Datasheet

MAX2078
Octal-Channel Ultrasound Front-End
with CW Doppler Mixers
______________________________________________________________________________________ 13
Pin Description
PIN NAME FUNCTION
1 IN2 Channel 2 Input
2 INC2 C hannel 2 C l am p Inp ut. C onnect to a coup l i ng cap aci tor . S ee the Typ i cal Ap p l i cati on C i r cui t for d etai l s.
3 ZF3 Channel 3 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
4 IN3 Channel 3 Input
5 INC3 C hannel 3 C l am p Inp ut. C onnect to a coup l i ng cap aci tor . S ee the Typ i cal Ap p l i cati on C i r cui t for d etai l s.
6 ZF4 Channel 4 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
7 IN4 Channel 4 Input
8 INC4
Channel 4 Clamp Input. Connect to the input coupling capacitor. See the Typical Application Circuit
for details.
9, 28, 31 GND Ground
10 AG AC Ground. Connect a low-ESR 1µF capacitor to ground.
11 ZF5 Channel 5 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
12 IN5 Channel 5 Input
13 INC5 C hannel 5 C l am p Inp ut. C onnect to a coup l i ng cap aci tor . S ee the Typ i cal Ap p l i cati on C i r cui t for d etai l s.
14 ZF6 Channel 6 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
15 IN6 Channel 6 Input
16 INC6 C hannel 6 C l am p Inp ut. C onnect to a coup l i ng cap aci tor . S ee the Typ i cal Ap p l i cati on C i r cui t for d etai l s.
17 ZF7 Channel 7 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
18 IN7 Channel 7 Input
19 INC7
Channel 7 Clamp Input. Connect to the input coupling capacitor. See the Typical Application Circuit
for details.
20 ZF8 Channel 8 Active Impedance Matching Line. AC-couple to source with a 10nF capacitor.
21 IN8 Channel 8 Input
22 INC8 C hannel 8 C l am p Inp ut. C onnect to a coup l i ng cap aci tor . S ee the Typ i cal Ap p l i cati on C i r cui t for d etai l s.
23, 33,
53, 64
V
CC2
4.75V Power Supply. Connect to an external 4.75V power supply. Connect all 4.75V supply pins
together externally and bypass with 100nF capacitors as close as possible to the pin.
24 V
REF
External 2.5V 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 V
REF
. Use a low-noise supply for V
REF
.
25, 44, 63 V
CC1
3.3V Power Supply. Connect to an external 3.3V power supply. Connect all 3.3V supply pins together
externally and bypass with 100nF capacitors as close as possible to the pin.
26 VG+
27 VG-
VGA Analog Gain Control Differential Input. Set the differential voltage to -3V for minimum gain and to
+3V for maximum gain.
29 CLP CW Low-Power Mode Select Input. Drive CLP high to place CW mixers in low-power mode.
30 PD
Power-Down Mode Select Input. Set PD to V
CC1
to place the entire device in power-down mode.
Drive PD low for normal operation. This mode overrides the standby mode.
32 DOUT Serial Port Data Output. Data output for ease of daisy-chain programming. The level is 3.3V CMOS.
34 OUT8- Channel 8 Negative Differential Output
35 OUT8+ Channel 8 Positive Differential Output
36 OUT7- Channel 7 Negative Differential Output