首页 RT8855

RT8855

举报
开通vip

RT8855 RT8855 1 DS8855-00 July 2008 www.richtek.com Ordering Information Note : Richtek Green products are : ` RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes....

RT8855
RT8855 1 DS8855-00 July 2008 www.richtek.com Ordering Information Note : Richtek Green products are : ` RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. 4/3/2/1-Phase PWM Controller for AMD AM2/AM2+ CPUs General Description The RT8855 is a 4/3/2/1-phase synchronous buck controller with two integrated MOSFET drivers for CPU power application and a single-phase buck with integrated MOSFET driver for North-Bridge (NB) chipset.The RT8855 uses differential inductor DCR current sense to achieve phase current balance and active voltage positioning. Other features include adjustable operating frequency, power good indication, external error-amp compensation, over voltage protection, over current protection and enable/ shutdown for various applications. The RT8855 comes to a small footprint with WQFN-48L 7x7 package. Features zzzzz 12V Power Supply Voltage zzzzz 4/3/2/1-Phase Power Conversion for VCORE Power zzzzz 3 Embedded MOSFET Drivers (2 for CPU and 1 for NB) zzzzz Internal Regulated 5V Output zzzzz Support AMD AM2 6-bit Parallel and AM2+ 7-bit Serial VID Tables zzzzz Continuous Differential Inductor DCR Current Sense zzzzz Adjustable Frequency (Typically at 300kHz) zzzzz Selectable 1 or 2 Phase in Power-Saving (PS) Mode zzzzz Phase-Interleaving for VCORE and NB Controller zzzzz Power Good Indication zzzzz Adjustable Over Current Protection zzzzz Over Voltage Protection zzzzz Small 48-Lead WQFN Package zzzzz RoHS Compliant and Halogen Free Applications z Desktop CPU Core Power z Low Voltage, High Current DC/ DC Converter Pin Configurations WQFN-48L 7x7 (TOP VIEW) IM A X _N B IM AX IS N 1 IS P1 IS N 2 IS P2 VC C 5 IS N 3 IS P3 IS N 4 IS P4 PS EN PG O O D VI D 5 VI D 4 VI D 3/ SV C VI D 2/ SV D U G AT E_ N B VI D 1/ PV I VI D 0/ VF IX EN VC C 12 _N B LG AT E _N B PH A SE _N B BOOT_NB PHASE1 UGATE1 PWM4 PWM3 BOOT2 UGATE2 PHASE2 LGATE2 LGATE1 VCC12 BOOT1 PWROK FBRTN_NB FBRTN FB COMP OFS ADJ ISN_NB ISP_NB FB_NB COMP_NB RT 36 35 34 33 32 31 30 29 28 27 26 25 373839404142434445464748 1 2 3 4 5 6 7 8 9 10 11 12 242322212019181716151413 GND 49 Package Type QW : WQFN-48L 7x7 (W-Type) RT8855 Operating Temperature Range G : Green (Halogen Free with Commer- cial Standard) RT8855 2 DS8855-00 July 2008www.richtek.com Typical Application Circuit 24 34 33 32 142 1 5 1 92 6 A D J V C C 5 R T U G AT E1 IS N 1 R T8 85 5 IM A X LG AT E1 9 35 B O O T1 P W M 3 PH A S E 1 IS N 3 IS P 1 16 L1 12 V IS P 3 20 P W M 4 25 N TC VC C P W M B O O T U G A TE P H A S E LG A TE L2 12 V 12 V G N D VC C P W M B O O T U G A TE P H A S E LG A TE L2 12 V 12 V G N D IS N 4 IS P 4 22 21 27 28 29 30 18 U G AT E2 B O O T2 IS P2 P H A S E2 IS N 2 17 LG AT E 2 L2 12 V C O M P 11 FB 12 LO A D C O M P_ N B 6 FB _N B 536 37 38 39 7 U G AT E_ N B B O O T_ N B I S P_ N B P H A S E_ N B IS N _N B 8 LG AT E_ N B L2 12 V LO A D V C C 12 31 12 V V C C 12 _N B 40 12 V 13 IM AX _N B 1 0 O F S 46 to 4 1 V ID [5 :0 ] 48 E N 1 P W R O K 47 P G O O D 3 4 FB R T N _N B FB R TN R T9 61 9 R T9 61 9 R O FS P S 23 RT8855 3 DS8855-00 July 2008 www.richtek.com Table 1. 