8 Detailed Description

8.1 Overview

The SN74HCS273 contains 8 positive-edge-triggered D-type flip-flops with shared direct active low clear (CLR)

input.

Information at the data (D) inputs meeting the setup time requirements is transferred to the (Q) outputs on the

positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a particular voltage level and is not

related directly to the transition time of the positive-going pulse. When CLK is at either the high or low level or

transitioning from a high level to a low level, the D input has no effect at the output.

Information at the data (Q) outputs can be asychronously cleared with a low level input through the clear (CLR)

pin.

8.2 Functional Block Diagram

One of Eight Channels

Shared Control Inputs

One of Eight D-Type Flip-Flops

CLK

C

C

xD

CLR

C

C

C

C

C

C

C

C

xQ

R

R

8.3 Feature Description

8.3.1 Balanced CMOS Push-Pull Outputs

This device includes balanced CMOS push-pull outputs. The term balanced indicates that the device can sink

and source similar currents. The drive capability of this device may create fast edges into light loads, so routing

and load conditions should be considered to prevent ringing. Additionally, the outputs of this device are capable

of driving larger currents than the device can sustain without being damaged. It is important for the output power

of the device to be limited to avoid damage due to overcurrent. The electrical and thermal limits defined in the

Absolute Maximum Ratings must be followed at all times.

Unused push-pull CMOS outputs should be left disconnected.

8.3.2 CMOS Schmitt-Trigger Inputs

This device includes inputs with the Schmitt-trigger architecture. These inputs are high impedance and are

typically modeled as a resistor in parallel with the input capacitance given in the Electrical Characteristics table

from the input to ground. The worst case resistance is calculated with the maximum input voltage, given in the

Absolute Maximum Ratings table, and the maximum input leakage current, given in the Electrical Characteristics

table, using Ohm's law (R = V ÷ I).

www.ti.com

SN74HCS273

SCLS851D – MARCH 2021 – REVISED JANUARY 2023

Copyright © 2023 Texas Instruments Incorporated

Submit Document Feedback

9

Product Folder Links: SN74HCS273