ST NE555 User Manual

Features

■ Low turn-off time

■ Maximum operating frequency greater than

500 kHz

■ Timing from microseconds to hours

■ Operates in both astable and monostable

modes

■ Output can source or sink up to 200 mA

■ Adjustable duty cycle

■ TTL compatible

■ Temperature stability of 0.005% per °C

Description

NE555

SA555 - SE555

General-purpose single bipolar timers

N

DIP8

(Plastic package)

D

SO8

(Plastic micropackage)

The NE555, SA555, and SE555 monolithic timing circuits are highly stable controllers 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 200 mA.

Pin connections

(top view)

1

2

36

4

1 - GND 2 - Trigger 3 - Output 4 - Reset

8

7

5

5 - Control voltage 6 - Threshold 7 - Discharge 8 - V

CC

January 2012 Doc ID 2182 Rev 6 1/20

www.st.com

20

Schematic diagrams NE555 - SA555 - SE555

1 Schematic diagrams

Figure 1. Block diagram

+

V

CC

5kΩ

THRESHOLD

CONTROL VOLTAGE

TRIGGER

COMP

5kΩ

COMP

5kΩ

R

FLIP-FLOP

S

INHIBIT/ RESET

Q

DISCHARGE

OUT

RESET

Figure 2. Schematic diagram

S

2/20 Doc ID 2182 Rev 6

NE555 - SA555 - SE555 Absolute maximum ratings and operating conditions

2 Absolute maximum ratings and operating conditions

Table 1. Absolute maximum ratings

Symbol Parameter Value Unit

V

CC

I

OUT

R

thja

R

thjc

ESD

Supply voltage 18 V

Output current (sink & source) ±225 mA

(1)

85

125

41 40

1000

100

1500

°C/W

Thermal resistance junction to ambient

DIP8 SO-8

Thermal resistance junction to case

DIP8 SO-8

Human body model (HBM)

Charged device model (CDM)

(2)

(3)

(4)

Latch-up immunity 200 mA

T

LEAD

T

j

T

stg

1. Short-circuits can cause excessive heating. These values are typical.

2. Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a

1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating.

3. Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations while the other pins are floating.

4. Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly to the ground through only one pin. This is done for all pins.

Table 2. Operating conditions

Lead temperature (soldering 10 seconds) 260 °C

Junction temperature 150 °C

Storage temperature range -65 to 150 °C

VMachine model (MM)

Symbol Parameter Value Unit

Supply voltage

V

CC

NE555 SA555 SE555

, V

cl

th

, V

I

OUT

trig

reset

,

Maximum input voltage V

Output current (sink and source) ±200 mA

V

4.5 to 16

4.5 to 18

CC

Operating free air temperature range

T

oper

NE555 SA555 SE555

0 to 70

-40 to 105

-55 to 125

°C

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V

Electrical characteristics NE555 - SA555 - SE555

3 Electrical characteristics

Table 3. T

= +25° C, VCC = +5 V to +15 V (unless otherwise specified)

amb

Symbol Parameter

Supply current (RL = ∝) Low state V

I

CC

High state V

= +5 V

CC

VCC = +15 V

= +5 V

CC

Timing error (monostable) (R

= 2 kΩ to 100 kΩ, C = 0.1 μF)

A

Initial accuracy

(1)

Drift with temperature Drift with supply voltage

Timing error (astable) (R

R

= 1 kΩ to 100 kΩ, C = 0.1 μF, VCC= +15 V)

,

A

B

Initial accuracy

(1)

Drift with temperature Drift with supply voltage

Control voltage level

V

CL

VCC = +15 V

= +5 V

V

CC

Threshold voltage

V

th

V

CC

= +15 V

VCC = +5 V

Threshold current

I

th

(2)

Trigger voltage

V

trig

I

trig

reset

VCC = +15 V

= +5 V

V

CC

Trigger current (V

Reset voltage

(3)

= 0 V) 0.5 0.9 0.5 2.0 µA

trig

Reset current

I

reset

V V

reset

= +0.4 V = 0 V

Low level output voltage

= +15 VI

V

CC

V

OL

VCC = +5 V I

O(sink)

I

O(sink)

I

O(sink)

I

O(sink)

I

O(sink)

= 10 mA

= 50 mA

= 100 mA = 200 mA = 8 mA = 5 mA

SE555 NE555 - SA555

Min. Typ. Max. Min. Typ. Max.

3

10

2

0.5 30

0.05

1.5 90

0.15

9.6

2.9103.33

9.4

2.7103.33

5

12

3

10

2

100

0.2

1

50

0.130.5

2.25 150

0.3

10.4

3.892.6103.33114

10.648.8

2.4103.33

6

15

ppm/°C

11.2

4.2

0.1 0.25 0.1 0.25 µA

4.8

1.4551.67

5.2

1.9

4.5

1.151.67

5.6

2.2

0.4 0.7 1 0.4 0.7 1 V

0.1

0.4

0.1

0.4

2.5

0.1

0.05

0.4 1

0.15

0.5

2

2.2

0.1

0.4

0.1

0.4 2

0.4

1.5

0.25

0.75

2.5

0.25

0.2

0.3

0.25

0.4

0.35

Unit

mA

%

%/V

%

%/V

V

mA

V

4/20 Doc ID 2182 Rev 6

NE555 - SA555 - SE555 Electrical characteristics

Table 3. T

= +25° C, VCC = +5 V to +15 V (unless otherwise specified) (continued)

amb

SE555 NE555 - SA555

Symbol Parameter

Min. Typ. Max. Min. Typ. Max.

High level output voltage

= +15 VI

V

OH

CC

VCC = +5 V I

I

dis(off)

V

dis(sat)

Discharge pin leakage current (output high) V

Discharge pin saturation voltage (output low)

(4)

VCC = +15V, I VCC = +5V, I

t

Output rise time

r

t

Output fall time

f

Turn off time

t

off

1. Tested at VCC = +5 V and VCC = +15 V.

2. This will determine the maximum value of R operation and 3.5 MΩ for +5 V 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 0 V to 0.8 x V output pin. Trigger is tied to threshold.

(5)

O(sink)

I

O(sink)

= 10 V

dis

= 15 mA

dis

= 4.5 mA

dis

(V

reset

= 200 mA = 100 mA = 100 mA

13

3

12.5

13.3

3.3

12.7 5

2.75

12.5

13.3

3.3

20 100 20 100 nA

18080480

200

100 100

200 200

18080480

200

100 100

300 300

= VCC)0.50.5µs

+ RB for 15 V operation. The maximum total (RA + RB) is 20 MΩ for +15 V

A

) on the threshold pin to the transition from high to low on the

CC

Unit

V

mV

ns

Doc ID 2182 Rev 6 5/20

Electrical characteristics NE555 - SA555 - SE555

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

Figure 8. Low output voltage versus output

sink current

6/20 Doc ID 2182 Rev 6

sink current