ALD ALD7555 Single/dual cmos analog rc timer Datasheet

ADVANCED
LINEAR
DEVICES, INC.
ALD7555/ALD7556
SINGLE/DUAL CMOS ANALOG RC TIMER
GENERAL DESCRIPTION
The ALD7555/ALD7556 timers are high performance single/dual monolithic analog RC timing circuits. They offer significantly upgraded performance in speed, leakage currents, supply current, stability, temperature
voltage stability, and discharge output drive when compared to SE555/
NE555,ICL7555, TLC555, and ICM7555.
BENEFITS
• Saves battery power
• Eliminates additional buffer
• Smaller, lower cost capacitor
• Extended range of time constants
APPLICATIONS
• High speed one-shot (monostable)
• Precision sequential timing
• Long delay timer
• Pulse width and pulse position modulation
Each timer is capable of producing accurate time delays and oscillations in • Missing pulse detector
both monostable and astable operation, and operates in the one-shot • Frequency divider
(monostable) mode or 50% duty cycle free running oscillation mode with a • Synchronized timer
single resistor R and one capacitor C. The inputs and outputs are fully
compatible with CMOS, NMOS or TTL logic.
PIN CONFIGURATION
The ALD7555/ALD7556 offer the benefits of high input impedance, thereby
allowing smaller timing capacitors and a longer timing cycle; high speed;
low power dissipation for battery operated environment; reduced supply
current spikes, allowing smaller and lower cost decoupling capacitors.
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.
When the trigger input is below the trigger level, the output is in the high
state and sourcing 2mA. When the 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. The discarge output has been
signifcantly enhanced to eliminate the need for a separate external driver.
FEATURES
• Improved accuracy and temperature stability
• High speed operation -- 2.5MHz typical oscillation at 5V
• High Discharge Sinking Current of 80mA at 5V
• Guaranteed low operating supply voltage of 2V to 10V
• Functional equivalent to and same pin-out as NE555/NE556,
SE555, TLC555, ICM7555/ICM7556
• Greatly expanded high and low frequency ranges
• High speed, low power, monolithic CMOS technology
• Low supply current, typically: 50µA for ALD7555, 100µA for ALD7556
• Extremely low trigger, threshold and reset currents 10pA typical
• Operates in both monostable and astable modes
• Fixed 50% duty cycle or adjustable duty cycle
• CMOS, NMOS and TTL compatible input/output
• Low supply current spikes
• Rail to rail output
ORDERING INFORMATION (“L” suffix denotes lead-free (RoHS))
0°C to +70°C
Operating Temperature Range *
0°C to +70°C
-55°C to +125°C
8-Pin Small Outline
Package (SOIC)
ALD7555SAL
8-Pin Plastic
DIP Package
ALD7555PAL
8-Pin CERDIP
Package
ALD7555DA
14-Pin Small Outline
Package (SOIC)
ALD7556SBL
14-Pin Plastic
DIP Package
ALD7556PBL
14-Pin CERDIP
Package
ALD7556DB
ALD7555
V+
1
8
TRIG
2
7
DISC
OUT
3
6
THRES
RST
4
5
CONT
GND
SAL, PAL, DA PACKAGES
ALD7556
DSC1
1
14
V+
THRES1
2
13
DSC2
CONT1
3
12
THRES2
RST1
4
11
CONT2
OUT1
5
10
RST2
TRIG1
6
9
OUT2
GND
7
8
TRIG2
SBL, PBL, DB PACKAGES
BLOCK DIAGRAM (EACH TIMER)
V+
(8)
RESET
(4)
THRESHOLD
(6)
CONTROL
(5)
R
R
OUTPUT
(3)
R
S
TRIGGER
(2)
DISCHARGE
(7)
R
GND
(1)
* Contact factory for leaded (non-RoHS) or high temperature versions.
