Rainbow Electronics MAX6934 - Manual (Page 7)

MAX6922/MAX6932/MAX6933/MAX6934
27-, 28-, and 32-Output, 76V,
Serial-Interfaced VFD Tube Drivers
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Detailed Description
The MAX6922/MAX6932/MAX6933/MAX6934 are VFD
tube drivers comprising a 4-wire serial interface driving
high-voltage Rail-to-Rail
 output ports. The driver is suit-
able for both static and multiplexed displays.
The output ports feature high current-sourcing capabili-
ty to drive current into grids and anodes of static or
multiplex VFDs. The ports also have active current sink-
ing for fast discharge of capacitive display electrodes
in multiplexing applications.
The 4-wire serial interface comprises a shift register
and transparent latch with 32 bits for the MAX6922/
MAX6934, 28 bits for the MAX6933, and 27 bits for the
MAX6932. The shift register is written through a clock
input CLK and a data input DIN. For the MAX6922/
MAX6932/MAX6934, the data propagates to a data out-
put DOUT. The data output allows multiple drivers to be
cascaded and operated together. The output latch is
transparent to the shift register outputs when LOAD is
high, and latches the current state on the falling edge
of LOAD.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
SERIAL-TO-PARALLEL SHIFT REGISTER
LATCHES
CLK
DIN
LOAD
BLANK
OUT0 OUT1 OUT2 OUTn
WHERE n =
27 FOR MAX6932
28 FOR MAX6933
32 FOR MAX6922/MAX6934
DOUT
MAX6922/MAX6932/
MAX6934 ONLY
MAX6922
MAX6932
MAX6933
MAX6934
Figure 1. MAX6922/MAX6932/MAX6933/MAX6934 Functional Diagram
SLEW-RATE
CONTROL
V BB
OUT_
40Ω
TYPICAL
750Ω
TYPICAL
SLEW-RATE
CONTROL
V BB
V
SS
OUT_
40Ω
TYPICAL
750Ω
TYPICAL
Figure 2. MAX6922 CMOS Output Driver Structure Figure 3. MAX6932/MAX6933/MAX6934 CMOS Output Driver
Structure