74148 – 8-3 Line Priority Encoder

Part Number : 74148

Function : 8-3 Line Priority Encoder

Manufactures : National Semiconductor

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Description :

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 V […]

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74148 Datasheet


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