RT9173/A 1.5A/3A Bus Termination Regulator General Description Features The RT9173/A regulator is designed to convert z voltage supplies ranging from 1.8V to 6V into a Support Both DDR 1 (1.25VTT) and DDR 2 (0.9VTT) Requirements desired output voltage which adjusted by two external z Power TO-263-5 and SOP-8 Packages resistors, voltage divider. The regulator is capable of z Capable of Sourcing and Sinking Current sourcing or sinking up to 1.5A/3A of current while regulating an output voltage to within 2% or less. 1.5A/3A z Current-limiting Protection The RT9173/A, used in conjunction with series z Thermal Protection termination resistors, provides an excellent voltage z Integrated Power MOSFETs source for active termination schemes of high speed z Generates Termination Voltages for SSTL-2 transmission lines as those seen in high speed z High Accuracy Output Voltage at Full-load memory buses and distributed backplane designs. z Adjustable VOUT by External Resistors The voltage output of the regulator can be used as a z Minimum External Components termination voltage for DDR SDRAM. z Shutdown for Standby or Suspend Mode Operation with High-impedance Output Current limits in both sourcing and sinking mode, plus on-chip thermal shutdown make the circuit tolerant of Pin Configurations the output fault conditions. Part Number Applications z Computers z Disk Drives z CD-ROM z Supply Splitter z Graph Card Pin Configurations RT9173ACM5 TOP VIEW (Plastic TO-263-5) 1. 2. 3. 4. 5. 1 2 3 4 5 RT9173CS Ordering Information (Plastic SOP-8) RT9173/A Package type M5 : TO-263-5 S : SOP-8 Operating temperature range C: Commercial standard VIN GND VCNTL (TAB) REFEN VOUT TOP VIEW VIN 1 8 VCNTL GND 2 7 VCNTL REFEN 3 6 VCNTL VOUT 4 5 VCNTL Function Block Diagram 3A sink & source 1.5A sink & source VCNTL VIN Current Limiting Sensor CNTL REFEN VOUT Thermal GND DS9173/A-06 March 2002 www.richtek-ic.com.tw 1 RT9173/A Pin Description Pin Name Pin Function VIN Power Input GND Ground VCNTL Gate Drive Voltage REFEN Reference Voltage Input and Chip Enable VOUT Output Voltage Absolute Maximum Ratings z Input Voltage 7V z Power Dissipation Internally Limited z ESD Rating 2KV z Storage Temperature Range -65°C to 150°C z Lead Temperature (Soldering, 5 sec.) 260°C z Package Thermal Resistance TO-263,θJC 7.7°C/W TO-263,θJA 19.4°C/W SOP-8, θJC SOP-8, θJA 15.7°C/W Note 45°C/W Note: θJA is measured with the component mounted on an evaluation PC board in free air that the required area of 2 copper is 300mm or larger. Electrical Characteristics (Limits in standard typeface are for TA = 25°C, unless otherwise specified: VIN = 2.5V, VCNTL = 3.3V, VREFEN = 1.25V, COUT = 10µF (Ceramic)) Parameter Symbol Test Conditions Min Typ Max Units -20 0 20 mV IL : 0 → 1.5A, Fig.1 -- 0.8 2 IL : 0A → -1.5A -- 0.8 2 1.8 2.5 -- Output Offset Voltage VOS Fig.1 Load Regulation ∆VLOAD Input Voltage Range VIN Keep VCNTL ≥ VIN on operation (DDR 1) VCNTL power on and power off sequences -- 3.3 6 Current In Shutdown Mode ISHDN VREFEN < 0.2V, RL = 180Ω, Fig.2 -- 50 90 Fig.3,4 2.1 -- -- Fig.3,4 3.0 -- -- Thermal Shutdown Temperature TSD 3.3V ≤ VCNTL ≤ 5V 125 150 -- °C Thermal Shutdown Hysteresis Guaranteed by design -- 50 -- °C Output = High, Fig.5 0.8 -- -- Output = Low, Fig.5 -- -- 0.2 % V µA Short Circuit Protection Current limit RT9173 RT9173A ILIMIT A Over Temperature Protection Shutdown Function Shutdown