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NA555P_TI(德州仪器)中文资料_英文资料_价格_PDF手册

2024/6/23 15:48:15

242

NA555P

精密计时器

 


 

                                              更多技术详情请登录www.mroic.cn       


 

 

1 Features

 

• Timing From Microseconds to Hours

• Astable or Monostable Operation

• Adjustable Duty Cycle

• TTL-Compatible Output Can Sink or Source Up to 200 mA

• On Products Compliant to MIL-PRF-38535,All Parameters Are Tested Unless Otherwise Noted. On All Other Products, Production Processing Does Not Necessarily Include Testing of All Parameters.

 

 

 

 

 

2 Applications

 

• Fingerprint Biometrics

• Iris Biometrics

• RFID Reader

 

 

                                                       

 

 

3 Description

 

These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the time-delay or mono-stable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the a-stable 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 output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.