Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - display driver VF 4-wire, Seriell 1 mA SOIC 20

● White Goods

● Gaming Machines

● Avionics

● Industrial Weighing

● Security

● Telecom

General Description

The MAX6920 is a 12-output, 76V, vacuum fluo-

rescent display (VFD) tube driver that interfaces a

multiplexed VFD tube to a VFD controller such as the

MAX6850–MAX6853 or to a microcontroller. The

MAX6920 is also ideal for driving either static VFD tubes

or telecom relays.

Data is inputted using an industry-standard 4-wire serial

interface (CLOCK, DATA, LOAD, BLANK) for compatibil-

ity with both industry-standard drivers and Maxim’s VFD

controllers.

For easy display control, the active-high BLANK input

forces all driver outputs low, turning the display off, and

automatically puts the MAX6920 into shutdown mode.

Display intensity may also be controlled by pulse-width

modulating the BLANK input.

The MAX6920 has a serial interface data output pin,

DOUT, allowing any number of devices to be cascaded

on the same serial interface.

The MAX6920 is available in a 20-pin SO pack-

age. Maxim also offers VFD drivers with either 20

(MAX6921/MAX6931) or 32 outputs (MAX6922 and

MAX6932).

Features

● 5MHz Industry-Standard 4-Wire Serial Interface

● 3V to 5.5V Logic Supply Range

● 8V to 76V Grid/Anode Supply Range

● Push-Pull CMOS High-Voltage Outputs

● Outputs can Source 40mA, Sink 4mA Continuously

● Outputs can Source 75mA Repetitive Pulses

● Outputs can be Paralleled for Higher Current Drive

● Any Output can be Used as a Grid or an Anode

Driver

● Blank Input Simplifies PWM Intensity Control

● Small 20-Pin SO Package

● -40°C to +125°C Temperature Range

Applications

PART TEMP RANGE PIN-PACKAGE

MAX6920AWP -40°C to +125°C 20 Wide SO

MAX6920

DIN

CLK

LOAD

OUT0 – OUT11

VFD TUBE

VFDOUT

VFLOAD

VFCLK

BLANK

VFBLANK

120

GND

+60V+5V

100nF

µC

TOP VIEW

DIN

OUT0

OUT1

OUT2

OUT3

OUT4

OUT5

LOAD

CLKGND

BLANK

OUT6

OUT7

OUT8

OUT9

OUT10

OUT11

DOUT

MAX6920AWP

Typical Operating Circuit

Ordering Information

Pin Conguration

MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver

19-3061; Rev 1; 8/14

Summary of content (10 pages)

PAGE 1
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver General Description The MAX6920 is a 12-output, 76V, vacuum fluorescent display (VFD) tube driver that interfaces a multiplexed VFD tube to a VFD controller such as the MAX6850–MAX6853 or to a microcontroller. The MAX6920 is also ideal for driving either static VFD tubes or telecom relays.
PAGE 2
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Absolute Maximum Ratings Voltage (with respect to GND) VBB.....................................................................-0.3V to +80V VCC.......................................................................-0.3V to +6V OUT_......................................................-0.3V to (VBB + 0.3V) All Other Pins........................................ -0.3V to (VCC + 0.3V) OUT_ Continuous Source Current ...................................
PAGE 3
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Electrical Characteristics (continued) (Typical Operating Circuit, VBB = 8V to 76V, VCC = 3V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) TYP MAX UNITS Rise Time OUT_ (20% to 80%) PARAMETER SYMBOL tR VBB = 60V, CL = 50pF, RL = 2.3kW CONDITIONS MIN 0.9 2 µs Fall Time OUT_ (80% to 20%) tF VBB = 60V, CL = 50pF, RL = 2.3kW 0.6 1.
PAGE 4
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Typical Operating Characteristics (VCC = 5.0V, VBB = 76V, and TA = +25°C, unless otherwise noted.) VBB = 76V 1.0 0.8 VBB = 40V 0.6 VBB = 8V 1.4 1.2 1.0 0.6 0.4 0.2 0.2 -40 -15 10 35 60 85 VBB = 76V 0.8 0.4 0 0 110 VBB = 40V -40 -20 TEMPERATURE (°C) 40 60 80 VCC = 5V, CLK = IDLE VCC = 3.3V, CLK = IDLE -40 14 VCC = 5V, CLK = IDLE 100 0 VCC = 3.
PAGE 5
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Pin Description PIN NAME FUNCTION 1 VBB 2 DOUT VFD Tube Supply Voltage 3–8, 13–18 OUT0 to OUT11 VFD Anode and Grid Drivers. OUT0 to OUT11 are push-pull outputs swinging from VBB to GND. 9 BLANK Blanking Input. High forces outputs OUT0 to OUT11 low, without altering the contents of the output latches. Low enables outputs OUT0 to OUT11 to follow the state of the output latches. 10 GND Ground 11 CLK Serial-Clock Input.
PAGE 6
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver the shift register outputs when LOAD is high, and latches the current state on the falling edge of LOAD. Each driver output is a slew-rated controlled CMOS pushpull switch driving between VBB and GND. The output rise time is always slower than the output fall time to avoid shoot-through currents during output transitions.
PAGE 7
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Table 1.
PAGE 8
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Since dissipation is proportional to current squared, the maximum current that can be delivered for a given multiplex ratio is given by: higher for multiplexed tubes. When using multiple driver devices, try to share the average dissipation evenly between the drivers.
PAGE 9
12-Output, 76V, Serial-Interfaced VFD Tube Driver This means that the driver can be operated in this application up to the MAX6920’s +125°C maximum operating temperature. Typical Application Circuit MAX685x Power-Supply Considerations The MAX6920 operates with multiple power-supply voltages. Bypass the VCC and VBB power-supply pins to GND with a 0.1µF capacitor close to the device.
PAGE 10
MAX6920 12-Output, 76V, Serial-Interfaced VFD Tube Driver Revision History REVISION NUMBER REVISION DATE 0 10/03 Initial Release — 1 8/14 Removed automotive reference from data sheet 1 DESCRIPTION PAGES CHANGED For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.