PT8A2514A
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New Toaster Controller
Features
Operating voltage: 3.5V~5.5V.
Have Defrost, Reheat and Bagel function
Relay output disable without external oscillator
Adjustable timer: 30s~10mins
Few external components
Low cost 8-Pin DIP package
Description
The PT8A2514A is a CMOS LSI chip designed for
toasters application. It will use different timer when
different function was active, and the time can be
adjusted by external R/C. It has Reheat, Defrost, Bagel
function.
The chip includes: Power on reset circuit, Logic
control circuit, Output driver circuit, Key scan circuit,
Ordering Information
Part No.
PT8A2514APE
Notes:
1. E = Pb-free and Green
timer circuit, Built-in internal oscillator and external R/C
oscillator circuit etc. It is enclosed in lead free DIP-8
Package
Lead free DIP-8
package.
Application
Toaster Controller
Function comparison table
PT8A2514A
DEFROST and REHEAT key interlock each other, and BEGAL key is individual
Block Diagram
DEFROST
REHEAT
BAGEL
Output
driver
Power On
Reset
VCC
Key
scan
Logic control
Circuit
RX
CX
GND
System
Oscillator
Timer
Oscillator
OSC
12-03-0003
1
PT0271-2
03/28/12
PT8A2514A
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New Toaster Controller
Pin Configuration
PT8A2514A/BPE
DEFROST
REHEAT
BAGEL
VCC
1
2
3
4
8
7
6
5
PT8A2515/6NE
GND
CX
OSC
RX
4
3
2
1
1-RELAY
2-VCC
3-OSC
4-GND
Pin Description
Pin No.
1
2
3
4
5
6
7
8
Pin Name
Defrost
Reheat
Bagel
VCC
RX
OSC
CX
GND
I/O
I/O
I/O
I/O
I
O
I/O
O
I
Description
As input, requires a negative pulse to active "Defrost" function.
As output, gives a "Defrost" function indicator, active low.
As input, requires a negative pulse to active "Reheat" function.
As output, gives a "Reheat" function indicator, active low.
As input, requires a positive pulse to active "Bagel" function.
As output, gives a "Bagel" function indicator, active high.
Power supply
Shorts to VCC when Reheat function is active.
Oscillator's Frequency of 8.192KHz with an external R1, C1.
Shorts to GND when defrost function is active.
Ground
12-03-0003
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PT0271-2
03/28/12
PT8A2514A
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New Toaster Controller
Function Description
(Refer to Block Diagram)
The chip mainly includes: Power on reset circuit, Logic
control circuit, Output driver circuit, Key scan circuit, timer
circuit, external R/C oscillator circuit and internal oscillator
circuit etc.
Power on reset circuit
Internal power on reset circuit will reset all the logic circuit
and the timer; it will clear all output pins when power on.
Logic control circuit
The logic circuit will carries out all the logic control function.
It will scan key status, then control the output drive circuit
drive a LED to indicate the work status, at the same time it
will control CX or RX output to change the frequency of
oscillator. When timer is out, it will pull down Defrost, Reheat
pins to release relay.
Output driver circuit
The pin DEFROST, REHEAT and BAGEL, will drive a LED
to indicate work status, at the same time DEFROST and
REHEAT pin will driver a relay. BAGEL pin will drive a
relay when bagel function is active, and it will drive a LED to
indicate the bagel status.
Key scan circuit
This circuit will detect the key status, when DEFROST or
REHEAT key have a low negative pulse, it will active the
corresponding work status. When BAGEL key have a high
positive pulse, it will active the corresponding work status.
Note:
For PT8A2514A, DEFROST or REHEAT key, if one
key press, another lock up accordingly. BAGEL key is
independent.
Timer circuit
This circuit will provide a timer to logic control circuit. When
Fosc = 8.192KHz, timer output is 245720/8192=30s.
External R/C Oscillator circuit
This circuit will produce a system frequency depend on
external resistor and cap. The frequency is about 8.192KHz
when R1=47 KΩ and C1=332. (Refer
to Fig 1).
Note:
The system frequency with external resistor and cap
must be between 200Hz to 20KHz.
Internal oscillator
An on-chip RC oscillator with frequency about 256 KHz is
used to check the input signal and the wrong statue of external
RC oscillator.
Maximum Ratings
Storage Temperature…………………………………………..- 40
o
C to +125
o
C
Supply Voltage to Ground Potential (Inputs & V
CC
only)……- 0.5 to V
CC
+0.5V
Supply Voltage to Ground Potential (Outputs & D/O only) …- 0.5 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
Sym
V
CC
V
IH
V
IL
T
A
Description
Supply voltage.
“H” Input Voltage
“L” Input Voltage
Operation temperature
Min
3.5
0.8 V
CC
-
0
Typ
5.0
-
-
25
Max
5.5
-
0.35 V
CC
85
Unit
V
V
V
C
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PT0271-2
03/28/12
PT8A2514A
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New Toaster Controller
DC Electrical Characteristics
(Unless otherwise noted, V
CC
= 5V, T
A
= 0 ~ 85º
C)
Symbol
V
IL
V
IH
I
OH1
I
OH2
I
OH3
I
OH5
I
OL1
I
OL2
I
OL3
I
IH
I
IL
OSC
I
CC
Parameter
Input “L” Voltage (Defrost, Reheat)
Input “H” Voltage (Bagel)
Output Source Current (Defrost, Reheat)
Output Source Current (Defrost, Reheat)
Output Source Current (Bagel)
Output Source Current (RX)
Output Sink Current(Defrost, Reheat)
Output Sink Current(Bagel)
Output Sink Current(CX)
Input high leakage current(CX,RX)
Input low leakage current(CX,RX)
Frequency of normal oscillator
Power supply current
Test Condition
-
-
V
OH
=4.5V, Input key
scan
V
OH
=4.5V, Drive load
V
OH
=4.5V
V
OH
=4.5V
V
OL
=0.5V
V
OL
=0.5V
V
OL
=0.5V
V
IH
=5V
V
IL
=0V
R1=47KΩ C1=332, see
Fig 1
V
CC
=5V, R1=47 KΩ,
C1=332, all output
floating. See Fig 1
Min
-
2.5
-5
-10
-10
-1.5
4
10
4.0
-
-
7808
-
Typ
-
--
--
-
-
-
-
--
-
-
-
8192
-
Max
2.5
-
-40
-
-
-
-
100
-
-1
1
8576
500
Unit
V
V
uA
mA
mA
mA
mA
uA
mA
A
A
Hz
A
Fig1 Test circuit
12-03-0003
4
PT0271-2
03/28/12
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