NE555PWR

Part: NE555 — Texas Instruments

Type: Precision Timer

Description: A precision timing circuit capable of producing accurate time delays or oscillation, with timing from microseconds to hours, and an output capable of sinking or sourcing up to 200 mA.

Operating Conditions:

• Supply voltage: 4.5–16 V
• Operating temperature: 0 to 70 °C (suffix-dependent — see Ordering Information for grade-specific ranges)
• Output current: ±200 mA

Absolute Maximum Ratings:

• Max supply voltage: 18 V
• Max continuous current: ±225 mA
• Max junction/storage temperature: 150 °C

Key Specs:

• THRES voltage level (VCC = 15 V): 8.8 V (min) to 11.2 V (max)
• THRES current: 30 nA (typ) to 250 nA (max)
• TRIG voltage level (VCC = 15 V): 4.5 V (min) to 5.6 V (max)
• TRIG current (TRIG at 0 V): 0.5 μA (typ) to 2 μA (max)
• Low-level output voltage (VCC = 15 V, IOL = 10 mA): 0.1 V (typ) to 0.15 V (max)
• High-level output voltage (VCC = 15 V, IOH = -100 mA): 13 V (min) to 13.3 V (typ)
• Supply current (Output low, No load, VCC = 15 V): 10 mA (typ) to 15 mA (max)
• Output-pulse rise time (CL = 15 pF, TA = 25 °C): 100 ns (typ) to 300 ns (max)

Features:

• Timing From Microseconds to Hours
• Astable or Monostable Operation
• Adjustable Duty Cycle
• TTL-Compatible Output Can Sink or Source up to 200 mA

Applications:

• Missing-Pulse Detector
• Frequency Divider
• Pulse-Width Modulation

Package:

• PDIP - P
• SOIC - D
• SOP - PS
• TSSOP - PW
• CDIP - JG
• LCCC - FK

• Timing From Microseconds to Hours
• Astable or Monostable Operation

VCC = 5 V to 15 V, T A = 25 ° C (unless otherwise noted)

over operating free-air temperature range (unless otherwise noted)

• (3) Maximum power dissipation is a function of T J (max), θ JA , and T A . The maximum allowable power dissipation at any allowable ambient temperature is P D = (T J (max) - T A )/ θ JA. Operating at the absolute maximum T J of 150 ° C can affect reliability.
• (4) The package thermal impedance is calculated in accordance with JESD 51-7.
• (5) Maximum power dissipation is a function of T J (max), θ JC , and T C . The maximum allowable power dissipation at any allowable case temperature is P D = (T J (max) - T C )/ θ JC . Operating at the absolute maximum T J of 150 ° C can affect reliability.
• (6) The package thermal impedance is calculated in accordance with MIL-STD-883.

over operating free-air temperature range (unless otherwise noted)

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Figure 10. Typical Monostable Waveforms

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Figure 11. Output Pulse Duration vs Capacitance

As shown in Figure 12, adding a second resistor, R B , to the circuit of Figure 9 and connecting the trigger input to the threshold input causes the timer to self-trigger and run as a multivibrator. The capacitor C charges through RA and RB and then discharges through RB only. Therefore, the duty cycle is controlled by the values of R A and RB.

ÏÏÏÏÏ ÏÏÏÏÏ Astable Operation

This astable connection results in capacitor C charging and discharging between the threshold-voltage level ( ≈ 0.67 × VCC) and the trigger-voltage level ( ≈ 0.33 × VCC). As in the monostable circuit, charge and discharge times (and, therefore, the frequency and duty cycle) are independent of the supply voltage.

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NOTE A: Decoupling CONT voltage to ground with a capacitor can improve operation. This should be evaluated for individual applications. Pin numbers shown are for the D, JG, P, PS, and PW packages.

Figure 12. Circuit for Astable Operation

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ÎÎÎÎÎÎÎÎÎÎ ÎÎÎÎÎÎÎÎÎÎ ÎÎÎÎÎÎÎÎÎÎ Figure 13. Typical Astable Waveforms

Figure 13 shows typical waveforms generated during astable operation. The output high-level duration t H and low-level duration t L can be calculated as follows:

Other useful relationships are shown below.

Output waveform duty cycle