19-3224; Rev 0; 1/04 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers The MAX6922/MAX6932/MAX6933/MAX6934 multi-output, 76V, vacuum-fluorescent display (VFD) tube drivers that interface a VFD tube to a microcontroller or a VFD controller, such as the MAX6850–MAX6853. The MAX6922/MAX6934 have 32 outputs, while the MAX6932 has 27 outputs, and the MAX6933 has 28 outputs. All devices are also suitable for driving telecom relays. Data is input using standard 4-wire serial interface (CLOCK, DATA, LOAD, BLANK) compatible with other VFD drivers and controllers. For easy display control, the active-high BLANK input forces all driver outputs low, turning the display off, and automatically puts the IC into shutdown mode. Display intensity may also be controlled by directly pulse-width modulating the BLANK input. The MAX6922/MAX6932/MAX6934 have a serial interface data output, DOUT, allowing any number of devices to be cascaded on the same serial interface. The MAX6932/MAX6933/MAX6934 have a negative supply voltage input, VSS, allowing the drivers’ output swing to be made bipolar to simplify filament biasing in many applications. The MAX6922 is available in a 44-pin PLCC package, the MAX6932 and MAX6933 are available in 36-pin SSOP packages, and the MAX6934 is available in 44pin PLCC and thin QFN packages. Maxim also offers a 12-output VFD driver (MAX6920) and 20-output VFD drivers (MAX6921/MAX6931). 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 (MAX6932/MAX6933/MAX6934 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 ♦ -40°C to +125°C Temperature Range as Standard Ordering Information PART PIN-PACKAGE MAX6922AQH -40°C to +125°C 44 PLCC MAX6932AAX -40°C to +125°C 36 SSOP MAX6933AAX -40°C to +125°C 36 SSOP MAX6934AQH -40°C to +125°C 44 PLCC MAX6934ATH -40°C to +125°C 44 Thin QFN Typical Operating Circuit Applications White Goods Gaming Machines Automotive Avionics Instrumentation TEMP RANGE Industrial Weighing Security Telecom VFD Modules Industrial Control +5V +60V C2 100nF C1 100nF 38 VCC 39 VBB MAX6934 Selector Guide VFDOUT VFCLK NO. OF OUTPUTS BIPOLAR OUTPUT SWING DOUT FOR CASCADING MAX6922 32 No Yes MAX6932 27 Yes Yes PART MAX6933 28 Yes No MAX6934 32 Yes Yes VFLOAD VFBLANK 37 17 18 15 32 DIN OUT0–OUT31 CLK LOAD BLANK VSS -7V C3 100nF VFD TUBE µC 12 GND 16 THIN QFN Pin Configurations appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX6922/MAX6932/MAX6933/MAX6934 General Description MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-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 (MAX6932/MAX6933/MAX6934 only)..............-12V to +0.3V VBB - VSS (MAX6932/MAX6933/MAX6934 only) ....-0.3V to +80V OUT_ (MAX6922 only) ..................(GND - -0.3V) to (VBB + 0.3V) OUT_ (MAX6932/MAX6933/MAX6934 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 .........................-840mA Total OUT_ Continuous Sink Current ...............................140mA 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) 36-Pin SSOP (derate 11.8mW/°C over +70°C)..................................................................941mW 44-Pin Thin QFN (derate 27mW/°C over +70°C)................................................................2165mW 44-Pin PLCC (derate 13.3mW/°C over +70°C)................................................................1067mW Operating Temperature Range (TMIN to TMAX) ...............................................