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| Preliminary RT9174 Triple Linear Regulator Controllers General Description The RT9174 is a triple linear regulator controller designed for motherboard application. The regulators are intended to regulate the computer system AGP (2X/4X) power, the 2.5V clock power, and the 1.8V power for North/South Bridge core voltage and/or cache memory circuits. All controllers can drive NPN or NMOSFET pass transistor. A special scheme employing driver voltage could be higher than VDD when driving NMOSFET through the 12V power. The RT9174 future a small SOP-8 package for saving board area. It also builds in current limiting and thermal shutdown protection function. Features Integrated Three Linear Controllers in a SOP-8 Package Driving NPN or NMOSFET Sourcing ( > 100mA) and Sinking ( > 5mA) Driver Tri-State Output Driver Low Internal 0.8V Reference Adjustable Output Voltage Setting High Output Stability VDDQ 1.5/3.3V Automatic Changing for AGP Wide 3V to 8V Input Voltage Range Current Limiting and Thermal Protection RoHS Compliant and 100% Lead (Pb)-Free Ordering Information RT9174 Package Type S : SOP-8 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard Applications Mother Boards Power Supply Graphic Cards Pin Configurations (TOP VIEW) VDD DRI 1 FB1 GND 2 3 4 8 7 6 5 DRI 3 FB3 DRI 2 FB2 Note : RichTek Pb-free and Green products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 100%matte tin (Sn) plating. SOP-8 Function Block Diagram VDD OC Thermal Limit + + FB2 OC + FB1 + + GND 0.8V 1.3V FB3 OC DRI2 DRI1 + - DRI3 Reference DS9174-06 March 2007 www.richtek.com 1 RT9174 Typical Application Circuit Preliminary 5V C1 1uF C1 1uF 3.3V Q1 PHD45N03LT VDDQ 1.5 / 3.3V R1 1K + 12V R1 5K 3.3V 1 2 3 VDD DRI1 FB1 GND DRI3 FB3 DRI2 FB2 8 7 6 5 Q2 2SD1802 R4 250 R5 200 VO2 1.8V + Q3 2SD1802 R6 424 R7 200 VO3 2.5V C3 470uF + C6 10nF 4 C3 470uF C2 1000uF R1 1K 3.3V D1 1N4148 R8 1K RT9174 #TYPEDET VDDQ = 3.3V if FB1>1.3V #TYPEDET = 0V to VDDQ = 1.5V #TYPEDET = Open to VDDQ = 3.3V Figure 1. Triple LDOs with VDDQ for M/B Application 5V C1 1uF C1 1uF 3.3V Q1 PHD45N03LT VDDQ 1.5 / 3.3V R2 4.3K + VTTPG R10 1K C8 0.01uF R9 1K Q3 MMBT3904 12V R1 5K 1 2 3 VDD DRI1 FB1 GND DRI3 FB3 DRI2 FB2 8 7 3.3V 6 5 Q2 2SD1802 R4 250 R11 374 R5 200 VTT + C6 10nF 4 C3 470uF R6 3K C7 1uF R12 8.2K C2 1000uF R3 4.99K 3.3V D1 1N4148 R8 1K RT9174 #TYPEDET VTTESL Figure 2. Dual LDOs with VTTPG for VRM 8.5 Application www.richtek.com 2 DS9174-06 March 2007 Preliminary 12V C5 0.1uF R8 3K R1 5K 5V Q1 PHD45N03LT VO1 3.3V R2 624 + RT9174 3.3V R9 1.2K 7.5V C1 1uF Q3 PHD4503LT R6 424 VO3 2.5V C4 470uF + 1 2 3 4 VDD DRI1 FB1 GND DRI3 FB3 DRI2 FB2 8 7 6 5 Q2 PHD4503LT R4 250 R5 200 R7 200 VO2 1.8V C3 + RT9174 470uF C2 1000uF R3 200 Figure 3. Triple LDOs Driving MOS Application Functional Pin Description Pin Name VDD DRI1 FB1 GND DRI2 FB2 DRI3 FB3 Pin Function Power Supply Input Regulator 1 Driver Output Regulator 1 Feedback Non-inverting Input Power Ground Regulator 2 Driver Output Regulator 2 Feedback Non-inverting Input Regulator 3 Driver Output Regulator 3 Feedback Non-inverting Input DS9174-06 March 2007 www.richtek.com 3 RT9174 Absolute Maximum Ratings Preliminary Input Voltage VDD ------------------------------------------------------------------------------------------------------ 8V Feedback FB1/FB2/FB3 --------------------------------------------------------------------------------------------- -0.3 to 8V Driver DRI1/DRI2/DRI3 ------------------------------------------------------------------------------------------------ -0.3 to 12V Power Dissipation, PD @ TA = 25C SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.625W Package Thermal Resistance SOP-8, JA -------------------------------------------------------------------------------------------------------------- 160 C/W Operating Junction Temperature Range -------------------------------------------------------------------------- -40C to 125C Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C Electrical Characteristics (VDD = 5V, CIN = 1F, TA = 25C, unless otherwise specified) Parameter Supply Current Symbol IDD No Load No Load Test Conditions Min -0.78 ---100 5 --1.0 -- Typ 0.8 0.8 2 5 10 -300 40 1.35 150 2.4 Max 2 0.82 10 10 15 --700 150 2.0 --- Units mA V mV mV Feedback Reference Voltage VREF Line Regulation Load Regulation VLINE VLOAD VDD = 4 to 7V Source 100mA, DRI1/DRI2/DRI3 = 2.5V Sink 5mA, DRI1/DRI2/DRI3 = 2.5V Sourcing, DRI1/DRI2/DRI3 = 2.5V Driving Capability IO Sink DRI1/DRI2/DRI3 = 2.5V Sourcing, DRI1/DRI2/DRI3 = 2.5V mA Driver Current Limiting Driver Tri-State Threshold Thermal Limit Power On Reset Voltage ICL VTS Sink DRI1/DRI2/DRI3 = 2.5V Sweep FB1/FB2/FB3 to Driver Output Off mA V C V POR -- www.richtek.com 4 DS9174-06 March 2007 Preliminary Typical Operating Characteristics Reference vs Temperature 0.82 RT9174 Driver Sourcing vs Drop Out 300 VDD = 5V 250 VDD = 5V -20C 25C 85C 150 100 50 Reference (V) 0.81 Sourcing(mA) 200 0.80 0.79 0.78 -50 -10 30 70 110 150 0 0 1 2 3 4 5 Temperature (C) VDD - VDRI1,2,3 (V) Supply Current vs Temperature 1.4 50 Driver Sinking vs VOUT VDD = 5V 85C 1.2 40 1 25C Sinking (mA) IQ(mA) 30 0.8 -20C -20C 25C 20 0.6 85C 0.4 3 4 5 6 7 8 10 0 1 2 3 4 5 VDD (V) VOUT (V) Tri-Sate Vth vs Temperature 1.6 400 Short Current vs Temperature VDD = 5V 350 VDD = 5V Short Current (mA) 1.4 300 250 200 150 Vth(V) 1.2 1.0 0.8 -50 -10 30 70 110 150 100 -50 -20 10 40 70 100 130 Temperature (C) DS9174-06 March 2007 Temperature (C) www.richtek.com 5 RT9174 Application Information Capacitors Selection Preliminary Layout Considerations There are two critical layout considerations. One is the divider resistors should be located to RT9174 as possible to avoid inducing any noise. The second is COUT should be put at near the pass transistor to avoid oscillation. VIN A 0.1F minimum capacitor is recommended between VDD and ground to increase stability. The linear controllers use dominant pole compensation integrated into the error amplifier and are sensitive to output capacitor selection. When driving external pass transistor, normally a minimum 470F capacitor must be placed at output for stability and good transient response. When using internal pass transistor, just need 10F capacitor for stable. Pass Transistor Selection The RT9174 are designed specifically to driver external NPN or NMOSFET pass transistor for up to 5A output current. The driver could deliver more 100mA when driving NPN transistor and sinking for a pull up resistor load when driving a NMOSFET. Typically pass transistor with NPN hfe > 50 at Imax or NMOSFET Rds-on 100m are suitable in most application. Output Voltage Setting The RT9174 develop a 0.8V reference voltage, especially suit for low voltage application. As shown in Figure 4, the output voltage could be easy set by R1 & R2 resistor. The divided resistor must keep below 1k for quick response and stability. Tri-state Operation A special Tri-state design is empolyed in the RT9174 for AGP 2X/4X power supply. Typical application shown the detail circuit. In AGP 2X SELECT = open, FB1 will be pulled up over 1.3V through R 8 to trip the Tri-state threshold. R8 has to meet the following relationship: R8 < 0.75 (V33 - 1.3) x R2, R3 + R2 if x 0.8 = 1.5 . R3 When in AGP 4X SELECT = GND, VDDQ will work in normal 1.5V setting. VDD 1uF VDD DR11 RT9174 DR12 DR13 FB1 FB2 FB3 VOUT R1 + COUT R2 As close as to RT9174 Figure 4 www.richtek.com 6 DS9174-06 March 2007 Preliminary Outline Dimension RT9174 A H M J B F C I D Dimensions In Millimeters Symbol Min A B C D F H I J M 4.801 3.810 1.346 0.330 1.194 0.170 0.050 5.791 0.400 Max 5.004 3.988 1.753 0.508 1.346 0.254 0.254 6.200 1.270 Dimensions In Inches Min 0.189 0.150 0.053 0.013 0.047 0.007 0.002 0.228 0.016 Max 0.197 0.157 0.069 0.020 0.053 0.010 0.010 0.244 0.050 8-Lead SOP Plastic Package Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Richtek Technology Corporation Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com DS9174-06 March 2007 www.richtek.com 7 |
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