SE555

NE555 SA555 - SE555 General purpose single bipolar timers Features ■ ■ ■ ■ ■ ■ ■ ■ Low turn off time Maximum operating frequency greater than 500kHz Timing from microseconds to hours Operates in both astable and monostable modes High output current can source or sink 200mA Adjustable duty cycle TTL compatible Temperature stability of 0.005% per °C D SO8 (Plastic micropackage) N DIP8 (Plastic package) Description The NE555 monolithic timing circuit is a highly stable controller capable of producing accurate time delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200mA. Pin connections (top view) 1 2 3 4 8 7 6 5 1 - GND 2 - Trigger 3 - Output 4 - Reset 5 - Control voltage 6 - Threshold 7 - Discharge 8 - VCC March 2007 Rev 4 1/20 www.st.com 20 Contents NE555 - SA555 - SE555 Contents 1 2 3 4 Schematic diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1 4.2 4.3 4.4 4.5 4.6 Monostable operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Astable operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Pulse width modulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Linear ramp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 50% duty cycle oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Additional information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 5 6 7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2/20 NE555 - SA555 - SE555 Schematic diagrams 1 Schematic diagrams Figure 1. Block diagram VCC+ 5kΩ COMP THRESHOLD CONTROL VOLTAGE R FLIP-FLOP 5kΩ COMP TRIGGER DISCHARGE Q OUT S INHIBIT/ RESET 5kΩ RESET S S - 8086 Figure 2. Schematic diagram CONTROL VOLTAGE THRESHOLD COMPARATOR OUTPUT VCC R1 4.7kW R2 830W R3 4.7kW R4 R8 1kW 5kW 5 R12 6.8kW Q21 Q5 Q6 Q7 Q8 Q9 Q19 Q20 R13 R11 5kW 3.9kW D1 Q23 R14 220W Q24 R16 100W R15 4.7kW 3 Q22 THRESHOLD Q1 Q2 Q3 Q4 R9 5kW Q13 Q16 D2 R17 4.7kW Q11 Q12 TRIGGER 2 Q10 Q18 RESET DISCHARGE 4 7 Q14 Q15 Q17 R5 10kW R6 100kW R7 100kW R10 5kW GND 1 TRIGGER COMPARATOR FLIP FLOP 3/20 Absolute maximum ratings and operating conditions NE555 - SA555 - SE555 2 Absolute maximum ratings and operating conditions Table 1. Symbol VCC Tj Tstg Supply voltage Junction temperature Storage temperature range Absolute maximum ratings Parameter Value 18 150 -65 to 150 Unit V °C °C Table 2. Operating conditions Parameter Supply voltage NE555 SA555 SE555 Value Unit Symbol VCC 4.5 to 16 4.5 to 16 4.5 to 18 VCC 0 to 70 -40 to 105 -55 to 125 V Vth, Vtrig, Vcl, Vreset Maximum input voltage Operating free air temperature range NE555 SA555 SE555 V Toper °C 4/20 NE555 - SA555 - SE555 Electrical characteristics 3 Table 3. Symbol Electrical characteristics Tamb = +25°C, VCC = +5V to +15V (unless otherwise specified) SE555 Parameter Min. Supply current (RL = ∝ ) Low stage VCC = +5V VCC = +15V High state VCC = 5V Timing error (monostable) (RA = 2k to 100kΩ C = 0.1μF) , Initial accuracy (1) Drift with temperature Drift with supply voltage Timing error (astable) (RA, RB = 1kΩ to 100kΩ C = 0.1μF, VCC = +15V) , Initial accuracy - (1) Drift with temperature Drift with supply voltage VCL Control voltage level VCC = +15V VCC = +5V Threshold voltage VCC = +15V VCC = +5V Threshold current (2) Trigger voltage VCC = +15V VCC = +5V Trigger current (Vtrig = 0V) Reset voltage (3) NE555 - SA555 Unit Max. Min. Typ. Max. Typ. ICC 3 10 2 5 12 3 10 2 6 15 mA 0.5 30 0.05 2 