DM9370 7-Segment Decoder/Driver/Latch with Open-Collector Outputs General Description The DM9370 is a 7-segment decoder driver incorporating input latches and output circuits to directly drive incandescent displays. It can also be used to drive common anode LED displays in either a multiplexed mode or directly with the aid of external current limiting resistors. Connection Diagram Dual-in-Line Package TL/F/9797 - 1 Order Number DM9370N See NS Package Number N16E Pin Names A0-A3 LE RBI RBO a-g C1995 National Semiconductor Corporation TL/F/9797 Description Address Inputs Latch Enable Input (Active LOW) Ripple Blanking Input (Active LOW) Ripple Blanking as Output (Active LOW) as Input (Active LOW) Segment Outputs (Active LOW) RRD-B30M115/Printed in U. S. A. DM9370 7-Segment Decoder/Driver/Latch with Open-Collector Outputs June 1989 Absolute Maximum Ratings (Note) Note: The ``Absolute Maximum Ratings'' are those values beyond which the safety of the device cannot be guaranteed. The devic should not be operated at these limits. The parametric values defined in the ``Electrical Characteristics'' table are not guaranteed at the absolute maximum ratings. The ``Recommended Operating Conditions'' table will define the conditions for actual device operation. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage Input Voltage Operating Free Air Temperature Range Commercial 7V 5.5V 0 C to a 70 C b 65 C to a 150 C Storage Temperature Range Recommended Operating Conditions Symbol DM9370 Parameter VCC Supply Voltage VIH High Level Input Voltage VIL Low Level Input Voltage IOH High Level Output Current IOL Low Level Output Current TA Free Air Operating Temperature ts (H) ts (L) Units Min Nom Max 4.75 5 5.25 V 2 V 0.8 V b 80 mA 3.2 mA 70 C Setup Time HIGH or LOW An to LE 30 20 ns th (H) th (L) Hold Time HIGH or LOW An to LE 0 0 ns tw (L) LE Pulse Width LOW 45 ns 0 Electrical Characteristics Over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min Typ (Note 1) Max Units b 1.5 V VI Input Clamp Voltage VCC e Min, II e b12 mA VOH High Level Output Voltage VCC e Min, IOH e Max VIL e Max VOL Low Level Output Voltage VCC e Min, IOL e Max VIH e Min II Input Current @ Max Input Voltage VCC e Max, VI e 5.5V IIH High Level Input Current VCC e Max, VI e 2.4V 40 mA IIL Low Level Input Current VCC e Max, VI e 0.4V b 1.6 mA IOS Short Circuit Output Current VCC e Max (Note 2) b 70 mA VOH Output HIGH Voltage RBO VCC e Min, IOH b80 mA VOL Output LOW Voltage RBO IOL e 3.2 mA a- g IOL e 25 mA IOH ICC DM74 VCC e Min Output HIGH Current, a- g Power Supply Current 2.4 3.4 0.2 b 20 V 0.4 V 1 mA 2.4 V 0.4 V 0.4 250 mA VCC e Max 105 mA A1, A2, A3, LE e GND VCC e Max, Outputs Open 105 A0, A1, A2, LE e GND VCC e Max, Outputs Open 94 2 mA Switching Characteristics VCC e a 5.0V, TA e a 25 C (See Section 1 for waveforms and load configurations) Symbol CL e 15 PF RL e 500X Parameter Min Units Max tPLH tPHL Propagation Delay An to a- g 75 50 ns tPLH tPHL Propagation Delay LE to a- g 90 70 ns Functional Description rate display voltage source, and clock failure detect circuitstraditionally found in incandescent multiplexed display systems are eliminated. It also allows low strobing rates to be used without display flicker. Another '70 feature is the reduced loading on the data inputs when the Latch Enable is HIGH (only 10 mA typ). This allows many '70s to be driven from a MOS device in multiplex mode without the need for drivers on the data lines. The '70 also provides automatic blanking of the leading and/or trailing-edge zeroes in a multidigit decimal number, resulting in an easily readable decimal display conforming to normal writing practice. In an 8-digit mixed integer fraction decimal representation, using the automatic blanking capability, 0060.0300 would be displayed as 60.03. Leadingedge 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 zeroes. 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. The '70 has active LOW outputs capable of sinking in excess of 25 mA which allows it to drive a wide variety of 7-segment incandescent displays directly. It may also be used to drive common anode LED displays, multiplexed or directly with the aid of suitable 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'' through ``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 '70 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. The latch/decoder combination is a simple system which drives incandescent displays with multiplexed data inputs from MOS time clocks, DVMs, calculator chips, etc. Data inputs are multiplexed while the displays are in static mode. This lowers component and insertion costs since several circuitsseven diodes per display, strobe drivers, a sepa- Logic Symbol TL/F/9797 - 2 VCC e Pin 16 GND e Pin 8 3 Truth Table TL/F/9797 - 4 TL/F/9797 - 6 *The RBI will blank the display only if binary zero is stored in the latches. **RBO used as an input overdrives all other input conditions. H e HIGH Voltage Level L e LOW Voltage Level X e Immaterial Numerical Designation TL/F/9797 - 5 4 Logic Diagram TL/F/9797 - 3 5 DM9370 7-Segment Decoder/Driver/Latch with Open-Collector Outputs Physical Dimensions inches (millimeters) 16-Lead Molded Dual-In-Line Package (N) Order Number DM9370N NS Package Number N16E LIFE SUPPORT POLICY NATIONAL'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 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