LND555
PRECISION TIMING CIRCUIT
Gnd
Vcc
Trigger
Discharge
Out
Threshold
Reset
Control Voltage
DATA SHEET
GENERAL DESCRIPTION
Timing from Microseconds to hours
Astable or Monostable Operation
Adjustable
Duty
Cycle
TTL-Compatible Output Can Sink or
Source UP to 200mA
Temperature Stability of 0.005% per C
Direct Replacement for Signetics
NE555 Timers
FEATURES
The LND555 is a monolithic timing circuit
capable of producing accurate time delays or
oscillation. In the time delay 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 may be independently controlled with
two external resistors and a single external
capacitor.
APPLICATIONS
Precision
timing
Pulse
generation
Sequential
timing
Time delay generation
Pulse
width
modulation
Pulse position modulation
Missing pulse detector
PIN CONFIGURATION
1
8
2
7
3
6
4
5
Linear Dimensions, Inc. 445 East Ohio Street, Chicago IL 60611 USA tel 312.321.1810 fax 312.321.1830
www.lineardimensions.com
(T
A
= 25C, unless otherwise specified)
PARAMETER
MIN
MAX
UNITS
Supply Voltage, V
cc
4.5
16
Input Voltage(control, reset,
threshold and trigger)
V
cc
V
Output Current
200
mA
Operating Free-Air Temperature
70
C
Storage Temperature Range, TSTG
-65
+150
RESET
TRIGGER VOLTAGE
THRESHOLD VOLTAGE*
OUTPUT
DISCHARGE SWITCH
Low
Irrelevant
Irrelevant
Low
On
High
<1/3V
CC
High
High
Off
High
>1/3 V
CC
>2/3 V
CC
Low
On
High
>1/3 V
CC
<2/3Vcc
As previously established
*Voltage Levels shown are normal
Absolute Maximum Rating
LND555
Function Table
Block Diagram
RESET can override TRIGGER, which can override THRESHOLD
Linear Dimensions, Inc. 445 East Ohio Street, Chicago IL 60611 USA tel 312.321.1810 fax 312.321.1830
www.lineardimensions.com
(T
A
=25C, Vcc=+5 to +15V, unless otherwise specified )
Parameter
Test Conditions
(see note 2)
Min
Typ
Max
Units
Operating Supply Voltage Range
4.5
16
V
Threshold Voltage Level
V
CC
=15V
V
CC
=5V
8.8
2.4
10
3.3
11.2
4.2
V
V
Threshold Current(see Note 1)
(see Note 1)
30
250
nA
Trigger Voltage Level
V
CC
=15V
V
CC
=5V
4.5
1.1
5
1.67
5.6
2.2
V
Trigger Current
Trigger at 0 V
0.5
2
A
Reset Voltage Level
0.3
0.7
1
V
Reset Current
Reset at V
CC
Reset at 0V
0.1
-0.4
0.4
-1.5
mA
Discharge Leakage Current
20
100
nA
Control Voltage Level
Vcc=15V
V
CC
=5V
9
2.6
10
3.3
11
4
V
V
Low-Level Output Voltage
V
CC
=15V
V
CC
=5V
I
OL
=10mA
I
OL
=50mA
I
OL
=100mA
I
OL
=200mA
I
OL
=5mA
I
OL
=8mA
0.1
0.4
2
2.5
0.25
0.3
0.25
0.75
2.5
0.35
0.4
V
High- Level Output Voltage
V
CC
=15V
I
OL
= -100mA
I
OL
= -200mA
I
OL
= -100mA
12.75
2.75
13.3
12.5
3.3
V
Supply Current
Output low,
No Load
Output High,
No Load
V
CC
=15 V
V
CC
=5 V
V
CC
=15 V
V
CC
=5 V
10
3
9
2
15
6
13
5
mA
Initial Error of Timing Interval
(see Note 3)
Monostable
(note 4)
Astable
(note 5)
T
A
=25
C
1
5
3
13
%
Temperature Coefficient of
Timing Interval
Monostable
Astable
T
A
= MIN to MAX
50
150
150
500
ppm/
C
Supply Voltage Sensitivity of
Timing Interval
Monostable
Astable
T
A
=25
C
0.1
0.3
0.5
1
%/V
Output Pulse Rise Time
C
L
= 15pF, T
A
=25
C
100
300
ns
Output Pulse Fall Time
C
L
= 15pF, T
A
=25
C
100
300
ns
Electrical Characteristics
LND555
Linear Dimensions, Inc. 445 East Ohio Street, Chicago IL 60611 USA tel 312.321.1810 fax 312.321.1830
www.lineardimensions.com
Notes:
1. This parameter influences the maximum value of the timing resistors R
A
and R
B
in the circuit on Figure 1. For example, when
Vcc=5V, the maximum value is R=R
A
+R
B
=3.4 M
, and Vcc=15V, the maximum value is 10M.
2. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
3. Timing interval error is defined as the difference between the measured value and the average value of a random sample from
each process run.
4. Values specified are for a device in a monostable circuit similar to Figure.2, with component values as follow: R
A
=2K
to 100
K
, C=0.1F.
5. Values specified are for a device in an astable circuit similar to Figure.1, with component values as follow: R
A
, R
B
=1K
to
100K
, C=0.1F.
LND555
Typical Application Data
LND555
Figure 1 :Circuit for Astable Operation
Note A : Bypassing the control voltage input to the ground
with a capacitor may improve operation. This should be
evaluated for individual applications
LND555
Figure 2 : Circuit for Monostable Operation
Linear Dimensions, Inc. 445 East Ohio Street, Chicago IL 60611 USA tel 312.321.1810 fax 312.321.1830
www.lineardimensions.com
PDF 
ZIP