DDR Switch-Mode Power Supply

Freescale Semiconductor Advance Information Document number: MC34712 Rev. 4.0, 5/2007 3.0 A 1.0 MHz Fully Integrated DDR Switch-Mode Power Supply The 34712 is a highly integrated, space efficient, low cost, single synchronous buck switching regulator with integrated N-channel power MOSFETs. It is a high performance point-of-load (PoL) power supply with the ability to track an external reference voltage. Its high efficient 3.0 A sink and source capability combined with its voltage tracking/sequencing ability and tight output regulation, makes it ideal to provide the termination voltage (VTT) for modern data buses such as Double-Data-Rate (DDR) memory buses. It also provides a buffered output reference voltage (VREF) to the memory chipset The 34712 offers the designer the flexibility of many control, supervisory, and protection functions to allow for easy implementation of complex designs. It is housed in a Pb-Free, thermally enhanced, and space efficient 24-Pin Exposed Pad QFN. Features • 45 mΩ Integrated N-Channel Power MOSFETs • Input Voltage Operating Range from 3.0 V to 6.0 V • ±1 % Accurate Output Voltage, Ranging from 0.7 V to 1.35 V • ±1 % Accurate Buffered Reference Output Voltage • Programmable Switching Frequency Range from 200 kHz to 1.0 MHz with a default of 1.0 MHz • Over Current Limit and Short Circuit Protection • Thermal Shutdown www.DataSheet4U.com • Output Overvoltage and Undervoltage Detection • Active Low Power Good Output Signal • Active Low Standby and Shutdown Inputs • Pb-Free Packaging Designated by Suffix Code EP. VIN (3.0V TO 6.0V) 34712 SWITCH-MODE POWER SUPPLY EP SUFFIX 98ARL10577D 24-PIN QFN ORDERING INFORMATION Device MC34712EP/R2 Temperature Range (TA) -40 to 85°C Package 24 QFN 34712 PVIN VDDQ VREFIN SW VIN VDDI FREQ GND SD VOUT VDDQ MEMORY BUS BOOT VTT TERMINATING RESISTORS INV COMP VREFOUT PGND PG VIN DDR MEMORY CHIPSET VREF DDR MEMORY CONTROLER VDDQ MCU STBY Figure 1. 34712 Simplified Application Diagram * This document contains certain information on a new product. Specifications and information herein are subject to change without notice. © Freescale Semiconductor, Inc., 2007. All rights reserved. INTERNAL BLOCK DIAGRAM INTERNAL BLOCK DIAGRAM STBY Thermal Monitoring PG M1 Ise nse System Reset Current Monitoring Discharge I li mit SD Internal Voltage Regulator VIN System Control VDDI M2 BOOT VIN VBOOT PVIN M3 SW Oscillator FREQ Prog. Frequency Buck Cntl. Logic FSW Gate Driver Isense M4 V DDI VDDI Bandgap Regulator VREFIN RREF1 RREF2 Buffer M6 Discharge M5 Discharge VOUT V BG PWM Comparator Error Amplifier INV PGND COMP Ramp Generator GND VREFOUT Figure 2. 34712 Simplified Internal Block Diagram 34712 2 Analog Integrated Circuit Device Data Freescale Semiconductor PIN CONNECTIONS PIN CONNECTIONS BOOT VDDI PVIN 24 GND FREQ NC PG STBY SD 23 22 21 20 19 18 PVIN 17 SW SW SW 1 2 3 4 5 6 7 VREFIN Transparent Top View PVIN VIN VIN 16 15 14 PGND 13 8 VREFOUT PGND 9 COMP 10 INV 11 VOUT 12 PGND Figure 3. 34712 Pin Connections Table 1. 34712 Pin Definitions A functional description of each pin can be found in the Functional Pin Description section beginning on page 10. Pin Number 1 2 3 4 5 6 7 8 9 10 11 12,13,14 15,16,17 18,19,20 21 Pin Name GND FREQ NC PG STBY SD Pin Function Ground Passive None Output Input Input Input Output Passive Input Output Ground Power Supply Passive Formal Name Signal Ground Analog signal ground of IC Definition Frequency Adjustment Buck converter switching frequency adjustment pin No Connect Power Good Standby Shutdown Voltage-TrackingReference Input Reference Voltage Output Compensation Error Amplifier Inverting Input Output Voltage Discharge FET Power Ground Switching Node Power-Circuit Supply Input Bootstrap No internal connections to this pin Active-low (open drain) power-good status reporting pin Standby mode input control pin Shutdown mode input control pin Voltage-Tracking-Reference voltage input Buffered output equal to 1/2 of voltage-tracking reference Buck converter external compensation network pin Buck converter error amplifier inverting input pin Discharge FET drain connection (connect to buck converter output capacitors) Ground return for buck converter and discharge FET Buck converter power switching node Buck converter main supply voltage input Bootstrap switching node (connect to bootstrap capacitor) VREFIN VREFOUT COMP INV VOUT PGND SW PVIN BOOT 34712 Analog Integrated Circuit Device Data Freescale Semiconductor 3 PIN CONNECTIONS Table 1. 