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74HCT299D 数据表(PDF) 2 Page - NXP Semiconductors |
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74HCT299D 数据表(HTML) 2 Page - NXP Semiconductors |
2 / 11 page December 1990 2 Philips Semiconductors Product specification 8-bit universal shift register; 3-state 74HC/HCT299 FEATURES • Multiplexed inputs/outputs provide improved bit density • Four operating modes: – shift left – shift right – hold (store) – load data • Operates with output enable or at high-impedance OFF-state (Z) • 3-state outputs drive bus lines directly • Can be cascaded for n-bits word length • Output capability: bus driver (parallel I/Os), standard (serial outputs) • ICC category: MSI GENERAL DESCRIPTION The 74HC/HCT299 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT299 contain eight edge-triggered D-type flip-flops and the interstage logic necessary to perform synchronous shift-right, shift-left, parallel load and hold operations. The type of operation is determined by the mode select inputs (S0 and S1), as shown in the mode select table. All flip-flop outputs have 3-state buffers to separate these outputs (I/O0 to I/O7) such, that they can serve as data inputs in the parallel load mode. The serial outputs (Q0 and Q7) are used for expansion in serial shifting of longer words. A LOW signal on the asynchronous master reset input (MR) overrides the Sn and clock (CP) inputs and resets the flip-flops. All other state changes are initiated by the rising edge of the clock pulse. Inputs can change when the clock is either state, provided that the recommended set-up and hold times, relative to the rising edge of CP, are observed. A HIGH signal on the 3-state output enable inputs (OE1 or OE2) disables the 3-state buffers and the I/On outputs are set to the high-impedance OFF-state. In this condition, the shift, hold, load and reset operations can still occur. The 3-state buffers are also disabled by HIGH signals on both S0 and S1, when in preparation for a parallel load operation. QUICK REFERENCE DATA GND = 0 V; Tamb =25 °C; tr =tf = 6 ns SYMBOL PARAMETER CONDITIONS TYPICAL UNIT HC HCT tPHL/ tPLH propagation delay CL = 15 pF; VCC =5 V CP to Q0, Q7 20 19 ns CP to I/On 20 19 ns tPHL MR to Q0, Q7 or I/On 20 23 ns fmax maximum clock frequency 50 46 MHz CI input capacitance 3.5 3.5 pF CI/O input/output capacitance 10 10 pF CPD power dissipation capacitance per package notes 1 and 2 120 125 pF 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 pF 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”. |
类似零件编号 - 74HCT299D |
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类似说明 - 74HCT299D |
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