NTE74LS279 Integrated Circuit TTL − Quad Set−Reset Latch Description: The NTE74LS279 offers 4 basic S−R flip−flop latches in a 16−Lead plastic DIP type package. Under conventional operation, the S−R inputs are normally held high. When the S input is pulsed low, the Q output will be set high. When R is pulsed low, the Q output will be reset low. Normally, the S−R inputs should not be taken low simultaneously. The Q output will be unpredictable in this condition. Absolute Maximum Ratings: (Note 1) Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V Operating Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0C to +70C Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65C to +150C Note 1. Unless otherwise specified, all voltages are referenced to GND. Recommended Operating Conditions: Parameter Symbol Min Typ Max Unit Supply Voltage VCC 4.75 5.0 5.25 V High−Level Output Voltage VOH 2 − − V Low−Level Output Voltage VOL − − 0.8 V High−Level Output Current IOH − − −0.4 mA Low−Level Output Current IOL − − 8 mA Pulse Duration, Low tw 20 − − ns Operating Temperature Range TA 0 − +70 C Electrical Characteristics: (Note 2, Note 3) Parameter Symbol Test Conditions Min Typ Max Unit − − −1.5 V 2.7 3.4 − V IOL = 4mA − 0.25 0.4 V IOL = 8mA − 0.25 0.5 V Input Clamp Voltage VIK VCC = MIN, II = −18mA High Level Output Voltage VOH VCC = MIN, VIL = MAX, IOH = −0.4mA Low Level Output Voltage VOL VCC = MIN, VIH = 2V Input Current II VCC = MAX, VI = 7V − − 0.1 mA High Level Input Current IIH VCC = MAX, VI = 2.7V − − 20 A Low Level Input Current IIL VCC = MAX, VI = 0.4V − − −0.2 mA Short−Circuit Output Current IOS VCC = MAX, Note 4 −20 − −100 mA Supply Current ICC VCC = MAX, Note 5 − 3.8 7 mA Note 2. .For conditions shown as MIN or MAX, use the appropriate value specified under “Recommended Operation Conditions”. Note 3. All typical values are at VCC = 5V, TA = +25C. Note 4. Not more than one output should be shorted at a time, and the duration of the short−circuit should not exceed one second. Note 5. ICC is measured with all R inputs grounded, all S inputs at 4.5V and all outputs open. Switching Characteristics: (VCC = 5V, RL = 667, TA = +25C unless otherwise specified) Parameter Propagation Delay Time (From S Input to Q Output) Propagation Delay Time (From R Input to Q Output) Symbol tPLH Test Conditions Min Typ Max Unit − 12 22 ns tPHL − 13 21 ns tPHL − 15 27 ns RL = 2k, CL = 15pF Function Table: Output Inputs S{ R Q H H Q0 L H H H L L L L H* H = HIGH Level L = LOW Level Q0 = The level of Q before the indicated input conditions were established. * This configuration is nonstable; that is, it may not persist when the S and R inputs return to their inactive (high) level. { For latches with double S inputs: H = Both S inputs high L = One or both S inputs low Logic Diagram (Latches 2 and 4) (Latches 1 and 3) R R S1 S2 Q Q S Pin Connection Diagram 1R 1 16 VCC 1S1 2 1S2 3 15 4S 14 4R 1Q 4 13 4Q 2R 5 12 3S2 1S 6 11 3S1 10 3R 2Q 7 GND 8 9 3Q 16 9 1 8 .870 (22.0) Max .260 (6.6) Max .200 (5.08) Max .100 (2.54) .700 (17.78) .099 (2.5) Min