RT8525D

RT8525D RICHTEK | Alldatasheet

Document overview

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Technical content

Features

z VIN Range : 4.5V to 25V z Programmable Soft-Start Time z Programmable Boost SW Frequency from 50kHz to 600kHz z Output Over Voltage Protection z Output Under Voltage Protection z 12-Lead WDFN Package z RoHS Compliant and Halogen Free

Applications

zzzzz LCD TV, Monitor Display Backlight zzzzz LED Driver Application zzzzz High Current High Output Voltage DC/DC Converters zzzzz High Input Voltage DC/DC Converters Package Type QW : WDFN-12L 3x3 (W-Type) RT8525D Lead Plating System G : Green (Halogen Free and Pb Free) VDC VIN FSW SS EN DRV GND OVP ISW COMP FAULT FB GND Simplified Application Circuit COUT RFB1 RFB2 ROVP1 ROVP2 RS RSLP VOUT DRV ISW GND OVP FAULT RT8525D VIN VDC CDC ENChip Enable CVIN CC2RC CC1 RSW CSS FSW SS COMP FB RFLT 12V COVP CIN VIN 0F=YM DNN 0F= : Product Code YMDNN : Date Code

www.richtek.com DS8525D-00 June 2012 Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Functional Pin Description Pin No. Pin Name Pin Function 1 VDC Output of Internal Pre-Regulator. 2 VIN IC Power Supply. 3 COMP Compensation for Error Amplifier. Connect a compensation network to ground. 4 SS External Capacitor to Adjust Soft-Start Time. 5 FSW Frequency Adjust Pin. This pin allows setting the switching frequency with a resistor from 50kHz to 600kHz. 6 FAULT Open Drain Output for Fault Detection. 7 FB Feedback to Error Amplifier Input. 8 OVP Sense Output Voltage for Over Voltage Protection and Under Voltage Protection. 9 ISW External MOSFET Switch Current Sense Pin. Connect the current sense resistor between the external N-MOSFET switch and ground. 10, 13 (Exposed Pad) GND Ground of Boost Controller. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 11 DRV Drive Output f or the N-MOSFET. 12 EN Chip Enable (Active High).

DS8525D-00 June 2012 www.richtek.com Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Function Block Diagram UVLO 12V LDO OTP OVP/OUVP Logic Q Q S R OSC OC Blanking PWM Controller - + -EA 0.1V 2.5V 0.4V 1.25V 4µA FAULT ProtectionFAULT VDC VIN FSW OVP DRV ISW FB COMP SS EN GND VOS Operation The RT8525D is a wide input operating voltage range and current mode step up controller. High voltage output and large output current are feasible by using an external N- MOSFET. The error amplifier EA adjusts COMP voltage by comparing the feedback signal from the output voltage with the internal 1.25V reference. Fault Protection The protection functions include output over voltage, output under voltage, over temperature protection. The FAULT pin will be pulled low once a protection is triggered, and a suitable pulled-high R FLT is required. The detail description can refer to the Figure 2. Fault Protection Function Block. Blanking N-MOSFET current is measured by external RS. The slope compensator works together with sensing voltage of R SENSE to the ISW pin. There is need blanking time to avoid noise and parasitism effect.

www.richtek.com DS8525D-00 June 2012 Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation.

Electrical Characteristics

(VIN = 21V, CIN = 10μF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Input Power Supply Quiescent Current I Q No Switching, R SW = 56kΩ -- 1.3 2 mA Shutdown Current I SHDN V EN = 0V -- 10 -- μA Under Voltage Lockout Threshold VUVLO V IN Rising -- 3.8 -- V Under Voltage Lockout Hysteresis ΔVUVLO -- 500 -- mV 12V Regulator 13.5V < VIN < 16V, 1mA < ILOAD < 100mA 16V < VIN < 20V, 1mA < ILOAD < 50mA Regulator Output Voltage V DC 20V < VIN < 25V, 1mA < ILOAD < 20mA 11.4 12 12.6 V Dropout Voltage V DROP V IN − VDC, VIN = 12V, ILOAD = 100mA -- 500 -- mV Short-Circuit Current Limit I SC V DC Short to GND -- 270 -- mA Control Input Logic-High V IH 2 -- -- EN Threshold Voltage Logic-Low VIL -- -- 0.8 V EN Sink Current I IH V EN = 5V -- 5 -- μA Absolute Maximum Ratings (Note 1) z Power Dissipation, PD @ TA = 25°C z Package Thermal Resistance (Note 2) z ESD Susceptibility (Note 3) Recommended Operating Conditions (Note 4)

