PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES 2A Sink/Source Regulator for Front Side Bus and DDR Memory Bus Termination Features • Product Description Ideal for both PC Front Side Bus and DDR memory VTT applications Sinks and sources 2A Over current protection Over temperature protection Shutdown functionality Integrated power MOSFETs. Excellent accuracy (0.5% of load regulation) Minimum external components 8 pin SOIC and PSOP packages • • • • • • • • Applications • • • • PC Front Side Bus termination DDR Memory Termination. Active Termination Buses. Graphics Card DDR Memory Termination. The CM3109 is a sinking and sourcing regulator specifically designed for series-parallel bus termination for high speed chip set buses as well as DDR memory systems. It can source and sink current up to 2A with high accuracy of 0.5 %. The VTT output voltage is selectable by VDDQSEL and FSBSEL pins. The VDDQSEL pin controls whether the CM3109 is in DDR memory mode with VTT = VDDQ/2, or in FSB mode. In FSB mode, FSBSEL controls whether VTT is 1.225V or 1.45V. This allows the same chip to be used in two different circuits on PC motherboards that support both Northwood and Prescott processors. The CM3109 requires no external components to use the GMCH Enable signal in Intel chipset or corresponding signals for other chip sets when powering up the PC. For the boards which support Suspend to RAM (STR) functionality, CM3109 provides a shutdown (SD#) pin. When SD# is set low, VTT will be in tri-state mode, causing the output to go high impedance. In this mode, CM3109 power is saved by significantly reducing the quiescent current. The CM3109 provides over current and over temperature protection. These features protect the chip from excessive heating due to high current and high temperature. The CM3109 is available in both 8-pin SOIC and PSOP packages. Simplified Electric Schematic © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 1 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES PACKAGE/PIN DIAGRAM PIN DESCRIPTIONS PIN 1 2 3 4 5 6 7 8 SYMBOL VDDQ VTT SD VSENSE FSBSEL GND VDDQSEL VCC DESCRIPTION Input Voltage VDDQ Output 1.225V/1.45V FSB or VDDQ/2 DDR (note1) Shutdown Feedback Input Select Input for FSB Output Voltage 1.225V/1.45V Ground Select Input for DDR/FSB Output Power for Control Blocks Table1. VTT Output Selection Truth Table. VDDQSEL "1" OPEN or "0" OPEN or "0" FSBSEL Don't Care "0" "1" VTT VDDQSEL/2(note1) 1.225V 1.45V Note For DDR For FSB For FSB Note1: Assume VDDQ and VDDQSEL are tide together in the DDR application. STANDARD PART ORDERING INFORMATION Pins Package Ordering Part Number Part Marking 8 SOIC CM3109-00SN CM3109-00SN 8 PSOP CM3109-00SB CM3109-00SB © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 2 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Specifications Absolute Maximum Ratings Parameter Rating VCC Operating Supply Voltage 7 VDDQ Input Voltage 7 Pin Voltages VTT Output 7 Any Other Pins 7 ESD Protection (HBM) 2000 Storage Temperature Range -40 to +150 Operating Temperature Range Ambient -45 to +85 Junction -45 to +150 Note2 Power Dissipation Internally Limited Unit V V V V V °C °C °C W Note 2: The devices must be derated based on thermal resistance at elevated temperature. The CM3109-xxSN must be derated at θJA = 151°C/W. Standard Operating Conditions Parameter Range VDDQ, VCC , VDDQSEL 2.5 Ambient OperatingTemperature 25 COUT 220 ± 20% Unit V °C µF Electrical Operating Characteristics 3 Conditions Symbol VDDQ VCC ICC Parameter Input Voltage Range VDDQ Input Voltage Range VCC VCC Quiescent Current VTT Output Voltage VR LOAD Load Regulation ILim VFSBSEL VSD VTT Current Limit Output Selection Logic (FSBSEL) Shutdown Logic TDISABLE THYST Shutdown temperature Thermal hysteresis MIN 2.2 2.2 TYP 2.5 2.5 450 MAX VCC 5.5 UNIT V V µA 1.225 1.2 1.425 1.25 1.225 1.45 1.275 1.25 1.475 V V V 1.2 1.425 1.225 1.45 6.25 1.25 1.475 V V mV IVTT = 0A IVTT = 0A, VDDQ = 2.5V VDDQSEL = "1" = 2.5V VDDQSEL = "0", FSBSEL = "0" VDDQSEL = "0", FSBSEL = "1" IVTT = 0A, VDDQ = 3.3V VDDQSEL = "0", FSBSEL = "0" VDDQSEL = "0", FSBSEL = "1" IVTT = 0A to 2A or IVTT = -2A to 0A 2.5 Logic "1" Level Logic "0" Level Logic "1" Level Logic "0" Level 1.5 0.4 1.5 0.4 150 50 A V V V V °C °C Note 3: Operating characteristics are over Standard Operating Conditions unless otherwise specified. © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 3 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Performance Information Typical DC Characteristics (nominal conditions unless specified otherwise) Output Voltage with Supply (VDDQSEL=2.5V) Load Regulation (Sink) Reference Voltage with Supply (VDDQSEL = 2.5V) Load Regulation (Source) © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 4 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Performance Information (cont'd) Typical DC Characteristics (nominal conditions unless specified otherwise) Over Current Limit (Source) Over Current