General Description

The MAX6921/MAX6931 are 20-output, 76V, vacuum-

fluorescent display (VFD) tube drivers that interface a

multiplexed VFD tube to a VFD controller, such as the

MAX6850–MAX6853, or to a microcontroller. The

MAX6921/MAX6931 are also ideal for driving static VFD

tubes or telecom relays.

Data is input using an industry standard 4-wire serial

interface (CLOCK, DATA, LOAD, BLANK), compatibile

with either Maxim’s or industry-standard VFD driver and

controller.

For easy display control, the active-high BLANK input

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

automatically puts the MAX6921/MAX6931 into shut-

down mode. Display intensity may also be controlled by

directly pulse-width modulating the BLANK input.

The MAX6921 has a serial interface data output, DOUT,

allowing any number of devices to be cascaded on the

same serial interface.

allowing the drivers’ output swing to be made bipolar to

simplify filament biasing in many applications.

The MAX6921 is available in 28-pin TSSOP, SO, and

PLCC packages. The MAX6931 is available in a 28-pin

TSSOP package.

Maxim also offers 12-output VFD drivers (MAX6920) and

32-output VFD drivers (MAX6922/MAX6932).

Applications

White Goods

Industrial Weighing

Gaming Machines

Security

Automotive

Telecom

Avionics

VFD Modules

Instrumentation

Industrial Control

Features

o 5MHz Industry-Standard 4-Wire Serial Interface

o 3V to 5.5V Logic Supply Range

o 8V to 76V Grid/Anode Supply Range

o -11V to 0V Filament Bias Supply (MAX6931 Only)

o Push-Pull CMOS High-Voltage Outputs

o Outputs can Source 40mA, Sink 4mA

Continuously

o Outputs can Source 75mA Repetitive Pulses

o Outputs can be Paralleled for Higher Current Drive

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

Driver

o Blank Input Simplifies PWM Intensity Control

o Small 28-Pin TSSOP Package

o -40°C to +125°C Temperature Range

20-Output, 76V, Serial-Interfaced

VFD Tube Drivers

________________________________________________________________ Maxim Integrated Products

1

Ordering Information

19-3020; Rev 0; 10/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-PACKAGE

MAX6921AUI

-40

°C to +125°C

28 TSSOP

MAX6921AWI

-40

°C to +125°C

28 Wide SO

MAX6921AQI

-40

°C to +125°C

28 PLCC

MAX6931AUI

-40

°C to +125°C

28 TSSOP

MAX6931

DIN

CLK

LOAD

BLANK

VFDOUT

VFCLK

VFLOAD

VFBLANK

921

GND

-7V

6

22

µC

23

20

C1

100nF

C3

100nF

+5V

7

C2

100nF

+60V

8

OUT0–OUT19

20

Typical Operating Circuit

Pin Configurations appear at end of data sheet.