74HCT147 Datasheet | Philips Semiconductors

FEATURES - Encodes 10-line decimal to 4-line BCD - Useful for 10-position switch encoding - Used in code converters and generators - Output capability: standard - ICC category: MSI GENERAL DESCRIPTION 74HC/HCT147 The 74HC/HCT147 are high-speed Si-gate CMOS devices and are pin patible with low power Schottky TTL (LSTTL). They are specified in pliance with JEDEC standard no. 7A. The 74HC/HCT147 9-input priority encoders accept data from nine active LOW inputs (A0 to A8) and provide a binary representation on the four active LOW outputs (Y0 to Y3). A priority is assigned to each input so that when two or more inputs are simultaneously active, the input with the highest priority is represented on the output, with input line A8 having the highest priority. The devices provide the 10-line to 4-line priority encoding function by use of the implied decimal “zero”. The “zero” is encoded when all nine data inputs are HIGH, forcing all four outputs HIGH. QUICK REFERENCE DATA GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns TYPICAL SYMBOL t PHL/ t PLH CI CPD Notes 1. CPD is used to determine the dynamic power dissipation (PD in µW): PD = CPD × VCC2 × fi + ∑ (CL × VCC2 × fo) where: fi = input frequency in MHz fo = output frequency in MHz ∑ (CL × VCC2 × fo) = sum of outputs CL = output load capacitance in p F VCC = supply voltage in V 2. For HC the condition is VI = GND to VCC For HCT the condition is VI = GND to VCC - 1.5 V ORDERING INFORMATION See “74HC/HCT/HCU/HCMOS Logic Package Information”. PARAMETER propagation delay An to Yn input capacitance power dissipation capacitance per package notes 1 and 2 CONDITIONS HC CL = 15 p F; VCC = 5 V 15 3.5 30 HCT 17 3.5 33 ns p F p F UNIT December 1990 Philips Semiconductors Product specification 10-to-4 line priority encoder PIN DESCRIPTION PIN NO. 8 9, 7, 6, 14 11, 12, 13, 1, 2, 3, 4, 5, 10 15 16 SYMBOL NAME AND FUNCTION GND Y0 to Y3 A0 to A8 n.c. VCC ground (0 V) BCD address outputs (active LOW) decimal data inputs (active LOW) not...