100 0.2 1 50 0.1 3 0.5 % ppm/°C %/V 1.5 90 0.15 9.6 2.9 9.4 2.7 10 3.33 10 3.33 0.1 4.8 1.45 5 1.67 0.5 0.4 0.7 0.1 0.4 0.1 0.4 2 2.5 0.1 0.05 12.5 13.3 3.3 10.4 3.8 10.6 4 0.25 5.2 1.9 0.9 1 0.4 1 0.15 0.5 2.2 0.25 0.2 0.4 4.5 1.1 9 2.6 8.8 2.4 2.25 150 0.3 10 3.33 10 3.33 0.1 5 1.67 0.5 0.7 0.1 0.4 0.1 0.4 2 2.5 0.3 0.25 12.5 13.3 3.3 11 4 11.2 4.2 0.25 5.6 2.2 2.0 1 0.4 1.5 0.25 0.75 2.5 0.4 0.35 % ppm/°C %/V V Vth Ith Vtrig Itrig Vreset Ireset V µA V µA V mA Reset current Vreset = +0.4V Vreset = 0V Low level output voltage VCC = +15V IO(sink) = 10mA IO(sink) = 50mA IO(sink) = 100mA IO(sink) = 200mA VCC = +5V IO(sink) = 8mA IO(sink) = 5mA High level output voltage VCC = +15V IO(sink) = 200mA IO(sink) = 100mA VCC = +5V IO(sink) = 100mA VOL V VOH 13 3 12.75 2.75 V 5/20 Electrical characteristics Table 3. Symbol NE555 - SA555 - SE555 Tamb = +25°C, VCC = +5V to +15V (unless otherwise specified) SE555 Parameter Min. Typ. 20 Max. 100 Min. Typ. 20 Max. 100 nA Discharge pin leakage current (output high) Vdis = 10V Discharge pin saturation voltage (output low) (4) VCC = +15V, Idis = 15mA VCC = +5V, Idis = 4.5mA Output rise time Output fall time Turn off time (5) (Vreset = VCC) NE555 - SA555 Unit Idis(off) Vdis(sat) 180 80 100 100 0.5 480 200 200 200 180 80 100 100 0.5 480 200 300 300 mV tr tf toff ns µs 1. Tested at VCC = +5V and VCC = +15V. 2. This will determine the maximum value of RA + RB for 15V operation. The maximum total (RA + RB) is 20MΩ for 15V operation and 3.5MΩ for +5V operation. 3. Specified with trigger input high. 4. No protection against excessive pin 7 current is necessary, providing the package dissipation rating is not exceeded. 5. Time measured from a positive pulse (from 0V to 0.8xVCC) on the Threshold pin to the transition from high to low on the Output pin. Trigger is tied to Threshold. 6/20 NE555 - SA555 - SE555 Electrical characteristics Figure 3. Minimum pulse width required for triggering Figure 4. Supply current versus supply voltage Figure 5. Delay time versus temperature Figure 6. Low output voltage versus output sink current Figure 7. Low output voltage versus output sink current Figure 8. Low output voltage versus output sink current 7/20 Electrical characteristics NE555 - SA555 - SE555 Figure 9. High output voltage drop versus output Figure 10. Delay time versus supply voltage Figure 11. Propagation delay versus voltage level of trigger value 8/20 NE555 - SA555 - SE555 Application information 4 4.1 Application information Monostable operation In the monostable mode, the timer generates a single pulse. As shown in Figure 12, the external capacitor is initially held discharged by a transistor inside the timer. Figure 12. Typical schematics in monostable operation VCC = 5 to 15V Reset R1 4 Trigger 2 8 7 NE555 Output 6 C1 3 1 5 Control Voltage 0.01μF The circuit triggers on a negative-going input signal when the level reaches 1/3 VCC. Once triggered, the circuit remains in this state until the set time has elapsed, even if it is triggered again during this interval. The duration of the output HIGH state is given by t = 1.1 R1C1 and is easily determined by Figure 14. Note that because the charge rate and the threshold level of the comparator are both directly proportional to supply voltage, the timing interval is independent of supply. Applying a negative pulse