-40°C to +125°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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. ELECTRICAL CHARACTERISTICS (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) MAX UNITS Logic Supply Voltage PARAMETER VCC 3 5.5 V Tube Supply Voltage VBB 8 76 V Bias Supply Voltage (MAX6932/ MAX6933/MAX6934 Only) VSS -11 0 V Total Supply Voltage (MAX6932/ MAX6933/MAX6934 Only) VBB - VSS 76 V Logic Supply Operating Current SYMBOL ICC CONDITIONS 81 All outputs OUT_ high, TA = +25°C CLK = idle TA = -40°C to +125°C 860 IBB All outputs OUT_ high Bias Supply Operating Current (MAX6932/MAX6933/MAX6934 Only) All outputs OUT_ low ISS All outputs OUT_ high VBB ≥ 15V, IOUT = -25mA High-Voltage OUT_ VH VBB ≥ 15V, IOUT = -40mA 8V < VBB < 15V, IOUT = -25mA 2 TYP All outputs OUT_ low, TA = +25°C CLK = idle TA = -40°C to +125°C All outputs OUT_ low Tube Supply Operating Current MIN 200 2.4 TA = -40°C to +125°C 1.3 TA = -40°C to +125°C 2.1 mA 2.2 -1.3 -0.65 -3 TA = +25°C -2.3 TA = -40°C to +125°C -2.5 TA = +25°C TA = -40°C to +85°C µA 5 6.9 TA = +25°C TA = +25°C 1400 1500 TA = +25°C TA = -40°C to +125°C 170 -1.5 mA VBB - 1.1 VBB - 2 TA = -40°C to +125°C VBB - 2.5 TA = -40°C to +85°C VBB - 3.5 TA = -40°C to +125°C VBB - 4.0 TA = +25°C V VBB - 1.2 TA = -40°C to +85°C VBB - 2.5 TA = -40°C to +125°C VBB - 3.0 _______________________________________________________________________________________ 27-, 28-, and 32-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.) (Note 1) PARAMETER SYMBOL CONDITIONS VBB ≥ 15V, IOUT = 1mA Low-Voltage OUT_ (MAX6932 Only) VL 8V < VBB < 15V, IOUT = 1mA Low-Voltage OUT_ (MAX6932/MAX6933/MAX6934 Only) VBB ≥ 15V, IOUT = 1mA VL 8V < VBB < 15V, IOUT = 1mA MIN TA = +25°C TYP MAX 0.75 1.2 TA = -40°C to +85°C 1.5 TA = -40°C to +125°C 2.1 TA = +25°C 0.8 1.3 TA = -40°C to +85°C 1.7 TA = -40°C to +125°C 2.2 TA = +25°C UNITS V VSS + 0.75 VSS + 1.2 TA = -40°C to +85°C VSS + 1.5 TA = -40°C to +125°C VSS + 2.1 TA = +25°C VSS + 0.8 VSS + 1.3 TA = -40°C to +85°C VSS + 1.7 TA = -40°C to +125°C VSS + 2.2 V Rise Time OUT_ (20% to 80%) tR VBB = 60V, CL = 50pF, RL =2.3kΩ 0.9 2 µs Fall Time OUT_ (80% to 20%) tF VBB = 60V, CL = 50pF, RL =2.3kΩ 0.6 1.5 µs SERIAL INTERFACE TIMING CHARACTERISTICS LOAD Rising to OUT_ Falling Delay (Notes 2, 3) 0.9 3 µs LOAD Rising to OUT_ Rising Delay (Notes 2, 3) 1.2 5.5 µs BLANK Rising to OUT_ Falling Delay (Notes 2, 3) 0.9 3 µs BLANK Falling to OUT_ Rising Delay (Notes 2, 3) 1.3 5.5 µs 0.05 10 µA Input Leakage Current CLK, DIN, LOAD, BLANK IIH, IIL Logic-High Input Voltage CLK, DIN, LOAD, BLANK VIH Logic-Low Input Voltage CLK, DIN, LOAD, BLANK VIL Hysteresis Voltage DIN, CLK, LOAD, BLANK ∆VI High-Voltage DOUT VOH ISOURCE = -1.0mA Low-Voltage DOUT VOL ISINK = 1.0mA 0.5 0.8 x VCC V 0.3 x VCC 0.6 V V VCC 0.5 V 0.5 V _______________________________________________________________________________________ 3 MAX6922/MAX6932/MAX6933/MAX6934 ELECTRICAL CHARACTERISTICS (continued) 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 MIN TYP MAX 3V to 4.5V 80 130 4.5V to 5.5V 50 80 UNITS ns CLK Clock Period tCP 200 ns CLK Pulse-Width High tCH 90 ns CLK Pulse-Width Low tCL 90 ns (Note 2) 100 ns 5 ns 3.0V to 4.5V 