CD4541B CMOS Programmable Timer - High Voltage Type (20V Rating) |

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CMOS Programmable Timer - High Voltage Type (20V Rating)

CMOS Programmable Timer - High Voltage Type (20V Rating) - CD4541B


CD4541B programmable timer consists of a 16-stage binary counter, an oscillator that is controlled by external R-C components (2 resistors and a capacitor), an automatic power-on reset circuit, and output control logic. The counter increments on positive-edge clock transitions and can also be reset via the MASTER RESET input.

The output from this timer is the Q or Q\ output from the 8th, 10th, 13th, or 16th counter stage. The desired stage is chosen using time-select inputs A and B (see Frequency Select Table).

The output is available in either of two modes selectable via the MODE input, pin 10 (see Truth Table). When this MODE input is a logic "1", the output will be a continuous square wave having a frequency equal to the oscillator frequency divided by 2N. With the MODE input set to logic "0" and after a MASTER RESET is initiated, the output (assuming Q output has been selected) changes from a low to a high state after 2N-1 counts and remains in that state until another MASTER RESET pulse is applied or the MODE input is set to a logic "1".

Timing is initialized by setting the AUTO RESET input (pin 5) to logic "0" and turning power on. If pin 5 is set to logic "1", the AUTO RESET circuit is disabled and counting will not start until after a positive MASTER RESET pulse is applied and returns to a low level. The AUTO RESET consumes an appreciable amount of power and should not be used if low-power operation is desired. For reliable automatic power-on reset, VDD should be greater than 5V.

The RC oscillator, shown in Figure 2, oscillates with a frequency determined by the RC network and is calculated using:

Where f is between 1kHz and 100kHz and RS and 2RTC.


  • Low Symmetrical Output Resistance, Typically 100 at VDD = 15V
  • Built-In Low-Power RC Oscillator
  • Oscillator Frequency Range . . . DC to 100kHz
  • External Clock (Applied to Pin 3) can be Used Instead of Oscillator
  • Operates as 2 N Frequency Divider or as a Single-Transition Timer
  • Q/Q\ Select Provides Output Logic Level Flexibility
  • AUTO or MASTER RESET Disables Oscillator During Reset to Reduce Power Dissipation
  • Operates With Very Slow Clock Rise and Fall Times
  • Capable of Driving Six Low Power TTL Loads, Three Low-Power Schottky Loads, or Six HTL Loads Over the Rated Temperature Range
  • Symmetrical Output Characteristics
  • 100% Tested for Quiescent Current at 20V
  • 5V, 10V, and 15V Parametric Ratings
  • Meets All Requirements of JEDEC Standard No. 13B, "Standard Specifications for Description of ’B’ Series CMOS Devices"

Data sheet acquired from Harris Semiconductor


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Part number Order Technology Family VCC (Min) (V) VCC (Max) (V) Bits (#) Voltage (Nom) (V) F @ nom voltage (Max) (MHz) ICC @ nom voltage (Max) (mA) tpd @ nom Voltage (Max) (ns) IOL (Max) (mA) IOH (Max) (mA) Operating temperature range (C) Schmitt trigger Package Group
CD4541B Order now CD4000     3     18     1     10     8     0.3     10000     4     -4     -55 to 125     No     PDIP | 14
SOIC | 14
SO | 14
TSSOP | 14