Limit (Sink) Output Voltage with Supply Voltage (VDDQSEL=0V, FSBSEL=0 Output Voltage with Supply Voltage (VDDQSEL=0V, FSBSEL=2.5V) Supply Current with Supply Voltage © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 5 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Performance Information (cont'd) Typical Transient Characteristics (nominal conditions unless specified otherwise) Load Transient (0A to 1.5A Sink) Line Transient (0A to 1.5A Source) © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 6 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Typical Thermal Characteristics The overall junction to ambient thermal resistance (θJA) for device power dissipation (PD) consists primarily of two paths in series. The first path is the junction to the case (θJC) which is defined by the package style, and the second path is case to ambient (θCA) thermal resistance which is dependent on board layout. The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: CM3109-00SN and maximum instantaneous current of 2A should not be exceeded 29% of the time. For CM3109-00SB, the maximum RMS current increases from 1.3A to 2.2A. Thus, the maximum continuous current can be 2A all the time. Duty Cycle vs. Ambient Temperature (2A) TJUNC = TAMB + PD (θJC ) + PD (θCA ) = TAMB + PD (θJA) When a CM3109–00SN (SOIC) is mounted on a double sided printed circuit board with two square inches of copper allocated for “heat spreading," the resulting θJA is 151°C/W. Based on the over temperature limit of 150°C with an ambient of 85°C, the available power of this package will be: PD = (150°C - 85°C) / 151°C/W = 0.43W. For the CM3109-00SB (PSOP) the θJA is 40°C/W, and the available power for this package will be: PD = (150°C -85°C) / 40°C/W = 1.625W. Duty Cycle vs. Output Current (70C) DDR Memory Application Since the output voltage is 1.25V, and the device can either source current from VDDQ or sink current to Ground, the power dissipated in the device at any time is 1.25V times the current load. This means the maximum average RMS current (in either direction) is 0.344A for CM3109-00SN and 1.3A for CM3109-00SB. The maximum instantaneous current is specified at 2A, so this condition should not be exceeded 17% and 65% of the time for CM3109-00SN and CM3109-00SB, respectively. It is highly unlikely in most usage of DDR memory that this might occur, because it means the DDR memory outputs are either all high or all low for 17% (SOIC) and 65% (PSOP) of the time. If the ambient temperature is 40°C instead of 85°C, which is typically the maximum in most DDR memory applications, the power dissipated PD can be 0.73W for CM3109-00SN and 2.75W for CM3109-00SB. So the maximum average RMS current increases from 0.42A to 0.58A for © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 7 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Typical (cont') Thermal Characteristics The CM3109-00SB has a heat spreader attached to the underneath of the PSOP-8 package in order for heat to be transferred much easier from the package to the PCB. The heat spreader is a copper pad of dimensions just smaller than the package itself. By positioning the matching pad on the PCB top layer to connect to the spreader during manufacturing, the heat will be transferred between the two pads. The drawing below shows the recommended PCB layout. Note that there are six vias on either side to allow the heat to dissipate into the ground and power planes on the inner layers of the PCB. Vias can be placed underneath the chip, but this can cause blockage of the solder. The ground and power planes should be at least 2 sq in. of copper by the vias. It also helps dissipation to spread if the chip is positioned away from the edge of the PCB, and not near other heat dissipating devices. A good thermal link from the PCB pad to the rest of the PCB will ensure a thermal link from the CM3109 package to ambient, θJA, of around 40°C/W. Top layer copper connects to heat spreader Filled via between top layer copper and ground plane Ground layer Solder mask opening for heat slug soldering (not shown for other soldering locations) © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 8 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES Application Information – Front Side Bus The above diagram shows the CM3109 connected to the Intel 865 GMCH Front Side Bus VTT pin GMCHVCCP. The Enable signal GMCH_EN is used to shut down the output of the CM3109 to save power during shutdown periods. The VDDQSEL input ensures that the CM3109 is in Front Side Bus mode, and the BOOTSEL from the GMCH ensures the right Microprocessor VTT voltage is applied. © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 9 PRELIMINARY CM3109 CALIFORNIA MICRO DEVICES SOIC-8 or PSOP-8 Package Dimensions © 2003 California Micro Devices Corp. All rights reserved. 09/10/03 430 N. McCarthy BLVD, Milpitas, California 95035 Tel: (408) 263-3214 Fax: (408) 263-7846 www.calmicro.com 10