Rev 2.0 ©2010 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, CA 94089-1706 Tel: (408) 747-1155 Fax: (408) 747-1286
www.aldinc.com
ABSOLUTE MAXIMUM RATINGS
Supply voltage, V+
Input voltage range
Power dissipation
Operating temperature range
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
SAL, SBL, PAL, PBL package
DA, DB package
Storage temperature range
Lead temperature, 10 seconds
OPERATING ELECTRICAL CHARACTERISTICS
TA = 25oC V+ = +5V unless otherwise specified
Parameter
Symbol
Supply Voltage
V+
Supply Current ALD7555
Supply Current ALD7556
IS
IS
Timing error / Astable mode
Initial Accuracy
terr
Drift with Temperature 1
Drift with Supply Voltage 1
∆t/∆T
∆t/∆V+
Threshold Voltage
VTH
3.233
3.333
3.433
V
Trigger Voltage
VTRIG
1.567
1.667
1.767
V
Trigger Current 2
ITRIG
.01
0.4
nA
Reset Voltage
VRST
0.7
1.0
V
Reset Current 2
IRST
.01
0.4
nA
Threshold Current 2
ITH
.01
0.4
nA
Control Voltage Level
VCONT
3.333
3.467
V
Output Voltage Drop (Low)
VOL
0.2
0.4
V
ISINK = 10mA
Output Voltage Drop (High)
VOH
V
ISOURCE = -2mA
Rise Time of Output 1
tr
10
30
ns
RL = 10MΩ
Fall Time of Output 1
tf
10
30
ns
CL = 10pF
Discharge Transistor
Leakage Current
IDL
.01
10
nA
Discharge Voltage Drop
VDISC
0.5
0.2
1.0
0.4
V
V
I DISCHARGE = 80mA
I DISCHARGE = 30mA
Maximum Frequency
Astable Mode
fMAX
MHz
RA = 470Ω
RB = 200Ω
CT =100pF
Minimum Trigger Pulse Width1
tTRIG
Notes:
1
2
ALD7555/ALD7556
Min
Typ
2
Max
3.200
4.2
1.0
Test Conditions
10
V
50
100
90
180
µA
µA
Outputs Unloaded
1.0
2.5
%
C = 0.1µF
ppm/°C
%/V
RA = 1KΩ
RB = 1KΩ
10.0
0.2
0.4
Unit
4.6
2.5
50
100
ns
Sample tested parameters.
Consists of junction leakage currents with strong temperature dependence.
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APPLICATION NOTES
GENERAL INFORMATION
The ALD7555 and the ALD7556 devices are analog timers
that are, in most situations, direct replacements or direct same
pin-out upgrades for the ICM7555, ICM7556, NE/SE555 and
NE/SE556 devices. Significantly improved performances for
the ALD7555 and the ALD7556 include precision in timing,
reduced leakage currents at all the pin terminals, faster
switching speeds, reduced switching current spikes, enhanced discharge output drive currents, better temperature
stability, and better timing stability as a function of power
supply.
These improvements not only improve on the timer function,
but also improve on many of the thousands of circuits that
depend on this timer architecture, such as modulation circuits, Schmitt triggers, astable circuits, and myriads of measurement and control circuits where the user may have
reached performance limits with their ICM7555, ICM7556,
NE/SE555 and NE/SE556 devices. For a given design, one
or more specification of the timer device may become the
circuit performance limiting factor. The ALD7555 and the
ALD7556 devices are designed to address such limitations
and in many cases offer a solution that is simpler and lower
cost for a given design challenge than by other solutions by
using other circuit means and techniques.
The three most basic modes of these external connections
are shown as Astable Mode (Free Running Mode), 50% Duty
Cycle Mode, and the Monostable Mode. See Typical Applications. There are thousands of application circuits developed that allow the user to manipulate this feedback function, and which then produces many unique functions that is
beyond a basic timer function. The application versatility of
The ALD7555 and the ALD7556 is only limited by the imagination of the circuit designer.
LOW POWER SUPPLY REQUIREMENTS
The CMOS process and the design of the ALD7555 and the
ALD7556 devices utilize three well-matched on-chip high
impedance resistors to build the internal reference resistor
string to provide very low power supply operation. Another
technique to achieve low power supply requirement is by
using low power MOSFET circuits on-chip, and by allowing
the user to use a combination of off-chip timing resistor and
capacitor that would reduce their power consumption as well.
Generally, this is accomplished by using higher values for R
and lower values for C in a combination that would still provide the timing required. Furthermore, reduced on-chip leakage currents improve on not only timing precision, but also
greatly increased ranges of usable R and C values to generate the same RC time constant.
ARCHITECTURE
ENHANCED DISCHARGE OUTPUT DRIVE
The ALD7555 and the ALD7556 are analog timers that operate based on the RC timing principle, using an external timing resistor R and an external timing capacitor C. The C is
charged by the R and then discharged via one of the two
output pin connections provided by the ALD7555 and the
ALD7556. The control of the two outputs are provided by
one of the 4 input pins. The inputs are named THRESHOLD, CONTROL, RESET and TRIGGER. THRESHOLD and
TRIGGER are connected to two separate voltage comparators with their respective comparator control levels set by an
internal resistor string, consisting of three equal-valued and
matched resistors. The output of the two comparators set an
internal RS flip-flop circuit, which in turn controls an OUTPUT and a DISCHARGE output. See Block Diagram for a
simplified equivalent circuit. The OUTPUT swings from rail
to rail of the supply voltage, whereas the DISCHARGE only
sinks current when it is active.
