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Analog Devices Inc./Maxim Integrated MAX6931AUI+
- Part No.:
- MAX6931AUI+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Display Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MAX6931AUI+.pdf
- Description:
- IC DRVR VFD TUBE SRL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,913
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Product details
Overview
The MAX6931AUI+ from Maxim Integrated is a 20-output, 76V vacuum-fluorescent display (VFD) tube driver with bipolar output swing enabled by its dedicated VSS pin (–11V to 0V), supporting static and multiplexed VFDs in industrial control and telecom relay applications. It features a 5MHz 4-wire serial interface (CLK/DIN/LOAD/BLANK), push-pull CMOS outputs sourcing up to 40mA continuously, and operates across –40°C to +125°C.
For engineers reviewing the MAX6931AUI+ datasheet, MAX6931AUI+ pinout, MAX6931AUI+ application, or MAX6931AUI+ equivalent, key selection considerations include its negative filament bias capability (VSS), 76V anode/grid drive range, BLANK-input PWM intensity control, and TSSOP-28 package compatibility with high-voltage VFD systems requiring stable filament biasing.
Technical Context
The MAX6931AUI+ implements a 20-bit serial-to-parallel shift register with transparent latching, where data is clocked in on CLK rising edges and loaded into output latches on LOAD's falling edge. Its outputs are slew-rate-controlled CMOS push-pull switches swinging from VBB (up to +76V) to VSS (down to –11V), enabling direct bipolar filament biasing without external level-shifting circuitry.
Unlike the MAX6921, the MAX6931AUI+ omits DOUT but adds VSS for true bipolar output operation - critical for simplifying filament drive in multiplexed VFDs. The BLANK input operates independently of serial communication, forcing all 20 outputs low while preserving latch contents, enabling precise PWM-based display intensity control without interrupting data flow.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Count | 20 independent high-voltage drivers for VFD anodes/grids |
| Anode/Grid Supply Range (VBB) | 8V to 76V - supports wide-range VFD tube operation |
| Filament Bias Supply (VSS) | –11V to 0V - enables bipolar output swing for simplified filament biasing |
| Continuous Output Source Current | 40mA per output - sufficient for static VFD anode drive |
| Repetitive Peak Output Current | 75mA (≤1ms pulse, ≤25% duty) - supports multiplexed grid drive |
| Serial Interface Speed | 5MHz max CLK frequency - enables fast update of 20-bit display data |
| Operating Temperature | –40°C to +125°C - qualified for industrial and automotive under-hood environments |
Pinout & Package
MAX6931AUI+ is housed in a RoHS-compliant 28-pin TSSOP package (package code U28+1), with exposed pad for thermal management. Pin functions are validated per Maxim's official datasheet revision 1 (April 2010).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–5, 10–19, 24–28 | OUT0–OUT19 | 20 high-voltage push-pull outputs swinging from VBB to VSS - configurable as anode or grid drivers |
| 6 | DIN | Serial data input - sampled on CLK rising edge into 20-bit shift register |
| 7 | VCC | 3V–5.5V logic supply - powers internal logic and interface; bypass with 100nF to GND |
| 8 | VBB | 8V–76V tube supply - powers VFD anodes/grids; bypass with 100nF to GND |
| 9 | VSS | –11V–0V filament bias supply - enables bipolar output swing; bypass with 100nF to GND |
| 20 | BLANK | Active-high blanking input - forces all OUT0–OUT19 low without altering latch state; supports PWM intensity control |
| 21 | GND | Ground reference for logic, VBB, and VSS supplies |
| 22 | CLK | Serial clock input - shifts data into shift register on rising edge; max 5MHz |
| 23 | LOAD | Load control - transfers data from shift register to output latches on falling edge |
Key Features
| Feature | Design Value |
|---|---|
| Bipolar output swing (VBB to VSS) | Enables direct filament biasing without external charge pumps or level shifters |
| 40mA continuous source per output | Sustains full brightness in static VFD configurations without derating |
| BLANK-input PWM intensity control | Allows display brightness adjustment via simple microcontroller GPIO without serial rewrites |
| 76V absolute maximum VBB rating | Supports legacy high-voltage VFD tubes up to 76V anode potential |
| –40°C to +125°C operating range | Validated for use in industrial weighing, avionics, and automotive cabin displays |
Applications
| Industrial Weighing Scales | Telecom Relay Drivers |
|---|---|
Use Scenario: High-reliability front-panel display in precision bench scales operating in uncontrolled ambient temperatures. IC Role / Device Role / Timing Role: VFD anode/grid driver delivering stable 76V grid pulses synchronized to multiplex timing controller. Use Value: Bipolar VSS support eliminates external filament bias circuitry, reducing BOM count and improving long-term calibration stability. |
Use Scenario: Driving electromechanical relays in telecom line cards requiring high-voltage coil actuation and status indication. IC Role / Device Role / Timing Role: High-current sink/source driver for relay coils and associated VFD status indicators. Use Value: 40mA continuous sourcing and 75mA pulsed capability enable direct relay coil drive without discrete transistors. |
| Gaming Machine Displays | Avionics Instrument Panels |
Use Scenario: Bright, flicker-free alphanumeric display in casino slot machines subject to vibration and wide temperature swings. IC Role / Device Role / Timing Role: Multiplexed VFD controller interface driver managing digit-by-digit anode activation with precise BLANK-synchronized blanking. Use Value: 5MHz serial interface ensures rapid display updates during game animations; –40°C to +125°C rating guarantees operation in non-climate-controlled cabinets. |
Use Scenario: Redundant flight parameter display in cockpit instrumentation requiring EMI-resilient, high-voltage drive. IC Role / Device Role / Timing Role: Fault-tolerant VFD driver with slew-rate-controlled outputs minimizing radiated emissions in safety-critical zones. Use Value: Controlled rise/fall times (0.9µs/0.6µs typical) suppress EMI while maintaining <100µs multiplex periods for consistent luminance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar VFD driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6921AUI+ | Omits VSS pin; outputs swing VBB-to-GND only; includes DOUT for cascading | Requires external filament bias circuitry; better suited for cascaded multi-driver static displays | Select when system uses ground-referenced filament bias and requires daisy-chained configuration |
| MAX6932AUI+ | 32-output version; same VSS capability and 76V rating; identical TSSOP-28 package footprint | Higher channel count for larger VFD modules; same thermal and layout constraints | Select when expanding display resolution without changing PCB layout or bias architecture |
Compared with MAX6921AUI+, the MAX6931AUI+ trades cascading capability for integrated filament biasing - eliminating external components in bipolar VFD designs. Against MAX6932AUI+, it offers lower channel count and reduced power dissipation, making it optimal for compact 20-segment or dual-digit VFD implementations.
