Programmable Timer Single 14-Pin SOP T/R

The HCF4541B is a monolithic integrated circuit fabricated in Metal Oxide Semiconductor technology available in DIP and SOP packages.This device is composed of a 16-stages binary counter, an oscillator controlled by 2 external resistors and a capacitor, an output control logic and an automatic power-on reset circuit. The counter varies on positive-edge clock transition and it can be cleared by the MASTER RESET input. The output from this timer is the Q or Q output from the 8th, 13th, or 16th counter stage. The choice of the stage depends on the time select inputs A or B. The output is available in one of the two modes that can be selected via the MODE input. The output turns out as a continuos square wave, with a frequency equal to the oscillator frequency divided by 2N when this MODE input is a logic "1". When it is a logic "0" and after a MASTER RESET is started, and Q output has been selected, the output goes up to a high state after 2 N-1 counts. It remains in that state till another MASTER RESET pulse is apply or the mode input is a logic "1". The process starts by setting the AUTO RESET input (pin 5) to logic "0" and switching power on. If pin 5 is set to logic "1", the AUTO RESET circuit is not enabled and counting cannot start till a positive MASTER RESET pulse is applied, returning to a low level. The AUTO RESET consumes a remarkable amount of power and should not be used if low power operation is wanted. The frequency of the oscillator depends on the RC network. It can be calculated using the following formula :f = 1 / 2.3 RTC CTCwhere f is between 1KHz and 100KHz and RS =10 KOand ~2 RTC

16 STAGE BINARY COUNTER

LOW SYMMETR. OUTPUT RESISTANCE, TYPICALLY 100O at V_DD = 15V

OSCILLATOR FREQUENCY RANGE : DC to 100KHz

AUTO OR MASTER RESET DISABLES OSCILLATOR DURING RESET TO REDUCE POWER DISSIPATION

OPERATES WITH VERY SLOW CLOCK RISE AND FALL TIMES

BUILT-IN LOW-POWER RC OSCILLATOR

EXTERNAL CLOCK (applied to pin 3) CAN BE USED INSTEAD OF OSCILLATOR

OPERATES AS 2ⁿ FREQUENCY DIVIDER OR AS A SINGLE-TRANSITION TIMER

Q/Q SELECT PROVIDES OUTPUT LOGIC LEVEL FLEXIBILITY

CAPABLE OF DRIVING SIX LOW POWER TTL LOADS, THREE LOW POWER SCHOTTKY LOADS, OR SIXHTL LOADS OVER THE RATED TEMP. RANGE

5V, 10V AND 15V PARAMETRIC RATINGS

100% TESTED FOR QUIESCENT CURRENT AT 20V

MEETS ALL REQUIREMENTS OF JEDEC JESD13B " STANDARD SPECIFICATIONS FOR DESCRIPTIONOF B SERIES CMOS DEVICES"