SN74LS374

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Octal D-Type Edge Triggered Flip-Flops with 3-State Outputs

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Product details

Parameters

Technology Family LS Input type Bipolar Output type 3-State VCC (Min) (V) 4.75 VCC (Max) (V) 5.25 Channels (#) 8 Clock Frequency (Max) (MHz) 35 ICC (uA) 40000 IOL (Max) (mA) 24 IOH (Max) (mA) -2.6 Features High speed (tpd 10-50ns) Rating Catalog open-in-new Find other D-type flip-flop

Package | Pins | Size

PDIP (N) 20 229 mm² 24.33 x 9.4 SOIC (DW) 20 132 mm² 12.8 x 10.3 SOP (NS) 20 98 mm² 12.6 x 7.8 SSOP (DB) 20 38 mm² 5.3 x 7.2 open-in-new Find other D-type flip-flop

Features

  • Choice of Eight Latches or Eight D-Type Flip-Flops in a Single Package
  • 3-State Bus-Driving Outputs
  • Full Parallel Access for Loading
  • Buffered Control Inputs
  • Clock-Enable Input Has Hysteresis to Improve Noise Rejection (’S373 and ’S374)
  • P-N-P Inputs Reduce DC Loading on Data Lines (’S373 and ’S374)

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Description

These 8-bit registers feature 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. The high-impedance 3-state and increased high-logic-level drive provide these registers with the capability of being connected directly to and driving the bus lines in a bus-organized system without need for interface or pullup components. These devices are particularly attractive for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.

The eight latches of the ’LS373 and ’S373 are transparent D-type latches, meaning that while the enable (C or CLK) input is high, the Q outputs follow the data (D) inputs. When C or CLK is taken low, the output is latched at the level of the data that was set up.

The eight flip-flops of the ’LS374 and ’S374 are edge-triggered D-type flip-flops. On the positive transition of the clock, the Q outputs are set to the logic states that were set up at the D inputs.

Schmitt-trigger buffered inputs at the enable/clock lines of the ’S373 and ’S374 devices simplify system design as ac and dc noise rejection is improved by typically 400 mV due to the input hysteresis. A buffered output-control (OC) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly.

OC\ does not affect the internal operation of the latches or flip-flops. That is, the old data can be retained or new data can be entered, even while the outputs are off.

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Technical documentation

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Type Title Date
* Datasheet Octal D-Type Transparent Latches And Edge-Triggered Flip-Flops datasheet (Rev. B) Aug. 23, 2002
Selection guides Logic Guide (Rev. AB) Jun. 12, 2017
Application notes Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) Dec. 02, 2015
Application notes Power-Up Behavior of Clocked Devices (Rev. A) Feb. 06, 2015
User guides LOGIC Pocket Data Book (Rev. B) Jan. 16, 2007
Application notes Semiconductor Packing Material Electrostatic Discharge (ESD) Protection Jul. 08, 2004
More literature Logic Cross-Reference (Rev. A) Oct. 07, 2003
Application notes TI IBIS File Creation, Validation, and Distribution Processes Aug. 29, 2002
Application notes Designing With Logic (Rev. C) Jun. 01, 1997
Application notes Designing with the SN54/74LS123 (Rev. A) Mar. 01, 1997
Application notes Input and Output Characteristics of Digital Integrated Circuits Oct. 01, 1996
Application notes Live Insertion Oct. 01, 1996

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

EVALUATION BOARDS Download
document-generic User guide
$10.00
Description
This EVM is designed to support any logic device that has a D, DW, DB, NS, PW, P, N, or DGV package in a 14 to 24 pin count.
Features
  • Board design allows for versatility in evaluation
  • Supports a wide-range of logic devices

Design tools & simulation

SIMULATION MODELS Download
SDLM010A.ZIP (6 KB) - IBIS Model

CAD/CAE symbols

Package Pins Download
PDIP (N) 20 View options
SO (NS) 20 View options
SOIC (DW) 20 View options
SSOP (DB) 20 View options

Ordering & quality

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