RT8525

RT8525 RICHCO | Alldatasheet

Document overview

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Technical content

Features

z VIN Range : 4.5V to 29V 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 14-Lead SOP Package z RoHS Compliant and Halogen Free

Applications

zzzzz LCD TV, Monitor Display Backlight zzzzz LED Driver Application RT8525 GSYMDNN DRV PGND ISW EN OOVP FB FAULT VDC VIN COMP SS FSW AGND PWMI Typical Application Circuit Package Type S : SOP-14 RT8525 Lead Plating System G : Green (Halogen Free and Pb Free) RS RSLP DRV ISW PGND OOVP FAULT RT8525 VIN VDCCDC ENChip Enable CC2RC CC1 RSW CSS FSW SS COMP FB RFLT AGND 6 PWMI PWMI7 VIN 12V 33µH 2.4k 50m 100k COVP 0.33µF 56k 33k 27nF CVIN CIN 100µF 1µF 1µF ROVP1 ROVP2 150k RFB1 RFB2 117k COUT VOUT 100µF x 2 50V24V

www.richtek.com DS8525-01 March 2012 ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Function Block Diagram 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 AGND Analog Ground. 7 PWMI External Digital Input for Dimming Function. 8 FAULT Open Drain Output for Fault Detection. 9 FB Feedback to Error Amplifier Input. 10 OOVP Sense Output Voltage for Over Voltage Protection and Under Voltage Protection. 11 I SW External MOSFET Switch Current Sense Pin. Connect the current sense resistor between the external N-MOSFET switch and ground. 12 EN Chip Enable (Active High). 13 PGND Power Ground of Boost Controller. 14 DRV Drive Output for the N-MOSFET. UVLO 12V LDO OTP OOVP/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 OOVP DRV ISW FB COMP SS EN VOSPWMI AGND PGND

DS8525-01 March 2012 www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation.

Electrical Characteristics

(VIN = 21V, VOUT = 50V, 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 < 29V, 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 Sleeping Mode tSLEEP R SW = 56kΩ, EN = L, 12V Regular Shutdown 55 -- -- ms Shutdown Delay Shutdown Mode tSHDN RSW = 56kΩ, EN = L, IC Shutdown 110 -- -- ms 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)

www.richtek.com DS8525-01 March 2012 ©Copyright 2012 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 low effective thermal conductivity single-layer test board per JEDEC 51-3. 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 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 1.225 1.25 1.275 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 PWM Dimming Control Logic-High V PWMI_H 2 -- -- PWMI Threshold Voltage Logic-Low V PWMI_L -- -- 0.8 V Protection Function OCP Threshold V OCP Including Slope Compensation Magnitude -- 0.4 -- V VOUT OVP Threshold V OVP 2.375 2.5 2.625 V VOUT UVP Threshold V UVP -- 0.1 -- V Thermal Shutdown Temperature TSD -- 150 -- °C Thermal Shutdown Hysteresis ΔTSD -- 50 -- °C

DS8525-01 March 2012 www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. 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) Typical Operating Characteristics Boost Efficiency vs. Load Current 100 0 0.4 0.8 1.2 1.6 2 Load Current (A) Efficiency(%) VIN = 24V, VOUT = 50V 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 -50 -25 0 25 50 75 100 125 Temperature (°C) Quiescent Current (mA) No Switching

©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. switching frequency within the resistor range. Figure 1. Boost Switching Frequency pin voltage and thereby limits the peak switch current. 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 Ric htek 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

0.4 D R 50 μR < I

released, the RT8525 will re-start. will be in normal operation.

©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. on the maximum power dissipation. where η is the efficiency of the power converter. Figure 3. The Output Ripple Voltage without the because of their fast recovery time and low forward voltage.

www.richtek.com DS8525-01 March 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 A B F J D C I H M Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 8.534 8.738 0.336 0.344 B 3.810 3.988 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.508 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.178 0.254 0.007 0.010 I 0.102 0.254 0.004 0.010 J 5.791 6.198 0.228 0.244 M 0.406 1.270 0.016 0.050 14–Lead SOP Plastic Package