This product is discontinued and has been replaced by CFA634-YFH-KU


Part Number: XE634BK-YFH-KU

XE634 USB LCD 20x4 External Enclosure, Yellow/Green LED Backlight, FSTN Positive, Transflective -20°C to +70°C 6:00 viewing angle, Includes 9' black low-drop captive USB "A" cable

These external modules are extremely rugged and well-suited for dusty or damp locations. They are splash-resistant and resistant to dust.

The outline of the case is very compact compared to the size of the display, only slightly larger than the bare module.

These are perfect for use in a wall-mounted or desktop application, since the display can be mounted at eye-level. With the addition of a simple metal bracket, the XE634 can form the bulk of a POS pole mounted display.

USB Interface: The USB interface version of the XE634 has the full feature set of the serial interface CFA634, but allows connection to a USB port, using only a single cable for both power and data. Full compatibility with existing software is preserved by using our "Virtual COM port" driver. Connect the display, install the driver, and your computer will show an additional COM port any time the display is connected.

  • FSTN (Film compensated Super Twisted Nematic) LCD glass. FSTN gives better contrast, faster response, and makes an all-around more readable display than STN.
  • Bright, even, software-adjustable LED backlight.
  • The display has the ability to store a customized boot screen of your design in its EEPROM. All features of the display are controlled: characters displayed, user-definable characters, backlight setting, contrast setting, cursor position, cursor style, "wrap" setting, "scroll" setting, and even the scrolling marquee.
  • Terminal style automatic scrolling and line wrapping, controlled in software. Unique "Scrolling Marquee" feature continuously scrolls a message across the display without host intervention.
  • Enhanced CGROM version with many useful characters: numeric superscripts, icons, mathematical symbols, some fractions, a great variety of arrows, many currency symbols, and more.
  • The processor's reset circuit can handle a wide range of slow-turn-on power supply conditions.
  • Negative voltage for contrast generated on board.
  • Large, easy-to-read characters are 7.3 mm (0.287") high
  • Large display area in a compact 144 mm x 69 mm (5.67" x 2.72") package.
  • Wide temperature
  • "Gapless" horizontal bar graphs.
  • Buffered communication.
  • Single board construction. No connectors to fail.
  • RoHS compliant.


Physical Characteristics

Characters x Lines 20 x 4
Module Overall width height depth
millimeters 144 69 26
inches 5.669 2.717 1.024
PCB Outline width height depth
millimeters 144 69 26
inches 5.669 2.717 1.024
Viewing Area width height
millimeters 102 41.5
inches 4.016 1.634
Active Area width height
millimeters 93.54 34
inches 3.683 1.339
Character Size width height
millimeters 3.84 6.38
inches 0.151 0.251
Character Pitch width height
millimeters 4.68 8.9
inches 0.184 0.350
Dot Size width height
millimeters 0.72 0.86
inches 0.028 0.034
Dot Pitch width height
millimeters 0.78 0.92
inches 0.031 0.036
Weight 413g

Optical Characteristics

Glass Type/Glass Color FSTN/Light Gray
Polarizer Transflective
View Direction 6 o'clock
Sunlight Readable Yes
Backlight Color Yellow-Green
Backlight Type LED
Mode Positive
Foreground Color Dark
Background Color Yellow-Green


Operating Temperatures min max
Celsius -20° 70°
Fahrenheit -4° 158°
Storage Temperatures min max
Celsius -30° 80°
Fahrenheit -22° 176°
Humidity min max
Non-condensing 0% 90%


Interface USB

Part Change Notice

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Part Change Notice #10318: Incorporate the newest CFA634 hardware / firmware into to the XE634BK builds.

Product Affected: XE634BK-YFH-KU
Date Issued: February 1, 2011
Summary: Incorporate the newest CFA634 hardware / firmware into to the XE634BK builds.
Last revision: Hardware v2.3, Firmware v2.3
Description: In a continuation of product improvement the XE634BK-YFH-KU has the following improvement:
  1. Wide temperature support with -20°C to +70°C operation / -30°C to +80°C storage

This new revision incorporates the improved v2.4 hardware and firmware into the XE634BK-YFH-KU. See PCN #10316 and #10308:

The XE634BK-YFH-KU is a special order part.
Reason: Base module of XE634BK-YFB-KU, the CFA634-YFH-KU have been upgraded and improved. Older CFA634-YFB-KU have been obsoleted.
Impact: The new version is designed to be Fit, Form, and Function compatible with previous versions of the XE634 series
Recommendation: Engineering samples are available only on a special order basis.

The XE634BK-YFH-KU is a special order part.
Availability: The XE634BK-YFH-KU is a special order part.
Price Change: The XE634BK-YFH-KU is a special order part.
For reference only. For design purposes, please use the specifications in the datasheet.

Product Notes

Due to the encapsulation process (a hot molding technique) causing too high a rate of damage to displays during manufacturing, we have discontinued this product. If you would like your module encapsulated, you can still order a CFA634-YFH-KU display, then contract independently with another vendor for encapsulation (which may void your module's warranty). You may also contact us and we would be happy to provide you with encapsulation design files, and other advice and experience that we have learned.