NE555 SA555 NA555

NE555/SA555/NA555
PRECISION TIMERS
Description
Pin Assignments
NEW PRODUCT
These devices are precision timing circuits capable of
producing accurate time delays or oscillation. In the timedelay or monostable mode of operation, the timed interval is
controlled by a single external resistor and capacitor network.
In the astable mode of operation, the frequency and duty
cycle can be controlled independently with two external
resistors and a single external capacitor.
The threshold and trigger levels normally are two-thirds and
one-third, respectively, of VCC. These levels can be altered
by use of the control-voltage terminal. When the trigger input
falls below the trigger level, the flip-flop is set, and the output
goes high. If the trigger input is above the trigger level and
the threshold input is above the threshold level, the flip-flop is
reset and the output is low. The reset (RESET) input can
override all other inputs and can be used to initiate a new
timing cycle. When RESET goes low, the flip-flop is reset,
and the output goes low. When the output is low, a lowimpedance path is provided between discharge (DISCH) and
ground.
(Top View)
GND
VCC
TRIG
DISCH
OUT
THRES
RESET
CONT
SO-8
The output circuit is capable of sinking or sourcing current up
to 200mA. Operation is specified for supplies of 5V to 15V.
With a 5-V supply, output levels are compatible with TTL
inputs.
Features
•
•
•
•
•
•
Timing from microseconds to hours
Astable or monostable operation
Adjustable duty cycle
TTL compatible output can source or sink up to 200mA
“Green” Molding Compound (No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
Notes:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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NE555/SA555/NA555
PRECISION TIMERS
NEW PRODUCT
Pin Descriptions
Pin Name
Pin Number
GND
1
Description
Ground
TRIG
2
Trigger set 1/3VCC
OUT
RESET
CONT
3
4
5
Timer output
Reset active low
External adjustment of internal threshold and trigger voltages
THRES
6
Threshold set to 2/3 VCC
DISCH
7
Low impedance discharge path
VCC
8
Chip supply voltage
Functional Block Diagram
RESET can override TRIG, which can override THRESH
Functional Table
Pin Name
Nominal Trigger
Voltage
Threshold
Voltage
Output
Discharge
Switch
GND
Irrelevant
Irrelevant
Low
On
TRIG
<1/3VCC
Irrelevant
High
Off
OUT
<1/3VCC
<2/3VCC
Low
On
RESET
<1/3VCC
<2/3VCC
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
As previously established
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NE555/SA555/NA555
PRECISION TIMERS
Absolute Maximum Ratings (Note 2) @ TA = 25°C unless otherwise stated
Symbol
NEW PRODUCT
VCC
Parameter
Rating
Unit
18
V
VCC
V
Supply voltage (Note 3)
VI
Input voltage
IO
Output current
±225
mA
θJA
Package thermal resistance Junction-to-Ambient (Note 4)
130
°C/W
CONT, RESET, THRES, TRIG
θJC
Package thermal resistance Junction-to-Case (Note 5)
15
°C/W
TJ
Junction temperature
150
°C
TSTG
Storage temperature
-65 to 150
°C
Recommended Operating Conditions (TA = 25°C)
Symbol
VCC
Notes:
Parameter
Supply voltage
VI
Input voltage
IO
Output current
TA
Operating Ambient Temperature
Min
Max
4.5
16
V
VCC
V
±200
mA
CONT, RESET, THRES, TRIG
NE555
0
70
SA555
NA555
-40
-40
85
105
Unit
°C
2. Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only.
Functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
3. All voltage values are with respect ground.
4. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature
is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability.
5. Maximum power dissipation is a function of TJ(max), θJC, and TA. The maximum allowable power dissipation at any allowable ambient temperature
is PD = (TJ(max) – TC)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability.
Electrical Characteristics (VCC = 5V to 15V, TA = 25°C unless otherwise stated)
Symbol
Parameter
VTH
Threshold voltage level
ITH
Threshold current (Note 6)
VTR
Trigger voltage level
ITR
Trigger current
VRST
RESET voltage level
IRST
RESET current
IDIS
DISCH switch off-state current
VDIS
DISCH saturation voltage with
output low (Note 7)
VCON
CONT voltage (open circuit)
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
Min
Typ.
