DSD-40BCD ETC1

Document overview

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Technical content

Features

Figure 1. DSD-40BCD Series Simplified Schematic an expensive and limited-availability situation. controlled by simply lowering the digit-drive input duty cycle. applications can now benefit from the superior readability offered by LED displays.

4½ D I G I T , S L A V E L E D D I S P L A Y Control Inputs Min. Typ. Max. Units BCD (pins I-L) and TEST (pin 2) Inputs: Low-Level Input Voltage (VIL) +0.8 Volts Low-Level Input Current (IIL) 0.4 mA High-Level Input Voltage (VIH) +2.4 Volts High-Level Input Current (IIH) 0.05 mA Polarity Input (pin F): Low-Level Input Voltage (VIL) +0.8 Volts Low-Level Input Current (IIL) 0.4 mA High-Level Input Voltage (VIH) +4.5 Volts High-Level Input Current (IIH) 0.05 mA Digit Drive Inputs (pins A-E): Low-Level Input Voltage (VIL) +0.8 Volts Low-Level Input Current (IIL) 0.4 mA High-Level Input Voltage (VIH) +4.5 Volts High-Level Input Current (IIH) mA DP1-DP4 Inputs (pins 4-6, 8): Low-Level Input Voltage (VIL) +0.8 Volts Low-Level Input Current (IIL) mA High-Level Input Voltage (VIH) +4.5 Volts High-Level Input Current (IIH) 0.05 mA Power Supply Requirements Supply Voltage +4.75 +5.00 +5.25 Volts Supply Current: DSD-40BCD-GS +100 +130 mA DSD-40BCD-RL +35 +45 mA DSD-40BCD-RS +85 +110 mA Display Display Type and Size 4½ Digit LED, 0.52"/13.2mm high LED Peak Wavelength (λλλλλ): DSD-40BCD-GS 565 nm DSD-40BCD-RL 660 nm DSD-40BCD-RS 635 nm Physical/Environmental Operating Temperature +70 Storage Temperature –40 +75 Humidity (Non-condensing) Case Material Polycarbonate Weight 1 ounce (28 grams) BCD Inputs and Resultant Displays Functional Specifications TA = +25°C and supply voltage = +5V, unless otherwise noted. Technical Notes 1. DSD-40BCD Operation (Please Refer to the Timing and Pinout Diagrams for the Following Discussion): The DSD-40BCD display has five digits, labeled digit 1 (left-most digit or MSD) through digit 5 (right- most digit or LSD), which are turned on by bringing their respective DIGIT DRIVE inputs to a high logic level. The binary coded decimal data (BCD) on pins I-L is decoded into the corresponding seven- segment LED outputs necessary to display the numerals "0" through "9". Since there are effectively five digits and only one set of BCD data inputs, the DSD-40BCD's digits have their segments tied ("multi- plexed") together. The top segment, referred to as segment A, of digit 5 is connected to the A segment of the other three digits (digit 1 has no A segment). The remaining B, C, D, E, F and G segments are connected to each other in the same fashion. As an example of how the multiplexing scheme works, assume that the BCD data inputs are 0001 (the BCD code for the decimal number 1) and also assume that the DIGIT DRIVE 3 input is high. Under these conditions, the B and C segments of digits 1-5 will all be enabled. However, only the digits whose DIGIT DRIVE inputs are high, in this case only digit 3, will display the numeral "1". All the other digits will be off. This example, while technically valid, will produce an extremely bright "1" for digit 3. This will be explained in greater detail in the section titled "Controlling the Display Brightness." 2. DSD-40BCD Timing Diagram (See Figure 2): The timing diagram depicts the required typical input conditions and timing relationships that allow the user to access all 5 digits. The recommended display scan rate is 100Hz. All 5 digits are scanned in 10ms, and each individual digit is "on" for 2ms (20% duty cycle). The 100Hz figure is not critical; it can go as low as 70Hz without any impact on display visibility. The timing diagram shows the digits being scanned from left to right (DIGIT 1 to DIGIT 5), but this order is not mandatory. Any drive sequence can be used, as long as BCD data is presented at the correct corresponding DIGIT DRIVE interval. An important point to keep in mind is that the DSD-40BCD has no internal data latches! The DIGIT DRIVE and BCD data inputs must be continuously strobed to keep the display properly illuminated. 3. Decimal Point Inputs (DP1-DP4, Pins 4-6, 8): The four, active-low, decimal point segments are multiplexed in a similar, though not identical, manner as the rest of the digit segments. The four decimal points are controlled by their respective DIGIT DRIVE inputs. A selected decimal point may be permanently connected to ground. It will only be illuminated when its respective DIGIT DRIVE input is high. For example, if pin 6 (DP1) is hard-wired to pin 3 (5V RETURN), DP1 will only be on during the time interval that DIGIT DRIVE 1 is high. As the specifications table clearly states, DP1-DP4 each require 20mA of sink current in order to achieve good illumination levels. Unused decimal points may be left open. The specified minimum VIH applies only if logic-level devices are used to select the decimal points. 4. POLARITY (Pin F): The function of this active-low pin is to turn on the minus sign if negative readings are desired. The polarity input, like the decimal points, can also be permanently connected to ground. However, POLARITY is logic-level compatible and does not require DSD-40BCD - R S LED Color: GS = Standard Green RL = Low-Power Red RS = Standard Red Accessories: DMS-30-CP Panel cutout punch DMS-BZL1 DSD-40 bezel assembly DMS-BZL2 DSD-40 bezel assembly with sealing gasket