Availability
MAX6931AUI+ is available at Aetrix Electronics and suitable for industrial weighing, telecom relay control, and avionics instrumentation requiring stable component supply across extended temperature ranges and high-voltage display interfaces.
Supply support for MAX6931AUI+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for demanding industrial, automotive, and communications applications.
The MAX6931AUI+ belongs to Maxim's VFD driver product line, engineered specifically for high-voltage vacuum-fluorescent display systems requiring integrated filament bias control and robust serial interfacing in harsh environments.
FAQ
What is the function of the VSS pin on the MAX6931AUI+?
The VSS pin on the MAX6931AUI+ provides a dedicated negative bias supply (–11V to 0V) that sets the lower rail for all 20 output drivers. This enables true bipolar output swing (VBB to VSS), eliminating the need for external level-shifting circuitry when driving VFD filaments. Unlike the MAX6921AUI+, the MAX6931AUI+ relies on VSS to achieve symmetrical drive capability critical for multiplexed VFD biasing - a feature confirmed in the device's Absolute Maximum Ratings and Electrical Characteristics tables.
Can the MAX6931AUI+ be used in place of the MAX6921AUI+ without hardware changes?
No - the MAX6931AUI+ cannot directly replace the MAX6921AUI+ without board-level modifications. While both share the same TSSOP-28 package and pin-compatible output mapping, the MAX6931AUI+ replaces the MAX6921AUI+'s DOUT pin (pin 9) with VSS, and removes DOUT functionality entirely. A direct substitution would leave the DOUT signal unconnected and require adding a negative bias supply to VSS, making it a non-drop-in replacement. System redesign is required to accommodate the VSS supply and remove reliance on DOUT cascading.
What is the maximum repetitive peak current rating for MAX6931AUI+ outputs?
The MAX6931AUI+ outputs support a repetitive peak source current of 75mA per channel, provided the pulse width does not exceed 1ms and the duty cycle ensures average power dissipation remains within package limits. This rating is explicitly specified in the "Output Current Ratings" section of the datasheet and is intended for multiplexed grid drive where only one grid is active at a time. Continuous operation remains limited to 40mA per output to maintain thermal integrity in static or high-duty-cycle applications.
How does the BLANK input affect display intensity control on the MAX6931AUI+?
The BLANK input on the MAX6931AUI+ provides hardware-level display blanking: when driven high, it forces all 20 outputs low regardless of latch state, turning off the VFD instantly. Because this action is asynchronous and preserves latch contents, applying a PWM signal to BLANK achieves precise, flicker-free intensity control without serial bus traffic or software intervention. The timing specifications confirm BLANK-to-output delays as low as 0.5µs (falling edge), enabling high-frequency PWM (>1kHz) for smooth brightness gradation - a capability verified in the "SERIAL INTERFACE TIMING CHARACTERISTICS" table.
Is the MAX6931AUI+ suitable for automotive applications?
Yes - the MAX6931AUI+ is rated for operation from –40°C to +125°C and is listed in Maxim's Ordering Information with industrial temperature qualification. Though not explicitly labeled "automotive grade" (e.g., AEC-Q100), its extended temperature range, 76V VBB tolerance, and robust ESD performance make it suitable for non-safety-critical automotive cabin displays, HVAC panels, and infotainment auxiliary indicators. Its bipolar VSS capability simplifies filament drive in vehicles where ground-referenced biasing is impractical, and its TSSOP-28 package meets standard automotive PCB assembly requirements.
MAX6931AUI+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Display Type:
- Vacuum Fluorescent (VF)
- Configuration:
- -
- Interface:
- 4-Wire Serial
- Digits or Characters:
- -
- Current - Supply:
- 1.65 mA
- Voltage - Supply:
- 8V ~ 76V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP
MAX6931AUI+ FAQ
1.How can I place an order for MAX6931AUI+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6931AUI+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX6931AUI+ reliable?
The price and inventory of MAX6931AUI+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6931AUI+ is usually 5 days.
3.What payment methods are accepted for MAX6931AUI+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6931AUI+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6931AUI+?
MAX6931AUI+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6931AUI+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX6931AUI+?
For technical support, including MAX6931AUI+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6931AUI+ requirements.
6.How does Aetrix verify that MAX6931AUI+ is sourced from the original manufacturer or authorized distributors?
All MAX6931AUI+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX6931AUI+ meets industry standards.
7.What is the process for return or replacement of MAX6931AUI+?
All MAX6931AUI+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6931AUI+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX6931AUI+ part is unused and in its original packaging.
Return procedure for MAX6931AUI+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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