产品介绍

HCF4541 Programmable Timer

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 (see frequency selection table). The output is available in one of the two modes that can be selected via the MODE input pin 10 (see truth table). 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 CTC

where f is between 1KHz and 100KHz and RS ≥ 10 KΩand ~2 RTC

技术特性

• STAGE BINARY COUNTER
• LOW SYMMETR. OUTPUT RESISTANCE, TYPICALLY 100Ω at VDD = 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 SIX HTL 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 DESCRIPTION OF B SERIES CMOS DEVICES

HCF4541 订购信息

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