20 4.5V to 5.5V 15 CLK Rise to LOAD Rise Hold tCSH DIN Setup Time tDS DIN Hold Time tDH DOUT Propagation Delay tDO LOAD Pulse High CDOUT = 10pF ns 3.0V to 4.5V 25 120 240 4.5V to 5.5V 20 75 150 tCSW ns 60 ns 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. Typical Operating Characteristics (VCC = 5.0V, VBB = 76V, and TA = +25°C, unless otherwise noted.) TUBE SUPPLY CURRENT (IBB) vs. TEMPERATURE (OUTPUTS HIGH) 1.6 1.2 0.8 0.4 1.4 1.2 1.0 VBB = 40V VBB = 8V 0.8 0.6 -40 -20 0 20 40 60 80 TEMPERATURE (°C) 100 120 MAX6922 toc03 0.9 VCC = 5V, CLK = 5MHz 0.8 0.7 VCC = 3.3V, CLK = 5MHz 0.6 0.5 0.4 VCC = 3.3V, CLK = IDLE 0.3 0.4 0.2 0.2 0.1 0 0 4 1.6 1.0 SUPPLY CURRENT (mA) VBB = 40V VBB = 8V VBB = 76V 1.8 SUPPLY CURRENT (mA) 2.4 2.0 2.0 MAX6922 toc01 VBB = 76V 2.8 LOGIC SUPPLY CURRENT (ICC) vs. TEMPERATURE (OUTPUTS LOW) MAX6922 toc02 TUBE SUPPLY CURRENT (IBB) vs. TEMPERATURE (OUTPUTS LOW) SUPPLY CURRENT (mA) MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers VCC = 5V, CLK = IDLE 0 -40 -20 0 20 40 60 80 TEMPERATURE (°C) 100 120 -40 -20 0 20 40 60 80 TEMPERATURE (°C) _______________________________________________________________________________________ 100 120 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers VCC = 3.3V, CLK = 5MHz 0.9 0.8 VCC = 5V, CLK = IDLE VBB = 40V 10 8 6 VBB = 8V -40 -20 0 20 40 0 60 80 TEMPERATURE (°C) 100 120 VBB = 40V 2.5 VBB = 76V 2.0 1.5 VBB = 8V 1.0 0.5 2 VCC = 3.3V, CLK = IDLE IOUT = -40mA 3.0 4 0.7 0.6 12 3.5 OUTPUT VOLTAGE (V) 1.0 OUTPUT VOLTAGE (VBB - VT) vs. TEMPERATURE (OUTPUTS HIGH) MAX6922 toc05 VCC = 5V, CLK = 5MHz VBB = 76V IOUT = 4mA 14 OUTPUT VOLTAGE (V) SUPPLY CURRENT (mA) 1.1 16 MAX6922 toc04 1.2 OUTPUT VOLTAGE vs. TEMPERATURE (OUTPUTS LOW) MAX6922 toc06 LOGIC SUPPLY CURRENT (ICC) vs. TEMPERATURE (OUTPUTS HIGH) 0 -40 -20 0 20 40 60 80 100 120 -40 -20 TEMPERATURE (°C) 0 20 40 60 80 100 120 TEMPERATURE (°C) OUTPUT FALL AND RISE TIME MAX6922 toc07 BLANK 2V/div OUT 20V/div 1µs/div _______________________________________________________________________________________ 5 MAX6922/MAX6932/MAX6933/MAX6934 Typical Operating Characteristics (continued) (VCC = 5.0V, VBB = 76V, and TA = +25°C, unless otherwise noted.) MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers Pin Description PIN MAX6922/ MAX6934 PLCC MAX6932/ MAX6933 SSOP MAX6934 THIN QFN NAME 1 1 39 VBB 2 2 40 6 VFD Supply Voltage Serial-Data Output. Data is clocked out of the internal shift register to DOUT DOUT (MAX6932) on CLK’s falling edge. For the MAX6933 only—VFD anode and grid driver. (OUT27) (OUT27 is a push-pull output swinging from VBB to VSS.) (MAX6933) 2 3, 4, 5, 7– 17, 19, 20, 25, 26, 27, 30–42 FUNCTION — 1–11, 13, 14, 19, 20, 21, 24–36, 41, 42, 43 OUT0 to OUT31 VFD Anode and Grid Drivers. OUT_ are push-pull outputs swinging from GND to VSS for the MAX6922 and from VBB to VSS for the MAX6934. — 3 –13, 15, 16, 21–34 — OUT0 to OUT26 VFD Anode and Grid Drivers. OUT_ are push-pull outputs swinging from VBB to VSS. 6, 28, 29 — 22, 23, 44 N.C. 18 — — N.C. (VSS) — 14 12 VSS 21 17 15 BLANK 22 18 16 GND Ground 23 19 17 CLK Serial-Clock Input. Data is loaded into the internal shift register on CLK’s rising edge. On CLK’s falling edge, data is clocked out of DOUT. 24 20 18 LOAD 43 35 37 DIN Serial-Data Input. Data is loaded into the internal shift register on CLK’s rising edge. 44 36 38 VCC Logic Supply Voltage No Connection. Not internally connected. For the MAX6922—No Connection. Not internally connected. For the MAX6934—bias supply voltage. Bias Supply Voltage Blanking Input. High forces outputs OUT_ low without altering the contents of the output latches. Low enables outputs OUT_ to follow the state of the output latches. 