Rainbow Electronics MAX2038 - Manual (Page 12)

MAX2038
Ultrasound VGA Integrated
with CW Octal Mixer
12 ______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
37, 93 V REF
+5V Reference Supply. Connect to a low-noise power supply. Bypass 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 voltage if the supply for V CC exhibits low noise.
38 EXT_RES
External Resistor. Connect a 0.1% 7.5k Ω 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 mixers are powered down. Set CW_VG to a logic-low to enable the CW mixers
while 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 frequency of the internal lowpass filter for
the CW path. Set CW_FILTER to a logic-high for a corner frequency 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 logic-high to override the serial port and activate all 8 channels of the
CW path.
44 LOW_PWR Low-Power Enable. Set high to enable low-power CW mixer mode for the device.
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 Differential Input. Set the differential voltage to -2V for maximum gain
(+29.5dB), and to +2V for minimum gain (-12.5dB).
64 LO_LVDS- CW LVDS LO Inverting Differential 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