January 2009 Rev 2 1/16
16
NE556
SA556 - SE556
General-purpose dual bipolar timers
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
The NE556, SA556 and SE556 dual 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 circuits may be triggered and reset on falling
waveforms, and the output structure can source
or sink up to 200 mA.
N
DIP14
(Plastic package)
D
SO14
(Plastic micropackage)
Pin connections
(top view)
Trigger
Output
Control Voltage
4
8
5
6
7
9
10
11
12
13
14
Trigger
Threshold
Discharge
Reset
Output
Discharge
GND
1
2
3
Threshold
Control Voltage
Reset
CC
V
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Schematic diagrams NE556 - SA556 - SE556
2/16
1 Schematic diagrams
Figure 1. Block diagram
Figure 2. Schematic diagram
THRESHOLD
COMP
5k
W
5k
W
5k
W
TRIGGER
R
FLIP-FLOP
S
Q
DISCHARGE
OUT
INHIBIT/
RESET
RESET
COMP
S
+
CONTROL VOLTAGE
VCC
1/2 NE55
6
OUTPUT
CONTROL
VOLTAGE
THRESHOLD
COMPARATOR
VCC
R1
4.7k
W
R2
830
W
Q5 Q6 Q7 Q8 Q9
R3
4.7k
W
R4
1kW
R8
5kW
Q1
Q2 Q3
Q4
Q10
Q11 Q12
Q13
T
HRESHOLD
TRIGGER
RESET
DISCHARGE
G N D
2
4
7
1
Q14
Q15
R5
10k
W
R6
100k
W
R7
100k
W
R10
5kW
Q17
Q16 Q18
R9
5kW
D2
R16
100W
R15
4.7k
W
R14
220W
Q24
Q23
R17
4.7k
W
3
Q22
R13
D1
Q19
Q20
Q21
R12
6.8k
W
5
TRIGGER COMPARATOR FLIP FLOP
R11
5k
W
3.9k
W
NE556 - SA556 - SE556 Absolute maximum ratings and operating conditions
3/16
2 Absolute maximum ratings and operating conditions
Table 1. Absolute maximum ratings
Symbol Parameter Value Unit
VCC Supply voltage 18 V
IOUT Output current (sink and source) ±225 mA
Rthja
Thermal resistance junction to ambient(1)
DIP14
SO-14
1. Short-circuits can cause excessive heating. These values are typical and valid only for a single layer PCB.
80
105
°C/W
Rthjc
Thermal resistance junction to case (1)
DIP14
SO-14
33
31
°C/W
ESD
Human body model (HBM)(2)
2. Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a
1.5kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations
while the other pins are floating.
1000
VMachine model (MM)(3)
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.
150
Charged device model (CDM)(4)
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.
1500
Latch-up immunity 200 mA
TLEAD Lead temperature (soldering 10 seconds) 260 °C
TjJunction temperature 150 °C
Tstg Storage temperature range -65 to 150 °C
Table 2. Operating conditions
Symbol Parameter Value Unit
VCC
Supply voltage
NE556
SA556
SE556
4.5 to 16
4.5 to 16
4.5 to 18
V
Vth, Vtrig,
Vcl, Vreset
Maximum input voltage VCC V
IOUT Output current (sink and source) ±200 mA
Toper
Operating free air temperature range
NE556
SA556
SE556
0 to 70
-40 to 105
-55 to 125
°C
Electrical characteristics NE556 - SA556 - SE556
4/16
3 Electrical characteristics
Table 3. Tamb = +25° C, VCC = +5 V to +15 V (unless otherwise specified)
Symbol Parameter
SE556 NE556 - SA556
Unit
Min. Typ. Max. Min. Typ. Max.
