74HC374 PHILIPS

Document overview

  • PDF pages: 8

Technical content

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Octal D-type flip-flop; positive

edge-trigger; 3-state

FEATURES

  • 3-state non-inverting outputs for bus oriented applications
  • 8-bit positive, edge-triggered register
  • Common 3-state output enable input
  • Independent register and 3-state buffer operation
  • Output capability: bus driver
  • ICC category: MSI

GENERAL DESCRIPTION

The 74HC/HCT374 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.

QUICK REFERENCE DATA

GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns

The 74HC/HCT374 are octal D-type flip-flops featuring separate D-type inputs for each flip-flop and 3-state outputs for bus oriented applications. A clock (CP) and an output enable (OE) input are common to all flip-flops.

The 8 flip-flops will store the state of their individual D-inputs that meet the set-up and hold times requirements on the LOW-to-HIGH CP transition. When OE is LOW, the contents of the 8 flip-flops are available at the outputs. When OE is HIGH, the outputs go to the high impedance OFF-state. Operation of the OE input does not affect the state of the flip-flops. The “374” is functionally identical to the “534”, but has non-inverting outputs.

SYMBOL PARAMETER CONDITIONS TYPICAL UNIT
HC HCT
t / t PHL PLH propagation delay CP to Q n C = 15 pF; V = 5 V L CC 15 13 ns
f max maximum clock frequency 77 48 MHz
C I input capacitance 3.5 3.5 pF
C PD power dissipation capacitance per flip-flop notes 1 and 2 17 17 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”.

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PIN DESCRIPTION

PIN NO. SYMBOL NAME AND FUNCTION
1 2, 5, 6, 9, 12, 15, 16, 19 3, 4, 7, 8, 13, 14, 17, 18 10 11 20 OE Q to Q 0 7 D to D 0 7 GND CP V CC 3-state output enable input (active LOW) 3-state flip-flop outputs data inputs ground (0 V) clock input (LOW-to-HIGH, edge-triggered) positive supply voltage
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Fig.2 Logic symbol.

Fig.1 Pin configuration.

Fig.3 IEC logic symbol.

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FUNCTION TABLE

Column 1 Column 2 Column 3 Column 4 Column 5 Column 6
OPERATING MODES INPUTS INTERNAL FLIP-FLOPS OUTPUTS
OE CP D n Q to Q 0 7
load and read register L L ↑ ↑ l h L H L H
load register and disable outputs H H ↑ ↑ l h L H Z Z
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Notes 1. H = HIGH voltage level h = HIGH voltage level one set-up time prior to the LOW-to-HIGH CP transition L = LOW voltage level I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition Z = high impedance OFF-state ↑ = LOW-to-HIGH CP transition

Fig.4 Functional diagram.

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Fig.5 Logic diagram.

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DC CHARACTERISTICS FOR 74HC

For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”. Output capability: bus driver ICC category: MSI

AC CHARACTERISTICS FOR 74HC

GND = 0 V; tr = tf = 6 ns; CL = 50 pF

SYMBOL PARAMETER T (°C) amb UNIT TEST CONDITIONS
74HC V CC (V) WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
t / t PHL PLH propagation delay CP to Q n 50 18 14 165 33 28 205 41 35 250 50 43 ns 2.0 4.5 6.0 Fig.6
t / t PZH PZL 3-state output enable time OE to Q n 41 15 12 150 30 26 190 38 33 225 45 38 ns 2.0 4.5 6.0 Fig.7
t / t PHZ PLZ 3-state output disable time OE to Q n 50 18 14 150 30 26 190 38 33 225 45 38 ns 2.0 4.5 6.0 Fig.7
t / t THL TLH output transition time 14 5 4 60 12 10 75 15 13 90 18 15 ns 2.0 4.5 6.0 Fig.6
t W clock pulse width HIGH or LOW 80 16 14 19 7 6 100 20 17 120 24 20 ns 2.0 4.5 6.0 Fig.6
t su set-up time D to CP n 60 12 10 14 5 4 75 15 13 90 18 15 ns 2.0 4.5 6.0 Fig.8
t h hold time D to CP n 5 5 5 −6 −2 −2 5 5 5 5 5 5 ns 2.0 4.5 6.0 Fig.8
f max maximum clock pulse frequency 6.0 30 35 23 70 83 4.8 24 28 4.0 20 24 MHz 2.0 4.5 6.0 Fig.6

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DC CHARACTERISTICS FOR 74HCT

For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”. Output capability: bus driver ICC category: MSI

Note to HCT types The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications. To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.

INPUT UNIT LOAD COEFFICIENT
OE CP D n 1.25 0.90 0.35

AC CHARACTERISTICS FOR 74HCT

GND = 0 V; tr = tf = 6 ns; CL = 50 pF

SYMBOL PARAMETER T (°C) amb UNIT TEST CONDITIONS
74HCT V CC (V) WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
t / t PHL PLH propagation delay CP to Q n 16 32 40 48 ns 4.5 Fig.6
t / t PZH PZL 3-state output enable time OE to Q n 16 30 38 45 ns 4.5 Fig.7
t / t PHZ PLZ 3-state output disable time OE to Q n 18 28 35 42 ns 4.5 Fig.7
t / t THL TLH output transition time 5 12 15 18 ns 4.5 Fig.6
t W clock pulse width HIGH or LOW 19 11 24 29 ns 4.5 Fig.6
t su set-up time D to CP n 12 7 15 18 ns 4.5 Fig.8
t h hold time D to CP n 5 −3 5 5 ns 4.5 Fig.8
f max maximum clock pulse frequency 26 44 21 17 MHz 4.5 Fig.6

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