

8

6

10

12

14

0

0

2.0

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 11

Pin Description

PIN NAME FUNCTION

1 CWIN2- CW Mixer Channel 2 Inverting Differential Input

2 CWIN2+ CW Mixer Channel 2 Noninverting Differential Input

3 VGIN3- VGA Channel 3 Inverting Differential Input

4 VGIN3+ VGA Channel 3 Noninverting Differential Input

5, 10, 19, 24,

29, 34, 58,

79, 81, 96

GND Ground

6 CWIN3- CW Mixer Channel 3 Inverting Differential Input

7 CWIN3+ CW Mixer Channel 3 Noninverting Differential Input

8 VGIN4- VGA Channel 4 Inverting Differential Input

9 VGIN4+ VGA Channel 4 Noninverting Differential Input

11 CWIN4- CW Mixer Channel 4 Inverting Differential Input

12 CWIN4+ CW Mixer Channel 4 Noninverting Differential Input

13 EXT_C1

External Compensation. Connect a 4.7μF capacitor to ground as close as possible to the p in to
bypass the internal biasing circuitry.

14 EXT_C2

External Compensation. Connect a 4.7μF capacitor to ground as close as possible to the p in to
bypass the internal biasing circuitry.

15 EXT_C3

External Compensation. Connect a 4.7μF capacitor to ground as close as possible to the p in to
bypass the internal biasing circuitry.

16, 42, 46,

54, 72, 82, 87

V

CC

5V Power Supply. Connect to an external +5V power supply. Bypass each V

CC

supply to ground

with 0.1μF capacitors as close as possible to the pins.

17 VGIN5- VGA Channel 5 Inverting Differential Input

18 VGIN5+ VGA Channel 5 Noninverting Differential Input

20 CWIN5- CW Mixer Channel 5 Inverting Differential Input

21 CWIN5+ CW Mixer Channel 5 Noninverting Differential Input

22 VGIN6- VGA Channel 6 Inverting Differential Input

23 VGIN6+ VGA Channel 6 Noninverting Differential Input

25 CWIN6- CW Mixer Channel 6 Inverting Differential Input

26 CWIN6+ CW Mixer Channel 6 Noninverting Differential Input

27 VGIN7- VGA Channel 7 Inverting Differential Input

28 VGIN7+ VGA Channel 7 Noninverting Differential Input

30 CWIN7- CW Mixer Channel 7 Inverting Differential Input

31 CWIN7+ CW Mixer Channel 7 Noninverting Differential Input

32 VGIN8- VGA Channel 8 Inverting Differential Input

33 VGIN8+ VGA Channel 8 Noninverting Differential Input

35 CWIN8- CW Mixer Channel 8 Inverting Differential Input

36 CWIN8+ CW Mixer Channel 8 Noninverting Differential Input

37, 93 V

REF

5V Reference Supply. Connect to a low-noise power supply. B ypass to GND with a 0.1μF capacitor
as close as possible to the pins. Note that 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 vo ltage if the supply for V

CC

exhib its low no ise.

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

12 ______________________________________________________________________________________

PIN NAME FUNCTION

38 EXT_RES

External Resi stor. Connect a 0.1% 7.5k resistor to ground as close as possible to the pin to set
the bias for the internal biasing circuitry.

39 CW_VG

CW Mixer VGA Enable. Selects for VGA or CW mixer operation. Set CW_VG to a logic-high to enable
the VGAs while the CW mi xers are powered down. Set CW_VG to a logic-low to enable the CW
mixers whi le the VGAs are powered down.

40 PD

Power-Down Switch. Drive PD high to set the device in power-down mode. Drive PD low for normal
operation.

41 CW_FILTER

CW Filter Mode Corner Frequency Select. Selects in corner frequenc y of the internal lowpas s f ilter
for the CW path. Set CW_FILTER to a logic-high for a corner frequenc y of 9.5MHz. Set CW _FILTER
to a logic-low for a corner frequency of 4.5MHz.

43 M4_EN

Mode 4 Enable. Set M4_EN to a log ic-high to override the serial port and act ivate all 8 channe ls of
the CW path.

44 LOW_PWR Low-Power Enable. Set high to enable low-power CW mi xer mode for the devi ce.

45 DOUT

Serial Port Data Output. Data output for ease of daisy-chaining CW channels for analog beam­forming programming.