7-bit VID Code Table for AM2+ CPU (Serial) SVID[6:0] Voltage SVID[6:0] Voltage SVID[6:0] Voltage SVID[6:0] Voltage 0000000 1.5500 0100000 1.1500 1000000 0.7500 1100000 0.3500 0000001 1.5375 0100001 1.1375 1000001 0.7375 1100001 0.3375 0000010 1.5250 0100010 1.1250 1000010 0.7250 1100010 0.3250 0000011 1.5125 0100011 1.1125 1000011 0.7125 1100011 0.3125 0000100 1.5000 0100100 1.1000 1000100 0.7000 1100100 0.3000 0000101 1.4875 0100101 1.0875 1000101 0.6875 1100101 0.2875 0000110 1.4750 0100110 1.0750 1000110 0.6750 1100110 0.2750 0000111 1.4625 0100111 1.0625 1000111 0.6625 1100111 0.2625 0001000 1.4500 0101000 1.0500 1001000 0.6500 1101000 0.2500 0001001 1.4375 0101001 1.0375 1001001 0.6375 1101001 0.2375 0001010 1.4250 0101010 1.0250 1001010 0.6250 1101010 0.2250 0001011 1.4125 0101011 1.0125 1001011 0.6125 1101011 0.2125 0001100 1.4000 0101100 1.0000 1001100 0.6000 1101100 0.2000 0001101 1.3875 0101101 0.9875 1001101 0.5875 1101101 0.1875 0001110 1.3750 0101110 0.9750 1001110 0.5750 1101110 0.1750 0001111 1.3625 0101111 0.9625 1001111 0.5625 1101111 0.1625 0010000 1.3500 0110000 0.9500 1010000 0.5500 1110000 0.1500 0010001 1.3375 0110001 0.9375 1010001 0.5375 1110001 0.1375 0010010 1.3250 0110010 0.9250 1010010 0.5250 1110010 0.1250 0010011 1.3125 0110011 0.9125 1010011 0.5125 1110011 0.1125 0010100 1.3000 0110100 0.9000 1010100 0.5000 1110100 0.1000 0010101 1.2875 0110101 0.8875 1010101 0.4875 1110101 0.0875 0010110 1.2750 0110110 0.8750 1010110 0.4750 1110110 0.0750 0010111 1.2625 0110111 0.8625 1010111 0.4625 1110111 0.0675 0011000 1.2500 0111000 0.8500 1011000 0.4500 1111000 0.0500 0011001 1.2375 0111001 0.8375 1011001 0.4375 1111001 0.0375 0011010 1.2250 0111010 0.8250 1011010 0.4250 1111010 0.0250 0011011 1.2125 0111011 0.8125 1011011 0.4125 1111011 0.0125 0011100 1.2000 0111100 0.8000 1011100 0.4000 1111100 OFF 0011101 1.1875 0111101 0.7875 1011101 0.3875 1111101 OFF 0011110 1.1750 0111110 0.7750 1011110 0.3750 1111110 OFF 0011111 1.1625 0111111 0.7625 1011111 0.3625 1111111 OFF RT8855 4 DS8855-00 July 2008www.richtek.com Table 2. 6-bit VID Code Table for AM2 CPU (Parallel) VID[5:0] Voltage VID[5:0] Voltage VID[5:0] Voltage VID[5:0] Voltage 000000 1.5500 010000 1.1500 100000 0.7625 110000 0.5625 000001 1.5250 010001 1.1250 100001 0.7500 110001 0.5500 000010 1.5000 010010 1.1000 100010 0.7375 110010 0.5375 000011 1.4750 010011 1.0750 100011 0.7250 110011 0.5250 000100 1.4500 010100 1.0500 100100 0.7125 110100 0.5125 000101 1.4250 010101 1.0250 100101 0.7000 110101 0.5000 000110 1.4000 010110 1.0000 100110 0.6875 110110 0.4875 000111 1.3750 010111 0.9750 100111 0.6750 110111 0.4750 001000 1.3500 011000 0.9500 101000 0.6625 111000 0.4625 001001 1.3250 011001 0.9250 101001 0.6500 111001 0.4500 001010 1.3000 011010 0.9000 101010 0.6375 111010 0.4375 001011 1.2750 011011 0.8750 101011 0.6250 111011 0.4250 001100 1.2500 011100 0.8500 101100 0.6125 111100 0.4125 001101 1.2250 011101 0.8250 101101 0.6000 111101 0.4000 001110 1.2000 011110 0.8000 101110 0.5875 111110 0.3875 001111 1.1750 011111 0.7750 101111 0.5750 111111 0.3750 RT8855 5 DS8855-00 July 2008 www.richtek.com Functional Pin Description Pin No. Pin Name Pin Function 1 PWROK PWROK Input Signal. 