NE555 LINEAR INTEGRATED CIRCUIT SINGLE TIMER DESCRIPTION The Contek NE555 is a highly stable timer integrated circuit. It can be operated in Astable mode and Monostable mode. With monostable operation, the time delay is controlled by one external and one capacitor. With a stable operation, the frequency and duty cycle are accurately controlled with two external resistors and one capacitor. SOP-8 FEATURES *High current driver capability(=200mA) *Adjustable duty cycle *Timing from mSec to Hours *Turn off time less than 2 mSec. DIP-8 APPLICATIONS *Precision timing *Pulse generation *Time delay generation BLOCK DIAGRAM Threshold 6 Vcc Control Voltage Trigger 8 5 2 Contek Tri. Comp. Thr. Comp. Output 3 Output Dischage FlipFlop Reset 4 7 1 GND Contek Microelectronics Co.,Ltd. CONTEK http://www.contek-ic.com E-mail:sales@contek-ic.com 1 NE555 LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATINGS (Ta=25 PARAMETER C) SYMBOL Supply Voltage Power Dissipation Lead Temperature Operating Temperature Storage Temperature VALUE Vcc Pd Tlead Topr Tstg ELECTRICAL CHARACTERISTICS( Ta=25 PARAMETER Supply voltage Supply Current (Note 1) Timing Error(monostable) Initial Accurary(Note 2) Drift with Temperature Drift with Supply Voltage Timing Error(astable) Initial Accurary(Note 2) Drift with Temperature Drift with Supply Voltage Control Voltage SYMBOL Vcc Icc MIN 4.5 Vcc=5V,RL= Vcc=15V,RL= TYP 3 7.5 RA=1k to 100kmW C=0.1mF 1.0 50 0.1 ACCUR Dt/DT Dt/DVcc Vc RA=1k to 100kmW C=0.1mF 2.25 150 0.3 10.0 3.33 10.0 3.33 0.1 1.67 5 0.01 0.7 0.1 VTH Threshold Current(Note 3) Trigger Voltage ITH Vtr Trigger Current Reset Voltage Reset Current Itr Vrst Irst Low Output Voltage VOL VOH Rise Time of Output Fall Time of Output Dischage Leakage Current C ,Vcc=5 ~ 15V) TEST CONDITIONS V mW C C C ACCUR Dt/DT Dt/DVcc Threshold Voltage High Output Voltage UNIT 16 600 300 0 to 70 -65 to 150 tR tF Vcc=15V Vcc=5V Vcc=15V Vcc=5V 9.0 2.6 Vcc=5V Vcc=15V Vtr=0 1.1 4.5 0.4 Vcc=15V Isink=10mA Isink=50mA Vcc=5V Isink=5mA Vcc=15V Isource=200mA Isource=100mA Vcc=5V Isource=100mA 12.75 2.75 ILKG MAX UNIT 3.0 % ppm/ C %/V 16 6 15 0.5 V mA mA 0.25 2.2 5.6 2.0 1.0 0.4 % ppm/ C %/V V V V V mA V V mA V mA 0.06 0.3 0.25 0.75 V V 0.05 0.35 V 11.0 4.0 12.5 13.3 V V 3.3 100 100 20 V nSec nSec nA 100 Note 1:Supply current when output is high is typically 1mA less at Vcc 5V. Note 2:Tested at Vcc=5.0V and Vcc=15V. Note 3:this will determine the maximum value of RA+RB for 15V operation, The maximum total is R=20M W, and for 5V operation the maximum total is R=6.7M W. Contek Microelectronics Co.,Ltd. CONTEK http://www.contek-ic.com E-mail:sales@contek-ic.com 2 NE555 LINEAR INTEGRATED CIRCUIT APPLICATION CIRCUIT RB Threshold C1 Trigger 2 6 RA Discharge 7 5 Q1 Lower comparator Upper comparator R3 1 R2 R1 VCC 8 GND FLIP-FLOP Contek NE555 4 Reset 3 APPLICATION NOTES The application circuit shows astable mode configuration. Pin 6 (Threshold ) is tied to Pin 2 ( Trigger ) and Pin 4 ( reset ) is tied to Vcc ( Pin 8 ). The external capacitor C1 of Pin 6 and Pin 2 charges through RA,RB and dischages through RB only. In the internal circuit of Contek NE555 , one input of the upper comparator is at voltage of 2/3Vcc(R1=R2=R3),another input is connected to Pin 6.As soon as C1 is charging to higher than 2/3Vcc, transistor Q1 is turned ON and discharge C1 to collector voltage of transistor Q1. Therefore, the flip-flop circuit is reset and output is low. One input of lower comparator is at voltage of 1/3Vcc, discharge transistor Q1 turn off and C1 charges through RA and RB. Therefore, the flip-flop circuit is set output high. That is, when C1 charges through RA and RB , output is high and when C1 discharge through RB ,output is low. The charge time(output is high) t1 is 0.6 9 3( RA+RB) C1 and the discharge time (output is low) T2 is 0.6 9 3 RB*C1. 1 Vcc - Vcc 3 =0.693 ln 2 Vcc - Vcc 3 Thus the total period time T is given by T1=0.693*(RA+RB)*C1 T2=0.693*RB*C1 T=T1+T2=0.693(RA+2RB)*C1. Then the frequency of astable mode is given by f = 1 T = 1.44 (RA + RB) * C1 The duty cycle is given by D. C. = T2 T = RB RA + 2RB . Contek Microelectronics Co.,Ltd. CONTEK http://www.contek-ic.com E-mail:sales@contek-ic.com 3