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 shutdown mode. Display intensity can 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.

The MAX6931 has a negative supply voltage input, V_SS, 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).

MAX6921, MAX6931: Typical Operating Circuit

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Key Features

5MHz Industry-Standard 4-Wire Serial Interface
3V to 5.5V Logic Supply Range
8V to 76V Grid/Anode Supply Range
-11V to 0V Filament Bias Supply (MAX6931 Only)
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 28-Pin TSSOP Package
-40°C to +125°C Temperature Range

Applications/Uses

Automotive
Avionics
Gaming Machines
Industrial Control
Industrial Weighing
Instrumentation
Security
Telecom
VFD Modules
White Goods

Parametric Specs

Part Number

Controller/ Drvr.

Display Type

Interface

Cursor Control

Blink Cntrl.

V_SUPPLY
(V)

Package/Pins

Budgetary
Price

See Notes

MAX6921

Driver

Any type

Serial 4-Wire

8.0 to 76.0

PLCC/28

SOIC (W)/28

TSSOP/28

$4.18 @1k

See All VFD Display Drivers (4)

Pricing Notes:

This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Design Resources

Technical Documents

Tutorial 1154 Vacuum-Fluorescent-Display (VFD) Tube Manufacturers' Web Sites

Quality and Environmental Data

Request Reliability Report for: MAX6921
Lead-Free Package Tin (Sn) Whisker Reports

Quality And Environmental

Device	Fab Process	Technology	Sample size	Rejects	FIT at 25°C	FIT at 55°C

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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