2 RT Connect this pin to GND by a resistor to adjust frequency. 3 FBRTN Remote sense ground for CORE. 4 FBRTN_NB Remote sense ground for NB. 5 FB_NB Inverting input of error-amp for NB. 6 COMP_NB Output of error-amp and input of PWM comparator for NB. 7 ISP_NB Positive current sense pin of NB 8 ISN_NB Negative current sense pin of NB 9 ADJ Connect this pin to GND by a resistor to set load line of VCORE. 10 OFS Connect this pin to GND/5VCC by a resistor to set no-load offset voltage of VCORE. 11 COMP Output of error-amp and input of PWM comparator of VCORE. 12 FB Inverting input of error-amp of VCORE. 13 IMAX_NB Connect this pin to GND by a resistor to set OCP of NB. 14 IMAX Connect this pin to GND by a resistor to set OCP of VCORE. 15, 17, 19, 21 ISN1, ISN2, ISN3, ISN4 Negative current sense pin of channel 1, 2, 3 and 4. 16, 18, 20, 22 ISP1, ISP2, ISP3, ISP4 Positive current sense pin of channel 1, 2, 3 and 4. 23 PS Power Saving Mode Selection Pin. 24 VCC5 Output of internal 5V regulator for control circuits power supply. Connect this pin to GND by a ceramic capacitor larger than 1uF. 25,26 PWM4, PWM3 PWM output for channel 4 and channel 3. 27, 35, 36 BOOT2, BOOT1, BOOT_NB Bootstrap supply for channel 2 and channel 1 and NB. 28, 34, 37 UGATE2, UGATE1, UGATE_NB Upper gate driver for channel 2 and channel 1 and NB. 29, 33, 38 PHASE2, PHASE1, PHASE_NB Switching node of channel 2 and channel 1 and NB. 30, 32, 39 LGATE2, LGATE1, LGATE_NB Lower gate driver for channel 2 and channel 1 and NB. 31, 40 VCC12, VCC12_NB IC power supply. Connect this pin to 12V. 41 VID0/VFIXEN PVI Mode : Used as voltage identification input for DAC. SVI Mode : Functions as VFIXEN selection input. 42 VID1/PVI This pin selects PVI/SVI mode based on the state of this pin prior to EN signal. PVI Mode : Used as voltage identification input for DAC. 43 VID2/SVD PVI Mode : Used as voltage identification input for DAC. SVI Mode : Serial data input. 44 VID3/SVC PVI Mode : Used as voltage identification input for DAC. SVI Mode : Serial clock input. 45, 46 VID4, VID5 PVI Mode : Used as voltage identification input for DAC. 47 PGOOD Power Good Indicator (open drain). 48 EN Enable Input Signal. Exposed pad (49) GND Reference Ground for the IC. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. RT8855 6 DS8855-00 July 2008www.richtek.com Function Block Diagram VCC12 VCC5 BOOT1 UGATE1 PHASE1 LGATE1 BOOT2 UGATE2 PHASE2 LGATE2 PWM3 PWM4 ISP1 ISN1 ISP2 ISN2 ISP3 ISN3 ISP4 ISN4 ADJ FBRTN_NB VID5 to VID0 I_SEN1 I_SEN2 I_SEN3 I_SEN4 IMAX OC POR POR VIDOFF PWROK FB 1.8V OV COMP OC OV RT 1.25V EN OFS Power-On Reset 5V Regulator MOSFET Driver MOSFET Driver CH3_EN Detector CH4_EN Detector CH1 Current SENSE CH2 Current SENSE CH3 Current SENSE CH4 Current SENSE AVG VID Table Generator Transient Response Enhancement Soft Start and Fault Logic Transient Response Enhancement Offset Modulator Waveform Generator + - + - + - + - + - + + - + + - EA + - + - +- +- +- PGOOD FBRTN ISP_NB ISN_NB I_SENNB NB Current