LM555/I SINGLE TIMER SINGLE TIMER 8 DIP The LM555/ is a highly stable controller capable of producing accurate timing pulses. With monostable operation, the time delay is controlled by one external and one capacitor. With astable operation, the frequency and duty cycle are accurately controlled with two external resistors and one capacitor. FEATURES High Current Drive Capability (= 200mA) 8 SOP Adjustable Duty Cycle Temperature Stability of 0.005%/C Timing From wSec To Hours Turn Off Time Less Than 2uSec APPLICATIONS Precision Timing Pulse Generation Time Delay Generation Sequential Timing ORDERING INFORMATION Device |Package Operating Temperature LMS555CN_| 8DIP 0~ 470C LM555CM_| 8 SOP LMS555CIN | 8 DIP 40 ~ 485C BLOCK DIAGRAM LMS55CIM | 8 SOP vec Contrat Voltage 8 5 Ft Re @-j Ww c +2) Tiager Tr Rs @ypecharge TN oY Flip Flop +4 Reset Output Stage @O Output GND sonprenapanapssanansannnpnanssnsasessecasanel FAIRCHILD a SEMICONDUCTOR =v 1999 Fairchild Semiconductor Corporation Rev. BLM555/I SINGLE TIMER ABSOLUTE MAXIMUM RATINGS (T, = 25c) Characteristic Symbol Value Unit Supply Voltage Vec 16 Vv Lead Temperature (soldering 10sec) TLeab 300 C Power Dissipation Pp 600 mW Operating Temperature Range LM555C T O0~+70 C LM555CI OPR - 40 ~ +85 C Storage Temperature Range Tsta - 65 ~ +150 C ELECTRICAL CHARACTERISTICS (Ta = 25C, Voc = 5 ~ 15V, unless otherwise specified) Characteristic Symbol Test Conditions Min Typ Max Unit Supply Voltage Vec 45 16 Vv Supply Current Voc = 5V, RL = 0 3 6 mA +! (low stable) lec Veo = 15V, RL= 0 75 15 mA *Timing Error (Monostable) * Initial Accuracy ACCUR Ra = 1KQ. to 1.0 3.0 % Drift with Temperature AAT 100KQ 50 ppmeC Drift with Supply Voltage AVAVco | C =0.1pF 0.1 0.5 IN *Timing Error (astable) Ra = 1KQ to 100KQ ?intial Accuracy ACCUR | C=0.i1pF 2.25 % Drift with Temperature AVAT 150 ppm/G Drift with Supply Voltage AVAVec 03 %IN Control Voltage Ve Voc = 15V 9.0 10.0 11.0 Vv Voc = 5V 2.6 3.33 4.0 Vv Threshold Voltage Vu Veo = 15V 10.0 V Voc = 5V 3.33 Vv **Threshold Current hu 0.1 0.25 LA Trigger Voltage Vir Veco = 5V 11 1.67 2.2 Vv Trigger Voltage Vir Veco = 15V 45 5 5.6 Vv Trigger Current kr Vip=0V 0.01 2.0 HA Reset Voltage Vast 0.4 0.7 1.0 Vv Reset Current Inst 0.1 0.4 mA saanepsaseesapananapssansananssapssnsessrananel FAIRCHILD ree SEMICONDUCTOR -wLM555/I SINGLE TIMER ELECTRICAL CHARACTERISTICS (Ta = 25C, Voc = 5 ~ 15V, unless otherwise specified) Characteristic Symbol conditions Min Typ Max Unit Voc = 15V lsink = 10MA 0.06 0.25 Vv Low Output Voltage VoL lsink = 50MA 0.3 0.75 Vv Veco =5V Isink =5mA 0.05 0.35 Vv Voc = 15V lsourcE = 200mA 12.5 Vv High Output Voltage Vou lsounce = 100MA 12.75 13.3 Vv Veco =5V lsourcE = 100mA 2.75 3.3 Vv Rise Time of Output tr 100 ns Fall Time of Output te 100 ns Discharge Leakage Current Ika 20 100 nA Notes: 1. Supply current when output is high is typically 1mA less at Voc = 5V 2. Tested at Vec = 5.0V and Vec= 15V 3. This will determine maximum value of Ra + Rg for 15V operation, the max. total R = 20MQ, and for 5V operation the max. total R = 6.7MQ APPLICATION CIRCUIT C1 Re RA t > AAde . Aad WT Vr WW TRIGGER I THRESHOLO CONTROL JT scnance 2 7 Low Upper comparator comparator GND Ra Ra Ri 3+) Wy NM ) vec id Flip-Flop L_()_! 4 3 Output sonprenapanapssanansannnpnanssnsasessecasanel FAIRCHILD a SEMICONDUCTOR =vLM555/I SINGLE TIMER APPLICATION NOTE The application circuit shows astable mode. Pin 6 (threshold) is tied to Pin 2 (trigger) and Pin 4 (reset) is tied to Vec (Pin 8). The external capacitor C, of Pin 6 and Pin 2 charges through Ra, Re and discharges through Rp only. In the internal circuit of the LM555 one input of the upper comparator is the 2/3 Vcc (*R1 =Re=Rs, another input if it If it is connected Pin 6. As soon as charging C, is higher than 2/3 Vcc, discharge transistor Q,; turns on and C, discharges to collector of transistor Q,. Therefore, the flip-flop circuit is reset and output is low. One input of lower comparator is the 1/3 Vcc, discharge transistor Q, turn off and C; charges through Ra and Rp. Therefore, the flip-flop circuit is set and output is high. So to say, when C, charges through Ra and R, output is high and when C, discharges through Reg output is low. The charge time (output is high) T, is 0.693 (Ra+Rp) C1 and the discharge time (output is low) Tz is 0.693 (Rg C1). Voc-1/3 cco (In Voc-2/3 693) Thus the total period time T is given by T=T, +To = 0.693 (Ra +2Rp) Cy. Then the frequency of astable mode is given by 144 = -L 14 f= ~T (Ra + 2Re)Cy The duty cycle is given by pce. & B2__ ~~ T Ra + 2Rp If you make use of the LM556 you can make two astable modes. sonprenapanapssanansannnpnanssnsasessecasanel FAIRCHILD a SEMICONDUCTOR =vLM555/I SINGLE TIMER Astable Operation The LM555 can free run as a mulitivibrator by triggering itself; refer to Fig.2. The output can swing from Vpp to GND and have 50 duty cycle square wave. Less than 1% frequency deviation can be observed, over a voltage range of 2 to 5V. f-1/1.4RC 0 Voc GND 1 ttt TRIGGER e ALTERNATE LM555C OUTPUT OUTPUT THRESHOLD a pe AAA Fig. 1. Astable Operation fit Cc Monostable Operation The LM555 can be used as a one-short, i.e. monostable multivibrator. Initially, because the inside discharge transistor is on state, external timing capacitor is held to GND potential. Upon application of a negative TRIGGER pulse pin 2, the intern discharge transistor is off state and the voltage across the capacitor increases with time constant T = RaC and OUTPUT goes to high state. When the voltage across the capacitor equals 2/3Vcc the inner comparator is reset by THRESHOLD input and the discharge transistor goes to on state, which in turn discharges the capacitor rapidly and drives the OUTPUT to its low state. Voc( 18V) Ra 8 uy | | TRIGGER 7] DISCHARGE LM555C fl OUTPUT re] THRESHOLD Lt RESET ig v OPTION = o-_ CAPACITOR | + TT Fig. 2. Monostable Operation saanepsaseesapananapssansananssapssnsessrananel FAIRGHILED eee SEMICONDUCTOR =vTRADEMARKS The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. 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