The ALD7555 and the ALD7556 operates by charging and
discharging the RC timing between 1/3 and 2/3 V+, and by a
feedback function provided by the user through the OUTPUT and/or DISCHAGE pins. This feedback is provided by
the application circuit external connections, which determines
the mode of the circuit operation. The architecture of this
timer takes advantage of the fact that all charging and discharging of C are referenced by the reference resistor string
that provide reference voltages proportional to supply voltage V+ (Vdd). As the charging and the discharging of the
capacitor C is also proportional to V+, the frequency of oscillation is independent of V+ voltage levels.
ALD7555/ALD7556
The Discharge Output Drive Currents of the ALD7555 and
the ALD7556 devices are increased significantly (80mA)
when compared to other timers so that in many applications
where the user may use this output as an output driver instead of having to add another output driver or buffer circuitry. For example, in many situations, the Discharge Output Drive Current is sufficient to drive a relay or a Power
MOSFET directly.
ASTABLE OPERATION
ALD7555 and the ALD7556 devices are designed to function as astable oscillators. These timers can be connected
to self trigger and run as a free running mutivibrator. In the
free running oscillator mode, the external capacitor C is
charged through Ra and Rb, and it is discharged through Rb
only. By adjusting the values of Ra and Rb in combination
with the value of C, both the frequency and the duty cycle of
the oscillator pulse can be adjusted. In the 50% astable mode,
the charging and the discharging of C are performed by the
same R between the same voltage levels set by the reference resistor string, and therefore timer provide a true 50%
duty cycle square wave that is symmetrical. (See typical
applications)
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APPLICATION NOTES (cont’d)
MONOSTABLE OPERATION
CONTROL Voltage and RESET pins
In this mode of operation the ALD7555 and the ALD7556
can be connected as a one-shot circuit which produces an
output pulse with a user-adjustable pulse delay time. The
pulse delay time is set by the external R and C values, which
together produce a RC time constant that is proportional to
the time delay. (See typical applications) The pulse is started
with an external negative going Trigger pulse applied to TRIGGER pin. This negative going pulse set an internal flip-flop
so that the external R and C can start the RC timing while
the OUTPUT pin is in the HIGH state. The external C is
being charged by the external R. When the voltage between
the R and C is charged passed the internal threshold voltage at the THRESHOLD pin, which is set at 66.6% of V+,
the internal comparator of the ALD7555 and the ALD7556
resets the internal flip-flop. This then turns on the Discharge
Driver at DISCHARGE pin, and discharges the timing capacitor C. The cycle is completed when the OUTPUT is driven
to a low state and the ALD7555 and the ALD7556 are again
waiting for the next negative going trigger pulse at TRIGGER pin.
The CONTROL pin directly accesses one input to the upper
comparator. As the input reference resistor string has onchip high impedance resistors, an input voltage at the CONTROL input can easily change the voltage at the comparator
input. This allows the user to change the oscillation frequency, or modulate the oscillation frequency of the analog
timer, with a separate user provided frequency. The CONTROL pin also allows a user-provided inhibit signal to stop
and start the timerís oscillation.
ALD7555/ALD7556
The RESET terminal directly resets the internal RS flip-flop
circuit, which in turn controls the OUTPUT and DISCHARGE
pins. This function is activated by a low voltage input of 0.7V
of 100 ns minimum duration. By injecting a variety of input
signals in a combination to the TRIGGER , THRESHOLD,
CONTROL and RESET pins, many interesting modulation
and demodulation signals can be manipulated and/or generated by the circuit designer.
