Timing Circuit. XR-L555 Datasheet

XR-L555 Circuit. Datasheet pdf. Equivalent


Exar XR-L555
XR·L555
Micropower Timing Circuit
GENERAL DESCRIPTION
FUNCTIONAL BLOCK DIAGRAM
The XR-L555 is a stable micropower controller capable
of producing accurate timing pulses. It is a direct re-
placement for the popular 555-timer for applications re-
quiring very low power dissipation. The XR-L555 has
approximately 1/15th the power dissipation of the stan-
dard 555-timer and can operate down to 2.7 volts with-
out sacrificing such key features as timing accuracy
and frequency stability. At 5-volt operation, typical
power dissipation of the XR-L555 is 900 microwatts.
The circuit contains independent control terminals for
triggering or resetting if desired. In the monostable
mode of operation, the time delay is controlled by one
external resistor and one capacitor. For astable opera-
tion as an oscillator the free-running frequency and the
duty cycle are accurately controlled with two external
resistors and one capacitor as shown in Figure 2. The
XR-L555 is triggered or reset on falling waveforms. Its
output can source up to 100 mA or drive TIL circuits.
Because of its temperature stability and low-voltage
(2.7V) operation capability, the XR-L555 is ideally suited
as a micropower clock oscillator or VCO for low-power
CMOS systems. It can operate up to 1500 hours with
only two 300 mA-Hr batteries.
FEATURES
Pin Compatible with Standard 555 Timer
Less than 1 mW Power DisSipation (V + = 5V)
Timing from Microseconds to Minutes
Over 1000-Hour Operation with 2 Batteries
Low Voltage Operation (V + = 2.7V)
Operates in Both Monostable and Astable Modes
CMOS TIL and DTL Compatible Outputs
APPLICATIONS
Battery Operated Timing
Micropower Clock Generator
Pulse Shaping and Detection
Micropower PLL Design
Power-On Reset Controller
Micropower Oscillator
Sequential Timing
Pulse Width Modulation
Appliance Timing
Remote-Control Sequencer
ABSOLUTE MAXIMUM RATINGS
Power Supply
18 volts
Power Dissipation (package limitation)
Ceramic Package
385 mW
Plastic Package
300 mW
Derate above + 25°C
2.5 mW/oC
Storage Temperature
- 65°C to + 125°C
ORDERING INFORMATION
Part Number
Package
Operating Temperature
XR-L555M
XR-L555CN
XR-L555CP
Ceramic
Ceramic
Plastic
-55°C to +125°C
DoC to + 70°C
DoC to + 70°C
SYSTEM DESCRIPTION
The XR-L555 is a micropower timing circuit similar to
the industry standard 555-type timer. It is capable of
both monostable and astable operation with timing in-
tervals ranging from low microseconds up through sev-
eral hours. Timing is independent of supply voltage
which may range from 2.7 V to 15 V. The output stage
can sou rce 50 mA.
In the monostabie (one shot) mode, timing is deter-
mined by one resistor and capacitor. Astable operation
(oscillation) requires an additional resistor, which con-
trols duty cycle. An internal resistive divider provides a
reference voltage of 2/3 VCC, the interval is indepen-
dent of supply voltage; however, for maximum accu-
racy, the user should ensure VCC does not vary during
timing.
The output of the XR-L555 is high during the timing in-
terval. It is triggered and reset on falling waveforms.
The control voltage input (Pin 5) may serve as a pulse
width modulation pOint.
For applications requiring dual L555-type timers, see
the XR-L556.
5-78


XR-L555 Datasheet
Recommendation XR-L555 Datasheet
Part XR-L555
Description Micropower Timing Circuit
Feature XR-L555; XR·L555 Micropower Timing Circuit GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM The XR-L555 is a .
Manufacture Exar
Datasheet
Download XR-L555 Datasheet




Exar XR-L555
ELECTRICAL CHARACTERISTICS
Test Conditions: (TA == 2SoC, VCC == + SV, unless otherwise specified.)
XR-L555M t
XR-L555C
XR·L555
PARAMETERS
Supply Voltage
Supply Current
Timing Error
Initial Accuracy
Drift with Temperature
Drift with Supply Voltage
Threshold Voltage
Trigger Voltage
Trigger Current
Reset Voltage
Reset Current
Threshold Current
Control Voltage Level
Output Voltage Drop (Low)
Output Voltage Drop (High)
Rise Time of Output
Fall Time of Output
Discharge Transistor
Leakage
t Tested only at 25°C
MIN
2.7
1.45
4.8
0.4
2.90
9.6
3.0
13
TYP
1S0
O.S
30
0.05
2/3
1.67
5.0
0.5
0.7
0.1
0.1
3.33
10.0
0.1
3.3
13.3
12.5
100
100
0.1
MAX
1S
300
2.0
100
1.9
5.2
1.0
0.25
3.80
10.4
0.3
MIN
2.7
0.4
2.60
9.0
2.75
12.75
TYP
190
1.0
SO
0.05
2/3
1.67
S.O
0.5
0.7
0.1
0.1
3.33
10.0
0.25
3.3
13.3
12.5
100
100
0.1
MAX
1S
SOO
1.0
0.25
4.00
11.0
0.35
UNITS
V
p,A
%
ppm/oC
%IV
x VCC
V
V
p,A
V
mA
p,A
V
V
V
V
V
nsec
nsec
p,A
CONDITIONS
Low State Output
VCC == SV, RL == 00
RA, RS == 1 KO to
100 KO
C == 0.1 p,F
O°C ~ TA ~ 75°C
VCC == 5V
VCC == 15V
VCC == 5V
VCC == 15V
Isink == 1.5 mA
Isource == 10 mA
VCC == 5V
VCC == 15V
Isource == 100 mA
VCC == 15V
~-----'---'--O+VCC
~OUT~P_U_T~_3~
f---l--j
If
TRIGGER 2
XR-L555 t--o----,
O.0 1 IJ F
I CONTROL
-= VOLTAGE
Figure 1. Monostable (One-Shot) Circuit
OUTPOU~T~b3~~_____. ,
LnI
CONTROL
INPUT ""'---"-""'-_..,.---1
f
=
1.46
(R A + 2R S)C
RS
DUTY CYCLE = RA + 2RS
Figure 2. Astable (Free-Running) Circuit
5-79



