MAX6921AUI+-MAX6931AUI Fast Delivery |IC PHOENIX CO.,LIMITED

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MAX6921AUI+-MAX6931AUI
20-Output, 76V, Serial-Interfaced VFD Tube Drivers
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, 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 GoodsIndustrial Weighing
Gaming MachinesSecurity
AutomotiveTelecom
AvionicsVFD Modules
InstrumentationIndustrial Control
Features5MHz Industry-Standard 4-Wire Serial Interface3V to 5.5V Logic Supply Range8V to 76V Grid/Anode Supply Range-11V to 0V Filament Bias Supply (MAX6931 Only)Push-Pull CMOS High-Voltage OutputsOutputs can Source 40mA, Sink 4mA
ContinuouslyOutputs can Source 75mA Repetitive PulsesOutputs can be Paralleled for Higher Current DriveAny Output can be Used as a Grid or an Anode
DriverBlank Input Simplifies PWM Intensity ControlSmall 28-Pin TSSOP Package-40°C to +125°C Temperature Range
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
Ordering Information
19-3020; Rev 1; 4/10
PARTTEMP RANGEPIN-PACKAGE
MAX6921AUI+-40°C to +125°C28 TSSOP
MAX6921AWI/V+-40°C to +125°C28 Wide SO
MAX6921AQI+-40°C to +125°C28 PLCC
MAX6931AUI+-40°C to +125°C28 TSSOP
MAX6931
DIN
CLK
LOAD
BLANK
VFDOUT
VFCLK
VFLOAD
VFBLANK
VFD TUBE
GND
-7V
100nF
100nF
+5V
VCC
VSS
100nF
+60V
VBB
OUT0–OUT19
Typical Operating Circuit
+Denotes a lead-free(Pb)/RoHS-compliant package.denotes an automotive qualified part.
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
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= TMINto TMAX, 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)
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 - -0.3V) to (VBB+ 0.3V)
OUT_ (MAX6931 only)....................(VSS- -0.3V) to (VBB+ 0.3V)
All Other Pins..............................................-0.3V to (VCC+ 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 (TA= +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
(TMINto TMAX)...............................................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Soldering Temperature (reflow)
Wide SO, TSSOP lead(Pb)-free...................................+260°C
PLCC lead(Pb)-free......................................................+245°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Logic Supply VoltageVCC35.5V
Tube Supply VoltageVBB876V
Bias Supply Voltage
(MAX6931 Only)VSS-110V
Total Supply Voltage
(MAX6931 Only)VBB - VSS76V
TA = +25°C78170All outputs OUT_ low,
CLK = idleTA = -40°C to +125°C200
TA = +25°C540900Logic Supply Operating CurrentICC
All outputs OUT_ high,
CLK = idleTA = -40°C to +125°C1000
TA = +25°C1.653.0All outputs OUT_ lowTA = -40°C to +125°C6.9
TA = +25°C0.851.3Tube Supply Operating CurrentIBB
All outputs OUT_ highTA = -40°C to +125°C1.4
TA = +25°C-0.8-0.38All outputs OUT_ lowTA = -40°C to +125°C-1.9
TA = +25°C-1.4-0.87
Bias Supply Operating Current
(MAX6931 Only)ISS
All outputs OUT_ highTA = -40°C to +125°C-1.5
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
ELECTRICAL CHARACTERISTICS (continued)
(Typical Operating Circuit, VBB= 8V to 76V, VCC= 3V to 5.5V, VSS= -11V to 0V, VBB- VSS≤76V, TA= TMINto TMAX, unless other-
wise noted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
TA = +25°CVBB - 2
TA = -40°C to +85°CVBB - 2.5VBB ≥ 15V
IOUT = -25mA
TA = -40°C to +125°C
TA = -40°C to +85°CVBB - 3.5VBB ≥ 15V
IOUT = -40mATA = -40°C to +125°CVBB - 4.0
TA = +25°CVBB - 1.2
TA = -40°C to +85°CVBB - 2.5
High-Voltage OUT_
8V < VBB < 15V
IOUT = -25mA
