ADVANCED
LINEAR
DEVICES, INC.
SINGLE/DUAL PRECISION HIGH SPEED MICROPOWER TIMER
GENERAL DESCRIPTION
The ALD1502/ALD2502 timers are high performance single/dual mono-
lithic timing circuits built with advanced silicon gate CMOS technology.
They offer the benefits of high input impedance, thereby allowing smaller
timing capacitors and a longer timing cycle; high speed, with typical cycle
time of 400ns; low power dissipation for battery operated environment;
reduced supply current spikes, allowing smaller and lower cost decoupling
capacitors.
Each timer is capable of producing accurate time delays and oscillations in
both monostable and astable operation, and 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.
FEATURES
• 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 12V
• Functional equivalent to and same pin-out as NE555/NE556
with greatly expanded high and low frequency ranges
• High speed, low power, monolithic CMOS technology
• Low supply current 50µA typical for ALD1502
and100µA typical for ALD2502
• 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
ALD1502/ALD2502
Operating Temperature Range *
-55°C to +125°C0°C to +70°C0°C to +70°C
8-Pin 8-Pin Small Outline 8-Pin Plastic Dip
CERDIP Package Package (SOIC) Package
ALD1502 DA ALD1502 SA ALD1502PA
14-Pin 14-Pin Small Outline 14-Pin Plastic Dip
CERDIP Package Package (SOIC) Package
ALD2502 DB ALD2502 SB ALD2502 PB
* Contact factory for industrial temperature range
PIN CONFIGURATION
BLOCK DIAGRAM (EACH TIMER)
ORDERING INFORMATION
DSC1
THRES1
CONT1
RST1
OUT1
TRIG1
GND TRIG2
OUT2
RST2
CONT2
THRES2
DSC2
V+
2
3
4
5
6
7
9
10
11
12
13
141
1
2
3
4
8
7
6
5
TOP VIEW
DA, PA, SA PACKAGE
GND
TRIG
OUT
RST
V+
DISC
THRES
CONT
TOP VIEW
DB, PB, SB PACKAGE
8
OUTPUT
(3)
DISCHARGE
(7)
RESET
(4)
R
S
R
R
R
TRIGGER
(2)
GND
(1)
CONTROL
(5)
THRESHOLD
(6)
V+
(8)
© 1998 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1155 Fax: (408) 747-1286 http://www.aldinc.com