TC74HC148AP/AF/AFN 8-TO-3 LINE PRIORITY ENCODER The TC74HC148A is a high speed CMOS 8-to-3 LINE ENCODER fabricated with silicon gate C* MOS technology. It achieves the high speed operation similar to equivalent LSTTL while maintaining the CMOS low power 16 dissipation. All data inputs and outputs of these encoders are active 1 when low. P(DIP16-P-300A) The encoder detects a low on the highest order among eight input signals and outputs the corresponding signal position in binary code. Enable Input El and Enable Output EO are used to easily 16 16 cascade without using external circuits. All inputs are equipped with protection circuits against ' ' static discharge or transient excess voltage. F(SOP16P-300) FN({SOL16P-150) FEATURES: * High Speed corserrscereerstsssesee ere ees ted=15ns(Typ.)at Voc=5V PIN ASSIGNMENT * Low Power Dissipation * Icc=4 A(Max. )at Ta=25T * High Noise Immunity ++ Vain=VnNit =28% Voc(Min.) 4 1 18 Vec *Qutput Drive Capability +--+: 10 LSTTL Loads 5 2C 16 EO * Symmetrical Output Impedance ** | lou|=loL=4mA(Min.) * Balanced Propagation Delays -*-*- tous tpt 6 3 4 Gs Wide Operating Voltage Range: Vcc(opr)=2V~6V 7 40 v3 Pin and Function Compatible with 74LS 148 Et 6 2 2 a2 6 101 Al 7 10 0 GND 8] 9 AO (TOP VIEW) IEC LOGIC SYMBOL HPAI/GIN 0-8) tora tof >1 Wea 414 2-02)_to/742 124 si etyz13 131 1415) gg yz 144 a) 5= 16/215 1 20a > GS p23) 6/218 16- 74) Wz WW to" a9 Vv 18 ag Al ENa 4afpp OL A2 ey HC-291 TC74HC148AP/AF/AFN TRUTH TABLE X:Don't Care OUTPUTS Al EO GS AO A2 INPUTS LOGIC DIAGRAM HC-292 TC74HC148AP/AF/AFN ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL VALUE UNIT Supply Voltage Range Voc ~0.5~7 Vv 500mW in the range of Ta= je wy... -40C~ 65C. From Ta=65C DC Input Voltage Vin 0-5 ~Voe 10-5 Vv to 85C a derating factor of DC Output Voltage Vout -0.5 ~ VQ 40-5 _ Vv ~lOmW/*C shall be applied Input Diode Current Ix +20 mA until 300mW. Output Diode Current low +20 mA DC Output Current lot #25 mA DC Vo-/Ground Current loc +50 mA Power Dissipation Py 500( DIP)+/180(SOIC) mW Storage Temperature Tstg ~65 ~150 Cc Lead Temperature 10sec T, 300 C RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL VALUE UNIT Supply Voltage Voc 2~6 Vv Input Voltage Vix 0~ Ver Vv Output Voltage Vout 0~ Va Vv Operating Temperature Topr 40 ~ 85 Cc 0 ~ 1000(V,.=2.0V) Input Rise and Fall Time | tr, tr O~ 500(Vec=4.5V) ns 0~ 400(V-=6.0V) DC ELECTRICAL CHARACTERISTICS Ta=25C Ta=-40 ~85 PARAMETER | SYMBOL TEST CONDITION Va | MIN. | TYP. [MAX.| MIN. [MAX. UNIT : 2.0 L5 - - 15 - High~ Level . . Vin 4.5 3.15 - - 3.15 ~ Vv Input Voltage 601 4.2 _ _ 42 . 2.0 - - 0.5 - 0.5 Low Level : . . Vit 4.5 - - 1.35 - 135 | V Input Voltage 6.0 _ _ 1.8 _ 1.8 2.0 1.9 2.0 - 1.9 - High-Level Vix = Ton =-20uA] 4.5 4.4 4.5 ~ 4,4 - Output Voltage Vax ViyorV 6.0 5.9 6.0 5.9 Vv 1 IL Igy =-4 mAT 4,5 4.18 4.31 - 4.13 - lou =-5,2mA] 6,0 5. 68 5. 80 = 5, 63 = 2.0 - 0.0 0.1 - 0.1 Low~Level Vin = Iq =20 uA] 4.5 7 0.0 0.1 - 0.1 Output Voltage Vo. ViyorV, 6.0 0.0 0.1 0.4 Vv A i Tg =4 mAT 45 - 0.17 0. 26 - 0, 33 Io. =5,2mA | 6.0 > 0, 18 0. 26 - 0, 33 Input Leakage Current Ty Vix =Vce or GND 6.0 = - +0. 1 - +10 A Quiescent Supply Current | Loe Vix =Vec or GND 6.0 = - 4,0 - 40,0 lu HC-293 TC74HC148AP/AF/AFN AC ELECTRICAL CHARACTERISTICS(C, =15pF, Voc=6V, Ta=26C) PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. jUNIT Output Transition Time tr - 4 8 P ion Delay Ti li ropagation Delay Time LH _ (IN-A0,A1,A2) | tug. 15 25 Propagation Delay Time | tpi; _ 15 95 (IN-EO,ES) toe ns Propagation Delay Time | tpjji - il 19 (EI-EO) tpHL Propagation Delay Time | tpi - i 19 (EI-GS) toh Propagation Delay Time | tpi; _ ul 19 (EI- A0,A1,A2) toHL AC ELECTRICAL CHARACTERISTICS(CL=60pF ,Input tr=tf=6ns) Ta= | Ta=40 ~85 PARAMETER SYMBOL| TEST CONDITION Voc a= 25C 4 0 c UNIT MIN. | TYP. | MAX.| MIN. | MAX. : 20] - 30 i! 95 Output Transition Time el 4.5 - 8 15 - 19 THL 6.0 - 7 13 | 16 t _ Propagation Delay Time | tyy, 2.0 52 150 | 190 n 45 | - 9 | 39 | 38 (IN-AQALA2) | tout. 6.0 | - ee a i 33 Propagation Delay Time | to.y a _ 2 - nF (IN-EO,GS) t pe 6.0 | - 15 26 | - 33 = ns Propagation Delay Time | tyj; 2.0 _ 40 MS - 145 EI-BOs : 4.5 4 23 29 Pel 60] - | wu | oa - | 2 Propagation Delay Time | tpy4 2.0 _ 40 Ms _ 145 EI-GS) t 4.5 14 23 29 ( Pll 6.0 | - 2 | 2 - 25 Propagation Delay Time | tot, ie _ i - Pe (El-A0,A1,A2) to 6.0 | - 12 20 | - 25 Input Capacitance Ci = 5 10 = 10 F Power Dissipation Capacitance Cpp = 55 = = = | P Note (1} Crp is defined as the value of the interna! equivalent operating current consumption without load. Average operating current can be obtained by the equation: loc opp =Cy Voce fn +lae HC-294 capacitance which is calculated from the TC74HC148AP/AF/AFN TYPICAL APPLICATION 4-bit CASCADE CONNECTION 1 a 061107 LL Et EO qi EO p EQ="L GS Az Al A0 Gs A2 Al AO With IN="H" ame : 4 0 TC74HCOBA Priority Flag A3 A2 Al AO o ~p 2 ob x 2 b b =~Db ~ ab oa oO 2 -op * wp wo nu b =p = obp o 4 HC-295