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NA555, NE555, SA555, SE555

SLFS022I – SEPTEMBER 1973 – REVISED SEPTEMBER 2014

xx555 Precision Timers

1 Features

3 Description

These devices are precision timing circuits capable of

1

•

Timing From Microseconds to Hours

producing accurate time delays or oscillation. In the

•

Astable or Monostable Operation

time-delay or mono-stable mode of operation, the

•

Adjustable Duty Cycle

timed interval is controlled by a single external

resistor and capacitor network. In the a-stable mode

•

TTL-Compatible Output Can Sink or Source

of operation, the frequency and duty cycle can be

Up to 200 mA

controlled independently with two external resistors

•

On Products Compliant to MIL-PRF-38535,

and a single external capacitor.

All Parameters Are Tested Unless Otherwise

The threshold and trigger levels normally are two-

Noted. On All Other Products, Production

Processing Does Not Necessarily Include

levels can be altered by use of the control-voltage

Testing of All Parameters.

terminal. When the trigger input falls below the trigger

level, the flip-flop is set, and the output goes high. If

2 Applications

the trigger input is above the trigger level and the

•

Fingerprint Biometrics

threshold input is above the threshold level, the flip-

flop is reset and the output is low. The reset (RESET)

•

Iris Biometrics

input can override all other inputs and can be used to

•

RFID Reader

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 × 6.35 mm

SOP (8)

6.20 mm × 5.30 mm

xx555

TSSOP (8)

3.00 mm × 4.40 mm

SOIC (8)

4.90 mm × 3.91 mm

(1) For all available packages, see the orderable addendum at

the end of the datasheet.

4 Simplified Schematic

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.