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TYPICAL PERFORMANCE CHARACTERISTICS
MINIMUM PULSE WIDTH
REQUIRED FOR TRIGGERING
800
100
50
V+ = 12V
TA = 25°C
MINIMUM PULSE WIDTH (ns)
DISCHARGE SINK CURRENT (mA)
DISCHARGE OUTPUT SINK CURRENT AS A
FUNCTION OF DISCHARGE LOW VOLTAGE
V+ = 5V
20
V+ = 2V
10
5.0
2.0
1.0
0.5
0.2
700
TA = 25°C
600
500
V+ = 2V
400
V+= 5V
300
V+ =12V
200
100
0
0.1
0.01
0.02
0.05
0.1
0.2
0.5
1.0
FREE RUNNING FREQUENCY AS
A FUNCTION OF RA, RB AND C
40
TA = 25°C
( RA- 2RB)
100 µF
10 µF
1 µF
10
10
100 nF
10 nF
10
0M
1 nF
1M
0K
Ω
M
Ω
10
1K
KΩ
Ω
Ω
Ω
FREQUENCY CHANGE (%)
+4
1 mF
+3
+2
+1
0
-1
-2
-3
100 pF
-4
0.1
0
1.0 10 100 1K 10K 100K 1M 10M 100M
2
FREQUENCY (Hz)
4
6
8
10
12
SUPPLY VOLTAGE (V)
TIME DELAY IN THE MONOSTABLE MODE
AS A FUNCTION OF RA AND C
SUPPLY CURRENT AS A FUNCTION OF
SUPPLY VOLTAGE
10 mF
100
RA
SUPPLY CURRENT (µA)
TA = 25°C
100 nF
10 nF
1 nF
Ω
0K
Ω
K
10
1 µF
10
1K
10 µF
Ω
100 µF
CAPACITANCE
30
FREQUENCY CHANGE IN THE ASTABLE
MODE AS A FUNCTION OF SUPPLY VOLTAGE
10 mF
1 mF
20
LOWEST VOLTAGE LEVEL OF TRIGGER
PULSE ( % V+ )
DISCHARGE LOW VOLTAGE (V)
CAPACITANCE
10
0
Ω
1M MΩ Ω
10 0M
10 Ω
1G
70
TA = - 40°C
60
TA = + 20°C
50
TA = + 85°C
40
30
20
10
100 pF
0
100ns 1µs 10µs 100µs 1ms 10ms 100ms 1s 10s 100s
0
2
4
6
8
10
12
SUPPLY VOLTAGE (V)
TIME DELAY
ALD7555/ALD7556
90
80
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OUTPUT SINK CURRENT AS A
FUNCTION OF OUTPUT VOLTAGE
OUTPUT SINK CURRENT (mA)
100
TA = 25°C
50
V+ = 5V
V+ = 12V
20
10
5.0
V+ = 2V
2.0
1.0
0.5
0.2
OUTPUT SOURCE CURRENT (mA)
TYPICAL PERFORMANCE CHARACTERISTICS (cont'd)
OUTPUT SOURCE CURRENT AS A
FUNCTION OF OUTPUT VOLTAGE
-0.1
V+ = 2V
V+ = 5V
V+ = 12V
-0.2
-0.5
-1.0
-2.0
-5.0
-10
-20
-50
-100
0.1
0.01
0.02
0.05
0.1
0.2
0.5
-1.0
1.0
-0.5
-0.2
-0.1
-0.05
-0.02
-0.01
OUTPUT VOLTAGE (V)
(REFERENCED TO V+)
OUTPUT VOLTAGE (V)
TYPICAL APPLICATIONS (EACH TIMER)
ASTABLE MODE OPERATION
(FREE RUNNING OSCILLATOR)
ASTABLE MODE OPERATION
50% DUTY CYCLE
V+
1
8
2
7
V+
1
8
2
7
RA
0.1µF
0.1µF
RB
R
3
6
V+
4
3
6
4
5
V+
C
5
Frequency f = 1/ (1.4 RC)
C
Frequency f = 1.46 / (RA + 2RB)C
Duty Cycle DC = RB / (RA + 2RB)
MONOSTABLE MODE OPERATION (ONE SHOT PULSE)
Pulse Delay td = 1.1 RC
V+
1
8
R
TRIGGER
INPUT
DELAYED PULSE
OUTPUT
2
7
3
6
4
5
0.1µF
C
RESET
ALD7555/ALD7556
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SOIC-8 PACKAGE DRAWING
8 Pin Plastic SOIC Package
E
Millimeters
Dim
S (45°)
D
A
Min
1.35
Max
1.75
Min
0.053
Max
0.069
A1
0.10
0.25
0.004
0.010
b
0.35
0.45
0.014
0.018
C
0.18
0.25
0.007
0.010
D-8
4.69
5.00
0.185
0.196
E
3.50
4.05
0.140
0.160
1.27 BSC
e
A
A1
e
Inches
0.050 BSC
H
5.70
6.30
0.224
0.248
L
0.60
0.937
0.024
0.037
ø
0°
8°
0°
8°
S
0.25
