LS7210

UL ® LSI/CSI LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 TRIGGER CLOCK SELECT OSCILLATOR EXTERNAL CLOCK V DD (-V) LS7210 (631) 271-0400 FAX (631) 271-0405 February 1998 PIN ASSIGNMENT - TOP VIEW A3800 PROGRAMMABLE DIGITAL DELAY TIMER FEATURES: Programmable Delay from 6 ms to "Infinity" Can be Cascaded for Sequential Events or Extended Delay +4.75V to +15V Operation (Vss -VDD) On Chip Oscillator or External Clock time base High Noise Immunity LS7210 (DIP), LS7210-S (SOIC)-See Figure 1 DESCRIPTION: The LS7210 is a monolithic MOS integrated circuit programmable digital timer that can generate a delay in the range of 6ms to infinity. The delay is programmed by 5 binary weighted input bits in combination with the time base provided. The chip can be operated in four different modes: Delayed Operate, Delayed Release, Dual Delay and One Shot. These modes are selected by the control inputs A and B. INPUT/OUTPUT DESCRIPTION: OSCILLATOR Input (Pin 5) The frequency of the internal oscillator is set by an RC network connected to the OSC input, as shown in Figure 2. The nominal oscillator frequency, f, at room temperature is given by f≈1/RC where R values range from a minimum of 47KΩ to a maximum 3MΩ. NOTE: Oscillation accuracy from chip to chip for a fixed value of RC, is + 10%. (Parts can supplied to tighter tolerances.) B 1 A 2 3 14 13 12 V SS (+V) OUT WB0 WB1 WB2 WB3 WB4 LSI LS7210 FIGURE 1 4 5 11 10 9 8 6 7 TABLE 1. WEIGHTING BITS ASSIG...