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. _______________________________________________________________________________________ 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers MAX6922/MAX6932/MAX6933/MAX6934 CLK MAX6922/MAX6932/ MAX6934 ONLY SERIAL-TO-PARALLEL SHIFT REGISTER DIN DOUT LATCHES LOAD BLANK MAX6922 MAX6932 MAX6933 MAX6934 WHERE n = 27 FOR MAX6932 28 FOR MAX6933 32 FOR MAX6922/MAX6934 OUT0 OUT1 OUT2 OUTn Figure 1. MAX6922/MAX6932/MAX6933/MAX6934 Functional Diagram VBB VBB 40Ω TYPICAL 40Ω TYPICAL SLEW-RATE CONTROL OUT_ 750Ω TYPICAL SLEW-RATE CONTROL OUT_ 750Ω TYPICAL VSS Figure 2. MAX6922 CMOS Output Driver Structure Detailed Description The MAX6922/MAX6932/MAX6933/MAX6934 are VFD tube drivers comprising a 4-wire serial interface driving high-voltage Rail-to-Rail output ports. The driver is suitable for both static and multiplexed displays. The output ports feature high current-sourcing capability to drive current into grids and anodes of static or multiplex VFDs. The ports also have active current sinking for fast discharge of capacitive display electrodes in multiplexing applications. Figure 3. MAX6932/MAX6933/MAX6934 CMOS Output Driver Structure The 4-wire serial interface comprises a shift register and transparent latch with 32 bits for the MAX6922/ MAX6934, 28 bits for the MAX6933, and 27 bits for the MAX6932. The shift register is written through a clock input CLK and a data input DIN. For the MAX6922/ MAX6932/MAX6934, 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. Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. _______________________________________________________________________________________ 7 MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers Each driver output is a slew-rate controlled CMOS push-pull switch driving between V BB and GND (MAX6922) or V BB and V SS (MAX6932/MAX6933/ MAX6934). 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 on power-up. All outputs and the interface output DOUT (MAX6922/MAX6932/MAX6934 only) initialize low regardless of the initial logic levels of the CLK, DIN, BLANK, and LOAD inputs. • DOUT is the interface data output, which shifts data out from the shift register on the rising edge of CLK. Data at DIN is propagated through the shift register and appears at DOUT (n CLK cycles + tDO) later, where n is the number of drivers in the IC. A fifth input, BLANK, can be taken high to force the outputs low, without altering the contents of the output latches. When the BLANK input is low, the outputs 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 operation of the serial interface. Data can be shifted into the serial interface shift register and latched regardless of the state of BLANK. Writing Device Registers Using the 4-Wire Serial Interface 4-Wire Serial Interface These driver ICs use a 4-wire serial interface with three inputs (DIN, CLK, LOAD) and a data