Product details

Function Counter Bits (#) 4 Technology Family HC Supply voltage (Min) (V) 2 Supply voltage (Max) (V) 6 Input type Standard CMOS Output type Push-Pull Features Balanced outputs, High speed (tpd 10-50ns), Positive input clamp diode
Function Counter Bits (#) 4 Technology Family HC Supply voltage (Min) (V) 2 Supply voltage (Max) (V) 6 Input type Standard CMOS Output type Push-Pull Features Balanced outputs, High speed (tpd 10-50ns), Positive input clamp diode
PDIP (N) 16 181 mm² 19.3 x 9.4 SOP (NS) 16 80 mm² 10.2 x 7.8 TSSOP (PW) 16 22 mm² 4.4 x 5
  • 2-V to 6-V VCC Operation (’HC190,191)
  • 4.5-V to 5.5-V VCC Operation (’HCT191)
  • Wide Operating Temperature Range of –55 to 125°C
  • Synchronous Counting and Asynchronous Loading
  • Two Outputs for n-Bit Cascading
  • Look-Ahead Carry for High-Speed Counting
  • Balanced Propagation Delay and Transition Times
  • Standard Outputs Drive Up To 15 LS-TTL Loads
  • Significant Power Reduction Compared to LS-TTL Logic ICs

  • 2-V to 6-V VCC Operation (’HC190,191)
  • 4.5-V to 5.5-V VCC Operation (’HCT191)
  • Wide Operating Temperature Range of –55 to 125°C
  • Synchronous Counting and Asynchronous Loading
  • Two Outputs for n-Bit Cascading
  • Look-Ahead Carry for High-Speed Counting
  • Balanced Propagation Delay and Transition Times
  • Standard Outputs Drive Up To 15 LS-TTL Loads
  • Significant Power Reduction Compared to LS-TTL Logic ICs

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters.

Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock.

When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2).

If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters.

Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock.

When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2).

If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).

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Technical documentation

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Type Title Date
* Data sheet CD54HC190, CD74HC190, CD54HC191, CD74HC191, CD54HCT191, CD74HCT191 datasheet (Rev. E) 07 Oct 2003
Application note Implications of Slow or Floating CMOS Inputs (Rev. E) 26 Jul 2021
Selection guide Logic Guide (Rev. AB) 12 Jun 2017
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) 02 Dec 2015
User guide LOGIC Pocket Data Book (Rev. B) 16 Jan 2007
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection 08 Jul 2004
User guide Signal Switch Data Book (Rev. A) 14 Nov 2003
More literature Logic Cross-Reference (Rev. A) 07 Oct 2003
Application note TI IBIS File Creation, Validation, and Distribution Processes 29 Aug 2002
Application note CMOS Power Consumption and CPD Calculation (Rev. B) 01 Jun 1997
Application note Designing With Logic (Rev. C) 01 Jun 1997
Application note Input and Output Characteristics of Digital Integrated Circuits 01 Oct 1996
Application note Live Insertion 01 Oct 1996
Application note SN54/74HCT CMOS Logic Family Applications and Restrictions 01 May 1996
Application note Using High Speed CMOS and Advanced CMOS in Systems With Multiple Vcc 01 Apr 1996

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Evaluation board

14-24-LOGIC-EVM — Generic Logic EVM Supporting 14 through 24 Pin PW, DB, D, DW, NS, P, N, and DGV Packages

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.
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Evaluation board

TMAG5110-5111EVM — TMAG511x evaluation module for high-sensitivity, 2D, dual-channel, Hall-effect latches

The TMAG5110-5111EVM is a rotary encoding board with dual Hall latches that have separate circuitry for both quadrature (TMAG5110) and speed and direction (TMAG5111) implementations. There are two different magnets and two magnet placement options to highlight the dual-latch capability of pole pitch (...)

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PDIP (N) 16 View options
SO (NS) 16 View options
TSSOP (PW) 16 View options

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