SENSE MOSFET Driver BOOT_NB UGATE_NB PHASE_NB LGATE_NB VCC12_NB + -RAMP_NB - +EA FB_NB OC_NBIMAX_NB OV_NB- + + 1.8V COMP_NB PS RAMP_NB OC Detection OC_NB Detection RT8855 7 DS8855-00 July 2008 www.richtek.com Electrical Characteristics Parameter Symbol Conditions Min Typ Max Unit VCC Supply Input VCC12 Supply Voltage VVCC12 10.8 12 13.2 V VCC12 Supply Current IVCC12 -- 10 -- mA VCC12_NB Supply Voltage VVCC12_NB 10.8 12 13.2 V VCC12_NB Supply Current IVCC12_NB -- 5 -- mA VCC5 Power VCC5 Supply Voltage VVCC5 ILOAD = 10mA 4.9 5 5.1 V VCC5 Output Sourcing IVCC5 10 -- -- mA Power-On Reset VCC12 Rising Threshold VVCC12TH VCC12 Rising 9.2 9.6 10 V VCC12 Hysteresis VVCC12HY VCC12 Falling -- 0.9 -- V Input Threshold Enable Input High Threshold VENHI EN Rising 2 -- -- V Enable Input Low Threshold VENLO EN Falling -- -- 0.8 V To be continued Recommended Operating Conditions (Note 3) z Supply Voltage, VCC12 -------------------------------------------------------------------------------------------------- 12V ± 10% z Junction Temperature Range-------------------------------------------------------------------------------------------- −40°C to 125°C z Ambient Temperature Range-------------------------------------------------------------------------------------------- 0°C to 70°C Absolute Maximum Ratings (Note 1) z Supply Input Voltage------------------------------------------------------------------------------------------------------ −0.3V to 15V z BOOTx to PHASEx ------------------------------------------------------------------------------------------------------- −0.3V to 15V z BOOTx to GND DC----------------------------------------------------------------------------------------------------------------------------- −0.3V to 30V <200ns ----------------------------------------------------------------------------------------------------------------------- −0.3V to 42V z PHASEx to GND DC----------------------------------------------------------------------------------------------------------------------------- −2V to 15V <200ns ----------------------------------------------------------------------------------------------------------------------- −5V to 30V z Input/Output Voltage or I/O Voltage ----------------------------------------------------------------------------------- −0.3V to 7V z Power Dissipation, PD @ TA = 25°C WQFN−48L 7x7 ------------------------------------------------------------------------------------------------------------ 3.226W z Package Thermal Resistance (Note 4) WQFN-48L 7x7, θJA ------------------------------------------------------------------------------------------------------- 31°C/W z Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C z Storage Temperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C z ESD Susceptibility (Note 2) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V (VCC12 = 12V, GND = 0V, TA = 25°C, unless otherwise specified) RT8855 8 DS8855-00 July 2008www.richtek.com Parameter Symbol Conditions Min Typ Max Unit PWROK Input High Threshold VPOKHI PWROK Rising 2 -- -- V PWROK Input Low Threshold VPOKLO PWROK Falling -- -- 0.8 V VID5 to VID0 Rising Threshold VVID5 