PT8A2521-3/31-3/41-3
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Universal Timer Controller
Features
Description
Universal timer is a mixed signal CMOS IC
designed for a fixed timer to drive external SCR to
implement safety power control. It is applied to
120V/240V and 50/60Hz AC power supply. It can
automatically shut-off load in order to prevent undesired
conditions from the system. Internal timer can present
several kinds of different time: 15mins, 30mins, 45mins,
1hr, 1.5hrs, 2hrs, 4hrs and 8hrs, which is decided by part
number.
Auto-shut off output once time-out
Button to ON/OFF/RESET timer
Available timer with high precision same as AC
50/60Hz
Build-in RC oscillator
Drive external SCR
Support 50/60Hz by part
Quick Test Mode (QTM) for manufacturer
Available timer of 15/30/45/60/90/120/240/480min
Low cost lead free package: TO-92 or DIP-8 or
SOIC-8
Applications
Universal Timer Controller
Pin Configuration
PT8A2521/2/3A-H
PT8A2531/2/3A-H
TO92-3 (Top View)
PT8A2541/2/3
DIP-8 or SOIC-8
(Top View)
TO92-3
Pin Description
PT8A2521/2/3A-H, PT8A2531/2/3A-H
Pin Name
Pin No
I/O
Pin Description
VCC
1
-
Power supply
SCR
2
I/O SCR output and button input, high active
GND
3
-
Ground
PT8A2541/2/3
Pin Name
TS2
TS1
TS0
GND
SCR
NC
ACSEL
VCC
Pin No.
1
2
3
4
5
6
7
8
I/O
I
I
I
-
I/O
I/O
I
-
Pin Description
Timer selection pins(TS2 TS1 TS0 from 000~111)
000: 15m, 001: 30m, 010: 45m, 011: 60m,
100: 90m, 101: 120m,110: 240m,111: 480m
Default 011 by TS2 internal pull down, TS1&TS0 internal pull up.
Ground.
SCR output and button input, high active.
No connection.
50/60Hz selection pin: default is 60Hz by internal pull down; connecting to VCC is
50Hz.
Power supply.
12-07-0006
1
PT0246-3
07/0612
PT8A2521-3/31-3/41-3
Universal Timer Controller
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Maximum Ratings
Storage Temperature ................................................................................... -40oC to +125oC
Supply Voltage to Ground Potential (Input & V
CC
Only).............. -0.5V to V
CC
+ 0.5V
Supply Voltage to Ground Potential (Output s & D/O Only) ....... -0.5V to V
CC
+ 0.5V
DC Input Voltage ................................................................................... -0.5V to V
CC
+ 0.5V
DC Output Current ...................................................................... 20mA
Power Dissipation ......................................................................................................... 500mW
Note:
Stresses greater than those listed under MAXIMUM
RATINGS may cause permanent damage to the
device. This is a stress rating only and functional
operation of the device at these or any other condi-
tions above those indicated in the operational sec-
tions of this specification is not implied. Exposure
to absolute maximum rating conditions for extended
periods may affect reliability.
Recommended operation conditions
Symbol
V
CC
T
A
Parameter
Operating Voltage
Operating temperature
Min
4.2
0
Typ
4.7
25
Max
5.2
85
Unit
V
℃
Electrical Characteristics
Test Conditions
Sym
Parameter
V
CC
V
CC
V
TH1
V
TH2
I
OH
I
OL
I
CC
F
OSC
Shunt Regulator output voltage
Input high threshold(SCR)
Input low threshold(SCR)
Output Source Current (SCR)
Output Sink Current (SCR)
Power supply current
Frequency of internal oscillator
-
5V
5V
5V
5V
4.0V
5V
Conditions
I
CC
=1mA
-
-
V
OH1
=2.5V
V
OL1
=0.5V
-
-
4.2
3.6
0.3
-0.2
6
-
96
4.7
4
0.65
-0.3
12
-
128
5.2
4.4
1.0
-0.4
24
0.5
160
V
V
V
mA
μA
mA
KHz
Min
Typ
Max
Unit
12-07-0006
2
PT0246-3
07/0612
PT8A2521-3/31-3/41-3
Universal Timer Controller
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Block Diagram
Figure 2 Function block diagram
AC SEL
Ref erence
circuit
Clock extracting
circuit
SCR driving
circuit
Button sampling
circuit
GND
VC C
Shunt
Regulator
SC R
Internal RC
Oscillator
PBO
Timer Chain
15/30/45/60m/90m/2h/4h/8h
Functional Description
(Note: In below description, “RELAY” presents a pin, while “relay” means a device.)
●
Reference and Shunt Regulator
Reference circuit generates 1.2V VCC-independent and
temperature-independent voltage to provide reference
voltage for the build-in shunt regulator. The regulator
supplies all internal function blocks.
Clock extracting circuit
VCC is not only the power supply pin but also clock
source for internal precise timer. With the help of the
external circuit, the AC 50/60Hz clock signal can be
extracted to be used as timer clock source.
