RT8855GQW

® RT8855 4/3/2/1-Phase PWM Controller for AMD AM2/AM2+ CPUs General Description Features 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.  12V Power Supply Voltage  4/3/2/1-Phase Power Conversion for VCORE Power 3 Embedded MOSFET Drivers (2 for CPU and 1 for NB) Internal Regulated 5V Output Support AMD AM2 6-bit Parallel and AM2+ 7-bit Serial VID Tables Continuous Differential Inductor DCR Current Sense Adjustable Frequency (Typically at 300kHz) Selectable 1 or 2 Phase in Power-Saving (PS) Mode Phase-Interleaving for VCORE and NB Controller Power Good Indication Adjustable Over Current Protection Over Voltage Protection Small 48-Lead WQFN Package RoHS Compliant and Halogen Free            Pin Configurations Richtek 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. UGATE_NB PHASE_NB LGATE_NB VID5 Note : PGOOD EN Lead Plating System G : Green (Halogen Free and Pb Free) VCC12_NB (TOP VIEW) Package Type QW : WQFN-48L 7x7 (W-Type) VID0/VFIXEN RT8855 VID1/PVI Ordering Information VID2/SVD  Desktop CPU Core Power Low Voltage, High Current DC/ DC Converter VID3/SVC   VID4 Applications 48 47 46 45 44 43 42 41 40 39 38 37 PWROK RT FBRTN FBRTN_NB FB_NB COMP_NB ISP_NB ISN_NB ADJ OFS COMP FB 1 36 2 35 3 34 4 33 5 32 31 6 GND 7 30 8 29 9 28 10 27 49 26 11 25 12 BOOT_NB BOOT1 UGATE1 PHASE1 LGATE1 VCC12 LGATE2 PHASE2 UGATE2 BOOT2 PWM3 PWM4 VCC5 PS ISP4 ISN4 ISN3 ISP3 ISN2 ISP2 ISP1 ISN1 IMAX IMAX_NB 13 14 15 16 17 18 19 20 21 22 23 24 WQFN-48L 7x7 Copyright © 2021 Richtek Technology Corporation. All rights reserved. DS8855-03 September 2021 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8855 Part Status Part No RT8855GQW Status Obsolete Package Type WQFN-48L 7x7 Lead plating System Green (Halogen Free and Pb Free) The part status values are defined as follows: Active: Device is in production and is recommended for new designs. Lifebuy: The device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Preview: Device has been announced but is not in production. Obsolete: Richtek has discontinued the production of the device. L2 4 13 IMAX_NB FBRTN_NB EN PWROK 47 PGOOD 2 RT 14 IMAX 1 48 VID[5:0] ISP_NB 7 8 ISN_NB FB_NB 5 COMP_NB 6 PHASE_NB 38 LGATE_NB 39 46 to 41 22 LGATE RT9619 ROFS ISP4 PWM4 25 GND PWM PHASE BOOT L2 L2 12V UGATE VCC 12V LGATE RT9619 21 ISN4 10 OFS BOOT_NB 36 UGATE_NB 37 3 FBRTN ISP2 18 17 ISN2 FB 12 COMP 11 ISN3 20 ISP3 26 VCC PWM PHASE UGATE BOOT GND 12V 12V Copyright © 2021 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 19 PHASE2 29 LGATE2 30 PWM3 BOOT2 27 UGATE2 28 23 PS ISP1 16 15 ISN1 VCC5 24 40 VCC12_NB 12V PHASE1 33 LGATE1 32 31 VCC12 12V BOOT1 35 UGATE1 34 9 ADJ RT8855 12V 12V 12V L2 L1 NTC LOAD LOAD Typical Application Circuit is a registered trademark of Richtek Technology Corporation. DS8855-03 September 2021 RT8855 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 Copyright © 2021 Richtek Technology Corporation. All rights reserved. DS8855-03 September 2021 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8855 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 Copyright © 2021 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8855-03 September 2021 RT8855 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 10 OFS 11 COMP Output of error-amp and input of PWM comparator of V CORE . 12 FB Inverting input of error-amp of V CORE. 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. Connect this pin to GND by a resistor to set load line of VCORE. Connect this pin to GND/5VCC by a resistor to set no-load offset voltage of V CORE. 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 24 VCC5 25,26 Power Saving Mode Selection Pin. Output of internal 5V regulator for control circuits power supply. Connect this pin to GND by a ceramic capacitor larger than 1uF. 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 31, 40 LGATE2, LGATE1, LGATE_NB Lower gate driver for channel 2 and channel 1 and NB. VCC12, VCC12_NB IC power supply. Connect this pin to 12V. PVI Mode : Used as voltage identification input for DAC. SVI Mode : Functions as VFIXEN selection input. 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. PVI Mode : Used as voltage identification input for DAC. 41 VID0/VFIXEN 42 VID1/PVI 43 VID2/SVD 44 VID3/SVC 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. Reference Ground for the IC. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Exposed pad GND (49) Copyright © 2021 Richtek Technology Corporation. All rights reserved. DS8855-03 September 2021 SVI Mode : Serial data input. PVI Mode : Used as voltage identification input for DAC. SVI Mode : Serial clock input. is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8855 Function Block Diagram RAMP_NB Modulator Waveform Generator RT VCC12 Power-On Reset POR 5V Regulator COMP VCC5 EA + FB BOOT1 Offset OFS MOSFET Driver + - UGATE1 PHASE1 LGATE1 + OV + 1.8V BOOT2 + MOSFET Driver - Transient Response Enhancement PWM3 - PGOOD PWROK EN Soft Start and Fault Logic CH3_EN Detector + PWM4 - CH4_EN Detector + PS + - I_SEN2 + + VID Table Generator FBRTN_NB I_SEN1 + 1.25V VID5 to VID0 FBRTN - - - I_SEN3 + OC Detection OC + OC_NB Detection IMAX_NB CH1 Current SENSE CH2 Current SENSE ISP1 ISN1 ISP2 ISN2 AVG ADJ IMAX PHASE2 LGATE2 + OV OC VIDOFF POR UGATE2 I_SEN4 OC_NB I_SENNB Transient Response Enhancement CH3 Current SENSE ISP3 ISN3 CH4 Current SENSE ISP4 NB Current SENSE ISP_NB ISN4 ISN_NB VCC12_NB COMP_NB BOOT_NB FB_NB + + - EA + OV_NB + RAMP_NB MOSFET Driver - UGATE_NB PHASE_NB LGATE_NB 1.8V Copyright © 2021 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS8855-03 September 2021 RT8855 Absolute Maximum Ratings            (Note 1) Supply Input Voltage -----------------------------------------------------------------------------------------------------BOOTx to PHASEx ------------------------------------------------------------------------------------------------------BOOTx to GND DC ----------------------------------------------------------------------------------------------------------------------------