simultaneously to the reset terminal (pin 4) and the trigger terminal (pin 2) during the timing cycle discharges the external capacitor and causes the cycle to start over. The timing cycle now starts on the positive edge of the reset pulse. During the time the reset pulse is applied, the output is driven to its LOW state. When a negative trigger pulse is applied to pin 2, the flip-flop is set, releasing the shortcircuit across the external capacitor and driving the output HIGH. The voltage across the capacitor increases exponentially with the time constant t = R1C1. When the voltage across the capacitor equals 2/3 VCC, the comparator resets the flip-flop which then discharges the capacitor rapidly and drives the output to its LOW state. Figure 13 shows the actual waveforms generated in this mode of operation. When Reset is not used, it should be tied high to avoid any possibility of unwanted triggering. 9/20 Application information Figure 13. Waveforms in monostable operation t = 0.1 ms / div INPUT = 2.0V/div NE555 - SA555 - SE555 OUTPUT VOLTAGE = 5.0V/div CAPACITOR VOLTAGE = 2.0V/div R1 = 9.1kΩ, C1 = 0.01μF, RL = 1kΩ Figure 14. Pulse duration versus R1C1 C (μF) 10 1k Ω 10 k 0.1 0.01 0.001 10 μs R 1.0 Ω 10 0k Ω 1M Ω 1= 100 μs 1.0 ms 10 ms 100 ms 10 M Ω 10 s (t d ) 4.2 Astable operation When the circuit is connected as shown in Figure 15 (pin 2 and 6 connected) it triggers itself and free runs as a multi-vibrator. The external capacitor charges through R1 and R2 and discharges through R2 only. Thus the duty cycle can be set accurately by adjusting the ratio of these two resistors. In the astable mode of operation, C1 charges and discharges between 1/3 VCC and 2/3 VCC. As in the triggered mode, the charge and discharge times and, therefore, frequency are independent of the supply voltage. 10/20 NE555 - SA555 - SE555 Figure 15. Typical schematics in astable operation VCC = 5 to 15V Application information R1 4 Output 3 8 7 NE555 Control Voltage 0.01μF 5 1 2 6 R2 C1 Figure 16 shows the actual waveforms generated in this mode of operation. The charge time (output HIGH) is given by: t1 = 0.693 (R1 + R2) C1 and the discharge time (output LOW) by: t2 = 0.693 (R2) C1 Thus the total period T is given by: T = t1 + t2 = 0.693 (R1 + 2R2) C1 The frequency of oscillation is then: 1 1.44 f = -- = -------------------------------------T ( R1 + 2R2 ) C1 It can easily be found from Figure 17. The duty cycle is given by: R2 D = ------------------------R1 + 2R2 11/20 Application information Figure 16. Waveforms in astable operation t = 0.5 ms / div OUTPUT VOLTAGE = 5.0V/div NE555 - SA555 - SE555 CAPACITOR VOLTAGE = 1.0V/div R1 = R2 = 4.8kΩ, C1= 0.1μF, RL = 1kΩ Figure 17. Free running frequency versus R1, R2 and C1 C (μF) 10 1.0 0.1 0.01 0.001 0.1 R 1 + R2 1M = 10 M 10 0k Ω Ω 1k Ω 10 kΩ Ω 1 10 100 1k 10k f o (Hz) 12/20 NE555 - SA555 - SE555 Application information 4.3 Pulse width modulator When the timer is connected in the monostable mode and triggered with a continuous pulse train, the output pulse width can be modulated by a signal applied to pin 5. Figure 18 shows the circuit. Figure 18. Pulse width modulator VCC RA 4 Trigger 2 8 7 NE555 Output 3 1 6 Modulation Input 5 C 4.4 Linear ramp When the pull-up resistor, RA, in the monostable circuit is replaced by a constant current source, a linear ramp is generated. Figure 19 shows a circuit configuration that will perform this function. Figure 19. Linear ramp VCC RE 4 Trigger 2 R1 8 7 NE555 Output 3 1 2N4250 or equiv. 