PS121 Version : A.018 Issue Date : 2010/08/23 File Name : SP-PS121-A.018.DOC Total Pages: 8 Voltage Detecting IC 新竹市科學園區展業一路 9 號 7 樓之 1 SILICON TOUCH TECHNOLOGY INC. 9-7F-1, Prosperity Road I, Science Based Industrial Park, Hsin-Chu, Taiwan 300, R.O.C. Tel：886-3-5645656 Fax：886-3-5645626 PS121 PS121 Voltage Detecting IC General Description PS121 is specially designed for +5V power good signal generating. Power good signal notifies microprocessor whether the +5V supply voltage is ready, therefore it can provide a stable and reliable power supply and computing environment. Delay circuit is also built-in to provide delay time by adding an external capacitor. Features 1. Power Good Logic to Check +5V 2. Adjustable delay time 3. 4-pin SIP package Block Diagram +5V INPUT 2 Id 23.6K 10K 1 PG OUTPUT 10K 1.25 V 4 GND Voltage Detecting IC Vth_cd 3 DELAY CAPACITOR Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 1 PS121 Function Diagram +5V INPUT VOLTAGE 4.3 4.3-Vhy t PG OUTPUT td td t Pin Descriptions SOT-26 Pin No PIN NAME 1 NC NO connect 2 VSS Ground 3 PG Power good output signal pin 4 +5V(VDD) 5 Cd External capacitor for PG delay 6 NC NO connect Voltage Detecting IC Descriptions +5V(VDD) input pin Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 2 PS121 Absolute Maximum Ratings Parameter Supply Voltage Symbol VDD Output Sink Current Isink Output Voltage VPG Power Dissipation Pd Storage Temperature Tstg Operating Temperature Junction Temperature Package Thermal Resistance Topr Rating -0.5 ~ Unit +7.5 V 30 -0.5 ~ mA +7.5 300 -40 -30 ~ ~ Tj 150 θ JA 160 V mW +125 o +90 o C C o C o C/W Electrical characteristics, Vcc=5V, Ta = 25 oC. (unless otherwise specified) Parameter Test Condition MIN TYP MAX Unit Vth Detecting Threshold Voltage 4.05 4.30 4.55 V Vhy Vth Hysteresis Voltage 0.1 0.2 0.3 V IDD Circuit Current VCC=5V 0.97 2.5 mA Td Delay Time Cd=0.1μF 21.4 Id Constant Current at Cd Pin Vsat PG Output Saturation Voltage Vthcd Threshold Voltage in Pin Cd ΔT Temperature coefficient Voltage Detecting IC 8.0 V+5=4.0V, Isink=10mA 8.7 ms 9.4 μA 0.128 0.192 V VDD = 0Æ 5 1.79 1.87 1.95 VDD = 5Æ 0 1.72 1.77 1.82 +1 Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. +2 V mV/°C PAGE 3 PS121 Typical Application (1) For Forward Type S.P.S Secondary Side +5V OUTPUT Vz=6V Rx X1 = X2 or X1 or +5V INPUT I2 Vpgi 2 Id Cd D1 3 N-PG 4 R1 Cx = C>0.01uF 1 PG GND X2 (2) For Flyback Type S.P.S Secondary Side +5V OUTPUT Vz=6V Rx X1 = X2 or X1 2 Id D1 Voltage Detecting IC or +5V INPUT I2 Vpgi Cx = C>0.01uF R1 Cd 3 N-PG 4 1 GND PG X2 Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 4 PS121 Note1: Once AC power is turned on, Vpgi will be pulled high before +5V input. At this time, diode D1 will be turn off. The PG delay time is dependent on Cd as follows, ⎛ C × Vthcd Cd × 1.85 Td −ON = 0.216 × Cd ( pF ) μ sec, ⎜⎜ T = d = 8 .7 μ I d −ON ⎝ ⎞ ⎟⎟ ⎠ Note2: Diode D1 is connected to Vpgi to control the PG delay time when AC is off. The AC off delay time can be controlled as follows, Td −OFF ≒ Cd × Vthcd Cd × Vthcd C d × Vthcd C d × 1.85 = = = 1 1 I2 − Id I d −OFF × (VCd + Vthcd ) × (VCd + 1.85) 2 2 R1 R1 1 Among Td −OFF equation, the × (VCd + Vthcd ) is discharged average current. 2 Note3: Since the maximum threshold voltage at Pin 3(Cd) is 1.95V, the voltage across R1 has to be higher than 2V at normal operation. Note4: In PCB layout condition, when the input-pin(VDD) smaller than detecting threshold voltage(Vth), the power good signal of PS121 will connect to LOW, so the ground-pin(VSS) must connect to the most clean ground of the power supply system to avoid noise appear. Note5: Suggested using RC filter circuit (Rx and Cx) to decrease ripples. Note6: Suggested using component X1 and R1 to cut down Vpgi voltage. Note7: Suggested using component X2 to avoid overshoot voltage damages IC. Voltage Detecting IC Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 5 PS121 Package Specification (SOT-26) Voltage Detecting IC Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 6 PS121 The products listed herein are designed for ordinary electronic applications, such as electrical appliances, audio-visual equipment, communications devices and so on. Hence, it is advisable that the devices should not be used in medical instruments, surgical implants, aerospace machinery, nuclear power control systems, disaster/crime-prevention equipment and the like. Misusing those products may directly or indirectly endanger human life, or cause injury and property loss. Silicon Touch Technology, Inc. will not take any responsibilities regarding the misusage of the products mentioned above. Anyone who purchases any products described herein with the above-mentioned intention or with such misused applications should accept full responsibility and indemnify. Silicon Touch Technology, Inc. and its distributors and all their officers and employees shall defend jointly and severally against any and all claims and litigation and all damages, cost and expenses associated with such intention and manipulation. Silicon Touch Technology, Inc. reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. Voltage Detecting IC Version：A.018 未經授權而逕予重製、複製、使用或公開本文件，行為人得被追究侵權之相關民刑事責任 Unauthorized reproduction, duplication, use or disclosure of this document will be deemed as infringement. PAGE 7