ASOT Datasheet | LSI Computer Systems

EATURES: - Minimizes external ponents and power consumption - Factory calibrated timer - Mask programmable from 2.5 minutes to 32 hours APPLICATIONS Control of household appliances, heaters, lighting and AC motors. DESCRIPTION The basic ASOT is a CMOS integrated circuit timer that can be mask programmed from 2.5 minutes to 32 hours as shown in Table 1. The output of the IC is used to turn on a 12V relay and has a duty cycle which can be mask programmed from 5% to 37.5% in 2.5% steps as shown in Table 2. The duty cycle can be selected to optimize operation for a particular relay coil. There are 5 different versions of the IC. The ASOT is a 3-Pin version housed in a TO-92 package. The application schematic is shown in Figure 2. When latching switch S1 is closed, the output turns on energizing relay L1 and keeping switch S1 closed. When the programmed time-out expires, the output turns off deenergizing relay L1 and causing switch S1 to open. The ASOTR is a 4-Pin version as shown in Figure 3. The output turns on in the same manner as in the 3-Pin version. If momentary switch S2 is closed, the timer resets and starts timing out again. The S2 input has an internal pull-up resistor. Every subsequent momentary switch closure resets the timer. As in the 3-Pin version, the output remains on until the timeout expires. The ASOTT is also a 4-Pin version as shown in Figure 4. In this version contacts C1 replace switch S1 and are not accessible. The application of power caused by closing TABLE 1 Timeout Numbers 01 - 10 DIP/SOIC V DD 1 2 3 4 8 7 6 5 NC NC NC January 2002 ASOTR1 and ASOTT1 GND OUT IN DUTY CYCLE IN 8-PIN VERSION TO-92 SIP V DD GND OUT IN ASOT ASOTR and ASOTT V DD GND OUT 3-PIN VERSION 4-PIN VERSION FIGURE 1. PACKAGE OPTIONS the momentary switch S2 causes the output to toggle on as in the 3-Pin version. If the momentary switch is closed again, the output toggles off causing contact C1 to open and power to be removed. The R2 input has an internal...