PT8A2514A Datasheet, PDF (3/6 Pages) Pericom Semiconductor Corporation – New Toaster Controller

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.
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.
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.
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^oC to +125^oC
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
Recommended Operation Conditions
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.
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
Max
Unit
5.0
5.5
V
-
-
V
-
0.35 V_CC
V
25
85
C
12-03-0003
PT0271-2 03/28/12
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