47 N.C. No Connect. Leave this pin unconnected.

48 LO8 CW LO Input for Channel 8. LO clock input for modes 3 and 4.

49 VGOUT8+ VGA Channel 8 Noninverting Differential Output

50 VGOUT8- VGA Channel 8 Inverting Differential Output

51 LO7 CW LO Input for Channel 7. LO clock input for modes 3 and 4.

52 VGOUT7+ VGA Channel 7 Noninverting Differential Output

53 VGOUT7- VGA Channel 7 Inverting Differential Output

55 LO6 CW LO Input for Channel 6. LO clock input for modes 3 and 4.

56 VGOUT6+ VGA Channel 6 Noninverting Differential Output

57 VGOUT6- VGA Channel 6 Inverting Differential Output

59 LO5 CW LO Input for Channel 5. LO clock input for modes 3 and 4.

60 VGOUT5+ VGA Channel 5 Noninverting Differential Output

61 VGOUT5- VGA Channel 5 Inverting Differential Output

62 VG_CTL-

63 VG_CTL+

VGA Analog Gain Control Different ia l Input. Set the differential to -2V for ma ximum gain (+39.5dB)
and +2V for min imum gain (-10.5dB).

64 LO_LVDS- CW LVDS LO Inverting Differentia l Input. LO clock inverting input for modes 1 and 2.

65 LO_LVDS+ CW LVDS LO Noninverting Differential Input. LO clock noninverting input for modes 1 and 2.

66 LO4 CW LO Input for Channel 4. LO clock input for modes 3 and 4.

67 VGOUT4+ VGA Channel 4 Noninverting Differential Output

68 VGOUT4- VGA Channel 4 Inverting Differential Output

69 LO3 CW LO Input for Channel 3. LO clock input for modes 3 and 4.

70 VGOUT3+ VGA Channel 3 Noninverting Differential Output

71 VGOUT3- VGA Channel 3 Inverting Differential Output

73 LO2 CW LO Input for Channel 2. LO clock input for modes 3 and 4.

74 VGOUT2+ VGA Channel 2 Noninverting Differential Output

75 VGOUT2- VGA Channel 2 Inverting Differential Output

Pin Description (continued)

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 13

PIN NAME FUNCTION

76 LO1 CW LO Input for Channel 1. LO clock input for modes 3 and 4.

77

VGA Channel 1 Noninverting Differential Output

78

VGA Channel 1 Inverting Differential Output

80 DIN Serial Port Data Input. Data input to program the serial shift registers.

83 CLK Serial Port Data Clock. Clock input for programming the serial shift registers.

84 CW_M1

CW Mode Select Input 1. Input for programming beamforming mode 1, 2, 3, or 4. See Table 1 for
mode programming details.

85 CW_M2

CW Mode Select Input 2. Input for programming beamforming mode 1, 2, 3, or 4. See Table 1 for
mode programming details.

86

VG_CLAMP_

MODE

VGA Clamp Mode Enable. Drive VG_CLAMP_MODE high to enable high VGA clamp mode. VGA
output is clamped at typically 2.4V

P-P

differential. Drive VG_CLAMP_MODE low to enable low VGA

clamp mode. VGA output is clamped at typically 2.8V

P-P

differential.

88 LOAD

Serial Port Load. Loads the data from the serial shift registers into the I/Q phase dividers. Pull LOAD
bus from high to low, and from low to high for programming the I/Q phase dividers.

89

CW Mixer Noninverting Differential Quadrature Output. CW Mixer output for 8 quadrature mixers
combined.

90

CW Mixer Inverting Differential Quadrature Output. CW Mixer output for 8 quadrature mixers
combined.

91

CW Mixer Inverting Differential In-Phase Output. CW mixer output for 8 in-phase mixers combined.

92

C W M i xer N oni nver ti ng D i ffer enti al In- P hase O utp ut. C W M i xer outp ut for 8 i n- p hase m i xer s com b i ned .

94 VGIN1- VGA Channel 1 Inverting Differential Input

95 VGIN1+ VGA Channel 1 Noninverting Differential Input

97 CWIN1- CW Mixer Channel 1 Inverting Differential Input

98 CWIN1+ CW Mixer Channel 1 Noninverting Differential Input

99 VGIN2- VGA Channel 2 Inverting Differential Input

100 VGIN2+ VGA Channel 2 Noninverting Differential Input

—EP

Exposed Pad. Internally connected to GND. Connect EP to a large PCB ground plane to maximize
thermal performance.

