DS7880/DS8880 High Voltage 7-Segment Decoder/Driver General Description The DS7880/DS8880 is custom designed to decode four lines of BCD and drive a gas-filled seven-segment display tube. Each output constitutes a switchable, adjustable current sink which provides constant current to the tube segment, even with high tube anode supply tolerance or fluctuation. These current sinks have a voltage compliance from 3V to at least 80V; typically the output current varies 1% for output voltage changes of 3 to 50V. Each bit line of the decoder switches a current sink on or off as prescribed by the input code. Each current sink is ratioed to the b-output current as required for even illumination of all segments. Output currents may be varied over the 0.2 to 1.5 mA range for driving various tube types or multiplex operation. The output current is adjusted by connecting an external pro- gram resistor (RP) from VCC to the Program input in accordance with the programming curve. The circuit design provides a one-to-one correlation between program input current and b-segment output current. The Blanking Input provides unconditional blanking of any output display, while the Ripple Blanking pins allow simple leading- or trailing-zero blanking. Features Y Y Y Y Y Y Current sink outputs Adjustable output currentÐ0.2 to 1.5 mA High output breakdown voltageÐ110V typ Suitable for multiplex operation Blanking and Ripple Blanking provisions Low fan-in and low power Logic Diagram TL/F/5845 – 1 C1995 National Semiconductor Corporation TL/F/5845 RRD-B30M105/Printed in U. S. A. DS7880/DS8880 High Voltage 7-Segment Decoder/Driver March 1988 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Transient Segment Output Current (Note 4) Storage Temperature Range VCC Lead Temperature (Soldering, 4 sec.) 7V Input Voltage (Except BI) Input Voltage (BI) Segment Output Voltage Power Dissipation Maximum Power Dissipation* at 25§ C Cavity Package Molded Package 6V VCC 80V 600 mW 50 mA b 65§ C to a 150§ C 260§ C Operating Conditions Supply Voltage (VCC) DS7880 DS8880 Temperature (TA) DS7880 DS8880 1509 mW 1476 mW *Derate cavity package 10.06 mW/§ C above 25§ C; derate molded package 11.81 mW/§ C above 25§ C. Min Max Units 4.5 4.75 5.5 5.25 V V b 55 a 125 a 70 §C §C 0 Electrical Characteristics (Notes 2 and 3) Symbol Parameter Conditions VIH Logical ‘‘1’’ Input Voltage VCC e Min VIL Logical ‘‘0’’ Input Voltage VCC e Min VOH Logical ‘‘1’’ Output Voltage VCC e Min, IOUT e b200 mA, RBO VOL Logical ‘‘0’’ Output Voltage VCC e Min, IOUT e 8 mA, RBO IIH Logical ‘‘1’’ Input Current VCC e Max, Except BI Logical ‘‘0’’ Input Current VCC e Max, VIN e 0.4V Min 2.4 VIN e 2.4V VIN e 5.5V IIL Units 0.8 V 3.7 V 0.13 0.4 V 2 15 mA mA 400 Except BI b 600 mA BI b 1.2 b 2.0 mA Power Supply Current VCC e Max, Rp e 2.2k, All Inputs e 0V Input Diode Clamp Voltage VCC e Max, TA e 25§ C, IIN e 12 mA IO SEGMENT OUTPUTS ‘‘ON’’ Current Ratio All Outputs e 50V, IOUTb e Ref. Outputs a, f, and g VCC e 5V, VOUTb e 50V, All Other Outputs t 5V, TA e 25§ C V 4 VCD Output b ‘‘ON’’ Current Max b 300 ICC Ib ON Typ 2.0 0.84 27 43 mA b 0.9 b 1.5 V 0.93 1.02 Outut c 1.12 1.25 1.38 Output d 0.90 1.00 1.10 Output e 0.99 1.10 1.21 Rp e 18.1k 0.15 0.20 0.25 mA Rp e 7.03k 0.45 0.50 0.55 mA Rp e 3.40k 0.90 1.00 1.10 mA Rp e 2.20k 1.35 1.50 1.65 mA 0.8 2.5 V 0.003 3 mA VSAT Output Saturation Voltage VCC e Min, Rp e 1k g 5%, IOUTb e 2 mA, (Note 5) ICEX Output Leakage Current VOUT e 75V, BI e 0V, Rp e 2.2k VBR Output Breakdown Voltage IOUT e 250 mA, BI e 0V, Rp e 2.2k tpd Propagation Delays BCD Input to Segment Output VCC e 5V, TA e 25§ C 80 110 V 0.4 10 ms BI to Segment Output 0.4 10 ms RBI to Segment Output 0.7 10 ms RBI to RBO 0.4 10 ms Note 1: ‘‘Absolute Maximum Rating’’ are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices should be operated at these limits. The table of ‘‘Electrical Characteristics’’ provides conditions for actual device operation. Note 2: Unless otherwise specified min/max limits apply across the b 55§ C to a 125§ C temperature range for the DS7880 and across the 0§ C to a 70§ C range for the DS8880. All typical values are for TA e 25§ C and VCC e 5V. Note 3: All currents into device pins shown as positive, out of device pins as negative, all voltages referenced to ground unless otherwise noted. All values shown as max or min or absolute value basis. Note 4: In all applications transient segment output current must be limited to 50 mA. This may be accomplished in dc applications by connecting a 2.2k resistor from the anode-supply filter capacitor to the display anode, or by current limiting the anode driver in multiplex applications. Note 5: For saturation mode the segment output currents are externally limited and ratioed. 2 Connection Diagram Dual-In-Line Package TL/F/5845 – 2 Top View Order Number DS7880J, DS8880J or DS8880N See NS Package Number J16A or N16A Typical Performance Characteristics Output Current Programming On Currents vs Temperature Output Characteristic TL/F/5845 – 3 3 Typical Application TL/F/5845 – 4 Truth Table TL/F/5845 – 5 4 Physical Dimensions inches (millimeters) Ceramic Dual-In-Line Package (J) Order Number DS7880J or DS8880J NS Package Number J16A 5 DS7880/DS8880 High Voltage 7-Segment Decoder/Driver Physical Dimensions inches (millimeters) (Continued) Molded Dual-In-Line Package (N) Order Number DS8880N NS Package Number N16A 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. 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