output (DOUT, MAX6922/MAX6932/MAX6934 only). This interface is used to write data to the ICs (Figure 4) (Table 1). The serial interface data word length is 32 bits for the MAX6922/MAX6934, 27 bits for the MAX6932, and 28 bits for the MAX6933. The functions of the four serial interface pins are: • CLK input is the interface clock, which shifts data into the shift register on its rising edge. • LOAD input passes data from the shift register to the output latch when LOAD is high (transparent latch), and latches the data on LOAD’s falling edge. • DIN is the interface data input, and must be stable when it is sampled on the rising edge of CLK. The MAX6922/MAX6932/MAX6933/MAX6934 are normally written using the following sequence: 1) Take CLK low. 2) Clock n bits of data in order Dn-1 first to D0 last into DIN, observing the data setup and hold times. 3) Load the n output latches with a falling edge on LOAD, where n is 27 for the MAX6932, 28 for the MAX6933, and 32 for the MAX6922 and MAX6934. LOAD may be high or low during a transmission. If LOAD is high, then the data shifted into the shift register at DIN appears at the OUT0 to OUTn-1 outputs. CLK and DIN may be used to transmit data to other peripherals. Activity on CLK always shifts data into the shift register. However, the output latches only update on the rising edge of LOAD, and the last n bits of data tCSW LOAD tCL tCSH tCH tCP CLK tDH tDS DIN Dn-1 Dn-2 D1 D0 tDO DOUT Dn-1 Figure 4. 4-Wire Serial Interface Timing Diagram 8 _______________________________________________________________________________________ 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers BLANKING SERIAL CLOCK SHIFT REGISTER CONTENTS LOAD OUTPUT CONTENTS LATCH CONTENTS INPUT INPUT DATA INPUT INPUT CLK D0 D1 D2 … Dn-2 Dn-1 LOAD D0 D1 D2 … Dn-2 Dn-1 BLANK D0 D1 D2 … Dn-2 Dn-1 DIN H H L L R0 R1 … Rn-2 Rn-1 X R0 R0 R1 … Rn-2 Rn-1 R1 R2 … Rn-1 X X X P0 P1 P2 … Pn-1 … X Rn X L R0 R1 R2 … Rn-1 Rn Pn H P0 P1 P2 … Pn-1 Pn L P0 X X X … X H L X P1 P2 … Pn-1 L L … Pn L L L = Low logic level. H = High logic level. X = Don’t care. P = Present state (shift register). R = Previous state (latched). clocked in are loaded. Therefore, multiple devices can share CLK and DIN, as long as they have unique LOAD controls. Determining Driver Output Voltage Drop The outputs are CMOS drivers, and have a resistive characteristic. The typical and maximum sink and source output resistances can be calculated from the VH and VL electrical characteristics. Use this calculated resistance to determine the output voltage drop at different output currents. Output Current Ratings The continuous current-source capability is 40mA per output. Outputs may drive up to 75mA as a repetitive peak current, subject to the on-time (output high) being no longer than 1ms, and the duty cycle being such that the output power dissipation is no more than the dissipation for the continuous case. The repetitive peak rating allows outputs to drive a higher current in multiplex grid driver applications, where only one grid is on at a time, and the multiplex time per grid is no more than 1ms. Since dissipation is proportional to current squared, the maximum current that can be delivered for a given multiplex ratio is given by: IPEAK = (grids x 1600)1/2 mA 