Pin Description (continued)

VGOUT1+

VGOUT1-

CW_QOUT+

CW_QOUT-

CW_IOUT-

CW_IOUT+

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

14 ______________________________________________________________________________________

Detailed Description

The MAX2036 is an 8-channel VGA integrated with a
programmable octal quadrature mixer array designed
for ultrasound imaging and Doppler applications. The
device is optimized for efficient power consumption,
high dynamic range, and exceptionally low-noise
performance. The VGA path features differential inputs,
analog variable gain control, differential outputs for
direct ADC drive, and a selectable output voltage
clamp to avoid ADC overdrive. The integrated octal
quadrature mixer array includes serial-programmable
LO phase generators for CWD beamforming applica­tions. The LO phase dividers can be programmed for 4,
8, or 16 quadrature phases. Lowpass filters are inte­grated at the input paths of each CW mixer. The out­puts for the mixers are summed into single I/Q
differential current outputs.

The MAX2036 also integrates an octal quadrature mixer
array and programmable LO phase generators for a
complete continuous wave (CW) Doppler beamforming
solution. The LO phase selection for each channel is
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 interface wiring. The LO phase dividers can
be programmed 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 single I and
Q differential 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, measured with 900mV

P-P

differential

clutter signal.

Variable Gain Amplifier (VGA)

The MAX2036’s VGAs are optimized for high linearity,
high dynamic range, and low output-noise perfor­mance, 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 ±0.5dB for minimal
channel-to-channel focusing error in an ultrasound sys­tem. Each VGA path includes circuitry for adjusting
analog gain, an output buffer with differential output
ports (VGOUT_+, VGOUT_-) for driving ADCs, and dif­ferential input ports (VGIN_+, VGIN_-), which are ideal
for directly interfacing to the MAX2034 quad LNA. See
the

High-Level Wave Mixer and Programmable Beam-

Former Functional Diagram

for details.

The VGA has an adjustable gain range from -10.5dB to
+39.5dB, achieving a total dynamic range of 50dB
(typ). The VGA gain can be adjusted using the differen­tial gain-control inputs VG_CTL+ and VG_CTL-. Set the
differential gain-control input voltage at +2V for mini­mum gain and -2V for maximum gain. The differential
analog control common-mode voltage is 3V (typ).

High-Level Wave Mixer and

Programmable Beamformer

Functional Diagram

VG_CTL+

VG_CTL-

VGIN1+

VGIN1-

VGIN8+

VGIN8-

LOW_PWR

CWIN1+

CWIN1-

CWIN8+

CWIN8-

+5V

+5V (LOW NOISE)

V

CC

VGA

•

•

•

PD

•

•

•

•

•

•

VGA

•

•

•

•

•

•

•

•

•

•

•

•

V

REF

MAX2036

I&Q

•

•

•

•

•

•

•

•

•

I&Q

50Ω

50Ω

50Ω

50Ω

•

•

•

•

•

•

•

•

•

•

•

•

VG_CLAMP_MODE

VGOUT1+

VGOUT1-

•

•

•

VGOUT8+

VGOUT8-

CW_IOUT+

CW_IOUT-

CW_QOUT+

CW_QOUT-

CW_VG

CW_FILTER

GND

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 15

VGA Clamp

A clamp is provided to limit the VGA output signals to
avoid overdriving the ADC or to prevent ADC saturation.
Set VG_CLAMP_MODE low to clamp the VGA differential
outputs at 2.2V

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. In 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 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 MAX2036 CW mixers are designed using an active
double-balanced topology. The mixers achieve high
dynamic range and high-linearity performance, with
exceptionally low noise, which is ideal for ultrasound
CWD signal reception. The octal quadrature mixer
array provides noise performance of -155dBc/Hz at
1kHz from a 1.25MHz carrier, and a two-tone, third­order, ultrasound-specific intermodulation product of
typically -50dBc. See the

Ultrasound-Specific IMD3

Specification

in the

Applications Information section.

The octal array exhibits quadrature and in-phase differ­ential current outputs (CW_QOUT+, CW_QOUT-,
CW_IOUT+, CW_IOUT-) to produce the total CWD
beamformed signal. The maximum differential current
output is typically 3mA

P-P

and the mixer output-compli-

ance voltage ranges from 4.75V to 12V.

