HEF4541B Datasheet | NXP Semiconductors

DESCRIPTION The HEF4541B is a programmable timer which consists of a 16-stage binary counter, an integrated oscillator to be used with external timing ponents, an automatic power-on reset and output control logic. The frequency of the oscillator is determined by the external ponents Rt and Ct within the frequency range 1 Hz to 100 k Hz. This oscillator may be replaced by an external clock signal at input RS, the timer advances on the positive-going transition of RS. A LOW on the auto reset input (AR) and a LOW on the master reset input (MR) enables the internal power-on reset. A HIGH level at input MR resets the counter independent on all other inputs. Resetting HEF4541B MSI disables the oscillator to provide no active power dissipation. A HIGH at input AR turns off the power-on reset to provide a low quiescent power dissipation of the timer. The 16-stage counter divides the oscillator frequency by 28, 210, 213 or 216 depending on the state of the address inputs (A0, A1). The divided oscillator frequency is available at output O. The phase input (PH) features a plementary output signal. If the mode select input (MODE) is LOW or HIGH the timer can be used respectively as a single transition timer or 2n frequency divider. Fig.1 Functional diagram. HEF4541BP(N): HEF4541BD(F): HEF4541BT(D): 14-lead DIL; plastic (SOT27-1) 14-lead DIL; ceramic (cerdip) (SOT73) 14-lead SO; plastic (SOT108-1) ( ): Package Designator North America FAMILY DATA, IDD LIMITS category MSI Fig.2 Pinning diagram. See Family Specifications January 1995 Philips Semiconductors Product specification Programmable timer HEF4541B MSI Fig.3 Logic diagram. January 1995 Philips Semiconductors Product specification Programmable timer PINNING A0, A1 MODE AR MR PH RTC CTC RS address inputs mode select input auto reset input master reset input phase input external resistor connection (Rt) external capacitor connection (Ct) external resistor connection (RS) or external clock input AR H L X X X...