Threshold Trigger www.richtek-ic.com.tw 2 V DS9173/A-06 March 2002 RT9173/A Typical Application Circuit VCNTL= 3.3V VIN = 2.5V R1 VIN VCNTL RT9173/A REFEN VOUT R2 GND 2N7002 EN RTT CCNTL CIN COUT CSS RDUMMY R1 = R2 = 100KΩ, RTT = 50Ω / 33Ω / 25Ω COUT,min = 10µF (Ceramic) + 1000µF under the worst case testing condition RDUMMY = 1kΩ as for VOUT discharge when VIN is not present but VCNTL is present CSS = 1µF, CIN = 470µF (Low ESR), CCNTL = 47µF Test Circuit 2.5V 3.3V VIN 1.25V REFEN VCNTL RT9173/A VOUT VOUT GND IL V COUT Fig.1 Output Voltage Tolerance, ∆VOUT 2.5V 3.3V A VIN 1.25V 0.2V REFEN VCNTL 1.25V VOUT RT9173/A VOUT GND V RL 0V COUT RL and COUT Time delay Fig.2 Current in Shutdown Mode, ISHCLN DS9173/A-06 March 2002 www.richtek-ic.com.tw 3 RT9173/A 2.5V 3.3V VIN REFEN 1.25V VCNTL VOUT VOUT RT9173/A GND A V IL COUT Fig.3 Current Limit for High Side, ICLHIGH Power supply with current limit 2.5V 3.3V VIN 1.25V REFEN A IL VCNTL RT9173/A VOUT VOUT GND V COUT Fig.4 Current Limit for Low Side, ICLLOW 3.3V 2.5V VIN 1.25V VREFEN REFEN 0.2V VCNTL RT9173/A VOUT VOUT GND RL V COUT 1.25V VOUT 0V VOUT would be low if VREFEN < 0.2V VOUT would be high if VREFEN > 0.8V RL and COUT Time delay Fig.5 REFEN Pin Shutdown Threshold, VTRIGGER www.richtek-ic.com.tw 4 DS9173/A-06 March 2002 RT9173/A Typical Operating Characteristics Sinking Current (Peak) vs. Temp. 8.0 7.0 7.0 6.0 6.0 Sinking Current (A) Sourcing Current (A) Sourcing Current (Peak) vs. Temp. 8.0 5.0 4.0 3.0 2.0 VCNTL = 3.3V VIN = 2.5V VOUT = 1.25V 1.0 0.0 -40 -20 0 20 40 60 80 Temperature ( ° C) 100 5.0 4.0 3.0 2.0 VCNTL = 3.3V VIN = 2.5V VOUT = 1.25V 1.0 0.0 120 -40 650 650 600 550 500 -20 0 20 40 60 Temperature ( ° C) 80 40 60 80 100 120 100 600 550 500 450 VCNTL = 3.3V VIN = 2.5V -40 20 Turn-On Threshold vs. Temp. 700 Threshold Voltage (mV) Threshold Voltage (mV) Turn-On Threshold vs. Temp. 400 0 Temperature ( °C) 700 450 -20 VCNTL = 5.0V VIN = 2.5V 400 120 -40 -20 0 20 40 60 80 100 120 Temperature ( °C) VIN = 2.5V 50 VREFEN = 1.25V 12 VCNTL = 3.3V Swing Frequency = 1KHz 0 -50 2 ≈ ≈ 1 0 8 6 4 2 0 -1 -2 -2 -4 Time (250µS/Div) DS9173/A-06 March 2002 VIN = 2.5V VCNTL = 3.3V VREFEN = 1.25V 10 Output Short Circuit (A) Output Current (A) Output Transient Voltage (mV) Transient Response 100 Force the output shorted to ground Time (5mS/Div) www.richtek-ic.com.tw 5 RT9173/A Applications Information Internal parasitic diode Thermal Consideration Avoid forward-bias internal parasitic diode, VOUT to RT9173/A regulators have internal thermal limiting VCNTL, and VOUT to VIN, the VOUT should not be circuitry designed to protect the device during forced some voltage respect to ground on this pin overload conditions. For continuous normal load while the VCNTL or VIN is disappeared. conditions Consideration while designs the resistance of however, the maximum junction temperature rating of 125°C must not be exceeded. voltage divider Higher continous currents or ambient temperature Make sure the sinking current capability of pull-down require additional heatsinking. Heat sinking to the IC NMOS if the lower resistance was chosen so that the package must consider the worst case power voltage on REFEN is below 0.2V. dissipation which may occur. In addition to item 1, the capacitor and voltage divider It should also be note that with the VCNTL equal to form the low-pass filter. There are two reasons doing 5V, the point of thermal shutdown will be degraded by this design; one is for output voltage soft-start while approx. 