MAX6850 MAXIM [Maxim Integrated Products], MAX6850 Datasheet - Page 33

• Manufacturer Part Number: MAX6850
• Description: 4-Wire Interfaced, 7-, 14-, and 16-Segment Alphanumeric Vacuum-Fluorescent Display Controller
• Manufacturer: MAXIM [Maxim Integrated Products]

4-Wire Interfaced, 7-, 14-, and 16-Segment Alpha-
The allowed range of f
set too high, the internal oscillator can stop working. An
internal fail-safe circuit monitors the multiplex clock and
detects a slow or nonworking multiplex clock. When a
slow or nonworking multiplex clock is detected, an
internal fail-safe oscillator generates a replacement
clock of about 200kHz. This backup clock ensures that
the VFD is not damaged by the multiplex operation halt-
ing inadvertently. The scan rate for 16 digits is about
15Hz in fail-safe mode, and flickers. A flickering display
is a good indication that there is a problem with the
multiplex clock.
The MAX6850 operates from a single 2.7V to 3.6V
power supply. Bypass the power supply to GND with a
0.1µF capacitor as close to the device as possible. Add
a bulk capacitor (such as a low-cost electrolytic 1µF to
22µF) if the MAX6850 is driving high current from any of
the general-purpose output ports.
TRANSISTOR COUNT: 129,898
PROCESS: CMOS
numeric Vacuum-Fluorescent Display Controller
______________________________________________________________________________________
OSC
is 2MHz to 8MHz. If f
Chip Information
Power Supplies
OSC
is
TOP VIEW
DOUT
OSC1
OSC2
CLK
DIN
CS
VFBLANK
VFDOUT
VFLOAD
PHASE1
PHASE2
VFCLK
PUMP
CHARACTER-
GENERATOR
V+
OUTPUT
ROM
MAP
RAM
GENERATOR
CLOCK
RAM
1
2
3
4
5
6
8
7
4-WIRE SERIAL INTERFACE
Functional Diagram
MAX6850
QSOP
Pin Configuration
CONFIGURATION
REGISTERS
BRIGHTNESS
CONTROL
FILAMENT
OUTPUTS
OUTPUT
SHIFTER
16
15
14
13
12
11
10
9
PWM
PWM
USER
OSC2
OSC1
PORT1
CS
DIN
SCLK
PORT0
GND
VFBLANK
VFDOUT
VFCLK
VFLOAD
PHASE 1
PHASE 2
PUMP
PORT 0
PORT 1
33