0.50
0.010
0.020
b
S (45°)
H
L
ALD7555/ALD7556
C
ø
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SOIC-14 PACKAGE DRAWING
14 Pin Plastic SOIC Package
Millimeters
E
S (45°)
Dim
A
Min
1.35
Max
1.75
Min
0.053
Max
0.069
A1
0.10
0.25
0.004
0.010
b
0.35
0.45
0.014
0.018
C
0.18
0.25
0.007
0.010
D-14
8.55
8.75
0.336
0.345
E
3.50
4.05
0.140
0.160
1.27 BSC
e
D
A
Inches
0.050 BSC
H
5.70
6.30
0.224
0.248
L
0.60
0.937
0.024
0.037
ø
0°
8°
0°
8°
S
0.25
0.50
0.010
0.020
A1
e
b
S (45°)
H
L
ALD7555/ALD7556
C
ø
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PDIP-8 PACKAGE DRAWING
8 Pin Plastic DIP Package
Millimeters
E
E1
D
S
A2
A1
e
b
A
L
Dim
Min
Max
Min
Max
A
3.81
5.08
0.105
0.200
A1
0.38
1.27
0.015
0.050
A2
1.27
2.03
0.050
0.080
b
0.89
1.65
0.035
0.065
b1
0.38
0.51
0.015
0.020
c
0.20
0.30
0.008
0.012
D-8
9.40
11.68
0.370
0.460
E
5.59
7.11
0.220
0.280
E1
7.62
8.26
0.300
0.325
e
2.29
2.79
0.090
0.110
e1
7.37
7.87
0.290
0.310
L
2.79
3.81
0.110
0.150
S-8
1.02
2.03
0.040
0.080
0°
15°
0°
15°
ø
b1
Inches
c
e1
ALD7555/ALD7556
ø
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PDIP-14 PACKAGE DRAWING
14 Pin Plastic DIP Package
Millimeters
E
E1
D
S
A2
A1
A
L
Inches
Dim
A
Min
Max
Min
3.81
5.08
0.105
Max
0.200
A1
0.38
1.27
0.015
0.050
A2
1.27
2.03
0.050
0.080
b
0.89
1.65
0.035
0.065
b1
0.38
0.51
0.015
0.020
c
0.20
0.30
0.008
0.012
D-14
17.27
19.30
0.680
0.760
E
5.59
7.11
0.220
0.280
E1
7.62
8.26
0.300
0.325
e
2.29
2.79
0.090
0.110
e1
7.37
7.87
0.290
0.310
L
2.79
3.81
0.110
0.150
S-14
1.02
2.03
0.040
0.080
ø
0°
15°
0°
15°
e
b
b1
c
e1
ALD7555/ALD7556
ø
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CERDIP-8 PACKAGE DRAWING
8 Pin CERDIP Package
E E1
Millimeters
D
A1
s
A
L
L2
b
b1
e
L1
Dim
A
A1
Min
Inches
3.55
Max
5.08
Min
0.140
Max
0.200
1.27
2.16
0.050
0.085
b
0.97
1.65
0.038
0.065
b1
0.36
0.58
0.014
0.023
C
0.20
0.38
0.008
0.015
D-8
--
10.29
--
0.405
E
5.59
7.87
0.220
0.310
E1
7.73
8.26
0.290
0.325
e
2.54 BSC
0.100 BSC
e1
7.62 BSC
0.300 BSC
L
3.81
5.08
0.150
0.200
L1
3.18
--
0.125
--
L2
0.38
1.78
0.015
0.070
S
--
2.49
--
0.098
0°
15°
0°
15°
Ø
C
e1
ALD7555/ALD7556
ø
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CERDIP-14 PACKAGE DRAWING
14 Pin CERDIP Package
Millimeters
E E1
D
A1
s
A
L
L1
L2
b
b1
e
Inches
Dim
A
Min
Max
Min
3.55
5.08
0.140
Max
0.200
A1
1.27
2.16
0.050
0.085
b
0.97
1.65
0.038
0.065
b1
0.36
0.58
0.014
0.023
C
0.20
0.38
0.008
0.015
D-14
--
19.94
--
0.785
E
5.59
7.87
0.220
0.310
E1
7.73
8.26
0.290
0.325
e
2.54 BSC
0.100 BSC
e1
7.62 BSC
0.300 BSC
L
3.81
5.08
0.150
0.200
L1
3.18
--
0.125
--
L2
0.38
1.78
0.015
0.070
S
--
2.49
--
0.098
Ø
0°
15°
0°
15°
C
e1
ALD7555/ALD7556
ø
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