High-Level CW Mixer and Programmable

Beamformer Functional Diagram

V

CC

V

REF

CW_FILTER M4_EN

CWIN8

•

•

•

CWIN2

CWIN1

LO_LVDS+

LO_LVDS-

LOAD

DIN

CLK

I Q

CHANNEL 1

I/Q

DIVIDER

PHASE

SELECTOR

5

5-BIT

SR

•

•

•

CW_IOUT2+

CW_QOUT2-

IQ I Q

CHANNEL 2

I/Q

DIVIDER

PHASE

SELECTOR

5

5-BIT

SR

•••

•••

•••

•••

•••

GNDCW_M2CW_M1

•••

•••

•••

•••

•••

LOW_PWR

CHANNEL 8

I/Q

DIVIDER

PHASE

SELECTOR

5

5-BIT

SR

PD

MAX2036

CW_IOUT+

CW_IOUT-

CW_QOUT-

CW_QOUT+

LO1

LO2

•

•

•

LO8

DOUT

MAX2036

CW Mixer Output Summation

The outputs from the octal mixer array are summed inter­nally to produce the total CWD summed beamformed
signal. The octal array produces eight differential quad­rature (Q) outputs and eight differential in-phase (I) out­puts. All quadrature and in-phase outputs are summed
into single I and Q differential current outputs
(CW_QOUT+, CW_QOUT-, CW_IOUT+, CW_IOUT-).

LO Phase Select

The LO phase dividers can be programmed through
the shift registers to allow for 4, 8, or 16 quadrature
phases for a complete CW beamforming solution.

CWD Beamforming Modes

There are four separate modes of operating the CWD
beamformer. See Table 1 for a summary of the different
modes of operation. The mode of operation can be
selected by the CW_M1 and CW_M2 logic inputs.
Phase generation is controlled through the serial inter­face. See the

Serial Interface

section in the

Applications

Information

section for details on how to program for

different quadrature phases.

Mode 1

For mode 1 operation, the LO_LVDS input frequency is
typically 16 x fLO. As the CWD LO frequency range is
1MHz to 7.5MHz, the input frequency ranges from
16MHz to 120MHz. This high LO clock frequency
requires a differential LVDS input. The 16 x fLOinput is
then divided by 16 to produce 16 phases. These 16
phases are generated for each of the 8 channels and
programmed for the selected phase by a serial shift
register. Each channel has a corresponding 5-bit shift
register, which is used to program the output phase of

the divide-by-16 circuit. The first 4 bits of the shift regis­ter are for programming the 16 phases; the fifth bit turns
each channel on/off individually. For mode 1, set both
CW_M1 and CW_M2 to a logic-low. See Table 2.

Ultrasound VGA Integrated
with CW Octal Mixer

16 ______________________________________________________________________________________

CW_M1

CW_M2

MODE

LO INPUT

CLOCK

PHASE

NO. OF
CLOCK

INPUTS

PROGRAM

SHIFT

(SSR)

NO. OF

USEFUL

BITS IN

SSR

NO. OF
DON’T-

CARE

BITS IN

SSR

0 0 1 16 x LVDS 16 phases 1 Yes 4 0

0 1 2 8 x LVDS 8 phases 1 Yes 3 1 MSB

103 4 x

4 phases 8 Yes 2

114 4 x

Quadrature

provided

8NoN/AN/A

Table 1. Summary of CWD Beamforming Methods

MODE 1
CW_M1 = 0
CW_M2 = 0

MSB LSB SHUTDOWN

DCBA SD

PHASE

(DEG)

(B0) (B1) (B2) (B3) (B4)

0 0 0 0 0 0/1

22.5 0 0 0 1 0/1

45 0 0 1 0 0/1

67.5 0 0 1 1 0/1

90 0 1 0 0 0/1

112.5 0 1 0 1 0/1

135 0 1 1 0 0/1

157.5 0 1 1 1 0/1

180 1 0 0 0 0/1

202.5 1 0 0 1 0/1

225 1 0 1 0 0/1

247.5 1 0 1 1 0/1

270 1 1 0 0 0/1

292.5 1 1 0 1 0/1

315 1 1 1 0 0/1

337.5 1 1 1 1 0/1

Table 2. Mode 1 Logic Table (B4 = 0:
Channel On/B4 = 1 Channel Off)

N/A = Not applicable.

FREQUENCY

INTERFACE

3V CMOS

3V CMOS

R ESO L U T IO N

PER CHIP

BY SERIAL

REGISTER

2 MSBs

Mode 2

The LO_LVDS input frequency is 8 x fLO(typ) for mode
2 operation. The CWD LO frequency range is 1MHz to

7.5MHz, and the input frequency ranges from 8MHz to
60MHz. This high LO clock frequency requires a differ­ential LVDS input. The 8 x f

LO

input is then divided by 8
to produce 8 phases. These 8 phases are generated
for each of the 8 channels and programmed for the
selected phase by the serial shift register. Note that the
serial shift register is common to modes 1, 2, and 3,
where each channel has a corresponding 5-bit shift
register, which is used to program the output phase.
However, since mode 2 generates 8 phases only, 3 of
the 4 phase-programming bits are used; 5 bits are still
loaded per channel using the serial shift register, but
the phase-programming MSB is a don’t-care bit. The
fifth bit in the shift register always turns each channel
on/off individually. For mode 2, set CW_M1 to a logic­low and set CW_M2 to a logic-high. See Table 3.

