NE555开发板套件编程器的射频评估开发套件开发板规格书PDF中文资料

1 Features

1• 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 Processing

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.