LSI Computer Systems, Inc. Programmable Timers and Oscillators LS7213R

The LS7213R is a CMOS integrated circuit designed for generating programmable time delays, suitable for applications such as time delay relays in HVAC equipment and industrial controls. It features eight timing ranges and four operational modes: On-Delay (OND), Off-Delay (OFD), Dual-Delay (DLD), and One-Shot (OST). The delay is initiated by a logic transition at the Trigger input, with outputs Out1 and Out2 indicating the completion of the delay. The device includes an on-chip RC controlled oscillator, allowing for flexible timing configurations based on external resistor-capacitor pairs. The timing delay can be calculated using the formula td = s/frc, where s is the selected scale factor and frc is the oscillator frequency. The LS7213R also incorporates a Power-On-Reset (POR) feature and a reset input for aborting delays. Output capabilities include complementary outputs for driving DC loads, with Out1 designed for high current sinking and Out2 for high current sourcing or as a delay-in-progress indicator, depending on the FlashEn input state. The device operates within a supply voltage range of 3.0V to 5.5V and is rated for an operating temperature range of -20¬8C to +85¬8C.