Internal RC oscillator circuit
It is employed to create pulse driving signal for RELAY,
it is a completely internal RC oscillator with frequency
of about 128KHZ.
Timer chain
Timer chain can be used to generate various timer
including 15/30/45/60/90/120/240/480min.
Button sampling circuit senses button’s operation 3 times
per 8ms.System will sample the button’s operation
during first 100ms after power on, if buttons are pressed
during this period, then system will start 3s timer to
check if the chip will enter into quick test mode (see test
mode section). If the related button is pressed over 3s
just after power on, chip will enter quick test mode as
soon as the button is released. If buttons are not pressed
during first 100ms, system will operate normally.
●
●
SCR driving circuit
System outputs high to drive high sensitive SCR.
Quick Test Mode(QTM)
In order to make the manufacturer’s test convenient,
quick test mode is designed to speed up the test.
QTM can be accessed by pressing button (ON/RESET)
over 3s (option 2s) once power on. It can exit
automatically after quick test timer is expired, system
needs to power on again to come back normal operation
after quick test mode. Any button operations will be
ignored in QTM.
●
●
●
●
Button sampling circuit
With external buttons, ON/OFF/RESET function can be
realized. User can select one button with once ON, once
OFF or two buttons to turn ON or OFF separately, also
use one button to restart timer.
Fig 4 operation illustration of entering into and exitting Quick
Power on
>3s
<100ms
First PB ON
sampling time
Second PB ON
*12s f or 2hrs
Quick test mode
3s warm up
test mode
will be ignored
Normal mode
Operation illustration of entering into and exiting Quick test mode
Below table shows the timer in QTM corresponding to real timer.
Table Real timer compared to the timer in QTM
Real timer
Timer in QTM
12-07-0006
3
15m
2s
30m
4s
45m
6s
60m
8s
90m
10s
120m
12s
240m
14s
PT0246-3
480m
16s
07/0612
PT8A2521-3/31-3/41-3
Universal Timer Controller
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Application Circuit
Note:
SCR is high sensitive SCR which the gate trigger current is about 200uA.
TO -92 Universal Timer to drive SC R with on e bu tton
ACL
D1
IN4007
R1
24K *1/2W
100K * 1/2W
LOAD
C3
104
110V/220 V
120V/240V
C1
22uF/16V
U1
VCC
SCR
2
1
S1
RESET or ON/O
FF
R2
5.6K
R3
3K
C2
104
Q1
ACN
GND
PT8A2521/2-PT8A2531/2
3
*Note1:
For 120VAC power supply system, R1 value is 24K.
For 240VAC power supply system, R1 value is 100K.
Note2:
C1 value range is 22uF to 68uF.
TO -92 Universal Timer to drive SC R with two bu ttons
ACL
D1
R1
24K *1/2W
100K * 1/2W
PT8A2523-PT8A2533
LOAD
U1
VCC
110V/220 V
120V/240V
C1
22uF/16V
C3
104
1
IN4007
S1
ON
2
Q1
R2
5.6K
SCR
GND
S2
OF
F
R3
3K
C2
104
ACN
*Note1:
For 120VAC power supply system, R1 value is 24K.
For 240VAC power supply system, R1 value is 100K.
Note2:
C1 value range is 22uF to 68uF.
12-07-0006
4
3
PT0246-3
07/0612
PT8A2521-3/31-3/41-3
Universal Timer Controller
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DIP8 Universal Timer to drive SCR with one button
D1
IN4007
VCC
ACL
R1
24K 1/2W *
100K 1/2W *
U1
1
2
3
TS2
TS1
TS0
GND
VCC
ACSEL
NC
SCR
8
7
K1
6
5
LOAD
S1
RESET or O N/O FF
Q1
R2
5.6K
R3
3K
C3
104
120V/240V
C1
22uF/16V
C2
104
4
PT8A2541/2PE
ACN
*Note1:
For 120VAC/60Hz power supply system, R1 value is 24K, ACSEL is connected to GND or floating.
For 240VAC/50Hz power supply system, R1 value is 100K, ACSEL is connected to VCC.
*Note2:
TS0, TS1 and TS2 are floating, the timer time out is 60 minutes.
Note3:
C1 value range is 22uF to 68uF.
DIP8 Universal Timer to drive SCR with two buttons
D1
IN4007
VCC
ACL
R1
24K 1/2W *
100K 1/2W *
U1
1
2
3
TS2
TS1
TS0
GND
VCC
ACSEL
NC
SCR
8
7
K1
6
5
LOAD
S1
ON
R2
5.6K
S2
O FF
R3
3K
C3
104
Q1
120V/240V
C1
22uF/16V
C2
104
4
PT8A2543PE
ACN
*Note1:
For 120VAC/60Hz power supply system, R1 value is 24K, ACSEL is connected to GND or floating.
For 240VAC/50Hz power supply system, R1 value is 100K, ACSEL is connected to VCC.
*Note2:
TS0, TS1 and TS2 are floating, the timer time out is 60 minutes.
Note3:
C1 value range is 22uF to 68uF.
12-07-0006
5
PT0246-3
07/0612
测试/测量
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