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 may be paralleled in order to raise the current drive or reduce the output resistance. Only parallel outputs directly (by shorting outputs together) if the interface control can be guaranteed to set the outputs to the same level. Although the sink output is relatively weak (typically 750Ω), that resistance is low enough to dissipate 530mW when shorted to an opposite level output at a VBB voltage of only 20V. A safe way to parallel outputs is to use diodes to prevent the outputs from sinking current (Figure 5). Because the diodes also stop the outputs from sinking current from the VFD tube, an external discharge resistor, R, is required. For static tubes, R can be a large value such as 100kΩ. For multiplexed tubes, the value of the resistor can be determined by the load capacitance and timing MAX6922 MAX6932 MAX6933 OUT0 MAX6934 D1 OUTPUT D2 OUT1 R Figure 5. Paralleling Outputs _______________________________________________________________________________________ 9 MAX6922/MAX6932/MAX6933/MAX6934 Table 1. 4-Wire Serial Interface Truth Table MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers characteristics required. Resistor R discharges tube capacitance C to 10% of the initial voltage in 2.3 x RC seconds. So, for example, a 15kΩ value for R discharges 100pF tube grid or anode from 40V to 4V in 3.5µs, but draws an additional 2.7mA from the driver when either output is high. Power Dissipation Take care to ensure that the maximum package dissipation ratings for the chosen package are not exceeded. Over-dissipation is unlikely to be an issue when driving static tubes, but the peak currents are usually higher for multiplexed tubes. When using multiple driver devices, try to share the average dissipation evenly between the drivers. Determine the power dissipation (PD) for the MAX6922/ MAX6932/MAX6933/MAX6934 for static tube drivers with the following equation: PD = (VCC x ICC) + (VBB x IBB) + ((VBB - VH) x IANODE x A)) where: A = number of anodes driven (maximum of 32 with the MAX6922/MAX6934). IANODE = maximum anode current. (VBB - VH) is the output voltage drop at the given maximum anode current IOUT. A static tube dissipation example follows: VCC = 5V ±5%, VBB = 10V to 18V, A = 32, IOUT = 2mA PD = (5.25V x 1.5mA)+ (18V x 2.2mA) + ((2.5V x 2mA/25mA) x 2mA x 32) = 60mW Determine the power dissipation (PD) for the MAX6922/ MAX6932/MAX6933/MAX6934 for multiplex tube drivers with the following equation: PD = (VCC x ICC) + (VBB x IBB) + ((VBB - VH) x IANODE x A) + ((VBB - VH) x IGRID)) where: A = number of anodes driven. G = number of grids driven. IANODE = maximum anode current. IGRID = maximum grid current. The calculation presumes all anodes are on, but only one grid is on. The calculated PD is the worst case, presuming one digit is always being driven with all its anodes lit. Actual PD can be estimated by multiplying this PD figure by the actual tube drive duty cycle, taking into account interdigit blanking and any PWM intensity control. 