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Technical content
Features
Common Mode Input Range up to 24V VCC Operating Current : 200μμμμμA VCC Shutdown Current : 10μμμμμA (under S3/S4/S5) Programmable Over-Current Level One Shot PROCHOT Signal when OCP Pull Low RESET Signal when OVP/UVP OVP/UVP with 8% Recover Hysteresis Range Programmable OVP/UVP De-glitch Time CSN RT9553A RESETCSP OutputInput ISENSE PROCHOT VCC EN ILIM OVSET UVSET TIMER RSENSE Enable
DS9553A-00 September 2014www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Functional Pin Description Pin No. Pin Name Pin Function 1 CSP Positive Current Sense Input.
2 VCC
Power Supply Input. Connect this pin to 5V and place a minimum 0.1 F decoupling capacitor. The decoupling capacitor should be placed to this pin as close as possible. 3 ILIM Over-Current Trip Point Setting Input. The setting range is from 0.4V to 2V. 4 EN Enable Control Input. 5 TIMER Deglitch Time Setting of OV/UV Protection. Connect a resistor from this pin tied to GND to set deglitch time. Do not parallel any filter capacitor to this pin. 6 UVSET Under-Voltage Trip Point Setting Input. The setting range is from 0.55V to 3V. 7 OVSET Over-Voltage Trip Point Setting Input. The setting range is from 0.55V to 3V. 8 RESET Open-Drain Output. Connect to an external resistor to pull high. When OV/UV occurs, this pin will be pulled low. 9 PROCHOT Open-Drain Output. Connect to an external resistor to pull high. When OC occurs, this pin will be pulled low. 10 CSN Negative Current Sense Input. 11 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Function Block Diagram POR Latch RESET GND OV_Comparator PROCHOT Deglitch UV_Comparator One Shot+ OC_Comparator Current Sensing Amplifier VRON UVSET OVSET ILIM CSN CSP VCC EN TIMER
DS9553A-00 September 2014 www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. OVP/UVP Deglitch Time The output signal of OV_comoparator or UV_comparator is delayed by deglitch timer. The delayed time is decided by the resistor (see spec.) connected to the TIMER pin. Over-/Under-Voltage Protection The OVSET voltage is set by users and it compares with the voltage which is 1/9 of CSP voltage with OV_comparator. The UVSET voltage is set by users and it also compares with the voltage which is 1/9 of CSP voltage with UV_comparator. Either the output of OV_comoparator or UV_comparator is high, the RESET voltage is pulled low. Operation The RT9553A consists of a current sensing amplifier, and two comparators, and it provides the following functions : over-current protection, over-voltage protection and under- voltage protection. Over-Current Protection With mΩ order of resistor shunts between CSP and CSN, the current sensing amplifier multiplies the voltage between CSP and CSN by 20 and compares the result with the ILIM voltage. If the output voltage of current sensing amplifier is larger than the ILIM voltage, the PROCHOT voltage is pulled low.
DS9553A-00 September 2014www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation.
Electrical Characteristics
(VCC = 5V, TA = 25 °C, unless otherwise specified) Absolute Maximum Ratings (Note 1) Power Dissipation, PD @ TA = 25°C Package Thermal Resistance (Note 2) ESD Susceptibility (Note 3) Recommended Operating Conditions (Note 4) Parameter Symbol Test Conditions Min Typ Max Unit CSN CSP Input Input Voltage Range V CSP, VCSN 5 -- 24 V ICSN + ICSP VCC = 5V, EN High -- 50 -- VCC = 5V, EN Low -- -- 5 VCC Input VCC Operating Current I VCC -- 200 -- A VCC Shutdown Current I VCC_shd -- -- 10 A VCC POR Rising Voltage V IN_POR Rising 2.8 -- 3.7 V Hysteresis -- 400 -- mV Enable Enable Input Voltage Logic-High V IH 0.7 -- -- V Logic-Low V IL -- -- 0.3 Over Current Protection System Response Time -- 50 -- s Open-Drain Output Duration TPROCHOT 10 -- 18 ms Open-Drain Output Ron R on_PROCHOT -- -- 10
DS9553A-00 September 2014 www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Note 1. Stresses beyond those listed “Absolute Maximum Ratings ” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θ JA is measured at T A = 25 °C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Parameter Symbol Test Conditions Min Typ Max Unit Input Current Sensing Accuracy OCacc V ILIM = 0.4V to 2V -- -- 5 % PROCHOT Leakage Current Ileak_PROCHOT EN Low -- -- 5 A ILIM Leakage Current I leak_ILIM EN Low -- -- 5 A ILIM Operation Range V ILIM 0.4 -- 2 V Over-/Under-Voltage Protection OVP Accuracy OVP acc V OVSET = 0.55V to 3V -- -- 5 % OVP Recover Hysteresis Range V OVSET = 0.55V to 3V -- 8 -- % UVP Accuracy UVP acc V UVSET = 0.55V to 3V -- -- 5 % UVP Recover Hysteresis Range V UVSET = 0.55V to 3V -- 8 -- % Open Drain Output Ron R on_RESET I Sink = 10mA -- -- 10 RESET Leakage Current I leak_RESET EN Low -- -- 5 A OVP/UVP De-glitch Time T Timer RTimer = 375k -- 15 -- s RTimer = 125k -- 5 --
