Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - display driver VF 4-wire, Seriell 1.65 mA PLCC 28

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 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

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

MAX6921/MAX6931

20-Output, 76V, Serial-Interfaced

VFD Tube Drivers

________________________________________________________________

Maxim Integrated Products

Ordering Information

19-3020; Rev 1; 4/10

For pricing, delivery, and ordering information, please contact Maxim 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/V+ -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

VFD TUBE

921

GND

-7V

µC

100nF

+5V

100nF

+60V

OUT0–OUT19

Typical Operating Circuit

Pin Configurations appear at end of data sheet.

Denotes a lead-free(Pb)/RoHS-compliant package.

/V denotes an automotive qualified part.

Summary of content (13 pages)

PAGE 1
9-3020; Rev 1; 4/10 20-Output, 76V, Serial-Interfaced VFD Tube Drivers The MAX6921/MAX6931 are 20-output, 76V, vacuumfluorescent 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.
PAGE 2
MAX6921/MAX6931 20-Output, 76V, Serial-Interfaced VFD Tube Drivers ABSOLUTE MAXIMUM RATINGS Voltage (with respect to GND) VBB .........................................................................-0.3V to +80V VCC ...........................................................................-0.3V to +6V VSS (MAX6931 only) ...............................................-12V to +0.3V VBB - VSS (MAX6931 only) .....................................-0.3V to +80V OUT_ (MAX6921 only) ..................(GND - -0.
PAGE 3
20-Output, 76V, Serial-Interfaced VFD Tube Drivers (Typical Operating Circuit, VBB = 8V to 76V, VCC = 3V to 5.5V, VSS = -11V to 0V, VBB - VSS ≤ 76V, TA = TMIN to TMAX, unless otherwise noted.
PAGE 4
ELECTRICAL CHARACTERISTICS (continued) (Typical Operating Circuit, VBB = 8V to 76V, VCC = 3V to 5.5V, VSS = -11V to 0V, VBB - VSS ≤ 76V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS CDOUT = 10pF (Note 2) Rise and Fall Time DOUT TYP MAX 3V to 4.5V MIN 60 100 4.5V to 5.
PAGE 5
20-Output, 76V, Serial-Interfaced VFD Tube Drivers LOGIC SUPPLY CURRENT (ICC) vs. TEMPERATURE (OUTPUTS HIGH) OUTPUT VOLTAGE (VBB - VH) vs. TEMPERATURE (OUTPUT HIGH) 650 600 VCC = 3.3V, CLK = 5MHz 550 VCC = 5V, CLK = IDLE 500 VBB = 8V 2.5 2.0 VBB = 40V 1.5 VBB = 76V 1.0 VCC = 3.3V, CLK = IDLE 0.5 450 400 0 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) OUTPUT VOLTAGE vs.
PAGE 6
MAX6921/MAX6931 20-Output, 76V, Serial-Interfaced VFD Tube Drivers Pin Description (continued) PIN WIDE SO/PLCC TSSOP MAX6921 MAX6931 MAX6921 — 9 — NAME VSS FUNCTION Filament Bias Supply Voltage. Bypass to GND with a 100nF capacitor. 10–19 10–19 — OUT19 to VFD Anode and Grid Drivers. OUT19 to OUT10 are push-pull outputs swinging from OUT10 VBB to GND (MAX6921 only), and from VBB to VSS (MAX6931 only). — — 3-12 OUT19 to VFD Anode and Grid Drivers.
PAGE 7
20-Output, 76V, Serial-Interfaced VFD Tube Drivers 40Ω TYPICAL 40Ω TYPICAL SLEW-RATE CONTROL OUT_ 750Ω TYPICAL SLEW-RATE CONTROL OUT_ 750Ω TYPICAL VSS Figure 2. MAX6921 CMOS Output Driver Structure Detailed Description The MAX6921/MAX6931 are VFD tube drivers comprising a 4-wire serial interface driving 20 high-voltage railto-rail output ports. The driver is suitable for both static and multiplexed displays.
PAGE 8
MAX6921/MAX6931 20-Output, 76V, Serial-Interfaced VFD Tube Drivers tCSW LOAD tCL tCSH tCH tCP CLK tDH tDS D19 DIN D18 D1 D0 tDO DOUT D19 Figure 4. 4-Wire Serial Interface Timing Diagram Table 1.
PAGE 9
20-Output, 76V, Serial-Interfaced VFD Tube Drivers where grids is the number of grids in a multiplexed display. This means that a duplex application (two grids) can use a repetitive peak current of 56.5mA, a triplex (three grids) application can use a repetitive peak current of 69.2mA, and higher multiplex ratios are limited to 75mA. Paralleling Outputs Any number of outputs within the same package can be paralleled in order to raise the current drive or reduce the output resistance.
PAGE 10
A multiplexed tube dissipation example follows: VCC = 5V ±5%, VBB = 36V to 42V, A = 12, G = 8, IANODE = 0.4mA, IGRID = 24mA PD = (5.25V x 1mA)+ (42V x 1.4mA) + ((2.5V x 0.4mA/25mA) x 0.4mA x 12) + ((2.5V x 24mA/25mA) x 24mA) = 122mW Thus, for a 28-pin wide TSSOP package (TJA = 1 / 0.0128 = 78.125°C/W from Absolute Maximum Ratings), the maximum allowed ambient temperature TA is given by: TJ(MAX) = TA + (PD x TJA) = 150°C = TA + (0.122 x 78.
PAGE 11
20-Output, 76V, Serial-Interfaced VFD Tube Drivers TOP VIEW VBB 1 28 VCC OUT4 1 28 OUT5 OUT4 1 28 OUT5 DOUT 2 27 DIN OUT3 2 27 OUT6 OUT3 2 27 OUT6 26 OUT0 OUT2 3 26 OUT7 OUT2 3 26 OUT7 25 OUT1 OUT1 4 25 OUT8 OUT1 4 25 OUT8 24 OUT2 OUT0 5 24 OUT9 OUT0 5 23 OUT3 DIN 6 23 LOAD DIN 6 OUT15 7 22 OUT4 VCC 7 22 CLK VCC 7 22 CLK OUT14 8 21 OUT5 VBB 8 21 GND VBB 8 21 GND OUT13 9 20 OUT6 DOUT 9 20 BLANK VSS 9 20 BLANK OUT12 10 19 OUT7 OUT19 10 19 OUT10 OUT19 10 19
PAGE 12
MAX6921/MAX6931 20-Output, 76V, Serial-Interfaced VFD Tube Drivers Package Information Chip Information PROCESS: BiCMOS For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 12 PACKAGE CODE DOCUMENT NO.
PAGE 13
20-Output, 76V, Serial-Interfaced VFD Tube Drivers REVISION NUMBER REVISION DATE 0 10/03 Initial release — 1 4/10 Added automotive and lead-free parts to Ordering Information 1 DESCRIPTION PAGES CHANGED Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.