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NA555_14 Datasheet, PDF (1/36 Pages) Texas Instruments – Precision Timers | |||
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NA555, NE555, SA555, SE555
SLFS022I â SEPTEMBER 1973 â REVISED SEPTEMBER 2014
xx555 Precision Timers
1 Features
â¢1 Timing From Microseconds to Hours
⢠Astable or Monostable Operation
⢠Adjustable Duty Cycle
⢠TTL-Compatible Output Can Sink or Source
Up to 200 mA
⢠On Products Compliant to MIL-PRF-38535,
All Parameters Are Tested Unless Otherwise
Noted. On All Other Products, Production
Processing Does Not Necessarily Include
Testing of All Parameters.
2 Applications
⢠Fingerprint Biometrics
⢠Iris Biometrics
⢠RFID Reader
3 Description
These devices are precision timing circuits capable of
producing accurate time delays or oscillation. In the
time-delay or mono-stable mode of operation, the
timed interval is controlled by a single external
resistor and capacitor network. In the a-stable mode
of operation, the frequency and duty cycle can be
controlled independently with two external resistors
and a single external capacitor.
The threshold and trigger levels normally are two-
thirds and one-third, respectively, of VCC. These
levels can be altered by use of the control-voltage
terminal. When the trigger input falls below the trigger
level, the flip-flop is set, and the output goes high. If
the trigger input is above the trigger level and the
threshold input is above the threshold level, the flip-
flop is reset and the output is low. The reset (RESET)
input can override all other inputs and can be used to
initiate a new timing cycle. When RESET goes low,
the flip-flop is reset, and the output goes low. When
the output is low, a low-impedance path is provided
between discharge (DISCH) and ground.
The output circuit is capable of sinking or sourcing
current up to 200 mA. Operation is specified for
supplies of 5 V to 15 V. With a 5-V supply, output
levels are compatible with TTL inputs.
Device Information(1)
PART NUMBER PACKAGE
BODY SIZE (NOM)
PDIP (8)
9.81 mm à 6.35 mm
xx555
SOP (8)
TSSOP (8)
6.20 mm à 5.30 mm
3.00 mm à 4.40 mm
SOIC (8)
4.90 mm à 3.91 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
4 Simplified Schematic
VCC
8
CONT
6
THRES
5 ÃÃÃÃ
RESET
4
ÃÃÃ R1
R
1ÃÃÃ
S
ÃÃÃ
3
OUT
2
TRIG
ÃÃÃ
1
GND
7
DISCH
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
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