Mode 3

The LO_LVDS input is not used in this mode. Separate
4 x fLOclock inputs are provided using LO1–LO8 for
each channel. The CWD LO frequency range is 1MHz to

7.5MHz, and the input frequency provides ranges from
4MHz to 30MHz. Note that the LO clock frequency can
utilize 3V CMOS inputs. The 4 x fLOLO1–LO8 inputs are
divided by 4 to produce 4 phases. These 4 phases are

generated for each of the 8 channels and programmed
for the selected phase by the serial shift register. For
mode 3, 4 phases are generated, and only 2 of the 4
phase-programming bits are required where the 2­phase programming MSBs are don’t-care bits. For
mode 3, set CW_M1 to a logic-high and set CW_M2 to
a logic-low. See Table 4.

Mode 4

The LO_LVDS input is not used in this mode. The
appropriate phases are externally provided using sepa­rate 4 x fLOLO1–LO8 inputs for each channel. A 4 x f

LO

input is required so the device can internally generate
accurate duty-cycle independent quadrature LO drives.
Note that the serial shift register is not used in this
mode. The CWD LO frequency range is 1MHz to

7.5MHz and the input frequency ranges from 4MHz to
30MHz. The appropriate inputs are provided at LO1 to
LO8. A reset line is provided to the customer so that all
the CWD channels can be synchronized. The reset line
is implemented through the RESET. For mode 4, set
both CW_M1 and CW_M2 to logic-high. See Table 5.

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 17

SHUTDOWN

MODE 2

CW_M1 = 0

CW_M2 = 1

DCBA SD

PHASE

(DEG)

(B4)

0

000 0/1

45

001 0/1

90

010 0/1

135

011 0/1

180

100 0/1

225

101 0/1

270

110 0/1

315

111 0/1

Table 3. Mode 2 Logic Table (DC = Don’t
Care, B4 = 0: Channel On/B4 = 1: Channel
Off)

MODE 3

CW_M1 = 1

CW_M2 = 0

SHUTDOWN

DCBA SD

PHASE

(DEG)

(B4)

0

00 0/1

90

01 0/1

180

10 0/1

270

11 0/1

Table 4. Mode 3 Logic Table (DC = Don’t
Care, B4 = 0: Channel On/B4 = 1: Channel
Off)

MODE 4

CW_M1 = 1

CW_M2 = 1

SHUTDOWN

DCBA SD

PHASE

(DEG)

(B4)

Serial bus
not used in
mode 4

N/A

Table 5. Mode 4 Logic Table

N/A = Not applicable.

(B0) (B1) (B2) (B3)

DC

DC

DC

DC

DC

DC

DC

DC

(B0) (B1) (B2) (B3)

DC DC

DC DC

DC DC

DC DC

(B0) (B1) (B2) (B3)

N/A N/A N/A N/A

MAX2036

Synchronization

Figure 1 illustrates the serial programming of the 8 indi­vidual channels through the serial data port. Note that
the serial data can be daisy chained from one part to
another, allowing a single data line to be used to pro­gram multiple chips in the system.

CW Lowpass Filter

The MAX2036 also includes selectable lowpass filters
between each CW differential input pair and corre­sponding mixer input. Shunt capacitors and resistors
are integrated on chip for high band and low band. The
parallel capacitor/resistor networks, which appear dif­ferentially across each of the CW differential inputs, are
selectable through the CW_FILTER. Drive CW_FILTER
high to set the corner frequency of the filter to be fC=

9.5MHz. Drive CW_FILTER low to set the corner fre­quency equal to fC= 4.5MHz. The CW_VG allows the
filter inputs to be disconnected from input nodes (inter­nal to chip) to prevent overloading the LNA output and
to not change the PW input common-mode voltage.

VGA and CW Mixer Operation

During normal operation, the MAX2036 is configured
such that either the VGA path is enabled while the mixer
array is powered down (VGA mode), or the quadrature

mixer array is enabled while the VGA path is powered
down (CW mode). During VGA mode, besides power­ing down the CW mixer array, the differential inputs to
the lowpass filters and CW mixers also are internally
disconnected from the input nodes, making the CW dif­ferential inputs (CWIN_+, CWIN_-) high impedance.
The CW mode disconnects the VGA inputs internally
from the input ports of the device. For VGA mode, set
CW_VG to a logic-high, while for CW mode, set CW_VG
to a logic- low.