DS8525D-00 June 2012 www.richtek.com Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek 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 Sleeping Mode t SLEEP RSW = 56kΩ, EN = L, 12V Regular Shutdown 55 -- -- ms Shutdown Delay Shutdown Mode tSHDN RSW = 56kΩ, EN = L, IC Shutdown 110 -- -- ms Boost Controller Switching Frequency f SW R SW = 56kΩ -- 200 -- kHz Minimum On-Time t MON -- 250 -- ns Maximum Duty D MAX Switching 90 -- -- % Feedback Voltage V FB -- 1.25 -- V Slope Compensation Peak Magnitude of Slope Compensation Current ISLOPE, PK -- 50 -- μA Soft-Start Soft-Start Current I SS 3 4 5 μA Gate Driver RDS(ON)_N I SINK = 100mA (N-MOSFET) -- 1 -- Ω DRV On-Resistance RDS(ON)_P I SOURCE = 100mA (P-MOSFET) -- 1.5 -- Ω Peak Sink Current I PEAKsk C LOAD = 1nF -- 2.2 -- A Peak Source Current I PEAKsr C LOAD = 1nF -- 2.55 -- A Rise Time t r C LOAD = 1nF -- 6 -- ns Fall Time t f C LOAD = 1nF -- 5 -- ns Protection Function OCP Threshold V OCP Including Slope Compensation Magnitude -- 0.4 -- V VOUT OVP Threshold V OVP -- 2.5 -- V VOUT UVP Threshold V UVP -- 0.1 -- V Thermal Shutdown Temperature TSD -- 150 -- °C Thermal Shutdown Hysteresis ΔTSD -- 50 -- °C

www.richtek.com DS8525D-00 June 2012 Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Typical Application Circuit COUT RFB1 RFB2ROVP1 ROVP2 RS RSLP D1 VOUT DRV ISW GND OVP FAULT RT8525D VIN VDC CDC ENChip Enable CVIN CC2RC CC1 RSW CSS FSW SS COMP FB 10, 13 (Exposed Pad) RFLT 12V 10µH 2.4k 50m 100k COVP 0.33µF 56k 5.6k 27nF CIN 22µF 1µF VIN 22µF x 2 12V 62k 43k

DS8525D-00 June 2012 www.richtek.com Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Typical Application Circuit Feedback Voltage vs. Temperature 1.0 1.1 1.2 1.3 1.4 1.5 -50 -25 0 25 50 75 100 125 Temperature (°C) Feedback Voltage (V) Feedback Voltage vs. Input Voltage 1.0 1.1 1.2 1.3 1.4 1.5 4 9 14 19 24 29 Input Voltage (V) Feedback Voltage (V) Switching Frequency vs. Temperature 100 140 180 220 260 300 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) Switching Frequency (kHz) 1 RSW = 56kΩ Quiescent Current vs. Input Voltage 0.0 0.5 1.0 1.5 2.0 2.5 3.0 4 9 14 19 24 29 Input Voltage (V) Quiescent Current (mA) No Switching Quiescent Current vs. Temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 - 5 0- 2 5 0 2 5 5 0 7 51 0 0 1 2 5 Temperature (°C) Quiescent Current (mA) No Switching Boost Efficiency vs. Load Current 100 0 0.4 0.8 1.2 1.6 2 Load Current (A) Efficiency (%) VIN = 5V, VOUT = 12V, RSW = 56kΩ

Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. switching frequency within the resistor range. Figure 1. Boost Switching Frequency below its threshold after shutdown delay or UVLO occurs. and fSW is boost switching frequency. compensation voltage also attributes magnitude to ISW.

Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. switching losses dominate the overall power loss. chosen for drain voltage, VDS, rating and low gate charge. voltage for N-MOSFET switch gate driver. Figure 2. Fault Protection Function Block where η is the efficiency of the power converter.

0.4 D R 50 μR < I

released, the RT8525D will re-start. will be in normal operation.

Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ri chtek Technology Corporation. Figure 3. The Output Ripple Voltage without the because of their fast recovery time and low forward voltage.

www.richtek.com DS8525D-00 June 2012 Richtek Technology Corporation 5F, No. 20, Taiyuen 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 0.150 0.250 0.006 0.010 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 1.400 1.750 0.055 0.069 e 0.450 0.018 L 0.350 0.450 0.014 0.018 W-Type 12L 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