6 C 5 0.01μF R2 13/20 Application information Figure 20 shows the waveforms generator by the linear ramp. The time interval is given by: (2/3 Vcc RE (R1+R2) C T = --------------------------------------------------------------- VBE = 0.6V R1 Vcc - VBE (R1+R2) NE555 - SA555 - SE555 Figure 20. Linear ramp VCC = 5V Time: 20µs/DIV R1 + 47kΩ R2 = 100kΩ RE = 2.7kΩ C = 0.01µF Top trace: input 3V/DIV Middle trace: output 5V/DIV Bottom trace: output 5V/DIV Bottom trace: capacitor voltage 1V/DIV 4.5 50% duty cycle oscillator For a 50% duty cycle, the resistors RA and RE can be connected as in figure 19. The time period for the output high is the same as for astable operation (see Section 4.2 on page 10): t1 = 0.693 RA C For the output low it is RB – 2RA t 2 = [(R. RB)/(RA+RB)].C.Ln -------------------------2RB – RA Thus the frequency of oscillation is: 1f = ---------------t1 + t2 14/20 NE555 - SA555 - SE555 Figure 21. 50% duty cycle oscillator VCC Application information VCC RA 51kΩ 4 2 8 RB 7 22kΩ NE55 Out 3 1 6 5 0.01μF C 0.01μF Note that this circuit will not oscillate if RB is greater than 1/2 RA because the junction of RA and RB cannot bring pin 2 down to 1/3 VCC and trigger the lower comparator. 4.6 Additional information Adequate power supply by passing is necessary to protect associated circuitry. The minimum recommended is 0.1µF in parallel with 1µF electrolytic. 15/20 Package information NE555 - SA555 - SE555 5 Package information In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com. 16/20 NE555 - SA555 - SE555 Figure 22. DIP8 package mechanical data Dimensions Ref. Min. A A1 A2 b b2 c D E E1 e eA eB L 2.92 3.30 0.38 2.92 0.36 1.14 0.20 9.02 7.62 6.10 3.30 0.46 1.52 0.25 9.27 7.87 6.35 2.54 7.62 10.92 3.81 0.115 4.95 0.56 1.78 0.36 10.16 8.26 7.11 Millimeters Typ. Max. 5.33 0.015 0.115 0.014 0.045 0.008 0.355 0.300 0.240 Min. Package information Inches Typ. Max. 0.210 0.130 0.018 0.060 0.010 0.365 0.310 0.250 0.100 0.300 0.195 0.022 0.070 0.014 0.400 0.325 0.280 0.430 0.130 0.150 17/20 Package information Figure 23. SO8 package mechanical data Dimensions Ref. Min. A A1 A2 b c D H E1 e h L k ccc 0.25 0.40 1° 0.10 1.25 0.28 0.17 4.80 5.80 3.80 4.90 6.00 3.90 1.27 0.50 1.27 8° 0.10 0.010 0.016 1° 0.48 0.23 5.00 6.20 4.00 Millimeters Typ. Max. 1.75 0.25 0.004 0.049 0.011 0.007 0.189 0.228 0.150 Min. NE555 - SA555 - SE555 Inches Typ. Max. 0.069 0.010 0.019 0.010 0.193 0.236 0.154 0.050 0.020 0.050 8° 0.004 0.197 0.244 0.157 18/20 NE555 - SA555 - SE555 Ordering information 6 Ordering information Table 4. Order codes Temperature range 0°C, +70°C NE555D/DT SA555N -40°C, +105°C SA555D/DT SE555N -55°C, + 125°C SE555D/DT SO8 Tube or tape & reel SE555 SO8 DIP8 Tube or tape & reel Tube SA555 SE555N SO8 DIP8 Tube or tape & reel Tube NE555 SA555N Package DIP8 Packing Tube Marking NE555N Part number NE555N 7 Revision history Date 1-Jun-2003 2004-2006 15-Mar-2007 Revision 1 2-3 4 Initial release. Internal revisions Expanded order code table. Template update. Changes 19/20 NE555 - SA555 - SE555 Please Read Carefully: Information in this document is provided solely in connection with ST products. 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