Ordering Information

A panel-mount retaining clip is supplied with each model. 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 Order on-line at www.datel.com

  1. Interfacing BCD-Output A/D Converters: The DSD-40BCD

remote-display applications.

  1. DISPLAY TEST (Pin 2): The DSD-40BCD's display can have all

as the digit drive inputs are continuously strobed. withstand most common manual and wave soldering operations. has no detrimental effects on low-speed digital devices. never displayed, the POLARITY input may be left open.

  1. Controlling Display Brightness: The LED current-setting
  2. Highlighting Selected Digits: In many instrument designs, it is

control of the digit drive inputs makes this a relatively simple task. intensity of the non-flashed digits uniform.

  1. Power Supply Decoupling: The DSD-40BCD is not sensitive to

ceramic capacitor will reduce the LED switching transients. Figure 2. BCD Data Timing Diagram

  1. Maximum allowable digit-to-digit overlap is 5 sec.
  2. Maximum allowable digit-to-BCD data skew is also 5 sec.

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com Email: sales@datel.com Data sheet fax back: (508) 261-2857 DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01 DATEL GmbH München, Germany Tel: 89-544334-0 DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025 DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark. ISO 9001 ISO 9001 R E G I S T E R E D DS-0335A 1/98 DSD-40BCD 4 ½ D I G I T , S L A V E L E D D I S P L A Y Mechanical Specifications MECHANICAL DIMENSIONS: Inches (mm) TOLERANCES: 2 PL DEC ±0.02 (±0.51) 3 PL DEC ±0.010 (±0.254) LEAD DIMENSIONS: 0.025 (0.635) x 0.025 (0.635) NOMINAL RECOMMENDED PC BOARD FINISHED HOLE DIAMETER: #2-56 INSERT 0.156 (3.96) DEEP FRONT VIEW 1.270 (32.26) 0.187 (4.75) OPTIONAL BEZEL (DMS-BZL1 and DMS-BZL2) 2.35 (59.69) 2.118 (53.80) 0.093 (2.362) DIAMETER (4 REQUIRED) ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS INTERNAL CORNER RADII: 0.032 (0.81) MAX. 1.07 (27.18) 0.878 (22.30) 0.096 (2.44) 0.116 (2.95) 2.55 (64.77) PANEL CUTOUT B1 (LSB) B8 (MSB) N.C. N.C. MADE IN USA DSD-40BCD-XX FRONT VIEW +5V SUPPLY DISPLAY TEST 5V RETURN DP3 DP2 DP1 N.C. N.C. 5V RETURN N.C. DP4 N.C. DP1 DP2 DP3 DP4 2.17 (55.12) 2.09 (53.09) 1.80 (45.72) 0.250 (6.35) TYP. 0.145 (3.68) TYP. 0.040 (1.02) 0.10 (2.54) TYP. 0.040 (1.02) 0.17 (4.32) TYP. 0.50 (12.70) 0.84 (21.34) 0.92 (23.37) PIN #1 IDENTIFIER 0.56 (14.22) (LSD) DIGIT DRIVE 5 (MSD) DIGIT DRIVE 1 DIGIT DRIVE 2 DIGIT DRIVE 3 DIGIT DRIVE 4 POLARITY A B C D E F L K J I H G 1.60 (40.64) 0.10 (2.54) TYP. A B C D E F L K J I H G 0.040 (1.02)