NE555/SA555/NA555
PRECISION TIMERS
Pin Descriptions
Pin Name
GND
Pin Number
Description
1
2
3
4
5
6
7
8
Ground
TRIG
Trigger set 1/3VCC
Timer output
Reset active low
OUT
RESET
CONT
THRES
DISCH
VCC
External adjustment of internal threshold and trigger voltages
Threshold set to 2/3 VCC
Low impedance discharge path
Chip supply voltage
Functional Block Diagram
RESET can override TRIG, which can override THRESH
Functional Table
Nominal Trigger
Threshold
Voltage
Discharge
Switch
On
Pin Name
Output
Voltage
Irrelevant
<1/3VCC
<1/3VCC
<1/3VCC
GND
TRIG
Irrelevant
Irrelevant
<2/3VCC
<2/3VCC
Low
High
Low
Off
OUT
On
RESET
As previously established
2 of 14
www.diodes.com
February 2012
© Diodes Incorporated
NE555/SA555/NA555
Document number: DS35112 Rev. 4 - 2
ETC [ ETC ]
