MAX14808 Datasheet, PDF (26/31 Pages) Maxim Integrated Products – Octal Three-Level/Quad Five-Level High-Voltage 2A Digital Pulsers with T/R Switch

MAX14808 / MAX14809
Octal Three-Level/Quad Five-Level High-Voltage
2A Digital Pulsers with T/R Switch
Disable Transmit Mode
All eight high-voltage transmit channels are disabled, no
pulse transmission is possible. The T/R switch (MAX14808
only) can be turn-on (to receive low-voltage signals) or
turn-off (for isolation).
Current Capability Selection
The devices feature pulser current drive capability selec-
tion. Two control inputs (CC0, CC1) control the current
drive capability (Table 5).
Table 5. Current Drive Selection
CC0
0
1
0
1
INPUTS
CC1
0
0
1
1
PULSER OUTPUT
CURRENT (typ)
2A
1.5A
1A
0.5A
Sync Function
The devices provide the ability to resynchronize all
the data inputs by means of a clean clock signal. In
ultrasound systems, the FPGA output signals are often
affected by a high jitter. The jitter induces phase noise
that is detrimental in Doppler analysis. The input clock
can be either a differential signal or a single-ended signal
running up to 160MHz. Data are clocked in on the rising
edge of the CLK input (falling edge of CLK). Connect
CLK to GND for single-ended operation. The sync feature
can be enabled or disabled by the SYNC control input.
Drive the SYNC input low to disable the synchroniza-
tion function (no external clock signal). Drive the SYNC
input high to enable the synchronization function (with an
external clock signal). Figure 6 shows the simplified CLK
and CLK inputs schematic.
VCC
CLK
VCC ^{DIFFERENTIAL TO}
SINGLE-ENDED
CONVERSION
40kI
2.5kI
40kI
2.5kI
2:1
VDD
MUX
SINGLE-ENDED
CLOCK
CLK
REFERENCE VOLTAGE
Figure 6. Simplified CLK and CLK Inputs Schematic
VCC
SELECT
Maxim Integrated
  26