DM9368N

DM9368N Datasheet

DM9368 7-Segment Decoder/Driver/Latch with Constant Current Source Outputs

Part	Datasheet
DM9368N	DM9368N (pdf)

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DM9368 7-Segment Decoder/Driver/Latch with Constant Current Source Outputs DM9368 7-Segment Decoder/Driver/Latch with Constant Current Source Outputs The DM9368 is a 7-segment decoder driver incorporating input latches and constant current output circuits to drive common cathode type LED displays directly. Ordering Code: Order Number Package Number Package Description DM9638N N16E 16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide Connection Diagram Logic Symbol Pin Descriptions VCC = Pin 16 GND = PIN 8 Pin Name RBO RBI LE Description Address Data Inputs Ripple Blanking Output Active LOW Ripple Blanking Input Active LOW Segment Drivers-Outputs Latch Enable Input Active LOW 2000 Fairchild Semiconductor Corporation DS009796 DM9368 Truth Table The RBI will blank the display only if a binary zero is stored in the latches. The RBO used as an input overrides all other input conditions. H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial Functional Description The DM9368 is a 7-segment decoder driver designed to drive 7-segment common cathode LED displays. The DM9368 drives any common cathode LED display rated at a nominal 20 mA at 1.7V per segment without need for current limiting resistors. This device accepts a 4-bit binary code and produces output drive to the appropriate segments of the 7-segment display. It has a hexadecimal decode format which produces numeric codes “0” thru “9” and alpha codes “A” through “F” using upper and lower case fonts. Latches on the four data inputs are controlled by an active LOW latch enable LE. When the LE is LOW, the state of the outputs is determined by the input data. When the LE goes HIGH, the last data present at the inputs is stored in the latches and the outputs remain stable. The LE pulse width necessary to accept and store data is typically 30 ns which allows data to be strobed into the DM9368 at normal TTL speeds. This feature means that data can be routed directly from high speed counters and frequency dividers into the display without slowing down the system clock or providing intermediate data storage. Another feature of the DM9368 is that the unit loading on the data inputs is very low −100 µA Max when the latch enable is HIGH. This allows DM9368s to be driven from an MOS device in multiplex mode without the need for drivers on the data lines. The DM9368 also has provision for automatic blanking of the leading and/or trailing edge zeros in a multidigit decimal number, resulting in an easily readable decimal display conforming to normal writing practice. In an eight digit mixed integer fraction decimal representation, using the automatic blanking capability, would be displayed as Leading edge zero suppression is obtained by connecting the Ripple Blanking Output RBO of a decoder to the Ripple Blanking Input RBI of the next lower stage device. The most significant decoder stage should have the RBI input grounded and since suppression of the least significant integer zero in a number is not usually desired, the RBI input of this decoder stage should be left open. A similar procedure for the fractional part of a display will provide automatic suppression of trailing edge zeros. The RBO terminal of the decoder can be OR-tied with a modulating signal via an isolating buffer to achieve pulse duration intensity modulation. A suitable signal can be generated for this purpose by forming a variable frequency multivibrator with a cross coupled pair of TTL or DTL gates. DM9368 Logic Diagram Numerical Designations Parallel Data Display System with Ripply Blanking Common Cathode LED Display DM9368 Display Demultiplexing System with Ripple Blanking Common Cathode LED Display Note Digit address data must be non-overlapping. Standard TTL decoders like the 9301, 9311, 7442 or 74155 must be strobed, since the address decoding glitches could cause erroneous data to be strobed into the latches. DM9368 Absolute Maximum Ratings Note 1 Supply Voltage Input Voltage 5.5V Operating Free Air Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation. Recommended Operating Conditions

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DM9368 7-Segment Decoder/Driver/Latch with Constant Current Source Outputs

DM9368 7-Segment Decoder/Driver/Latch with Constant Current Source Outputs

The DM9368 is a 7-segment decoder driver incorporating input latches and constant current output circuits to drive common cathode type LED displays directly.
Ordering Code:

Order Number Package Number

Package Description

DM9638N

N16E
16-Lead Plastic Dual-In-Line Package PDIP , JEDEC MS-001, Wide

Connection Diagram

Logic Symbol

Pin Descriptions

VCC = Pin 16 GND = PIN 8

Pin Name RBO RBI LE

Description Address Data Inputs Ripple Blanking Output Active LOW Ripple Blanking Input Active LOW Segment Drivers-Outputs Latch Enable Input Active LOW
2000 Fairchild Semiconductor Corporation DS009796

DM9368

Truth Table
*The RBI will blank the display only if a binary zero is stored in the latches. *The RBO used as an input overrides all other input conditions. H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial

Functional Description

The DM9368 is a 7-segment decoder driver designed to drive 7-segment common cathode LED displays. The DM9368 drives any common cathode LED display rated at a nominal 20 mA at 1.7V per segment without need for current limiting resistors.

This device accepts a 4-bit binary code and produces output drive to the appropriate segments of the 7-segment display. It has a hexadecimal decode format which produces numeric codes “0” thru “9” and alpha codes “A” through “F” using upper and lower case fonts.

Latches on the four data inputs are controlled by an active LOW latch enable LE. When the LE is LOW, the state of the outputs is determined by the input data. When the LE goes HIGH, the last data present at the inputs is stored in the latches and the outputs remain stable. The LE pulse width necessary to accept and store data is typically 30 ns which allows data to be strobed into the DM9368 at normal TTL speeds. This feature means that data can be routed directly from high speed counters and frequency dividers into the display without slowing down the system clock or providing intermediate data storage.

Another feature of the DM9368 is that the unit loading on the data inputs is very low −100 µA Max when the latch enable is HIGH. This allows DM9368s to be driven from an

MOS device in multiplex mode without the need for drivers on the data lines.

The DM9368 also has provision for automatic blanking of the leading and/or trailing edge zeros in a multidigit decimal number, resulting in an easily readable decimal display conforming to normal writing practice. In an eight digit mixed integer fraction decimal representation, using the automatic blanking capability, would be displayed as Leading edge zero suppression is obtained by connecting the Ripple Blanking Output RBO of a decoder to the Ripple Blanking Input RBI of the next lower stage device. The most significant decoder stage should have the RBI input grounded and since suppression of the least significant integer zero in a number is not usually desired, the RBI input of this decoder stage should be left open. A similar procedure for the fractional part of a display will provide automatic suppression of trailing edge zeros. The RBO terminal of the decoder can be OR-tied with a modulating signal via an isolating buffer to achieve pulse duration intensity modulation. A suitable signal can be generated for this purpose by forming a variable frequency multivibrator with a cross coupled pair of TTL or DTL gates.

DM9368

Logic Diagram

Numerical Designations Parallel Data Display System with Ripply Blanking

Common Cathode LED Display

DM9368

Display Demultiplexing System with Ripple Blanking

Common Cathode LED Display

Note Digit address data must be non-overlapping. Standard TTL decoders like the 9301, 9311, 7442 or 74155 must be strobed, since the address decoding glitches could cause erroneous data to be strobed into the latches.

DM9368

Absolute Maximum Ratings Note 1

Supply Voltage

Input Voltage
5.5V

Operating Free Air Temperature Range 0°C to +70°C

Storage Temperature Range
−65°C to +150°C

Note 1 The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

Recommended Operating Conditions

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Datasheet ID: DM9368N 513852