Max
VCC = 15V
Test conditions
8.8
10
11.2
VCC = 5V
2.4
3.3
4.2
30
250
Unit
V
nA
VCC = 15V
4.5
5
5.6
VCC = 5V
1.1
1.67
2.2
0.5
2
µA
0.3
0.7
1
V
TRIG at 0V
RESET at VCC
0.1
0.4
RESET at 0V
-0.4
-1.5
20
100
VCC = 15V, IDIS = 15mA
180
480
VCC = 5V, IDIS = 4.5mA
80
200
VCC = 15V
9
10
11
VCC = 5V
2.6
3.3
4
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V
mA
nA
mV
V
February 2012
© Diodes Incorporated
NE555/SA555/NA555
PRECISION TIMERS
Electrical Characteristics (VCC = 5V to 15V, TA = 25°C unless otherwise stated)
Symbol
VOL
Parameter
Low level output voltage
Typ.
Max
VCC = 15V, IOL = 10mA
Test conditions
Min
0.1
0.25
VCC = 15V, IOL = 50mA
0.4
0.75
VCC = 15V, IOL = 100mA
2
2.5
VCC = 15V, IOL = 200mA
2.5
VCC = 5V, IOL = 5mA
0.1
0.35
0.15
0.4
VCC = 5V, IOL = 8mA
NEW PRODUCT
VCC = 15V, IOH = -100mA
VOH
High level output voltage
12.75
VCC = 15V, IOH = -200mA
Output low, no load
ICC
Supply current
Output high, no load
TER
TTC
TVCC
Notes:
Initial error of timing interval
(Note 8)
V
3.3
VCC = 15V
10
15
VCC = 5V
3
6
VCC = 15V
9
13
VCC = 5V
2
5
1
3
Each time, monostable
(Note 9)
Each time, astable
(Note 10)
Each time, monostable
Temperature coefficient of timing (Note 9)
interval
Each time, astable
(Note 10)
Supply voltage sensitivity of
timing interval
2.75
V
13.3
12.5
VCC = 5V, IOH = -100mA
Unit
mA
%
2.25
TA = full
range
Each time, monostable
(Note 9)
Each time, astable
(Note 10)
50
ppm/°C
150
0.1
0.5
%/V
0.3
TRI
Output pulse rise time
CL = 15pF
100
300
ns
TFA
Output pulse fall time
CL = 15pF
100
300
ns
6. This parameter influences the maximum value of the timing resistors RA and RB in the circuit of Figure 12. For example, when VCC = 5 V, the
maximum value is R = RA + RB ≉ 3.4MΩ, and for VCC = 15 V, the maximum value is 10MΩ.
7. No protection against excessive pin 7 current is necessary providing package dissipation rating is not exceeded
8. Timing interval error is defined as the difference between the measured value and the average value of a random sample from each process run.
9. Values specified are for a device in a monostable circuit similar to Figure 9, with the following component values: RA = 2kΩ to 100kΩ, C = 0.1uF.
10. Values specified are for a device in an astable circuit similar to Figure 12, with the following component values: RA = 1kΩ to 100kΩ, C = 0.1uF.
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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NE555/SA555/NA555
PRECISION TIMERS
VOL - LOW - LEVEL OUTPUT VOLTAGE (V)
VCC = 5V
4
TA = 105°C
2
1
0.7
TA = 25°C
0.4
0.2
0.1
0.07
TA = -40°C
0.04
0.02
0.01
1
10
7
2
1
0.7
T A = 105°C
0.4
TA = 25°C
0.2
0.1
0.07
TA = -40°C
0.04
0.02
2
4
7 10
20
40 70 100
IOL - LOW LEVEL OUTPUT CURRENT (mA)
Low Level Output Voltage vs.
Low Level Output Current @ VCC = 10V
2
VCC = 15V
TA = 105°C
1
0.7
0.4
0.2
TA = 25°C
TA = -40°C
0.04
1.6
1.4
1.2
T A = 105°C
0.8
0.6
0.4
0
1
2
4
7 10
20
40 70 100
IOL - LOW LEVEL OUTPUT CURRENT (mA)
Low Level Output Voltage vs.
Low Level Output Current @ VCC = 15V
Document number: DS35112 Rev. 4 - 2
TA = 25°C
1
0.2
0.02
NE555/SA555/NA555
TA = -40°C
1.8
2
0.01
1
VCC = 10V
4
2
4
7 10
20
40 70 100
IOL - LOW LEVEL OUTPUT CURRENT (mA)
Low Level Output Voltage vs.
Low Level Output Current @ VCC = 5V
4
0.1
0.07
10
7
0.01
1
(VCC - VOH) VOLTAGE DROP (V)
VOL - LOW - LEVEL OUTPUT VOLTAGE (V)
10
7
VOL - LOW - LEVEL OUTPUT VOLTAGE (V)
NEW PRODUCT
Typical Performance Characteristics
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VCC = 5V to 15V
2
4
7 10
20
40 70 100
IOH - HIGH LEVEL OUTPUT CURRENT (mA)
Drop Between Supply Voltage and Output vs.