10 A multiplexed tube dissipation example follows: VCC = 5V ±5%, VBB = 36V to 42V, A = 20, G = 12, IANODE = 0.4mA, IGRID = 24mA PD = (5.25V x 1.5mA)+ (42V x 2.2mA) + ((2.5V x 0.4mA/25mA) x 0.4mA x 20) + ((2.5V x 24mA/25mA) x 24mA) = 158mW Thus, for a 44-pin PLCC package (TJA = 1 / 0.0133 = 75.188°C/W from Absolute Maximum Ratings), the maximum allowed ambient temperature TA is given by: TJ(MAX) = TA + (PD x TJA) = +150°C = TA + (0.158 x 75.188°C/W) So TA = +138°C. This means that the driver can be operated in this application with a PLCC package up to the +125°C maximum operating temperature. Power-Supply Considerations The MAX6922/MAX6932/MAX6933/MAX6934 operate with multiple power-supply voltages. Bypass the VCC, V BB , and V SS (MAX6932/MAX6933/MAX6934 only) power-supply pins to GND with 0.1µF capacitors close to the device. The MAX6932/MAX6933/MAX6934 may be operated with VSS tied to GND if a negative bias supply is not required. For multiplex applications, it may be necessary to add an additional bulk electrolytic capacitor of 1µF or greater to the VBB supply. Power-Supply Sequencing The order of the power-supply sequencing is not important. These ICs are damaged if any combination of VCC, VBB, and VSS is grounded while the other supply or supplies are maintained up to their maximum ratings. However, as with any CMOS device, do not drive the logic inputs if the logic supply VCC is not operational because the input protection diodes clamp the signals. Cascading Drivers (MAX6922/MAX6932/MAX6934 Only) Multiple driver ICs may be cascaded, as shown in the Typical Application Circuit, by connecting each driver’s DOUT to DIN of the next drivers. Devices may be cascaded at the full 5MHz CLK speed when VCC ≥ 4.5V. When VCC <4.5V, the longer propagation delay (tDO) limits the maximum cascaded CLK to 4MHz. ______________________________________________________________________________________ 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers MAX685x MAX6922 VFDOUT DIN VFCLK CLK VFLOAD LOAD VFBLANK BLANK DOUT MAX6922 VFD TUBE DIN CLK LOAD BLANK DOUT MAX6922 DIN CLK LOAD BLANK DOUT Chip Information TRANSISTOR COUNT: 3850 PROCESS: BiCMOS ______________________________________________________________________________________ 11 MAX6922/MAX6932/MAX6933/MAX6934 Typical Application Circuit 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers MAX6922/MAX6932/MAX6933/MAX6934 Pin Configurations 2 1 44 43 42 41 40 OUT2 3 OUT1 VCC 4 OUT0 VBB 5 DIN DOUT 6 OUT28 7 39 OUT3 OUT28 7 39 OUT3 OUT27 8 38 OUT4 OUT27 8 38 OUT4 37 OUT5 OUT26 9 37 OUT5 OUT26 9 OUT25 10 36 OUT6 OUT25 10 36 OUT6 OUT24 11 35 OUT7 OUT24 11 35 OUT7 OUT23 12 34 OUT8 OUT23 12 OUT22 13 33 OUT9 OUT22 13 33 OUT9 OUT21 14 32 OUT10 OUT21 14 32 OUT10 OUT20 15 31 OUT11 OUT20 15 31 OUT11 OUT19 16 30 OUT12 OUT19 16 30 OUT12 OUT18 17 29 N.C. OUT18 17 29 N.C. MAX6934 OUT2 34 OUT1 35 OUT0 36 DIN 37 VCC 38 VBB N.C. OUT13 OUT14 OUT15 LOAD CLK GND OUT16 PLCC 39 DOUT 40 OUT31 41 OUT30 42 OUT29 43 N.C. 44 BLANK VSS OUT17 N.C. OUT13 OUT14 OUT15 LOAD CLK 19 20 21 22 23 24 25 26 27 28 GND 18 OUT16 19 20 21 22 23 24 25 26 27 28 BLANK 18 N.C. 34 OUT8 OUT17 MAX6922 PLCC VBB 1 36 VCC DOUT(OUT27) 2 35 DIN OUT26 3 34 OUT0 OUT28 1 33 OUT3 OUT25 4 33 OUT1 OUT27 2 32 OUT4 OUT24 5 32 OUT2 OUT26 3 31 OUT5 OUT23 6 31 OUT3 OUT22 7 OUT21 8 OUT20 OUT25 4 30 OUT6 OUT24 5 29 OUT7 OUT23 6 28 OUT8 OUT22 7 27 OUT9 OUT21 8 26 OUT10 OUT20 9 25 MAX6934 MAX6932 MAX6933 30 OUT4 29 OUT5 9 28 OUT6 OUT19 10 27 OUT7 OUT18 11 26 OUT8 OUT17 12 25 OUT9 OUT11 OUT16 13 24 OUT10 VSS 14 23 OUT11 OUT15 15 22 OUT12 OUT14 16 21 