Datasheet
MAX2078
Typical Operating Characteristics (continued)
(
Typical Application Circuit
, V
REF
= 2.475V to 2.525V, V
CC1
= 3.13V to 3.47V, V
CC2
= 4.5V to 5.25V, T
A
= 0°C to +70°C, V
GND
= 0V,
NP = 0, PD = 0, CLP = 0, D43/D42/D41/D40 = 1/0/1/0 (R
IN
= 200Ω, LNA gain = 18.5dB), D45/D44 = 1/1 (f
C
= 18MHz), f
RF
= f
LO
/16
= 5MHz, capacitance to GND at each of the VGA differential outputs is 25pF, differential capacitance across VGA outputs is 15pF,
R
L
= 1kΩ differential, R
S
= 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, DOUT loaded with 10MΩ
and 60pF. Typical values are at V
CC1
= 3.3V, V
CC2
= 5V, T
A
= +25°C, unless otherwise noted.)
Octal-Channel Ultrasound Front-End
with CW Doppler Mixers
10 ______________________________________________________________________________________
THIRD-HARMONIC DISTORTION
vs. GAIN
MAX2078 toc07
GAIN (dB)
HD3 (dBc)
383226
-80
-70
-60
-50
-40
-30
-90
20 44
V
OUT
= 1V
P-P
f
RF
= 10MHz
f
RF
= 2MHz
f
RF
= 5MHz
TWO-TONE ULTRASOUND-SPECIFIC IMD3
vs. GAIN
MAX2078 toc08
GAIN (dB)
IMD3 (dBc)
383226
-70
-50
-30
-10
-90
20 44
V
OUT
= 1V
P-P
f
RF
= 10MHz
f
RF
= 2MHz
f
RF
= 5MHz
SECOND- AND THIRD-HARMONIC
DISTORTION vs. V
OUT_P-P
MAX2078 toc09
V
OUT_P-P
(V)
HD2 AND HD3 (dBc)
0.80.60.40.2
-80
-70
-60
-50
-90
01.0
GAIN = 26dB
f
RF
= 5MHz
HD2
HD3
SECOND- AND THIRD-HARMONIC
DISTORTION vs. FREQUENCY
MAX2078 toc10
FREQUENCY (MHz)
HD2 AND HD3 (dBc)
15105
-70
-60
-50
-40
-30
-80
020
V
OUT
= 1V
P-P
GAIN = 26dB
HD2
HD3
SECOND- AND THIRD-HARMONIC DISTORTION
vs. DIFFERENTIAL OUTPUT RESISTANCE
MAX2078 toc11
RESISTANCE (Ω)
HD2 AND HD3 (dBc)
900800700600500400300
-80
-70
-60
-50
-40
-30
-90
200 1000
V
OUT
= 1V
P-P
GAIN = 26dB
f
RF
= 5MHz
HD2
HD3
SECOND- AND THIRD-HARMONIC DISTORTION
vs. DIFFERENTIAL OUTPUT LOAD CAPACITANCE
MAX2078 toc12
CAPACITANCE (pF)
HD2 AND DH3 (dBc)
80604020
-80
-70
-60
-50
-40
-30
-90
0100
V
OUT
= 1V
P-P
GAIN = 26dB
f
RF
= 5MHz
HD2
HD3