20°C compared to the VCNTL equipped with another is for noise immunity. 3.3V. It is highly recommended that to use the 3.3V How to reduce power dissipation on Notebook PC or the dual channel DDR SDRAM application? In notebook application, using RichTek’s Patent rail acted as the VCNTL so as to minimize the thermal concern of the RT9173CS in the SOP-8 package. “Distributed Bus Terminator Topology” with choosing Layout Consideration RichTek’s product is encouraged. The RT9173CS regulator is packaged in plastic SOP8 package. This small footprint package is unable to convectively dissipate the heat generated when the regulator is operating at high current levels. In order Distributed Bus Terminating Topology to control die operating temperatures, the PC board Terminator Resistor R0 RT9173 VOUT R1 R2 R3 REFEN R4 R5 R6 RT9173 VOUT R7 R8 R9 RN RN1 www.richtek-ic.com.tw 6 layout should allow for maximum possible copper area at the VCNTL pins of the RT9173CS. BUS(0) BUS(1) The multiple VCNTL pins on the SOP-8 package are internally connected, but lowest thermal resistance BUS(2) will result if these pins are tightly connected on the BUS(3) PC board. This will also aid heat dissipation at high BUS(4) power levels. BUS(5) If the large copper around the IC is unavailable, a BUS(6) buried layer may be used as a heat spreader, Use BUS(7) vias to conduct the heat into the buried or backside of PCB layer. The vias should be small enough to retain BUS(8) solder when the board is wave-soldered. (See Fig.6 BUS(9) shown on next page). BUS(N+1) BUS(N) DS9173/A-06 March 2002 RT9173/A Use vias to conduct the heat into the buried or backside of PCB layer . RT9173CS (SOP-8) The PCB heat sink copper area should be solder-painted without masked. This approaches a “best case” pad heat sink. Fig. 6 Layout Consideration To prevent this maximum junction temperature from being exceeded, the appropriate power plane heat sink MUST be used. Higher continuous currents or ambient temperature require additional heatsinking. DS9173/A-06 March 2002 www.richtek-ic.com.tw 7 RT9173/A Package Information A D C B MARK E L1 L2 b2 b e U V Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max D 9.652 10.668 0.380 0.420 B 1.143 1.676 0.045 0.066 E 8.128 9.652 0.320 0.380 A 4.064 4.826 0.160 0.190 C 1.143 1.397 0.045 0.055 U 6.223 Ref. 0.245 Ref. V 7.620 Ref. 0.300 Ref. L1 14.605 15.875 0.575 0.625 L2 2.286 2.794 0.090 0.110 b 0.660 0.914 0.026 0.036 b2 0.305 0.584 0.012 0.023 e 1.524 1.829 0.060 0.072 5-Lead TO-263 Plastic Surface Mount Package www.richtek-ic.com.tw 8 DS9173/A-06 March 2002 RT9173/A H A M J B F C D Symbol I Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 4.801 5.004 0.189 0.197 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 M 0.406 1.270 0.016 0.050 F 1.194 1.346 0.047 0.053 I 0.102 0.254 0.004 0.010 J 5.791 6.198 0.228 0.244 H 0.178 0.254 0.007 0.010 8–Lead SOP Plastic Package DS9173/A-06 March 2002 www.richtek-ic.com.tw 9 RT9173/A RICHTEK TECHNOLOGY CORP. RICHTEK TECHNOLOGY CORP. Headquarter Taipei Office (Marketing) 6F, No. 35, Hsintai Road, Chupei City 8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5510047 Fax: (8863)5537749 Tel: (8862)89191466 Fax: (8862)89191465 Email: [email protected] www.richtek-ic.com.tw 10 DS9173/A-06 March 2002