DS9553A-00 September 2014www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Typical Application Circuit CSN GND RT9553A 1.05V 100nF VCC RESET CSP 100nF 10m 100nF ISENSE 2.2 100nF EN 10k 100nF ILIM 3.3V 63.4k 37.4k PROCHOT 10k 1.05V 10k OVSET UVSET 3.3V 20k 82.5k 82.5k 16.5k TIMER 375k 11 (Exposed Pad) Input Output 2.2nF 2.2nF 2.2nF
DS9553A-00 September 2014 www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Typical Operating Characteristics Time (50 μs/Div) OVP vs. Reset Behavior OVSET (1V/Div) RESET (1V/Div) VCC = 5V , OVSET = 2.6V , V CSP from 19V to 25V VCSP (7V/Div) OVP Recovery Hysteresis 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.0 OVSET (V) OVP Recovery Hysteresis (% ) VCC = 5V , OVSET = 0.4V to 3V OVP Accuracy OVSET (V) Accuracy (%) VCC = 5V , OVSET = 0.4V to 3V UVP Accuracy UVSET (V) Accuracy (%) VCC = 5V , UVSET = 0.4V to 3V OCP Accuracy ILIM (V) Accuracy (%) VCC = 5V , RSENSE = 10mΩ , ILIM = 0.4V to 2V UVP Recovery Hysteresis 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.0 UVSET (V) UVP Recovery Hysteresis (%) 1 VCC = 5V , UVSET = 0.4V to 3V
DS9553A-00 September 2014www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Time (1ms/Div) Mask Time VCC = 5V, RSENSE = 10mΩ, EN (5V/Div) ILOAD (2A/Div) PROCHOT (2V/Div) ILIM = 1V, ILOAD = 0A to 6A before En high VCC = 5V , UVSET = 0.55V , V CSP from 7V to 3V Time (10 μs/Div) UVP vs. Reset Behavior VCSP (2V/Div) UVSET (500mV/Div) RESET (2V/Div) VCC = 5V , ILIM = 1V , ILOAD = 0A to 6A Time (20 μs/Div) OCP vs. PROCHOT Behavior ILIM (1V/Div) ILOAD (2A/Div) PROCHOT (2V/Div)
DS9553A-00 September 2014 www.richtek.com ©Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. OVSET CSP R2V3 . 3 V R1 R2 R2V3 . 3 V 9 R1 R2 We suggest that the total resistance of divider network should be higher than 100kΩ. VCSP is over-voltage protection trigger point. Fighre1.Setting Network of Over-Voltage Protection and Under-Voltage Protection UVSET OVSET TIMER RTIMER 3.3V 3.3V CSP VCSP Under-Voltage Protection (UVP) The principle of under-voltage protection is the same as over-voltage protection function. The under-voltage protection threshold is set by the UVSET pin. When the CSP pin voltage is lower the setting threshold at the UVSET pin, the under-voltage protection will be triggered, and the RESET pin will be pull low after a deglitch time, the RESET is resumed when the CSP pin voltage up to 8% hysteresis. Over-Current Protection (OCP) As an industry standard, high accuracy current sense amplifier is used to monitor the input current that flows through current sense resistor. The RT9553A detects CSP- CSN differential voltage across the current sense resistor to monitor input current. The equation of over-current protection is shown as below : ILIM SENSE SENSE ILIM ILIMSENSE SENSE R6V3 . 3 V R5 R6 (I R ) 20 V VI 20 R We suggest that the total resistance of divider network should be higher than 100kΩ. ISENSE is over-current protection trigger point. The 20 is amplification of internal error amplifier. Figure 2. Setting Network of Over-Current Protection
Application Information
The RT9553A provides OVP, UVP, OCP protection functions with RESET, PROCHOT indicator to inform system. It can be operated minimize external components of switching power supply systems to achieve protection. For easily using and increasing PCB space utilization, the RT9553A is used in notebook applications. Over-Voltage Protection (OVP) The CSP pin voltage can be continuously monitored for over-voltage condition. When the CSP pin voltage exceeds the setting threshold at the OVSET pin, the over-voltage protection will be triggered, and the RESET pin will be pull low after a deglitch time, the RESET is resumed when the CSP pin voltage down to 8% hysteresis. For more details, please refer to the following information. The equation of over-voltage setting threshold is shown as below :
DS9553A-00 September 2014www.richtek.com Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnish ed by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringeme nts of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of R ichtek or its subsidiaries. Outline Dimension Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.180 0.300 0.007 0.012 D 2.950 3.050 0.116 0.120 D2 2.300 2.650 0.091 0.104 E 2.950 3.050 0.116 0.120 E2 1.500 1.750 0.059 0.069 e 0.500 0.020 L 0.350 0.450 0.014 0.018 W-Type 10L DFN 3x3 Package 1 122 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. DETAIL A Pin #1 ID and Tie Bar Mark Options D E A L be SEE DETAIL A