A
DVANCED
L
INEAR
D
EVICES,
I
NC.
ALD555
HIGH SPEED CMOS TIMER
GENERAL DESCRIPTION
The ALD555 timer is a high performance monolithic timing circuit built with
advanced silicon gate CMOS technology. It offers the benefits of high
input impedance, thereby allowing smaller timing capacitors and longer
timing cycle; high speed, with typical cycle time of 500ns; low power
dissipation for battery operated environment; reduced supply current
spikes, allowing smaller and lower cost decoupling capacitors. It is
capable of producing accurate time delays and oscillations in both
monostable and astable operation. It operates in the one-shot (mono-
stable) mode or 50% duty cycle free running oscillation mode with a single
resistor and one capacitor. The inputs and outputs are fully compatible
with CMOS, NMOS or TTL logic.
There are three matched internal resistors (approximately 200KΩ each)
that set the threshold and trigger levels at two-thirds and one-third
respectively of V +
.
These levels can be adjusted by using the control
terminal (pin 5). When the trigger input is below the trigger level, the
output is in the high state and sourcing 2mA. When threshold input is
above the threshold level at the same time the trigger input is above the
trigger level, the internal flip-flop is reset, the output goes to the low state
and sinks up to 10mA. The reset input overrides all other inputs and when
it is active (reset voltage less than 1V), the output is in the low state.
FEATURES
• Functional equivalent to NE555 with greatly expanded high
and low frequency ranges
• High speed, low power, monolithic CMOS technology
• Low supply current 100
µ
A typical
• Extremely low trigger, threshold and reset currents -- 1pA typical
• High speed operation -- 2MHz oscillation
• Low operating supply voltage 2 to 12V
• Operates in both monostable and astable modes
• Fixed 50% duty cycle or adjustable duty cycle
CMOS, NMOS and TTL compatible input/output
• High discharge sinking current (80mA)
• Low supply current spikes
ORDERING INFORMATION
Operating Temperature Range *
-55°C to +125°C
0°C to +70°C
0°C to +70°C
8-Pin
CERDIP
Package
ALD555 DA
8-Pin
Small Outline
Package (SOIC)
ALD555 SA
8-Pin
Plastic Dip
Package
ALD555 PA
APPLICATIONS
•
High speed one-shot (monostable)
•
•
•
•
•
•
pulse generation
Precision timing
Sequential timing
Long delay timer
Pulse width and pulse position
modulation
Missing pulse detector
Frequency divider
PIN CONFIGURATION
GROUND
TRIGGER
OUTPUT
RESET
1
2
3
4
8
7
6
5
V
+
DISCHARGE
THRESHOLD
CONTROL
TOP VIEW
DA, PA, SA PACKAGE
BLOCK DIAGRAM
V
+
(8)
RESET
(4)
THRESHOLD
(6)
CONTROL
(5)
R
R
S
DISCHARGE
(7)
R
OUTPUT
(3)
TRIGGER
(2)
R
GND
(1)
* Contact factory for industrial temperature range
© 1998 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1155 Fax: (408) 747-1286 http://www.aldinc.com
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V