ICC
Supply current (RL ∝) (2 timers)
Low state VCC = +5V
VCC = +15V
High State VCC = +5V
6
20
4
10
24
6
20
4
12
30 mA
Timing error (monostable)
(RA = 2kΩ to 100kΩ, C = 0.1μF)
Initial accuracy (1)
Drift with temperature
Drift with supply voltage
0.5
30
0.05
2
100
0.2
1
50
0.1
3
0.5
%
ppm/°C
%/V
Timing error (astable)
(RA, RB = 1kΩ to 100kΩ, C = 0.1μF, V CC= +15V)
Initial accuracy (1)
Drift with temperature
Drift with supply voltage
1.5
90
0.15
2.25
150
0.3
%
ppm/°C
%/V
VCL
Control voltage level
VCC = +15V
VCC = +5V
9.6
2.9
10
3.33
10.4
3.8
9
2.6
10
3.33
11
4
V
Vth
Threshold voltage
VCC = +15V
VCC = +5V
9.4
2.7
10
3.33
10.6
4
8.8
2.4
10
3.33
11.2
4.2
V
Ith Threshold current (2) 0.1 0.25 0.1 0.25 µA
Vtrig
Trigger voltage
VCC = +15V
VCC = +5V
4.8
1.45
5
1.67
5.2
1.9
4.5
1.1
5
1.67
5.6
2.2
V
Itrig Trigger current (Vtrig = 0V) 0.5 0.9 0.5 2.0 µA
Vreset Reset voltage (3) 0.4 0.7 1 0.4 0.7 1 V
Ireset
Reset current
Vreset = +0.4V
Vreset = 0V
0.1
0.4
0.4
1
0.1
0.4
0.4
1.5
mA
VOL
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
0.1
0.4
2
2.5
0.1
0.05
0.15
0.5
2.2
0.25
0.2
0.1
0.4
2
2.5
0.3
0.25
0.25
0.75
2.5
0.4
0.35
V
VOH
High level output voltage
VCC = +15V IO(sink) = 200mA
IO(sink) = 100mA
VCC = +5V IO(sink) = 100mA
13
3
12.5
13.3
3.3
12.75
2.75
12.5
13.3
3.3
V
NE556 - SA556 - SE556 Electrical characteristics
5/16
Idis(off)
Discharge pin leakage current (output high)
(Vdis = 10V) 20 100 20 100 nA
Vdis(sat)
Discharge pin saturation voltage (output low) (4)
VCC = +15V, Idis = 15mA
VCC = +5V, Idis = 4.5mA
180
80
480
200
180
80
480
200
mV
tr
tf
Output rise time
Output fall time
100
100
200
200
100
100
300
300 ns
toff Turn-off time (5) (Vreset = VCC)0.50.5µs
1. Tested at VCC = +5 V and VCC = +15 V
2. This will determine the maximum value of RA + RB for +15V operation the max total is R = 20 MΩ and for +5 V operation
the max total R = 3.5 MΩ
3. Specified with trigger input high
4. No protection against excessive pin 7 current is necessary, providing the package dissipation rating will not be exceeded
5. Time measured from a positive going input pulse from 0 to 0.8 x VCC into the threshold to the drop from high to low of the
output trigger is tied to threshold.
Table 3. Tamb = +25° C, VCC = +5 V to +15 V (unless otherwise specified) (continued)
Symbol Parameter
SE556 NE556 - SA556
Unit
Min. Typ. Max. Min. Typ. Max.
Electrical characteristics NE556 - SA556 - SE556
6/16
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
NE556 - SA556 - SE556 Electrical characteristics
7/16
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
Application information NE556 - SA556 - SE556
8/16
4 Application information
4.1 Typical application
Figure 12. 50% duty cycle oscillator
t1 = 0.693 RA.C
Figure 13. Pulse width modulator
Output
R
C
1/2
NE556
SE556
6
4
5
7
3
2
1
14
A
(8)
(10)
(9) (11)
(12)
V
CC
51k
W
(13)
22k
W
Rs
0.01nF
t2 = [(RARB)/(RA+RB)]CLn RB 2RA–
2RB RA–
---------------------------
f = t1
t1 t2+
----------------- RB < 1
2
--- RA ti
Output
R
C
1/2
NE556
SE556
6
4
5
7
3
2
1
14
A
(8)
(10)
(9) (11)
(12)
V
CC
(13)
Trigger
MODULATION
INPUT
t2
t1
NE556 - SA556 - SE556 Application information
9/16
Figure 14. Tone burst generator
For a tone burst generator the first timer is used as a monostable and determines the tone
duration when triggered by a positive pulse at pin 6. The second timer is enabled by the high
output or the monostable. It is connected as an astable and determines the frequency of the
tone.
