USA555中文资料PRECISION TIMERS数据手册UTC规格书

描述 Description

The UTC USA555 monolithic timing circuit is a highly stablecontroller capable of producing accurate time delays or oscillation. In the time-delay or monostable mode of operation, the timed interval is controlled by a single external resistor and capacitor network.   In the astable mode of operation, the frequency and duty cycle can be controlled independently with two external resistors and a single external capacitor. The threshold and trigger levels normally are two-thirds and one-third, respectively, of VCC. These levels can be altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low. The reset (RESET) input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200mA.Operation is specified for supplies of 5V~15V.

特性 Features

• Astable or monostable operation
• Low turn off time
• Operates in both astable and monostable modes
• Timing from microseconds to hours
• Adjustable duty cycle
• TTL-compatible output can sink or source up to 200Ma