LM555/I SINGLE TIMER SINGLE TIMER 8 DIP The LM555/I 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) Adjustable Duty Cycle Temperature Stability of 0.005%/°C Timing From µSec To Hours Turn Off Time Less Than 2µSec 8 SOP APPLICATIONS • • • • Precision Timing Pulse Generation Time Delay Generation Sequential Timing BLOCK DIAGRAM ORDERING INFORMATION Device Package LM555CN LM555CM LM555CIN LM555CIM 8 DIP 8 SOP 8 DIP 8 SOP Operating Temperature 0 ~ +70°C -40 ~ +85°C Rev. B 1999 Fairchild Semiconductor Corporation LM555/I SINGLE TIMER ABSOLUTE MAXIMUM RATINGS (TA = 25°C) Characteristic Supply Voltage Lead Temperature (soldering 10sec) Power Dissipation Operating Temperature Range LM555C LM555CI Storage Temperature Range Symbol Value VCC TLEAD 16 300 PD 600 0 ~ + 70 - 40 ~ + 85 - 65 ~ + 150 TOPR TSTG Unit V °C mW °C °C °C ELECTRICAL CHARACTERISTICS (TA = 25°C, VCC = 5 ~ 15V, unless otherwise specified) Characteristic Supply Voltage Supply Current ∗ (low stable) 1 Symbol ICC ∗Timing Error (Monostable) 2 Initial Accuracy Drift with Temperature Drift with Supply Voltage ACCUR ∆t/∆T ∆t/∆VCC ∗Timing Error (astable) 2 Intial Accuracy Drift with Temperature Drift with Supply Voltage ACCUR ∆t/∆T ∆t/∆VCC Control Voltage VC Threshold Voltage VTH ∗ Threshold Current Trigger Voltage Trigger Voltage Trigger Current VTR VTR ITR Reset Voltage Reset Current VRST IRST 3 Test Conditions Typ Max Unit VCC = 5V, RL = ∞ 3 16 6 V mA VCC = 15V, RL = ∞ 7.5 15 mA RA = 1KΩ to 100KΩ C = 0.1µF 1.0 50 0.1 3.0 % ppm/°C %/V VCC Min 4.5 RA = 1KΩ to 100KΩ C = 0.1µF 0.5 % ppm/°C %/V 2.25 150 0.3 10.0 3.33 10.0 3.33 0.1 11.0 4.0 V V V V 0.25 µA V V VCC = 15V VCC = 5V VCC = 15 V VCC = 5V 9.0 2.6 VCC = 5V VCC = 15V VTR = 0V 1.1 4.5 1.67 5 0.01 2.2 5.6 2.0 0.4 0.7 0.1 1.0 0.4 ITH µA V mA LM555/I SINGLE TIMER ELECTRICAL CHARACTERISTICS (TA = 25°C, VCC = 5 ~ 15V, unless otherwise specified) Characteristic Low Output Voltage High Output Voltage Rise Time of Output Fall Time of Output Discharge Leakage Current Symbol VOL VOH tR tF ILKG Test Conditions VCC = 15V ISINK = 10mA ISINK = 50mA VCC = 5V ISINK = 5mA VCC = 15V ISOURCE = 200mA ISOURCE = 100mA VCC = 5V ISOURCE = 100mA Min 12.75 2.75 Typ Max Unit 0.06 0.3 0.25 0.75 V V 0.05 0.35 V 12.5 13.3 V V 3.3 100 100 20 V ns ns nA 100 Notes: 1. Supply current when output is high is typically 1mA less at VCC = 5V 2. Tested at VCC = 5.0V and VCC = 15V 3. This will determine maximum value of RA + RB for 15V operation, the max. total R = 20MΩ, and for 5V operation the max. total R = 6.7MΩ APPLICATION CIRCUIT LM555/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 VCC (Pin 8). The external capacitor C1 of Pin 6 and Pin 2 charges through RA, RB and discharges through RB only. In the internal circuit of the LM555 one input of the upper comparator is the 2/3 VCC (∗R1 =R2=R3, another input if it If it is connected Pin 6. As soon as charging C1 is higher than 2/3 Vcc, discharge transistor Q1 turns on and C1 discharges to collector of transistor Q1. Therefore, the flip-flop circuit is reset and output is low. One input of lower comparator is the 1/3 VCC, discharge transistor Q1 turn off and C1 charges through RA and RB. Therefore, the flip-flop circuit is set and output is high. So to say, when C1 charges through RA and R1 output is high and when C1 discharges through RB output is low. The charge time (output is high) T1 is 0.693 (RA+RB) C1 and the discharge time (output is low) T2 is 0.693 (RB C1). CC (In VCC-1/3V = 0.693) VCC-2/3VCC Thus the total period time T is given by T=T1 +T2 = 0.693 (RA +2RB) C1. Then the frequency of astable mode is given by f= =1 T 1.44 (RA + 2RB)C1 The duty cycle is given by D.C = T =2 T RB RA + 2RB If you make use of the LM556 you can make two astable modes. LM555/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 VDD 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 Ο VCC 10KΩ GND 1 8 2 7 TRIGGER /// Ο VCC DISCHARGE • Ο ALTERNATE OUTPUT LM555C Ο OUTPUT • THRESHOLD 3 6 4 5 Ο VCC RESET • • Fig. 1. Astable Operation C /// 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. VCC ( 18V) Ο RA 8 1 /// TRIGGER Ο OUTPUT RESET Ο 2 7 • DISCHARGE LM555C 3 6 4 5 THRESHOLD • CONTROL VOLTAGE OPTION CAPACITOR C /// Fig. 2. Monostable Operation • /// TRADEMARKS 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. ACEx™ CoolFET™ CROSSVOLT™ E2CMOSTM FACT™ FACT Quiet Series™ FAST® FASTr™ GTO™ HiSeC™ ISOPLANAR™ MICROWIRE™ POP™ PowerTrench™ QS™ Quiet Series™ SuperSOT™-3 SuperSOT™-6 SuperSOT™-8 TinyLogic™ DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. 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