54LS279

54LS279 DM54LS279 DM74LS279 Quad S-R Latches May 1989 54LS279 DM54LS279 DM74LS279 Quad S-R Latches General Description The ’LS279 consists of four individual and independent SetReset Latches with active low inputs Two of the four latches have an additonal S input ANDed with the primary S input A low on any S input while the R input is high will be stored in the latch and appear on the corresponding Q output as a high A low on the R input while the S input is high will clear the Q output to a low Simultaneous transistion of the R and S inputs from low to high will cause the Q output to be indeterminate Both inputs are voltage level triggered and are not affected by transition time of the input data Features Y Alternate military aerospace device (54LS279) is available Contact a National Semiconductor Sales Office Distributor for specifications Connection Diagram Dual-In-Line Package TL F 6420 – 1 Order Number 54LS279DMQB 54LS279FMQB 54LS279LMQB DM54LS279J DM74LS279M or DM74LS279N See NS Package Number E20A J16A M16A N16E or W16A Function Table Inputs S(1) L L H H H e High Level L e Low Level Q0 e The Level of Q before the indicated input conditions were established This output level is pseudo stable that is it may not persist when the S and R inputs return to their inactive (high) level Note 1 For latches with double S inputs H e both S inputs high L e one or both S inputs low Output R L H L H Q H H L Q0 C1995 National Semiconductor Corporation TL F 6420 RRD-B30M105 Printed in U S A Absolute Maximum Ratings (Note) If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage 7V Input Voltage 7V Operating Free Air Temperature Range b 55 C to a 125 C DM54LS and 54LS DM74LS 0 C to a 70 C Storage Temperature Range b 65 C to a 150 C Note 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’’ table are not guaranteed at the absolute maximum ratings The ‘‘Recommended Operating Conditions’’ table will define the conditions for actual device operation Recommended Operating Conditions Symbol VCC VIH VIL IOH IOL TA Parameter Min Supply Voltage High Level Input Voltage Low Level Input Voltage High Level Output Current Low Level Output Current Free Air Operating Temperature b 55 DM54LS279 Nom 5 Max 55 Min 4 75 2 07 b0 4 DM74LS279 Nom 5 Max 5 25 Units V V 08 b0 4 45 2 V mA mA C 4 125 0 8 70 Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH Parameter Input Clamp Voltage High Level Output Voltage Low Level Output Voltage Conditions VCC e Min II e b18 mA VCC e Min IOH e Max VIL e Max VIH e Min VCC e Min IOL e Max VIL e Max VIH e Min IOL e 4 mA VCC e Min II IIH IIL IOS Input Current Input Voltage Max VCC e Max VI e 7V VCC e Max VI e 2 7V VCC e Max VI e 0 4V VCC e Max (Note 2) VCC e Max (Note 3) DM54 DM74 b 20 b 20 Min Typ (Note 1) Max b1 5 Units V V DM54 DM74 DM54 DM74 DM74 25 27 35 35 0 25 0 35 0 25 04 05 04 01 20 b0 4 b 100 b 100 VOL V mA mA mA mA mA High Level Input Current Low Level Input Current Short Circuit Output Current Supply Current ICC 38 7 Note 1 All typicals are at VCC e 5V TA e 25 C Note 2 Not more than one output should be shorted at a time and the duration should not exceed one second Note 3 ICC is measured with all R inputs grounded all S inputs at 4 5V and all outputs open 2 Switching Characteristics at VCC e 5V and TA e 25 C (See Section 1 for Test Waveforms and Output Load) Symbol Parameter From (Input) To (Output) RL e 2 kX CL e 15 pF Min tPLH tPHL tPHL Propagation Delay Time Low to High Level Output Propagation Delay Time High to Low Level Output Propagation Delay Time High to Low Level Output S to Q S to Q R to Q Max 22 15 27 CL e 50 pF Min Max 25 23 33 ns ns ns Units 3 Physical Dimensions inches (millimeters) Ceramic Leadless Chip Carrier Package (E) Order Number 54LS279LMQB NS Package Number E20A 16-Lead Ceramic Dual-In-Line Package (J) Order Number 54LS279DMQB or DM54LS279J NS Package Number J16A 4 Physical Dimensions inches (millimeters) (Continued) 16-Lead Small Outline Molded Package (M) Order Number DM74LS279M NS Package Number M16A 16-Lead Molded Dual-In-Line Package (N) Order Number DM74LS279N NS Package Number N16E 5 54LS279 DM54LS279 DM74LS279 Quad S-R Latches Physical Dimensions inches (millimeters) (Continued) 16-Lead Ceramic Flat Package (W) Order Number 54LS279FMQB or DM54LS279W NS Package Number W16A 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 National Semiconductor Corporation 1111 West Bardin Road Arlington TX 76017 Tel 1(800) 272-9959 Fax 1(800) 737-7018 2 A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor Europe Fax (a49) 0-180-530 85 86 Email cnjwge tevm2 nsc com Deutsch Tel (a49) 0-180-530 85 85 English Tel (a49) 0-180-532 78 32 Fran ais Tel (a49) 0-180-532 93 58 Italiano Tel (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel (852) 2737-1600 Fax (852) 2736-9960 National Semiconductor Japan Ltd Tel 81-043-299-2309 Fax 81-043-299-2408 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications