MAX2038CCQ+ Maxim Integrated Products, MAX2038CCQ+ Datasheet - Page 18

• Manufacturer Part Number: MAX2038CCQ+
• Description: IC VGA W/OCTAL MIXER 8CH 100TQFP
• Manufacturer: Maxim Integrated Products
• Type: Variable Gain Amplifierr

Specifications of MAX2038CCQ+

• Applications: Medical Ultrasound Imaging, Sonar
• Mounting Type: Surface Mount
• Package / Case: 100-TQFP Exposed Pad, 100-eTQFP, 100-HTQFP, 100-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Ultrasound VGA Integrated
with CW Octal Mixer
Figure 1 illustrates the serial programming of the 8 indi-
vidual 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 pro-
gram multiple chips in the system.
The MAX2038 also includes selectable lowpass filters
between each CW differential input pair and corre-
sponding mixer input. Shunt capacitors and resistors
are integrated on chip for high band and low band. The
parallel capacitor/resistor networks, which appear differ-
entially 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 f
9.5MHz. Drive CW_FILTER low to set the corner fre-
quency equal to f
ter inputs to be disconnected from input nodes (internal
to chip) to prevent overloading the LNA output and to
not change the VGA input common-mode voltage.
During normal operation, the MAX2038 is configured
such that either the VGA path is enabled while the mixer
array is powered down (VGA mode), or the quadrature
Figure 1. Data Flow of Serial Shift Register
Table 6. Logic Function of Standard Operating Modes
N/A = Not applicable.
18
INPUT
PD
1
1
0
0
0
______________________________________________________________________________________
CW_VG
INPUT
1
0
0
0
1
DATA_IN
CLOCK
C
VGA and CW Mixer Operation
LOW_PWR
= 4.5MHz. The CW_VG allows the fil-
N/A
N/A
N/A
0
1
B3 B2 B1 B0 B4
B3 B2 B1 B0 B4
A B C D SD
A B C D SD
CHANNEL 1
CHANNEL 5
VGA
CW Lowpass Filter
Off
Off
Off
Off
On
Synchronization
MIXER
CW
Off
Off
On
On
Off
B3 B2 B1 B0 B4
B3 B2 B1 B0 B4
A B C D SD
A B C D SD
INTERNAL
CHANNEL 2
CHANNEL 6
SWITCH
TO VGA
Off
Off
Off
Off
On
C
=
SWITCH TO LPF
AND CW MIXER
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 discon-
nected 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.
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 oper-
ation in this mode slightly reduces the dynamic perfor-
mance of the device. Table 6 shows the logic function
of standard operating modes.
B3 B2 B1 B0 B4
B3 B2 B1 B0 B4
A B C D SD
A B C D SD
INTERNAL
CHANNEL 3
CHANNEL 7
Off
Off
On
On
Off
Power-Down and Low-Power Modes
5V V
B3 B2 B1 B0 B4
B3 B2 B1 B0 B4
A B C D SD
A B C D SD
CONSUMPTION
CHANNEL 4
CHANNEL 8
CC
(mA)
245
245
204
CURRENT
27
27
DATA_OUT
11V V
CONSUMPTION
MIX
(mA)
106
53
0
0
0
CURRENT