Power-Down and Low-Power Modes

During device power-down, both the VGA and CW
mixer are disabled regardless of the logic set at
CW_VG. Both the VGA and CW mixer inputs are high
impedance since the internal switches to the inputs are
all disconnected. The total supply current of the device
reduces to 27mA. Set PD to a logic-high for device
power-down.

A low-power mode is available to lower the required
power for CWD operation. When selected, the complex
mixers operate at lower quiescent currents and the total
per-channel current is lowered to 53mA. Note that oper­ation in this mode slightly reduces the dynamic perfor­mance of the device. Table 6 shows the logic function
of standard operating modes.

Ultrasound VGA Integrated
with CW Octal Mixer

18 ______________________________________________________________________________________

Figure 1. Data Flow of Serial Shift Register

PD

CW_VG

CW

INTERNA

L SWITCH

INTERNAL

SWITCH TO LPF

5V VCC CURRENT

11V V

MIX

CURRENT

CONSUMPTION (mA)

11 N/A

Off Off Off 27 0

10 N/A

Off Off Off 27 0

00 0

On Off On 245 106

00 1

On Off On 245 53

01 N/A

Off On Off 204 0

Table 6. Logic Function of Standard Operating Modes

N/A = Not applicable.

CHANNEL 1

DATA_IN

CLOCK

ABCDSD

B3 B2 B1 B0 B4

CHANNEL 5

ABCDSD

B3 B2 B1 B0 B4

ABCDSD

B3 B2 B1 B0 B4

ABCDSD

B3 B2 B1 B0 B4

CHANNEL 2

CHANNEL 6

CHANNEL 3

ABCDSD

B3 B2 B1 B0 B4

CHANNEL 7

ABCDSD

B3 B2 B1 B0 B4

CHANNEL 4

ABCDSD

B3 B2 B1 B0 B4

CHANNEL 8

ABCDSD

B3 B2 B1 B0 B4

DATA_OUT

INPUT

INPUT

LOW_PWR VGA

Off

Off

Off

Off

On

MIXER

TO VGA

AND CW MIXER

CONSUMPTION (mA)

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.
One possible approach to interfacing the CW outputs to
an instrumentation amplifier used to drive an ADC is
shown in Figure 2. In this implementation, there are four
large-value (in the range of 470nF to 1µF) capacitors
between each of the CW_IOUT+, CW_IOUT-,
CW_QOUT+, CW_QOUT- outputs and the circuitry they
are driving. The output of the CW mixer usually drives
the input of an instrumentation amplifier made up of op
amps whose input impedance is set by common-mode
setting resistors.

There are clearly both a highpass corner and a lowpass
corner present in this output network. The lowpass cor­ner is set primarily by the 115Ω mixer pullup resistors,
the series 50Ω resistors, and the shunt 0.022µF capaci­tor. This lowpass corner is used to filter a combination
of LO leakage and upper sideband. The highpass cor­ner, however, is of a larger concern due to the fact that
it is dominated by the combination of a 1µF DC blocking
capacitor and the pair of shunt 31.6kΩ resistors.

If drawn, the simplified dominant highpass network
would look like Figure 3.

The highpass pole in this case is at f

P

= 1/(2 x pi x RC) ~
5Hz. Note that this low highpass corner frequency is
required in order to filter the downconverted clutter tone,
which appears at DC, but not interfere with CWD imaging
at frequencies as low as 400Hz. For example, if one want­ed to use CWD down to 400Hz, then a good choice for
the highpass pole would be at least a decade below this
(< 40Hz) as not to incur rolloff due to pole. Remember, if
the highpass pole is set to 400Hz, the response is 3dB
down at that corner frequency. The placement of the
highpass pole at 5Hz in the above example is between
the DC and 40Hz limitations just discussed.

The bottom line is that any reasonably sized DC block
between the output of the mixer and the instrumentation
amplifier pose a significant time constant that slows the
mode select switching speed.

An alternative solution to the approach in Figure 2,
which enables faster mode select response time, is
shown in Figure 4.

In Figure 4, the outputs of the CWD mixers are DC­coupled into the inputs of the instrumentation ampli­fiers. Therefore, the op amps must be able to accom­modate the full compliance range of the mixer outputs,
which is a maximum of +11V when the mixers are dis­abled, down to the +5V supply of the MAX2036 when
the mixers are enabled. The op amps can be powered
from +11V for the high rail and +5V for the low rail,
requiring a 6V op amp.