High Level Output Current
February 2012
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NE555/SA555/NA555
PRECISION TIMERS
Typical Performance Characteristics (cont.)
1000
14
Output Low, No Load
10
8
TA = 105°C
6
TA = 25°C
4
0
900
TPD - PROPAGATION DELAY TIME (ns)
ICC - SUPPLY CURRENT (mA)
TA = -40°C
2
800
700
600
500
400
300
200
100
0
5
6
7
8
9 10 11 12 13 14 15
VCC - SUPPLY VOLTAGE (V)
Supply Current vs. Supply Voltage
1.015
1.01
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
LOWEST LEVEL of TRIGGER PULSE -xVCC
Propagation Delay Time vs.
Lowest Voltage Level of Trigger Pulse
1.01
1.005
1.005
1
0.995
1
0.995
0.99
0.985
0
0
1.015
PULSE DURATION RELATIVE to VALUE
@ TA = 25°C
PULSE DURATION RELATIVE to VALUE
@ VCC = 10V
NEW PRODUCT
12
5
10
15
VCC - SUPPLY VOLTAGE (V)
Normalized Output Pulse Duration
(Monostable Mode) vs. Supply Voltage
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
20
0.99
0.0985
-75
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-50 -25
0
25
50
75 100 125
TA - FREE AIR TEMPERATURE (°C)
Normalized Output Pulse Duration
(Monostable Mode) vs. Free-Air Temperature
February 2012
© Diodes Incorporated
NE555/SA555/NA555
PRECISION TIMERS
Typical Applications Characteristics
Monostable Operation
For monostable operation, any of the ‘555 timers can be connected as shown in Figure 1. If the output is low, application of a
negative-going pulse to the trigger (TRIG) sets the internal flip-flop and drives the output high. Capacitor C is then charged
through RA until the voltage across the capacitor reaches the threshold voltage of the threshold (THRES) input. If TRIG has
returned to a high level, the output of the threshold comparator resets the internal flip-flop, drives the output low, and
discharges C.
NEW PRODUCT
VCC
(5V to 15V)
RA
5
CONT
4
RL
8
VCC
RESET
7
DISCH
6
THRES
2
TRIG
Input
C
OUT
3
Output
GND
1
Fig 1. Monostable operation
Monostable operation is initiated when TRIG voltage falls below the trigger threshold. Once initiated, the sequence ends only
if TRIG is high for at least 10μs before the end of the timing interval. When the trigger is grounded, the comparator storage
time can be as long as 10μs, which limits the minimum monostable pulse width to 10μs. Because of the threshold level and
saturation voltage of Q1, the output pulse duration is approximately tW = 1.1RAC. Figure 3 is a plot of the time constant for
various values of RA and C. The threshold levels and charge rates both are directly proportional to the supply voltage, VCC.
The timing interval is, therefore, independent of the supply voltage, so long as the supply voltage is constant during the time
interval.
Applying a negative-going trigger pulse simultaneously to RESET and TRIG during the timing interval discharges C and
reinitiates the cycle, commencing on the positive edge of the reset pulse. The output is held low as long as the reset pulse is
low. To prevent false triggering, when RESET is not used, it should be connected to VCC.
Fig. 2 Typical Monostable Waveforms
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
Fig. 3 Output Pulse Duration vs. Capacitance
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PRECISION TIMERS
Typical Applications Characteristics (cont.)
Astable Operation
As shown in Figure 4, adding a second resistor, RB, to the circuit of Figure 1 and connecting the trigger input to the threshold
input causes the timer to self-trigger and run as a multivibrator. The capacitor C charges through RA and RB and then
discharges through RB. Therefore, the duty cycle is controlled by the values of RA and RB.
This astable connection results in capacitor C charging and discharging between the threshold-voltage level (≉0.67VCC) and
NEW PRODUCT
the trigger-voltage level (≉0.33VCC). As in the monostable circuit, charge and discharge times (and, therefore, the frequency
and duty cycle) are independent of the supply voltage.
VCC
(5V to 15V)
0.01µF
Open
RA
RB
(See Note A) 5
CONT
4
RESET
7
DISCH
6
2
RL
8
VCC
OUT
3
Output
THRES
TRIG
C
GND
1
Decoupling CONT voltage to ground with a capacitor can
improve operation. This should be evaluated for individual
applications.