Figure 15. Monostable operation
RA
RB
OutputReset
Output
Control
f =
1.44
R + 2R ) C
B
A
Ground
Ground
0.01
m
FC2
Control
Trigger
Threshold
1/2
NE556
SE556
+15V
Discharge
11
12
8
13
14
9
5
3
10
0.01
m
F
Ground
1/2
NE556
SE556
Trigger
Threshold
C1
Discharge
Trigger
ResetVcc
414
6
1
2
Rt
T = 1.1 R .C1
t
Output
R
1/2
NE556
SE556
A
(10)
(8)
(11)
(12)
V
CC
(13)
RL
RL
7
6
2
1
414
3
C
10nF
(9)
5
Trigger
T = 1.1 R .C
A
Application information NE556 - SA556 - SE556
10/16
Figure 16. Astable operation
t1 = 0.693 (RA + RB) C output high
t2 = 0.693 RBC output low
Output
R
1/2
NE556
SE556
A
(10)
(9)
(11)
(12)
V
CC
(13)
RL
RL
7
5
2
1
414
36
(8)
RB
C
Operating frequency
0.01nF
f =
1.44
R + 2R ) C
B
A
t2
t1
NE556 - SA556 - SE556 Package information
11/16
5 Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Package information NE556 - SA556 - SE556
12/16
5.1 DIP14 package information
Figure 17. DIP14 package mechanical drawing
Note: D and E1 dimensions do not include mold flash or protrusions. Mold flash or protrusions
shall not exceed 0.25 mm.
Table 4. DIP14 package mechanical data
Dimensions
Ref.
Millimeters Inches
Min. Typ. Max. Min. Typ. Max.
A5.330.21
A1 0.38 0.015
A2 2.92 3.30 4.95 0.11 0.13 0.19
b 0.36 0.46 0.56 0.014 0.018 0.022
b2 1.14 1.52 1.78 0.04 0.06 0.07
c 0.20 0.25 0.36 0.007 0.009 0.01
D 18.67 19.05 19.69 0.73 0.75 0.77
E 7.62 7.87 8.26 0.30 0.31 0.32
E1 6.10 6.35 7.11 0.24 0.25 0.28
e2.54 0.10
e1 15.24 0.60
eA 7.62 0.30
eB 10.92 0.43
L 2.92 3.30 3.81 0.11 0.13 0.15
NE556 - SA556 - SE556 Package information
13/16
5.2 SO-14 package information
Figure 18. SO-14 package mechanical drawing
Note: D and F dimensions do not include mold flash or protrusions. Mold flash or protrusions must
not exceed 0.15 mm.
Table 5. SO-14 package mechanical data
Dimensions
Ref.
Millimeters Inches
Min. Typ. Max. Min. Typ. Max.
A 1.35 1.75 0.05 0.068
A1 0.10 0.25 0.004 0.009
A2 1.10 1.65 0.04 0.06
B 0.33 0.51 0.01 0.02
C 0.19 0.25 0.007 0.009
D 8.55 8.75 0.33 0.34
E 3.80 4.0 0.15 0.15
e1.27 0.05
H 5.80 6.20 0.22 0.24
h 0.25 0.50 0.009 0.02
L 0.40 1.27 0.015 0.05
k 8° (max.)
ddd 0.10 0.004
Ordering information NE556 - SA556 - SE556
14/16
6 Ordering information
Table 6. Order codes
Part number Temperature range Package Packing Marking
NE556N 0°C, +70°C DIP14 Tube NE556N
NE556D/DT SO-14 Tube or tape & reel NE556
SA556N -40°C, +105°C DIP14 Tube SA556N
SA556D/DT SO-14 Tube or tape & reel SA556
SE556N -55°C, + 125°C DIP14 Tube SE556N
SE556D/DT SO-14 Tube or tape & reel SE556
NE556 - SA556 - SE556 Revision history
15/16
7 Revision history
Table 7. Document revision history
Date Revision Changes
01-Jun-2003 1 Initial release.
27-Jan-2009 2
Document reformatted.
Added IOUT value in Table 1: Absolute maximum ratings and
Table 2: Operating conditions.
Added ESD tolerance, latch-up tolerance, Rthja and Rthjcin
Table 1: Absolute maximum ratings.
Updated Section 5.1: DIP14 package information and
Section 5.2: SO-14 package information.
NE556 - SA556 - SE556
16/16
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