MAX2036
Ultrasound VGA Integrated
with CW Octal Mixer
6 _______________________________________________________________________________________
AC ELECTRICAL CHARACTERISTICS—CW MIXER MODE (continued)
(Figure 7, V
CC
= V
REF
= 4.75V to 5.25V, T
A
= 0°C to +70°C, V
GND
= 0V, LOW_PWR = 0, M4_EN = 0, CW_FILTER = 1, TEST_MODE =
0, PD = 0, CW_VG = 0, CW_M1 = 0, CW_M2 = 0, VG_CLAMP_MODE = 1, f
RF
= f
LO
/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, T
A
= +25°C, unless otherwise noted.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX 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
100 ns
Minimum Data Clock Pulse Width
High
t
DCLKPWH
30 ns
Minimum Data Clock Pulse Width
Low
t
DCLKPWL
30 ns
Minimum Load Line t
LD
30 ns
Minimum Load Line High to Mixer
Clock On
t
MIXCLK
30 ns
Minimum Data Clock to Load
Line High
t
CLH
30 ns
Note 2: Specifications at T
A
= +25°C and T
A
= +70°C are guaranteed by production. Specifications at T
A
= 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
. 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 4: Total on-chip power dissipation is calculated as P
DISS
= V
CC
x I
CC
+ 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.