to 0 VID5 to VID0 Rising 0.75 0.8 0.85 V VID5 to VID0 Hysteresis V VID5 to 0 HYS VID5 to VID0 Falling -- 25 -- mV VID5 to VID0 Pull-Down Current IVID5 to 0 VVID5 to 0 = 1.5V -- 16 30 uA Reference Voltage accuracy DAC Accuracy 1V to 1.55V −0.5 -- +0.5 % 0.8V to 1V −8 -- +8 mV 0.5V to 0.8V −10 -- +10 mV Error Amplifier DC Gain ADC No Load -- 80 -- dB Gain-Bandwidth GBW CLOAD = 10pF -- 10 -- MHz Slew Rate SR CLOAD = 10pF 10 -- -- V/us Output Voltage Range VCOMP RLOAD = 47kΩ 0.5 -- 3.6 V Power Good Over-Voltage Threshold VPGOOD-OV FB Rising VDAC +210mV VDAC +240mV VDAC +270mV V Under-Voltage Threshold VPGOOD-UV FB Falling VDAC −330mV VDAC −300mV VDAC −270mV V Over-Voltage Threshold_NB VPGOOD-OV_NB FB_NB Rising VDAC +210mV VDAC +240mV VDAC +270mV V Under-Voltage Threshold_NB VPGOOD-UV_NB FB_NB Falling VDAC −330mV VDAC −300mV VDAC −270mV V Power Good Low Voltage VPGOOD IPGOOD = 4mA -- -- 0.4 V Current Sense Amplifier Max Current IGMMAX VCSP = 1.3V Sink Current from CSN 100 -- -- uA Input Offset Voltage VOSCS −2 0 +2 mV Oscillator Running Frequency fOSC RRT = 40kΩ 270 300 330 kHz Ramp Amplitude VRAMP -- 1.6 -- V Soft Start Soft Start Slew Rate SRSS Slew Rate 2.5 3.25 4 mV/us VID change Slew Rate SRVID Slew Rate 2.5 3.25 4 mV/us Protection Over-Voltage Threshold VOVP Sweep FB Voltage 1.7 1.8 1.9 V VOVP_NB Sweep FB_NB Voltage 1.7 1.8 1.9 V To be continued RT8855 9 DS8855-00 July 2008 www.richtek.com Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. 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 for extended periods may remain possibility to affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution is recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. θJA is measured in the natural convection at TA = 25°C on a effective single layer thermal conductivity test board of JEDEC thermal measurement standard. Parameter Symbol Conditions Min Typ Max Unit Over-Current Threshold IOCP RIMAX = 40kΩ 68 80 92 uA VIMAX RIMAX = 40kΩ 1.44 1.6 1.76 V IOCP_NB RIMAX_NB = 40kΩ 68 80 92 uA VIMAX_NB RIMAX_NB = 40kΩ 1.44 1.6 1.76 V Gate Driver UGATE Drive Source RUGATEsr BOOT − PHASE = 8V 250mA Source Current -- 1 -- Ω UGATE Drive Sink RUGATEsk BOOT − PHASE = 8V 250mA Sink Current -- 1 -- Ω LGATE Drive Source RLGATEsr VLGATE = 8V -- 1 -- Ω LGATE Drive Sink RLGATEsk 250mA Sink Current -- 0.9 -- Ω RT8855 10 DS8855-00 July 2008www.richtek.com Figure 1. SVI Communication-Send Byte Application Information The RT8855 is a dual output PWM controller supports hybrid power control of AMD processors which operate from either a 6-bit parallel VID interface (PVI) or a serial VID interface (SVI). One of the outputs is a 4/3/2/1-phase PWM controller with two integrated MOSFET drivers to support CPU core voltage (VDD) and another is a single- phase buck controller with an integrated MOSFET driver to power North-Bridge (NB) chipset (VDDNB) in SVI mode. In PVI mode, only multiphase PWM controller is active for single-plane VDD only processor. Richtek's proprietary Burst Transient Response(BTRTM), provides fastest initial response to high di/dt load transients and less bulk and ceramic output capacitance is required to meet transient