TA = -40°C to +125°CVBB - 3.0
TA = +25°C0.751
TA = -40°C to +85°C1.5VBB ≥ 15V
IOUT = 1mA
TA = -40°C to +125°C1.9
TA = +25°C0.81.1
TA = -40°C to +85°C1.6
Low-Voltage OUT_
(MAX6921 Only)VL
8V < VBB < 15V
IOUT = 1mA
TA = -40°C to +125°C2.0
TA = +25°CVSS + 0.75 VSS + 1
TA = -40°C to +85°CVSS + 1.5VBB ≥ 15V
IOUT = 1mA
TA = -40°C to +125°CVSS + 1.9
TA = +25°CVSS + 0.8 VSS + 1.1
TA = -40°C to +85°CVSS + 1.6
Low-Voltage OUT_
(MAX6931 Only)VL
8V < VBB < 15V
IOUT = 1mA
TA = -40°C to +125°CVSS + 2.0
Rise Time OUT_ (20% to 80%)tRVBB = 60V, CL = 50pF, RL =2.3kΩ0.92µs
Fall Time OUT_ (80% to 20%)tFVBB = 60V, CL = 50pF, RL =2.3kΩ0.61.5µs
SERIAL INTERFACE TIMING CHARACTERISTICS
LOAD Rising to OUT_ Falling Delay(Notes 2, 3)0.91.8µs
LOAD Rising to OUT_ Rising Delay(Notes 2, 3)1.22.4µs
BLANK Rising to OUT_ Falling Delay(Notes 2, 3)0.91.8µs
BLANK Falling to OUT_ Rising Delay(Notes 2, 3)0.51.32.5µs
Input Leakage Current
CLK, DIN, LOAD, BLANKIIH, IIL0.0510µA
Logic-High Input Voltage
CLK, DIN, LOAD, BLANKVIH0.8 x
VCCV
Logic-Low Input Voltage
CLK, DIN, LOAD, BLANKVIL0.3 x
VCCV
Hysteresis Voltage
DIN, CLK, LOAD, BLANKΔVI0.6V
High-Voltage DOUTVOHISOURCE = -1.0mAVCC -
0.5V
Low-Voltage DOUTVOLISINK = 1.0mA0.5V
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
ELECTRICAL CHARACTERISTICS (continued)
(Typical Operating Circuit, VBB= 8V to 76V, VCC= 3V to 5.5V, VSS= -11V to 0V, VBB- VSS≤76V, TA= TMINto TMAX, unless other-
wise noted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
3V to 4.5V60100Rise and Fall Time DOUTCDOUT = 10pF
(Note 2)4.5V to 5.5V3080ns
CLK Clock PeriodtCP200ns
CLK Pulse-Width HightCH90ns
CLK Pulse-Width LowtCL90ns
CLK Rise to LOAD Rise HoldtCSH(Note 2)100ns
DIN Setup TimetDS5ns
3.0V to 4.5V20DIN Hold TimetDH4.5V to 5.5V15ns
3.0V to 4.5V25120240DOUT Propagation DelaytDOCDOUT = 10pF4.5V to 5.5V2075150ns
LOAD Pulse HightCSW55ns
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)
VBB = 76V
VBB = 40VVBB = 8V
TUBE SUPPLY CURRENT (IBB)
vs. TEMPERATURE (OUTPUTS HIGH)
MAX6921/31 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
VBB = 76V
VBB = 40VVBB = 8V
LOGIC SUPPLY CURRENT (ICC)
vs. TEMPERATURE (OUTPUTS LOW)
MAX6921/31 toc03
TEMPERATURE (°C)
SUPPLY CURRENT (
VCC = 5V, CLK = 5MHz
VCC = 3.3V, CLK = 5MHz
VCC = 5V, CLK = IDLE
VCC = 3.3V, CLK = IDLE
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
OUTPUT RISE AND FALL WAVEFORM
MAX6921/31 toc07
1μs/div
BLANK
2V/div
OUT_
20V/div
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 (
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)
VBB = 76V
VBB = 40V
VBB = 8V
IOUT = -40mA
OUTPUT VOLTAGE
vs. TEMPERATURE (OUTPUT LOW)
MAX6921/31 toc06
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
VBB = 40V
VBB = 8V
VBB = 76V
IOUT = 4mA
PIN
TSSOPWIDE
SO/PLCC
MAX6921MAX6931MAX6921
NAMEFUNCTION
1–51–5—OUT4 to
OUT0
VFD Anode and Grid Drivers. OUT4 to OUT0 are push-pull outputs swinging from
VBB to GND (MAX6921 only), and from VBB to VSS (MAX6931 only).627DINSerial-Data Input. Data is loaded into the internal shift register on CLK’s rising edge.728VCCLogic Supply Voltage. Bypass to GND with 100nF capacitor.1VBBVFD Tube Supply Voltage. Bypass to GND with 100nF capacitor.2DOUTSerial-Clock Output. Data is clocked out of the internal shift register to DOUT on
CLK’s rising edge.
Pin Description
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
PIN
TSSOPWIDE
SO/PLCC
MAX6921MAX6931MAX6921
NAMEFUNCTION—VSSFilament Bias Supply Voltage. Bypass to GND with a 100nF capacitor.
