The NE556 dual monolithic timing circuit is a high-
ly stable controller 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 fre-
quency and the duty cycle are both accurately
controlled with two external resistors and one ca-
pacitor.
The circuit may be triggered and reset on falling
waveforms, and the output structure can source or
sink up to 200mA.
ORDER CODE
Package
Part Number
NE556
SA556
SE556
Temperature Range
N
0°C, 70°C
-40°C, 105°C
-55°C, 125°C
•
•
•
D
•
•
•
D
SO14
(Plastic Micropackage)
PIN CONNECTIONS
(top view)
Discharge
Threshold
1
2
14
13
12
11
10
9
8
VCC
Discharge
Threshold
Control Voltage
Reset
Output
Trigger
Control Voltage 3
Reset
Output
Trigger
GND
4
5
6
7
N =
Dual in Line Package (DIP)
D =
Small Outline Package (SO) - also available in Tape & Reel (DT)
June 2003
1/8
NE556- SA556-SE556
BLOCK DIAGRAM
V
CC
+
5k
W
THRESHOLD
CONTROL VOLTAGE
COMP
R
FLIP-FLOP
5k
W
COMP
TRIGGER
DISCHARGE
Q
OUT 1/2 NE556
S
INHIBIT/
RESET
5k
W
RESET
S
SCHEMATIC DIAGRAM
CONTROL
VOLTAGE
THRESHOLD
COMPARATOR
V
CC
R1
4.7kW
R2
830W
R3
4.7kW
R4 R8
1kW 5kW
5
R12
6.8k
W
Q21
Q5
Q6
Q7
Q8
Q9
Q19
Q20
31R
R11
5k
W
THRESHOLD
Q1
Q2
Q3
Q11 Q12
TRIGGER
2
Q10
Q4
R9
5kW
Q13
Q16
RESET
DISCHARGE
4
7
Q14
GND
1
Q15
Q17
R5
10kW
R6
100kW
R7
100kW
R10
5kW
Q18
R16
100W
R15
4.7kW
D2
R17
4.7kW
Q23
3.9kW
D1
R14
220W
Q24
3
Q22
OUTPUT
TRIGGER COMPARATOR
FLIP FLOP
ABSOLUTE MAXIMUM RATINGS
Symbol
V
CC
T
j
T
stg
Supply Voltage
Junction Temperature
Storage Temperature Range
Parameter
Value
18
150
-65 to 150
Unit
V
°C
°C
OPERATING CONDITIONS
Symbol
Supply Voltage
V
CC
V
th
, V
trig
, V
cl
, V
reset
T
oper
Parameter
NE556
SA556
SE556
Value
4.5 to 16
4.5 to 16
4.5 to 18
V
CC
0 to 70
-40 to 105
-55 to 125
Unit
V
V
°C
Maximum Input Voltage
Operating Free Air Temperature Range
for NE556
for SA556
for SE556
2/8
NE556-SA556-SE556
ELECTRICAL CHARACTERISTICS
T
amb
= +25°C, V
CC
= +5V to +15V (unless otherwise specified)
Symbol
Parameter
Supply Current (RL
∝)
- note
1)
(2 timers)
Low Stage
V
CC
= +5V
V
CC
= +15V
High State
V
CC
= +5V
Timing Error (monostable)
(R
A
= 2k to 100kΩ, C = 0.1µF)
Initial Accuracy - note
2)
Drift with Temperature
Drift with Supply Voltage
Timing Error (astable)
(R
A,
R
B
= 1kΩ to 100kΩ, C = 0.1µF, V
CC
= +15V)
Initial Accuracy - see note 2
Drift with Temperature
Drift with Supply Voltage
Control Voltage Level
V
CC
= +15V
V
CC
= +5V
Threshold Voltage
V
CC
= +15V
V
CC
= +5V
Threshold Current - note
3)
Trigger Voltage
V
CC
= +15V
V
CC
= +5V
Trigger Current (V
trig
= 0V)
4)
SE556
Min.
Typ.
6
20
4
Max.
10
24
NE556 - SA556
Min.
Typ.
6
20
4
Max.
12
30
Unit
I
CC
mA
0.5
30
0.05
2
100
0.2
1
50
0.1
3
0.5
%
ppm/°C
%/V
1.5
90
0.15
9.6
2.9
9.4
2.7
10
3.33
10
3.33
0.1
4.8
1.45
0.4
5
1.67
0.5
0.7
0.1
0.4
0.1
0.4
2
2.5
0.1
0.05
12.5
13.3
3.3
20
100
10.4
3.8
10.6
4
0.25
5.2
1.9
0.9
1
0.4
1
0.15
0.5
2.2
0.25
0.2
4.5
1.1
0.4
9
2.6
8.8
2.4
2.25
150
0.3
10
3.33
10
3.33
0.1
5
1.67
0.5
0.7
0.1
0.4
0.1
0.4
2
2.5
0.3
0.25
12.5
13.3
3.3
20
100
11
4
11.2
4.2
0.25
5.6
2.2
2.0
1
0.4
1.5
0.25
0.75
2.5
0.4
0.35
%
ppm/°C
%/V
V
V
CL
V
th
I
th
V
trig
I
trig
V
reset
V
µA
V
µA
V
mA
Reset Voltage
Reset Current
V
reset
= +0.4V
I
reset
V
reset
= 0V
Low Level Output Voltage
V
CC
= +15V
I
O(sink)
= 10mA
I
O(sink)
= 50mA
I
O(sink)
= 100mA
V
OL
I
O(sink)
= 200mA
V
CC
= +5V
I
O(sink)
= 8mA
I
O(sink)
= 5mA
High Level Output Voltage
V
CC
= +15V
I
O(sink)
= 200mA
V
OH
I
O(sink)
= 100mA
V
CC
= +5V
I
O(sink)
= 100mA
Discharge Pin Leakage Current
I
dis(off)
(output high) (V
dis
= 10V)
Discharge pin Saturation Voltage
(output low) - note
5)
V
dis(sat)
V
CC
= +15V, I
dis
= 15mA
V
CC
= +5V, I
dis
= 4.5mA
t
r
Output rise Time
Output Fall Time
t
f
toff
Turn off Time - note
6)
(V
reset
= V
CC
)
V
13
3
12.75
2.75
V
nA
180
80
100
100
0.5
480
200
200
200
180
80
100
100
0.5
480
200
300
300
mV
ns
µs
1. Supply current when output is high is typically 1mA less.
2. Tested at V
CC
= +5V and V
CC
= +15V
3. This will determine the maximum value of R
A
+ R
B
for +15V operation the max total is R = 20MΩ and for 5V operation the max total R = 3.5MΩ
4. Specified with trigger input high
5. No protection against excessive pin 7 current is necessary, providing the package dissipation rating will not be exceeded
6. Time measured from a positive going input pulse from 0 to 0.8x Vcc into the threshold to the drop from high to low of the output trigger is tied to threshold.
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