Rainbow Electronics MAX6931 User Manual

General Description

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.

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 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.

The MAX6931 has a negative supply voltage input, VSS, 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

♦ 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

MAX6921/MAX6931

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.

Typical Operating Circuit

Pin Configurations appear at end of data sheet.

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

µC

VFDOUT

VFLOAD

VFBLANK

VFCLK

100nF

+5V

7 V

MAX6931

DIN

CLK

LOAD

BLANK

921

-7V

8 V

OUT0–OUT19

GND

+60V

C2 100nF

VFD TUBE

MAX6921/MAX6931

20-Output, 76V, Serial-Interfaced VFD Tube Drivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Typical Operating Circuit, VBB= 8V to 76V, VCC= 3V to 5.5V, VSS= -11V to 0V, VBB- VSS≤ 76V, TA= T

MIN

to T

MAX

, unless other-

wise noted.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Voltage (with respect to GND) V

.........................................................................-0.3V to +80V

...........................................................................-0.3V to +6V

(MAX6931 only) ...............................................-12V to +0.3V

- VSS(MAX6931 only) .....................................-0.3V to +80V

OUT_ (MAX6921 only) ..................(GND - -0.3V) to (V

+ 0.3V)

OUT_ (MAX6931 only) ....................(V

- -0.3V) to (VBB+ 0.3V)

All Other Pins..............................................-0.3V to (V

+ 0.3V)

OUT_ Continuous Source Current ....................................-45mA

OUT_ Pulsed (1ms max, 1/4 max duty) Source Current ...-80mA

Total OUT_ Continuous Source Current .........................-540mA

Total OUT_ Continuous Sink Current .................................90mA

Total OUT_ Pulsed (1ms max, 1/4 max duty)

Source Current ...........................................................-960mA

OUT_ Sink Current .............................................................15mA

CLK, DIN, LOAD, BLANK, DOUT Current .......................±10mA

Continuous Power Dissipation (T

= +70°C) 28-Pin TSSOP (derate 12.8mW/°C

over +70°C)................................................................1025mW

28-Pin Wide SO (derate 12.5mW/°C

over +70°C)................................................................1000mW

28-Pin PLCC (derate 10.5mW/°C

over +70°C)..................................................................842mW

Operating Temperature Range

MIN

to T

MAX

) ...............................................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Logic Supply Voltage V

Tube Supply Voltage V

Bias Supply Voltage (MAX6931 Only)

Total Supply Voltage (MAX6931 Only)

Logic Supply Operating Current I

Tube Supply Operating Current I

Bias Supply Operating Current (MAX6931 Only)

High-Voltage OUT_ V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

- V

All outputs OUT_ low, CLK = idle

All outputs OUT_ high, CLK = idle

All outputs OUT_ low

All outputs OUT_ high

All outputs OUT_ low

All outputs OUT_ high

VBB ≥ 15V

= -25mA

OUT

VBB ≥ 15V

= -40mA

OUT

8V < VBB < 15V

= -25mA

OUT

3 5.5 V

876V

-11 0 V

76 V

TA = +25°C 78 170

= -40°C to +125°C 200

TA = +25°C 540 900

= -40°C to +125°C 1000

TA = +25°C 1.65 3.0

= -40°C to +125°C 6.9

TA = +25°C 0.85 1.3

= -40°C to +125°C 1.4

TA = +25°C -0.8 -0.38

= -40°C to +125°C -1.9

TA = +25°C -1.4 -0.87

= -40°C to +125°C -1.5

TA = +25°CV

- 1.1

TA = -40°C to +85°CVBB - 2

= -40°C to +125°CVBB - 2.5

TA = -40°C to +85°CVBB - 3.5

= -40°C to +125°CVBB - 4.0

TA = +25°CV

- 1.2

TA = -40°C to +85°CVBB - 2.5

= -40°C to +125°CVBB - 3.0

µA

MAX6921/MAX6931

20-Output, 76V, Serial-Interfaced

VFD Tube Drivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Typical Operating Circuit, VBB= 8V to 76V, VCC= 3V to 5.5V, VSS= -11V to 0V, VBB- VSS≤ 76V, TA= T

MIN

to T

MAX

, unless other-

wise noted.) (Note 1)

Low-Voltage OUT_ (MAX6921 Only)

Low-Voltage OUT_ (MAX6931 Only)