10–1910–19—OUT19 to
OUT10
VFD Anode and Grid Drivers. OUT19 to OUT10 are push-pull outputs swinging from
VBB to GND (MAX6921 only), and from VBB to VSS (MAX6931 only).—3-12OUT19 to
OUT10
VFD Anode and Grid Drivers. OUT19 to OUT10 are push-pull outputs swinging from
VBB to GND.2013BLANK
Blanking Input. High forces outputs OUT0 to OUT19 low, without altering the
contents of the output latches. Low enables outputs OUT0 to OUT19 to follow the
state of the output latches.2114GNDGround2215CLKS er i al - C l ock Inp ut. D ata i s l oad ed i nto the i nter nal shi ft r eg i ster on C LK’ s r i si ng ed g e.2316LOAD
Load Input. Data is loaded transparently from the internal shift register to the output
latch while LOAD is high. Data is latched into the output latch on LOAD’s rising
edge, and retained while LOAD is low.
24–2824–28—OUT9 to
OUT5
VFD Anode and Grid Drivers. OUT9 to OUT5 are push-pull outputs swinging from
VBB to GND (MAX6921 only), and from VBB to VSS (MAX6931 only).—17-26OUT9 to
OUT0
VFD Anode and Grid Drivers. OUT9 to OUT0 are push-pull outputs swinging from
VBB to GND.
Pin Description (continued)
SERIAL-TO-PARALLEL SHIFT REGISTER
LATCHES
CLK
DIN
LOAD
BLANK
OUT0OUT1OUT2OUT19
DOUT
MAX6921 ONLY
MAX6921
MAX6931
Detailed Description
The MAX6921/MAX6931 are VFD tube drivers compris-
ing a 4-wire serial interface driving 20 high-voltage rail-
to-rail output ports. The driver is suitable for both static
and multiplexed displays.
The output ports feature high current-sourcing capabili-
ty to drive current into grids and anodes of static or
multiplex VFDs. The ports also have active current sink-
ing for fast discharge of capacitive display electrodes
in multiplexing applications.
The 4-wire serial interface comprises a 20-bit shift reg-
ister and a 20-bit transparent latch. The shift register is
written through a clock input CLK and a data input DIN.
For the MAX6921, the data propagates to a data output
DOUT. The data output allows multiple drivers to be
cascaded and operated together. The output latch is
transparent to 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
push-pull switch driving between VBBand GND
(MAX6921) or VSS(MAX6931). The output rise time is
always slower than the output fall time to avoid shoot-
through currents during output transitions. The output
slew rates are slow enough to minimize EMI, yet are
fast enough so as not to impact the typical 100µs digit
multiplex period and affect the display intensity.
Initial Power-Up and Operation
An internal reset circuit clears the internal registers of
the MAX6921/MAX6931 on power-up. All outputs OUT0
to OUT19 and the interface output DOUT (MAX6921
only) initialize low regardless of the initial logic levels of
the CLK, DIN, BLANK, and LOAD inputs.
4-Wire Serial Interface
The MAX6921/MAX6931 use 4-wire serial interface with
three inputs (DIN, CLK, LOAD) and a data output
(DOUT, MAX6921 only). This interface is used to write
output data to the MAX6921/MAX6931 (Figure 4) (Table
1). The serial interface data word length is 20 bits,
D0–D19.
The functions of the four serial interface pins are:CLK input is the interface clock, which shifts data
into the MAX6921/MAX6931s’ 20-bit shift register on
its rising edge.LOAD input passes data from the MAX6921/
MAX6931s’ 20-bit shift register to the 20-bit output
latch when LOAD is high (transparent latch), and
latches the data on LOAD’s falling edgeDIN is the interface data input, and must be stable
when it is sampled on the rising edge of CLK.DOUT is the interface data output, which shifts data
out from the MAX6921’s 20-bit shift register on the
rising edge of CLK. Data at DIN is propagated
through the shift register and appears at DOUT (20
CLK cycles + tDO) later.
A fifth input, BLANK, can be taken high to force outputs
OUT0 to OUT19 low, without altering the contents of the
output latches. When the BLANK input is low, outputs
OUT0 to OUT19 follow the state of the output latches. A
common use of the BLANK input is PWM intensity control.
The BLANK input’s function is independent of the oper-
ation of the serial interface. Data can be shifted into the
serial interface shift register and latched regardless of
the state of BLANK.
MAX6921/MAX6931
20-Output, 76V, Serial-Interfaced
VFD Tube Drivers
SLEW-RATE
CONTROL
VBB
OUT_
40Ω
TYPICAL
750Ω
TYPICAL
Figure 2. MAX6921 CMOS Output Driver Structure
SLEW-RATE
CONTROL
VBB
VSS
OUT_
40Ω
TYPICAL
750Ω
TYPICAL
Figure 3. MAX6931 CMOS Output Driver Structure

Partno	Mfg	Dc	Qty	Available	Descript
MAX6921AUI+	N/A	N/a	2500	avai	20-Output, 76V, Serial-Interfaced VFD Tube Drivers
MAX6931AUI	MAXIM	N/a	12	avai	20-Output, 76V, Serial-Interfaced VFD Tube Drivers