Fig. 5 Typical Astable Waveforms
Fig. 4 Circuit for Astable Operation
Figure 5 shows typical waveforms generated during astable operation. The output high-level duration tH and low-level
duration tL can be calculated as follows:
tH = 0.693(RA +RB)C
tL = 0.693(RB)C
Other useful equations are:
period = tH + tL = 0.693(RA + 2RB)C
frequency = 1.44/(RA + 2RB)C
output driver duty cycle = tL/(tH + tL) = RB/(RA + 2RB)
output waveform duty cycle = tH/(tH + tL) = 1 – RB/(RA + 2RB)
low to high ratio = tL/tH = RB/(RA + RB)
Fig. 6 Free Running Frequency
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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PRECISION TIMERS
Typical Applications Characteristics (cont.)
Missing Pulse Detector
The circuit shown in Figure 7 can be used to detect a missing pulse or abnormally long spacing between consecutive pulses
in a train of pulses. The timing interval of the monostable circuit is retriggered continuously by the input pulse train as long as
the pulse spacing is less than the timing interval. A longer pulse spacing, missing pulse, or terminated pulse train permits the
timing interval to be completed, thereby generating an output pulse as shown in Figure 8.
NEW PRODUCT
Fig. 7 Circuit for Missing Pulse Dectector
Fig. 8 Timing Waveforms for Missing Pulse
Dectector
Frequency Divider
By adjusting the length of the timing cycle, the basic circuit of Figure 1 can be made to operate as a frequency divider. Figure
9 shows a divide-by-three circuit that makes use of the fact that retriggering cannot occur during the timing cycle.
Fig. 9 Divide by Three Circuit Waveforms
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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PRECISION TIMERS
Typical Applications Characteristics (cont.)
Pulse Width Modulation
NEW PRODUCT
The operation of the timer can be modified by modulating the internal threshold and trigger voltages, which is accomplished
by applying an external voltage (or current) to CONT. Figure 10 shows a circuit for pulse-width modulation. A continuous
input pulse train triggers the monostable circuit, and a control signal modulates the threshold voltage. Figure 11 shows the
resulting output pulse-width modulation. While a sine-wave modulation signal is shown, any wave shape could be used.
Fig 10. Circuit for Pulse width modulation
Fig 11. Pulse width modulation timing diagrams
Pulse Position Modulation
As shown in Figure 12, any of these timers can be used as a pulse-position modulator. This application modulates the
threshold voltage and, thereby, the time delay, of a free-running oscillator. Figure 13 shows a triangular-wave modulation
signal for such a circuit; however, any wave shape could be used.
Fig 12. Circuit for pulse position modulation
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
Fig 13. Pulse position modulation timing diagrams
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PRECISION TIMERS
Typical Applications Characteristics (cont.)
Sequential Timer
NEW PRODUCT
Many applications, such as computers, require signals for initializing conditions during start-up. Other applications, such as
test equipment, require activation of test signals in sequence. These timing circuits can be connected to provide such
sequential control. The timers can be used in various combinations of astable or monostable circuit connections, with or
without modulation, for extremely flexible waveform control. Figure 14 shows a sequencer circuit with possible applications in
many systems, and Figure 15 shows the output waveforms.
Fig 14. Circuit for Sequential Timer
Fig 15. Sequential timer waveforms
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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PRECISION TIMERS
Ordering Information
XXXXX X - X
Device
Package
NEW PRODUCT
NE555
SA555
NA555
S : SO-8
Device
Operating
Temperature
Package
Code
Packaging
(Note 10)
NE555S-13
SA555S-13
NA555S-13
0 to 70°C
-40 to 85°C
-40 to 105°C
S
S
S
SO-8
SO-8
SO-8
Notes:
Packing
13 : Tape & Reel
13” Tape and Reel
Quantity
Part Number Suffix
2500/Tape & Reel
2500/Tape & Reel
2500/Tape & Reel
-13
-13
-13
10. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Marking Information
SO-8
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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PRECISION TIMERS
Package Outline Dimensions (All Dimensions in mm)
0.254
SO-8
E1 E
A1
NEW PRODUCT
L
Gauge Plane
Seating Plane
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
SO-8
Dim
Min
Max
A
1.75
A1
0.10
0.20
A2
1.30
1.50
A3
0.15
0.25
b
0.3
0.5
D
4.85
4.95
E
5.90
6.10
E1
3.85
3.95
e
1.27 Typ
h
0.35
L
0.62
0.82
0°
8°
θ
All Dimensions in mm
D
Suggested Pad Layout
SO-8
X
C1
C2
Y
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
Dimensions
X
Y
C1
C2
Value (in mm)
0.60
1.55
5.4
1.27
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PRECISION TIMERS
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
NEW PRODUCT
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changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any
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Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B.
A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or
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concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
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Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2012, Diodes Incorporated
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NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
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