Exar XR-L555
XR·L555
GENERAL CHARACTERISTICS
400
A360
--~
320
280
-'
I I ) ~Io.
- TA - -25 ;;; ~TA - U5.~
~
~
....v~ 240
If .... ......v!a5: 200 r-
u
V- - "~v.~. 160 f-
120 f-j
?~ 80 J
/'
......
V
~~
,/P"
TA ··7SC- f -
40
2 4 6 8 10 12 14 18 18 20
Figure 3. Supply Curr8nt as a Function 01
Supply VoHag8
MONOSTABLE OPERATION
+4
~ +3 I--
a:
V~ +2
V:;;
CI +1
Z
Vi 0
i=
/S -1
N
1/~ -2
::;;
:5 -3
z
V
-4
o 5 10 15
Flgur8 6. Typical Timing Accuracy as a
Function 01 Supply Voltage
ASTABLE OPERATION
20
_ +2 r---r--,..---r-,..---r---.--r--,
~
~
!ca!:: +1
>~ 0
:l
S -1 I--t--II-I--t--t--t--t--t---f
~
~ -2 I--II-I-+-I-+-I-+--f
:::;
c(
~-31--t--1-+-1--t--~~--f
~ TA _25°C
_4~-L~~-L_~-L_~-L~
o 5 10 15 20
Figure 9. Typical Frequency Stability as a
Function 01 Supply Voltage
500
TA a ds'c
c( 400
- - -E
u
z~300
f---
~-NSvS5"-TmIMOERNA<
w
~2(!!)
;:)
U
~ 100
8:
\
\
;:)
0I/)
r-....
XR·LSSS
TIMER
o 200 - 400 800 800
Figure 12. Comparison 01 Supply Currellt
Transient 01 Conventional 555-Timer with
XR-L555 Micropower Timer
CHARACTERISTIC CURVES
1200
1100
~ 1000
~ 900
~ 800
TA - +2sbc
~ 700
~ GOO
::IE 500
i 400
Z 300
i 200
100 /
f-- ~
III
I
JJ
vce
-
II
2.SVl
III
1/ V
j
/J
/
ILIvJ-c
c
-
I
sv-
V
0.1 0.2 0.3 0.4
Figure 4. Minimum Pulse-Width Required lor
Triggering
-,- r1200
~1000
vcF
-
S
I
V+.TIA-1~0 >
l/1
J
---::::I
>
~
800 f-~A- +25OC
c --"""'
W
~ --2S"C-
Z 600
0
i=
c(
CI
400
~
0
f 200
0.1 0.2 0.3 0.4
Figure 5. Propagation Delay as a Function 01
Voltage Level 01 Trigger Pulse
-I'--r-.
~~
-~25 0 25°C 50
Figure 7. Typical Timing Accuracy as a
Function 01 Temperature (VCC = 51V,
RA = 100KO, C = 0.01 I'F)
75
2.0
~
,:
c(
Oil I.S
.c..
::IE
i= 1.0
~
~ O.S
o:a:IE:
Zo
o
/
V
J
/
~
VI
I
I
0.2 0.4 0.6 0.8 1.0
Figure 8. Normalized Time Delay as a Function
01 Control Voltage
_ +1.5
~
~
~ +1
" ,1\C
>
~ +0.5
:l
8
-..
:l:
1C::- 0.5
:::;
c(
T~ -1
o
Z
-1.5
vcc - 5V
I
-25 0
- r-.............. ...........
25 50 7S
Figure 10. Typical Frequency Stability as a
Function 01 Temperature (RA = RS = 10KO,
C = 0.11'F)
100r-~~r-'--'--~~~
2.0
>u
ffi
:::l I.S
S
S:l: 1.0
N:::;
c(
::;; O.S
oaz:
,
"'~
"~
I~
I i'-..
I
I
o 0.2 0.4 0.6 o.e 1.0
Figure 11. Normalized Frequency 01 Oscillation
as a Function 01 Control Voltage
100 ..-.......- ........--.....--.--.......-...,
.=.u: 10 ~-+--f--+
IIJ
~ 1.0 I---+---t~
cI;
I-
U 0.1
cI;
~
~ 0.01
o
0.001 "--.....iL-i(--.Il.-t---'---l--'
10 JlI 1.0 ml 100 ms 10 I
Figure 13. Timing Period, T, as a Function 01
External R-C Network
.u=:. 10
;:ozw 1.0
U 0.1 I--!---+-~-~~~-~
cI;
Q.
5 0.01
0.001 L---L_..l-_I...---L~..l-~
0.1 1.0 10 100 10K 1.0K 100KHz
Figure 14. Free Running Frequency as a
Function 01 External Timing Components
(Note: R = RA + 2RS)
5-80







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