regulation specifications. The RT8855 incorporates differential voltage sensing, continuous inductor DCR phase current sensing, programmable load- line voltage positioning and offset voltage to provide high accuracy regulated power for both VDD and VDDNB. While VDDNB is enabled in SVI mode, it will be automatically phase-shifted with respect to the CPU Core phases in order to reduce the total input RMS current amount. CPU_TYPE Detection and System Start-Up At system Start-up, on the rising-edge of EN signal, RT8855 monitors the status of VID1 and latches the PVI mode (VID1 = 1) or SVI mode (VID1 = 0). PVI Mode PVI is a 6-bit-wide parallel interface used to address the CPU Core section reference. According to the selected code, the device sets the Core section reference and regulates its output voltage according to Table 2. In this mode, NB section is kept in high impedance. Furthermore, PWROK information is ignored as well since the signal only applies to the SVI protocol. SVI Mode SVI is a two wire, Clock and Data, bus that connect a single master (CPU) to one slave (RT8855). The master initiates and terminates SVI transactions and drives the clock, SVC, and the data, SVD, during a transaction. The slave receives the SVI transactions and acts accordingly. SVI wire protocol is based on fast-mode I2C as shown in Figure1. SVI interface also consider two additional signals needed to manage the system start-up. These signals are EN and PWROK. The device asserts a PGOOD signal if the output voltages are in regulation. Set VID Command The Set VID Command is defined as the command sequence that the CPU issues on the SVI bus to modify the voltage level of the Core section and NB section, as shown is Figure 1. During a Set VID Command, the processor sends the start (Start) sequence followed by the address of the Section which the Set VID Command applies. The processor then sends the write (WRITE) bit. After the write bit, The Voltage Regulator (VR) sends the acknowledge (ACK) bit. The processor then sends the VID bits code during the data phase. The VR sends the acknowledge (ACK) bit after the data phase. Finally, the processor sends the stop (Stop) sequence. After the VR has detected the stop, it performs an On-the-Fly VID transition for the addressed section(s). Refer to Table 3 for the details of SVI send byte. RT8855 is able to manage individual power off for both VCORE and NB sections. The CPU may issue a serial VID command to power off or power on one section while the other one remains powered. In this case, the PGOOD signal remains asserted. Start Slave Addressing + W ACK ACKData Phase Stop SVC SVD Start Slave Addressing (7 Clocks) Write (1Ck) A
本文档为【RT8855】,请使用软件OFFICE或WPS软件打开。作品中的文字与图均可以修改和编辑, 图片更改请在作品中右键图片并更换,文字修改请直接点击文字进行修改,也可以新增和删除文档中的内容。
该文档来自用户分享,如有侵权行为请发邮件ishare@vip.sina.com联系网站客服,我们会及时删除。
[版权声明] 本站所有资料为用户分享产生,若发现您的权利被侵害,请联系客服邮件isharekefu@iask.cn,我们尽快处理。
本作品所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用。
网站提供的党政主题相关内容(国旗、国徽、党徽..)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。
下载需要: 免费 已有0 人下载
最新资料
资料动态
专题动态
is_930992
暂无简介~
格式:pdf
大小:339KB
软件:PDF阅读器
页数:18
分类:互联网
上传时间:2013-03-30
浏览量:21