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74HC148 Dataheets PDF



Part Number 74HC148
Manufacturers National Semiconductor
Logo National Semiconductor
Description 8-3 Line Priority Encoder
Datasheet 74HC148 Datasheet74HC148 Datasheet (PDF)

MM54HC148 MM74HC148 8-3 Line Priority Encoder February 1988 MM54HC148 MM74HC148 8-3 Line Priority Encoder General Description This priority encoder utilizes advanced silicon-gate CMOS technology It has the high noise immunity and low power consumption typical of CMOS circuits as well as the speeds and output drive similar to LB-TTL This priority encoder accepts 8 input request lines 0– 7 and outputs 3 lines A0–A2 The priority encoding ensures that only the highest order data line is encoded C.

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MM54HC148 MM74HC148 8-3 Line Priority Encoder February 1988 MM54HC148 MM74HC148 8-3 Line Priority Encoder General Description This priority encoder utilizes advanced silicon-gate CMOS technology It has the high noise immunity and low power consumption typical of CMOS circuits as well as the speeds and output drive similar to LB-TTL This priority encoder accepts 8 input request lines 0– 7 and outputs 3 lines A0–A2 The priority encoding ensures that only the highest order data line is encoded Cascading circuitry (enable input EI and enable output EO) has been provided to allow octal expansion without the need for external circuitry All data inputs and outputs are active at the low logic level All inputs are protected from damage due to static discharge by internal diode clamps to VCC and ground Features Y Typical propagation delay 13 ns Y Wide supply voltage range 2V – 6V Connection Diagram Dual-In-Line Package Truth Table Order Number MM54HC148 or MM74HC148 TL F 9390 – 1 Inputs Outputs EI 0 1 2 3 4 5 6 7 A2 A1 A0 GS EO HXXXXXXXX H H H H H L HHHHHHHH H H H H L L XXXXXXXL L L L L H L XXXXXXLH L L H L H L XXXXX LHH L H L L H L XXXX LHHH L H H L H L XXX LHHHH H L L L H L XX LHHHHH H L H L H L X LHHHHHH H H L L H L LHHHHHHH H H H L H H e High L e Low X e irrelevant C1995 National Semiconductor Corporation TL F 9390 RRD-B30M105 Printed in U S A Absolute Maximum Ratings (Notes 1 2) If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage (VCC) DC Input Voltage (VIN) DC Output Voltage (VOUT) Clamp Diode Current (IIK IOK) DC Output Current per pin (IOUT) DC VCC or GND Current per pin (ICC) Storage Temperature Range (TSTG) Power Dissipation (PD) (Note 3) S O Package only b0 5 to a7 0V b1 5 to VCC a1 5V b0 5 to VCC a0 5V g20 mA g25 mA g50 mA b65 C to a150 C 600 mW 500 mW Lead Temperature (TL) (Soldering 10 sec ) 260 C Operation Conditions Min Max Units Supply Voltage (VCC) DC Input or Output Voltage 2 0 (VIN VOUT) Operating Temperature Range (TA) MM74HC b40 6 VCC a85 V V C MM54HC b55 a125 C Input Rise or Fall Times (tr tf) VCC e 2 0V VCC e 4 5V VCC e 6 0V 1000 500 400 ns ns ns DC Electrical Characteristics (Note 4) Symbol Parameter Conditions 74HC 54HC VCC TA e 25 C TA e b40 to 85 C TA e b55 to 125 C Units Typ Guaranteed Limits VIH Minimum High Level Input Voltage 2 0V 4 5V 6 0V 15 3 15 42 15 3 15 42 15 V 3 15 V 42 V VIL Maximum Low Level Input Voltage 2 0V 4 5V 6 0V 05 1 35 18 05 1 35 18 05 V 1 35 V 18 V VOH Minimum High Level VIN e VIH or VIL Output Voltage lIOUTl s 20 mA 2 0V 2 0 1 9 4 5V 4 5 4 4 6 0V 6 0 5 9 19 44 59 19 V 44 V 59 V VIN e VIH or VIL lIOUTl s 4 0 mA lIOUTl s 5 2 mA 4 5V 4 7 3 96 6 0V 5 2 5 48 VOL Maximum Low Level VIN e VIH or VIL Output Voltage lIOUTl s 20 mA 2 0V 0 0 1 4 5V 0 0 1 6 0V 0 0 1 3 84 5 34 01 01 01 37 V 52 V 01 V 01 V 01 V VIN e VIH or VIL lIOUTl s 4 0 mA lIOUTl s 5 2 mA 4 5V 0 2 0 26 6 0V 0 2 0 26 IIN Maximum Input VIN e VCC or GND 6 0V Current g0 1 0 33 0 33 g1 0 04 04 g1 0 V V mA ICC Maximum Quiescent VIN e VCC or GND 6 0V Supply Current IOUT e 0 mA 80 80 160 mA Note 1 Absolute Maximum Ratings are those values beyond which damage to the device may occur Note 2 Unless otherwise specified all voltages are referenced to ground Note 3 Power Dissipation temperature derating plastic ‘‘N’’ package b12 mW C from 65 C to 85 C ceramic ‘‘J’’ package b12 mW C from 100 C to 125 C Note 4 For a power supply of 5V g10% the worst case output voltages (VOH and VOL) occur for HC at 4 5V Thus the 4 5V values should be used when designing with this supply Worst case VIH and VIL occur at VCC e 5 5V and 4 5V respectively (The VIH value at 5 5V is 3 85V ) The worst case leakage current (IIN ICC and IOZ) occur for CMOS at the higher voltage and so the 6 0V values should be used VIL limits are currently tested at 20% of VCC The above VIL specification (30% of VCC) will be implemented no later than Q1 CY’89 2 AC Electrical Characteristics VCC e 5V TA e 25 C CL e 15 pF tr e tf e 6 ns Symbol Parameter Conditions Typ tPHL tPLH Maximum Propagation Delay Any Input to Any Output 14 Units ns AC Electrical Characteristics VCC e 2 0V to 6 0V CL e 50 pF tr e tf e 6 ns (unless otherwise specified) Symbol Parameter VCC TA e 25 C Typ 74HC b40 C to a85 C 54HC b55 C to a125 C Guaranteed Limits Units tPHL tPLH Inputs 0–7 to Outputs A0 A1 A2 2 0V 140 4 5V 14 28 6 0V 24 175 35 30 210 ns 42 ns 36 ns tPHL tPLH Inputs 0–7 to Output EO 2 0V 140 4 5V 15 28 6 0V 24 175 35 30 210 ns 42 ns 36 ns tPHL tPLH Inputs 0–7 to Output GS 2 0V 160 4 5V 17 32 6 0V 27 200 40 34 240 ns 48 ns 41 ns tPHL tPLH Input EI to Outputs A0 A1 A2 2 0V 160 4 5V 17 32 6 0V 27 200 40 34 240 ns 48 ns 41 ns tPHL tPLH Input EI to Output GS 2 0V 100 4 5V 12 20 6 0V 17 125 25 21 150 ns 30 ns.


74148 74HC148 54HC148


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