Rise Time OUT_ (20% to 80%) t

Fall Time OUT_ (80% to 20%) t

SERIAL INTERFACE TIMING CHARACTERISTICS

LOAD Rising to OUT_ Falling Delay

LOAD Rising to OUT_ Rising Delay

BLANK Rising to OUT_ Falling Delay

BLANK Falling to OUT_ Rising Delay

Input Leakage Current CLK, DIN, LOAD, BLANK

Logic-High Input Voltage CLK, DIN, LOAD, BLANK

Logic-Low Input Voltage CLK, DIN, LOAD, BLANK

Hysteresis Voltage DIN, CLK, LOAD, BLANK

High-Voltage DOUT V

Low-Voltage DOUT V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

VBB ≥ 15V I

= 1mA

OUT

8V < VBB < 15V

= 1mA

OUT

VBB ≥ 15V I

= 1mA

OUT

8V < VBB < 15V

= 1mA

OUT

VBB = 60V, CL = 50pF, RL =2.3kΩ 0.9 2 µs

= 60V, C

TA = +25°C 0.75 1

TA = -40°C to +85°C 1.5

= -40°C to +125°C 1.9

TA = +25°C 0.8 1.1

TA = -40°C to +85°C 1.6

= -40°C to +125°C 2.0

TA = +25°CV

TA = -40°C to +85°CV

= -40°C to +125°CV

TA = +25°CV

TA = -40°C to +85°CV

= -40°C to +125°CV

= 50pF, RL =2.3kΩ 0.6 1.5 µs

(Notes 2, 3) 0.9 1.8 µs

(Notes 2, 3) 1.2 2.4 µs

(Notes 2, 3) 0.9 1.8 µs

(Notes 2, 3) 0.5 1.3 2.5 µs

, I

∆V

= -1.0mA

SOURCE

= 1.0mA 0.5 V

SINK

0.8 x V

0.5

+ 0.75 VSS + 1

+ 1.5

+ 1.9

+ 0.8 VSS + 1.1

+ 1.6

+ 2.0

0.05 10 µA

0.3 x V

0.6 V

Typical Operating Characteristics

(VCC= 5.0V, VBB= 76V, and TA= +25°C, unless otherwise noted.)

MAX6921/MAX6931

20-Output, 76V, Serial-Interfaced VFD Tube Drivers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(Typical Operating Circuit, VBB= 8V to 76V, VCC= 3V to 5.5V, VSS= -11V to 0V, VBB- VSS≤ 76V, TA= T

MIN

to T

MAX

, unless other-

wise noted.) (Note 1)

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design. Note 2: Guaranteed by design. Note 3: Delay measured from control edge to when output OUT_ changes by 1V.

TUBE SUPPLY CURRENT (IBB)

vs. TEMPERATURE (OUTPUTS LOW)

MAX6921/31 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

1008040 60020-20

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

-40 120

VBB = 76V

VBB = 40V

VBB = 8V

TUBE SUPPLY CURRENT (IBB)

vs. TEMPERATURE (OUTPUTS HIGH)

MAX6921/31 toc02

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

1008040 60020-20

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

-40 120

VBB = 76V

VBB = 40V

VBB = 8V

LOGIC SUPPLY CURRENT (ICC)

vs. TEMPERATURE (OUTPUTS LOW)

MAX6921/31 toc03

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

1008040 60020-20

100

150

200

250

300

350

400

-40 120

VCC = 5V, CLK = 5MHz

VCC = 3.3V, CLK = 5MHz

VCC = 5V, CLK = IDLE

VCC = 3.3V, CLK = IDLE

Rise and Fall Time DOUT

CLK Clock Period t

CLK Pulse-Width High t

CLK Pulse-Width Low t

CLK Rise to LOAD Rise Hold t

DIN Setup Time t

DIN Hold Time t

DOUT Propagation Delay t

LOAD Pulse High t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

3V to 4.5V 60 100

4.5V to 5.5V 30 80

200 ns

3.0V to 4.5V 25 120 240

4.5V to 5.5V 20 75 150

CSH

CSW

= 10pF

DOUT

(Note 2)

(Note 2) 100 ns

3.0V to 4.5V 20

4.5V to 5.5V 15

= 10pF

DOUT

90 ns

5ns

55 ns

MAX6921/MAX6931

20-Output, 76V, Serial-Interfaced

VFD Tube Drivers

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(VCC= 5.0V, VBB= 76V, and TA= +25°C, unless otherwise noted.)

LOGIC SUPPLY CURRENT (ICC)

vs. TEMPERATURE (OUTPUTS HIGH)

MAX6921/31 toc04

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

1008040 60020-20

450

500

550

600

650

700

750

800

400

-40 120

VCC = 5V, CLK = 5MHz

VCC = 3.3V, CLK = 5MHz

VCC = 5V, CLK = IDLE

VCC = 3.3V, CLK = IDLE

OUTPUT VOLTAGE (VBB - VH)

vs. TEMPERATURE (OUTPUT HIGH)

MAX6921/31 toc05

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

1008040 60020-20

0.5

1.0

1.5

2.0

2.5

3.0

3.5

-40 120

VBB = 76V

VBB = 40V

VBB = 8V

OUT

= -40mA

OUTPUT VOLTAGE

vs. TEMPERATURE (OUTPUT LOW)

MAX6921/31 toc06

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

1008040 60020-20

-40 120

VBB = 40V

VBB = 8V

VBB = 76V

OUT

= 4mA

OUTPUT RISE AND FALL WAVEFORM

1µs/div

MAX6921/31 toc07

BLANK 2V/div

OUT_ 20V/div

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