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 19

Figure 2. Typical Example of a CW Mixer’s Output Circuit

Figure 3. Simplified Circuit of Highpass Pole

Figure 4. Improved Mode Select Response Time Achieved with
DC-Coupled Input to Instrumentation Amplifier

CW_IOUT-

CW_IOUT+

115Ω115Ω

50Ω

1μF

31.6kΩ

0.022μF

31.6kΩ

1μF

+11V

1μF

31.6kΩ

+5V

MAX2036

Serial Interface

The serial interface of the MAX2036 programs the LO for
16, 8, or 4 quadrature phases using a serial shift register
implementation. Data is shifted into the device on DIN.
The serial shift register clock is applied to the CLK input.
The serial shift register has 5 bits per channel. The first 4
bits are for phase programming, and the fifth bit enables
or disables each channel of the mixer array.

Each mixer can be programmed to 1 of 16 phases;
therefore, 4 bits are required for each channel for pro­gramming. The master high-frequency mixer clock is
applied to differential inputs LO_LVDS+ and LO_LVDS­(for modes 1 and 2) and LO_ (for modes 3 and 4). The
LOAD input is provided to allow the user to load the
phase counters with the programming values to gener­ate the correct LO phases. The input signals for mixing
are applied to the eight differential inputs, CWIN_+ and
CWIN_-. The summed I/Q baseband differential outputs
are provided on CW_IOUT+/- and CW_QOUT+/-.
CW_M1 and CW_M2 are used to select one of the four
possible modes of operation. See Table 1.

The serial interface is designed to allow multiple
devices to be easily daisy chained in order to minimize
program interface wiring. DOUT is available for this
daisy-chain function.

Programming the Beamformer

During normal CWD operation, the mixer clock at LO_ or
CW_LVDS± is on and the programming signals on DIN,
CLK, and LOAD are off. (LOAD = high, CLOCK = low,
and DATA_IN = don’t care, but fixed to a high or low). To
start the programming sequence, turn off the mixer
clock. Data is shifted into the shift register at a recom­mended 10MHz programming rate or 100ns minimum
data clock period/time. See Figure 5 for timing details.

After the shift registers are programmed, pull the LOAD
bus to logic-low and then back to logic-high to load the
internal counters into I/Q phase divider/selectors with
the proper values. LOAD must remain low for a mini­mum time of t

CLH

. The user turns on the mixer clock to
start beamforming. The clock must turn on such that it
starts at the beginning of a mixer clock cycle.

Ultrasound VGA Integrated
with CW Octal Mixer

20 ______________________________________________________________________________________

Figure 5. Shift Register Timing Diagram

t

DSUtHLD

DIN

t

CLH

CLK

LOAD

MIXER

CLOCK ON

MIXER

CLOCK ON

t

DCLKPWH

t

DCLK

MIXER

CLOCK OFF

t

DCLKPWL

MIXER

CLOCK OFF

MIXER

CLOCK OFF

t

LD

MIXER

CLOCK ON

t

LDMIXCLK

MIXER

CLOCK ON

CW Mixer Output Summation

The maximum differential current output is typically
3mA

P-P

and the mixer output compliance voltage
ranges from 4.75V to 12V per mixer channel. The mixer
common-mode current in each of the differential mixer
outputs is typically 3.25mA. The total summed current
would equal N x 3.25mA in each of the 115Ω load resis­tors (where N = number of channels). In this case, the
quiescent output voltage at +V

SUM

and -V

SUM

outputs

would be +11V - (N x 3.25mA x 115) = +11 - (8 x

3.25mA x 115) = 8.05V. The voltage swing at each out­put, with one channel driven at max output current (dif­ferential 3mA

P-P

) while the other channels are not

driven, would be 1.5mA

P-P

x 115Ω or 174mV

P-P

and the

differential voltage would be 348mV

P-P

. The voltage
compliance range is defined as the valid range for
+V

SUM

and -V

SUM

in this example.

External Compensation

External compensation is required for bypassing inter­nal biasing circuitry. Connect, as close as possible,
individual 4.7µF capacitors from each pin EXT_C1,
EXT_C2, and EXT_C3 (pins 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 7.5kΩ (0.1%) resistor from EXT_RES (pin

38) to ground.

