A
DVANCED
L
INEAR
D
EVICES,
I
NC.
ALD4501
QUAD PRECISION HIGH SPEED MICROPOWER TIMER
GENERAL DESCRIPTION
The ALD4501 timer is a high performance QUAD 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; and reduced supply current
spikes allowing smaller and lower cost decoupling capacitors. Each of the
four timers can be independently operated in either the monostable,
astable, or 50% duty cycle mode.
Each timer is capable of producing accurate time delays and oscillations in
both monostable and astable operation. It operates in the one-shot
(monostable) 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 respec-
tively 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. All four timers share the same control
and reset pins so that timing functions are synchronized.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
High speed operation -- 2MHz typical oscillation at 5V
Each discharge output sinking current: 40mA at 5V
Guaranteed low operating supply voltage of 2 to 12V
Each timer is functionally equivalent to NE555 with greatly expanded
high and low frequency ranges
High speed, low power, monolithic CMOS technology
Low supply current 150µA typical
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
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
• Synchronized timer
PIN CONFIGURATION
RST
DSC
1
TRIG
1
DSC
2
TRIG
2
DSC
3
TRIG
3
DSC
4
TRIG
4
V
-
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
+
OUT
1
THRES
1
OUT
2
THRES
2
OUT
3
THRES
3
OUT
4
THRES
4
CONT
DE, PE, SE PACKAGE
BLOCK DIAGRAM (EACH TIMER)
V
+
RESET
ORDERING INFORMATION
Operating Temperature Range *
-55°C to +125°C
0°C to +70°C
0°C to +70°C
20-Pin
CERDIP
Package
ALD4501 DE
20-Pin
Small Outline
Package (SOIC)
ALD4501 SE
20-Pin
Plastic Dip
Package
ALD4501 PE
THRESHOLD
CONTROL
R
R
S
DISCHARGE
R
OUTPUT
TRIGGER
R
V
-
* 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
ALD [ ADVANCED LINEAR DEVICES ]
