PT8A5A Features Operating voltage:.5v~5.5v. Have Defrost, eheat and Bagel function elay output disable without external oscillator Adjustable timer: 0s~0mins Few external components Low cost 8-Pin DIP package Ordering Information Part No. PT8A5APE Notes:. E = Pb-free and Green Function comparison table PT8A5A Package Lead free DIP-8 Description The PT8A5A 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 /C. It has eheat, Defrost, Bagel function. The chip includes: Power on reset circuit, Logic control circuit, Output driver circuit, Key scan circuit, timer circuit, Built-in internal oscillator and external /C oscillator circuit etc. It is enclosed in lead free DIP-8 package. Application Toaster Controller DEFOST and key interlock each other, and BEGAL key is individual Block Diagram DEFOST Output driver Power On eset VCC Key scan Logic control Circuit X CX GND System Oscillator Timer Oscillator OSC -0-000 PT07-0/8/
PT8A5A Pin Configuration PT8A5A/BPE PT8A55/6NE DEFOST 8 GND 7 6 CX OSC -ELAY -VCC -OSC -GND VCC 5 X Pin Description Pin No. Pin Name I/O Description Defrost I/O As input, requires a negative pulse to active "Defrost" function. As output, gives a "Defrost" function indicator, active low. eheat I/O As input, requires a negative pulse to active "eheat" function. As output, gives a "eheat" function indicator, active low. Bagel I/O As input, requires a positive pulse to active "Bagel" function. As output, gives a "Bagel" function indicator, active high. VCC I Power supply 5 X O Shorts to VCC when eheat function is active. 6 OSC I/O Oscillator's Frequency of 8.9KHz with an external, C. 7 CX O Shorts to GND when defrost function is active. 8 GND I Ground -0-000 PT07-0/8/
PT8A5A Function Description (efer to Block Diagram) The chip mainly includes: Power on reset circuit, Logic control circuit, Output driver circuit, Key scan circuit, timer circuit, external /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 DEFOST or key have a low negative pulse, it will active the corresponding work status. When key have a high positive pulse, it will active the corresponding work status. Note: For PT8A5A, DEFOST or key, if one key press, another lock up accordingly. 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 X output to change the frequency of oscillator. When timer is out, it will pull down Defrost, eheat pins to release relay. Output driver circuit The pin DEFOST, and, will drive a LED to indicate work status, at the same time DEFOST and pin will driver a relay. 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 = 8.9KHz, timer output is 570/89=0s. External /C Oscillator circuit This circuit will produce a system frequency depend on external resistor and cap. The frequency is about 8.9KHz when =7 KΩ and C=. (efer to Fig ). Note: The system frequency with external resistor and cap must be between 00Hz to 0KHz. Internal oscillator An on-chip C oscillator with frequency about 56 KHz is used to check the input signal and the wrong statue of external C oscillator. Maximum atings Storage Temperature..- 0 o C to +5 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 0mA Power Dissipation 500mW ecommended Operation Conditions Note: Stresses greater than those listed under MAXIMUM ATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. Sym Description Min Typ Max Unit V CC Supply voltage..5 5.0 5.5 V V IH H Input Voltage 0.8 V CC - - V V IL L Input Voltage - - 0.5 V CC V T A Operation temperature 0 5 85 C -0-000 PT07-0/8/
PT8A5A DC Electrical Characteristics (Unless otherwise noted, V CC = 5V, T A = 0 ~ 85ºC) Symbol Parameter Test Condition Min Typ Max Unit V IL Input L Voltage (Defrost, eheat) - - -.5 V V IH Input H Voltage (Bagel) -.5 -- - V I OH Output Source Current (Defrost, eheat) V OH =.5V, Input key scan -5 -- -0 ua I OH Output Source Current (Defrost, eheat) V OH =.5V, Drive load -0 - - ma I OH Output Source Current (Bagel) V OH =.5V -0 - - ma I OH5 Output Source Current (X) V OH =.5V -.5 - - ma I OL Output Sink Current(Defrost, eheat) V OL =0.5V - - ma I OL Output Sink Current(Bagel) V OL =0.5V 0 -- 00 ua I OL Output Sink Current(CX) V OL =0.5V.0 - - ma I IH Input high leakage current(cx,x) V IH =5V - - - A I IL Input low leakage current(cx,x) V IL =0V - - A OSC Frequency of normal oscillator =7KΩ C=, see Fig 7808 89 8576 Hz I CC Power supply current V CC =5V, =7 KΩ, C=, all output floating. See Fig - - 500 A Fig Test circuit -0-000 PT07-0/8/
DN8 DEFOST DN8 DEFOST 5 SLOT SLOT PT8A5A Typical Application Circuit CONTOL BOAD HEATE.5K SW K C 0 C 7uF VZ 5.V K LED POWE 0/W D DN00 C 680uF/6V L L L L LED elay SW D 5.5K LED SW D 9.5K U PT8A5 DEFOST GND 8 VCC CX 7 OSC 6 X 5 C 0 7K C5 D DN8 S elay D5 DN8 7.5K 6.5K NTC V LED 50K 56K 680K 8 680 *7K SW CANCEL Q 8050 Q 8050 N 0VAC L -0-000 PT07-0/8/ 5
PT8A5A Mechanical Information PE (Lead free DIP-8) 8.0.80 6.09 7..55.00 9.0 0.6 7.6 8.5.00.5.5.50.9.8.00 typical.5.0.0.0 Max 5..05 Min 0.8.56.558 SEATING PLANE.008.0 0.0 0.5.0 Max 0.9 X.XX DENOTES DIMENSIONS X.XX IN MILLIMETES Note: ) Controlling dimensions in inches. ) ef: JEDEC MS-00 BA 0 O 5 o X.XX X.XX DENOTES DIMENSIONS IN MILLIMETES Note: ) Controlling dimensions in inches. ) ef: JDDEC MS-00 BA Pericom Semiconductor Corporation -800-5-6 www.pericom.com -0-000 PT07-0/8/ 6