Analog Input and Output Coupling

In typical applications, the MAX2036 is being driven
from a low-noise amplifier (such as the MAX2034) and
the VGA is typically driving a discrete differential anti­alias filter into an ADC (such as the MAX1436 octal
ADC). The differential input impedance of the MAX2036
is typically 240Ω. The differential outputs of the VGA
are capable of driving a differential load capacitance to
GND at each of the VGA differential outputs of 60pF,
and differential capacitance across the VGA outputs is
10pF, RL= 1kΩ. The differential outputs have a com­mon-mode bias of approximately 3.75V. 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 ultrasound­specific IMD3 two-tone specification. In this measure­ment, f1represents 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. The IMD3 product of interest (f1- (f2 - f1)) pre­sents itself as an undesired Doppler error signal in ultra­sound applications. See Figure 6.

PCB Layout

The pin configuration of the MAX2036 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
of signal processing.

The exposed pad (EP) of the MAX2036’s TQFP-EP
package provides a low thermal-resistance path to the
die. It is important that the PCB on which the MAX2036
is mounted be designed to conduct heat from the EP.
In addition, provide the EP with a low-inductance path
to electrical ground. The EP MUST be soldered to a
ground plane on the PCB, either directly or through an
array of plated via holes.

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

______________________________________________________________________________________ 21

Figure 6. Ultrasound IMD3 Measurement Technique

-25dB

ULTRASOUND

IMD3

f1 - (f2 - f1)f

1

f

2

+ (f2 - f1)f

2

MAX2036

Ultrasound VGA Integrated
with CW Octal Mixer

22 ______________________________________________________________________________________

Figure 7. Typical per-Channel Ultrasound Imaging Application

TO 10-BIT

IMAGING

ADC

TO I CHANNEL

CWD

ADC

CWD

I CHANNELS

IN

CWD

Q CHANNELS

IN

ADC

CWD

TO Q CHANNEL

VG_CTL+ VG_CTL-

GND

MIX

+V

MIX

+V

115Ω 115Ω

ANTI-ALIAS FILTER.

THIRD-ORDER BUTTERWORTH

REF

V

CC

V

0.1μF

VGOUT_+

50Ω

VGIN_+

0.1μF

50Ω

VGIN_-

VGOUT_-

12μH

CWIN_+

CW_IOUT+

12μH

CW_IOUT-

CWIN_-

CW_QOUT-

CW_QOUT+

CW_VG

CW_FILTER

115Ω 115Ω

CWD I/Q LO

LO DIVIDER

MAX2036

ONE CHANNEL

100nF

100nF

MAX2034

ONE CHANNEL

100nF

-V

D2, D1, D0

ZIN IN CONTROL

100nF

100nF

+V

IN

+V

MAX2036

Ultrasound VGA Integrated

with CW Octal Mixer

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.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________

23

© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

CWIN6-

GND

VGIN6-

CWIN5+

VGIN5+

VGIN5-

CWIN2-

1 2 3 4 5 6 7 8 9 10111213141516 171819202122232425

75747372717069686766656463626160595857565554535251

CWIN5-

GND

VGIN6+

V

CC

EXT_C2

EXT_C1

GND

VGIN4+

CWIN4+

CWIN4-

EXT_C3

CWIN3+

CWIN3-

VGIN3-

CWIN2+

GND

VGIN3+

VGIN4-

VGOUT7-

V

CC

LO6

VGOUT6-

GND

LO5

VGOUT2-

VGOUT7+

LO7

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

50

49

48

47

46

45

44

43

42

41

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

DIN

GND

V

CC

CW_M1

VGIN2+

GND

VGOUT1-

VGOUT1+

LO1

VGOUT8+
LO8

N.C.
V

CC

DOUT
LOW_PWR
M4_EN
V

CC

CW_FILTER
PD

CW_VG
EXT_RES
V

REF

CWIN8+

GND
VGIN8+

VGIN8­CWIN7+
CWIN7­GND
VGIN7+
VGIN7­CWIN6+

VGOUT8-

MAX2036

TOP VIEW

VGOUT6+

VGOUT5-

VG_CTL-

VG_CTL+

LO_LVDS+

LO4

VGOUT4+

VGOUT5+

LO_LVDS-

VGOUT4-

LO3

VGOUT3+

V

CC

LO2

VGOUT2+

VGOUT3-

LOAD

CW_QOUT+

CW_QOUT-

CW_IOUT+

V

CC

VG_CLAMP_MODE

CW_M2

CW_IOUT-

VGIN1+

GND

CWIN1-

VGIN2-

VGIN1-

V

REF

CWIN1+

CLK

CWIN8-

TQFP

Pin Configuration

Package Information

For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages

.

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

100 TQFP-EP C100E+3

21-0116

Chip Information

PROCESS: Silicon Complementary Bipolar