OUT13 20 LOAD 15 16 17 18 19 20 21 22 BLANK 17 GND CLK LOAD OUT15 OUT14 OUT13 N.C. N.C. BLANK 23 14 11 OUT16 OUT18 13 OUT12 OUT17 24 12 10 VSS OUT19 GND 18 THIN QFN 12 OUT31 44 43 42 41 40 OUT30 1 N.C. VCC 2 OUT29 VBB 3 OUT2 DOUT 4 OUT1 OUT31 5 OUT0 OUT30 6 DIN N.C. OUT29 TOP VIEW ( ) IS FOR THE MAX6933 19 CLK SSOP ______________________________________________________________________________________ 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers PLCC.EPS e A A1 A2 A3 B B1 C e D D1 D3 N INCHES MIN MAX 0.165 0.180 0.090 0.120 0.145 0.156 0.020 --0.013 0.021 0.026 0.032 0.009 0.011 0.050 D3 D1 D A A2 A1 B1 B A3 C D2 MIN MAX 4.20 4.57 3.04 2.29 3.69 3.96 0.51 --0.33 0.53 0.66 0.81 0.23 0.28 1.27 D D1 D2 D3 INCHES MAX MIN 0.385 0.395 0.350 0.356 0.290 0.330 0.200 REF MIN 9.78 8.89 7.37 5.08 MAX N 10.03 20 AA 9.04 8.38 REF D 0.485 D1 0.450 D2 0.390 D3 0.300 0.495 0.456 0.430 REF 12.32 11.43 9.91 7.62 12.57 28 AB 11.58 10.92 REF D 0.685 D1 0.650 D2 0.590 D3 0.500 0.695 0.656 0.630 REF 17.40 16.51 14.99 12.70 17.65 44 AC 16.66 16.00 REF D 0.785 D1 0.750 D2 0.690 D3 0.600 0.795 19.94 0.756 19.05 0.730 17.53 REF 15.24 20.19 19.20 18.54 REF 52 AD D 0.985 D1 0.950 D2 0.890 D3 0.800 0.995 25.02 0.958 24.13 0.930 22.61 REF 20.32 25.27 24.33 23.62 REF 68 AE NOTES: 1. D1 DOES NOT INCLUDE MOLD FLASH. 2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .20mm (.008") PER SIDE. 3. LEADS TO BE COPLANAR WITHIN .10mm. 4. CONTROLLING DIMENSION: MILLIMETER 5. MEETS JEDEC MO047-XX AS SHOWN IN TABLE. 6. N = NUMBER OF PINS. PROPRIETARY INFORMATION TITLE: FAMILY PACKAGE OUTLINE: 20L, 28L, 44L, 52L, 68L PLCC APPROVAL DOCUMENT CONTROL NO. REV. 21-0049 D 1 ______________________________________________________________________________________ 1 13 MAX6922/MAX6932/MAX6933/MAX6934 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) SSOP.EPS MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers 36 E DIM A A1 B C e E H L D H INCHES MILLIMETERS MAX MIN 0.104 0.096 0.004 0.011 0.012 0.017 0.009 0.013 0.0315 BSC 0.291 0.299 0.398 0.414 0.020 0.040 0.598 0.612 MAX MIN 2.44 2.65 0.10 0.29 0.30 0.44 0.23 0.32 0.80 BSC 7.40 7.60 10.11 10.51 0.51 15.20 1.02 15.55 1 TOP VIEW D A1 e B FRONT VIEW A C 0∞-8∞ L SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 36L SSOP, 0.80 MM PITCH APPROVAL DOCUMENT CONTROL NO. 21-0040 14 ______________________________________________________________________________________ REV. E 1 1 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers 32, 44, 48L QFN.EPS D2 D CL D/2 b D2/2 k E/2 E2/2 E CL (NE-1) X e E2 k L DETAIL A e (ND-1) X e CL CL L L e A1 A2 e DALLAS A SEMICONDUCTOR PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 32, 44, 48L THIN QFN, 7x7x0.8 mm APPROVAL DOCUMENT CONTROL NO. 21-0144 REV. C 1 2 ______________________________________________________________________________________ 15 MAX6922/MAX6932/MAX6933/MAX6934 Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) MAX6922/MAX6932/MAX6933/MAX6934 27-, 28-, and 32-Output, 76V, Serial-Interfaced VFD Tube Drivers Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) DALLAS SEMICONDUCTOR PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 32, 44, 48L THIN QFN, 7x7x0.8 mm APPROVAL DOCUMENT CONTROL NO. 21-0144 REV. C 2 2 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.