+
Input voltage range
Power dissipation
Operating temperature range
Storage temperature range
Lead temperature, 10 seconds
13.2V
-0.3V to V+ +0.3V
600 mW
0°C to +70°C
-55°C to +125°C
-65°C to +150°C
+260°C
PA,SA package
DA package
OPERATING ELECTRICAL CHARACTERISTICS
T
A
= 25
o
C V + = +5V unless otherwise specified
Parameter
Supply Voltage
Supply Current
Timing error / Astable mode
Initial Accuracy
Drift with Temperature
1
Drift with Supply Voltage
1
Threshold Voltage
Trigger Voltage
Trigger Current
2
Reset Voltage
Reset Current
2
Threshold Current
2
Control Voltage Level
Output Voltage Drop (Low)
Output Voltage Drop (High)
Rise Time of Output
1
Fall Time of Output
1
Discharge Transistor
Leakage Current
Discharge Voltage Drop
Symbol
V+
I
S
Min
2
Typ
Max
12
Unit
V
µA
Test Conditions
100
180
Outputs Unloaded
t
err
∆t/∆T
∆t/∆V
+
V
TH
V
TRIG
I
TRIG
V
RST
I
RST
I
TH
V
CONT
V
OL
V
OH
t
r
t
f
I
DL
3.273
0.4
3.273
1.607
1.0
10.0
0.1
3.333
1.667
.001
0.7
.001
.001
3.333
0.2
2.2
%
ppm/°C
%/V
C = 0.1µF
R
A
= 1KΩ
R
B
= 1KΩ
3.393
1.737
0.2
1.0
0.2
0.2
3.393
0.4
4.2
V
V
nA
V
nA
nA
V
V
V
ns
ns
nA
I
SINK
= 10mA
I
SOURCE
= -2mA
R
L
= 10MΩ
C
L
= 10pF
15
10
.01
30
20
V
DISC
0.5
0.2
1.0
0.4
V
V
I
DISCHARGE
= 80mA
I
DISCHARGE
= 30mA
R
A
= 470Ω
R
B
= 200Ω
C
T
= 200pF
Maximum Frequency
Astable Mode
1
2
f
MAX
1.4
2
MHz
Notes:
Sample tested parameters.
Consists of junction leakage currents with strong temperature dependence.
ALD555
Advanced Linear Devices
9-2
TYPICAL PERFORMANCE CHARACTERISTICS
DISCHARGE OUTPUT SINK CURRENT AS A
FUNCTION OF DISCHARGE LOW VOLTAGE
DISCHARGE SINK CURRENT (mA)
100
MINIMUM PULSE WIDTH
REQUIRED FOR TRIGGERING
800
MINIMUM PULSE WIDTH (ns)
50
20
10
5.0
2.0
1.0
0.5
0.2
0.1
0.01
T
A
= 25°C
V
+
= 12V
V
+
= 5V
V
+
= 2V
700
600
500
400
300
200
100
0
0
T
A
= 25°C
V
+
= 2V
V
+
= 5V
V
+
= 12V
0.02
0.05
0.1
0.2
0.5
1.0
DISCHARGE LOW VOLTAGE (V)
10
20
30
40
LOWEST VOLTAGE LEVEL OF TRIGGER
PULSE ( % V
+
)
FREE RUNNING FREQUENCY AS A
FUNCTION OF R
A,
R
B
AND C
10 mF
FREQUENCY CHANGE IN THE ASTABLE MODE
AS A FUNCTION OF SUPPLY VOLTAGE
+4
100
µF
( R
A
- 2R
B
)
FREQUENCY CHANGE (%)
1 mF
T
A
= 25°C
+3
+2
+1
0
-1
-2
-3
-4
CAPACITANCE
10
µF
1
µF
100 nF
10 nF
1 nF
100 pF
0.1 1.0 10
100 1K 10K 100K 1M 10M 100M
FREQUENCY (Hz)
10
1M 0K
Ω
10
Ω
10
M
Ω
0M
Ω
10
1K
Ω
K
Ω
0
2
4
6
8
10
12
SUPPLY VOLTAGE (V)
TIME DELAY IN THE MONOSTABLE MODE
AS A FUNCTION OF R
A
AND C
10 mF
1 mF
100
µF
SUPPLY CURRENT AS A FUNCTION OF
SUPPLY VOLTAGE
200
180
T
A
= 25°C
R
A
SUPPLY CURRENT (uA)
160
140
120
100
80
60
40
20
0
CAPACITANCE
1K
10
Ω
10
K
Ω
0K
Ω
10
µF
1
µF
100 nF
10 nF
1 nF
100 pF
T
A
= - 40°C
T
A
= + 20°C
T
A
= + 85°C
10
M
0M
Ω
Ω
1G
1M
Ω
10
Ω
100ns 1µs 10µs 100µs 1ms 10ms 100ms 1s
10s
100s
0
2
4
6
8
10
12
TIME DELAY
SUPPLY VOLTAGE (V)
ALD555
Advanced Linear Devices
9-3
PCB Design
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