34712 Pin Definitions (continued) A functional description of each pin can be found in the Functional Pin Description section beginning on page 10. Pin Number 22,23 24 Pin Name VIN Pin Function Supply Passive Formal Name Logic-Circuit Supply Input Internal Voltage Regulator Definition Logic circuits supply voltage input Internal Vdd Regulator (connect filter capacitor to this pin) VDDI 34712 4 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS Table 2. Maximum Ratings All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device. Ratings ELECTRICAL RATINGS Input Supply Voltage (VIN) Pin High-Side MOSFET Drain Voltage (PVIN) Pin Switching Node (SW) Pin BOOT Pin (Referenced to SW Pin) PG, VOUT, SD, and STBY Pins VDDI, FREQ, INV, COMP, VREFIN, and VREFOUT Pins Continuous Output Current (1) ESD Voltage (2) Human Body Model Device Charge Model (CDM) THERMAL RATINGS Operating Ambient Temperature (3) Storage Temperature Peak Package Reflow Temperature During Reflow Maximum Junction Temperature Power Dissipation (TA = 85 °C) (6) (4), (5) Symbol Value Unit VIN PVIN VSW VBOOT - VSW IOUT VESD1 VESD3 -0.3 to 7.0 -0.3 to 7.0 -0.3 to 7.5 -0.3 to 7.5 -0.3 to 7.0 -0.3 to 3.0 ±3.0 V V V V V V A ±2000 ±750 V TA TSTG TPPRT TJ(MAX) PD -40 to 85 -65 to +150 Note 5 +150 2.9 °C °C °C °C W Notes 1. Continuous output current capability so long as TJ is ≤ TJ(MAX). 2. 3. 4. 5. ESD1 testing is performed in accordance with the Human Body Model (CZAP = 100 pF, RZAP = 1500 Ω), ESD3 testing is performed in accordance with the Charge Device Model (CDM). The limiting factor is junction temperature, taking into account power dissipation, thermal resistance, and heatsinking. Pin soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause malfunction or permanent damage to the device. Freescale’s Package Reflow capability meets Pb-free requirements for JEDEC standard J-STD-020C. For Peak Package Reflow Temperature and Moisture Sensitivity Levels (MSL), Go to www.freescale.com, search by part number [e.g. remove prefixes/suffixes and enter the core ID to view all orderable parts. (i.e. MC33xxxD enter 33xxx), and review parametrics. Maximum power dissipation at indicated ambient temperature. 6. 34712 Analog Integrated Circuit Device Data Freescale Semiconductor 5 ELECTRICAL CHARACTERISTICS MAXIMUM RATINGS Table 2. Maximum Ratings (continued) All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage to the device. Ratings THERMAL RESISTANCE (7) Thermal Resistance, Junction to Ambient, Single-Layer Board (1s) (8) Thermal Resistance, Junction to Ambient, Four-Layer Board (2s2p) Thermal Resistance, Junction to Board (10) (9) Symbol Value Unit RθJA RθJMA RθJB 139 43 22 °C/W °C/W °C/W Notes 7. The PVIN, SW, and GND pins comprise the main heat conduction paths. 8. Per SEMI G38-87 and JEDEC JESD51-2 with the single-layer board (JESD51-3) horizontal. 9. Per JEDEC JESD51-6 with the board (JESD51-7) horizontal. There are no thermal vias connecting the package to the two planes in the board. 10. Thermal resistance between the device and the printed circuit board per JEDEC JESD51-8. Board temperature is measured on the top surface of the board near the package. 34712 6 Analog Integrated Circuit Device Data Freescale Semiconductor ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS STATIC ELECTRICAL CHARACTERISTICS Table 3. Static Electrical Characteristics Characteristics noted under conditions 3.0 V ≤ VIN ≤ 6.0 V, - 40°C ≤ TA ≤ 85°C, GND = 0 V unless otherwise noted. Typical values noted reflect the approximate parameter means at TA = 25°C under nominal conditions unless otherwise noted. Characteristic IC INPUT SUPPLY VOLTAGE (VIN) Input Supply Voltage Operating Range Input DC Supply Current (11) Normal Mode: SD = 1 & STBY = 1, Unloaded Outputs Input DC Supply Current (11) Standby Mode, SD = 1 & STBY = 0 Input DC Supply Current (11) Shutdown Mode, SD = 0 & STBY = X INTERNAL SUPPLY VOLTAGE OUTPUT (VDDI) Internal Supply Voltage Range BUCK CONVERTER (PVIN, SW, GND, BOOT, INV, COMP) High-side MOSFET Drain Voltage Range Output Voltage Adjustment Range Output Voltage Accuracy Line Regulation (12) (12) Symbol Min Typ Max Unit VIN IIN IINQ IINOFF 3.0 - - 6.0 25 V mA - - 15 mA - - 100 µA VDDI 2.35 2.5 2.65 V PVIN VOUT REGLN REGLD 2.5 0.7 -1.0 -1.0 - 6.0 1.35 1.0 1.0 V V % % (12), (13), (14) Normal Operation, VIN = 3.0 V to 6.0 V, IOUT = ±3.0 A Load Regulation (12) Normal Operation, IOUT = -3.0 A to 3.0 A Error Amplifier Common Mode Voltage Range (12), (15) Output Undervoltage Threshold Output Overvoltage Threshold Continuous Output Current Over Current Limit, Sinking and Sourcing Short Circuit Current Limit (Sourcing and Sinking) High-Side N-CH Power MOSFET (M3) RDS(ON) (12) IOUT = 1.0 A, VBOOT - VSW = 3.3 V Low-Side N-CH Power MOSFET (M4) RDS(ON) (12) IOUT = 1.0 A, VIN = 3.3 V Notes 11. 12. 13. 14. 15. -1.0 0.0 -1.5 1.5 -3.0 - 4.0 6.5 1.0 1.35 -8.0 8.0 3.0 - % V % % A A A VREF VUVR VOVR IOUT ILIM ISHORT RDS(ON)HS RDS(ON)LS 10 -