CM8500A 3A BUS TERMINATOR GENERAL DESCRIPTION FEATURES ◆ Patent Filed #6,452,366 ◆ pin PTSSOP and PSOP package ◆ Source and sink up to 3A, no heat sink required ◆ Peak Current to 6A ◆ Integrated Power MOSFETs ◆ Output voltage can be programmed by external resistors default mode, when the VIN/2 pin is open, the output voltage ◆ Separate voltages for VCCQ and PVDD is 50% of the VCCQ. The CM8500A can also be used to ◆ V OUT of ±3% or less at 3A produce various user-defined voltages by forcing a voltage on ◆ Minimum external components the VIN/2 pin. In this case, the output voltage follows the ◆ Shutdown for standby or suspend mode operation ◆ Thermal shutdown protection ◆ 6A Low Noise Current Limit Protection ◆ External Soft Start ◆ Rail to Rail output Buck Converter The CM8500A is a switching regulator designed to provide a desired output voltage or termination voltage for various applications by converting voltage supplies ranging from 2.0V to 5.0V. The CM8500A can be implemented to produce regulated output voltages in two different modes. In the VIN/2 pin input voltage. The switching regulator is capable of sourcing or sinking up to 3A of current while regulating an output V TT voltage to within 3% or less. The CM8500A, used in conjunction with series termination resistors, provides an excellent voltage source for active termination schemes of high speed transmission lines as APPLICATIONS those seen in high speed memory buses and distributed backplane designs. ◆ Mother Board The voltage output of the regulator can be used as a ◆ PCI / AGP Graphics termination voltage for other bus interface standards such as ◆ Game / Play Station SSTL, CMOS, Rambus ™ ,GTL+, VME, LV-CMOS, LV-TTL, ◆ Set Top Box and PECL. ◆ IPC ◆ SCSI-III Bus terminator ◆ Buck Converter PIN CONFIGURATION PSOP-16 (PS16)/PTSSOP-16 (PT16) Top View 2008/01/16 1 VCC 1 2 P V DD1 3 VL1 4 PG N D 1 PG N D 2 13 5 AG N D AG N D 12 6 SD VFB 11 7 VIN /2 VC CQ 10 8 AG SE N AG N D 9 VC C2 16 PV D D 2 15 VL2 14 Champion Microelectronic Corporation Page 1 CM8500A 3A BUS TERMINATOR PIN DESCRIPTION Pin No. Symbol Description Operating Rating Typ. Max. Min. Unit 1,16 VCC1,VCC2 Voltage supply for internal circuits 2 2.5 5 V 2,15 PVDD1,PVDD2 Voltage supply for output power transistors 2 2.5 5 V 3,14 VL1,VL2 Output voltage/inductor connection -3 3 A 0.75 X VCC + V VCC 0.3V 0 VIN V (IDD1+IDD2, Output RMS current) 4,13 PGND1,PGND2 Ground for output power transistors AGND Ground for internal reference voltage divider 8 AGSEN Ground for remote sensing 6 SD Shutdown active high. CMOS input level 5,9,12 7 VIN/2 Input for external reference voltage 10 VCCQ Voltage reference for external voltage divider 5 V 11 VFB Feedback node for the VTT 5 V BLOCK DIAGRAM VCCQ VCC1 10 1 PVDD1 2 SD 6 VCC2 16 PVDD2 15 OSCILLATOR/ RAMP GENERATOR 3 VL1 14 100K 7 AGND 5 AGND 9 Q R Q VL2 ERROR AMP VIN/2 S + + RAMP AMP COMPARATOR - 100K 20PF AGND12 8 AGND 4 PGND1 11 VFB 13 PGND2 ORDERING INFORMATION Part Number Temperature Range CM8500AIT -40℃ to 85 16-Pin PTSSOP (PT16) CM8500AIS -40℃ to 85 16-Pin PSOP (PS16) CM8500AGIT* -40℃ to 85 16-Pin PTSSOP (PT16) CM8500AGIS* -40℃ to 85 16-Pin PSOP (PS16) CM8500ATEVAL *Note: G : Suffix for Pb Free Product 2008/01/16 Champion Microelectronic Corporation Package Evaluation Board (T16) Page 2 CM8500A 3A BUS TERMINATOR ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the Junction Temperature ...…………………… ……………150°C device could be permanently damaged. Storage Temperature PVDD/VCC/VCCQ ......................................….......-0.3V to 6.0V Lead Temperature (Soldering, 5 sec)………………….. 260°C Voltage on Any Other Pin ………... GND – 0.3V to VCC + 0.3V Thermal Resistance(θJA )….. …………..…………….. .40°C/W ……................……. -65°C to 125°C Output RMS Current, Source or Sink .....…………........…...3.0A OPERATING CONDITIONS Temperature Range ............................. -40°C to 85°C PVDD Operating Range .........................2.0V to 5.0V ELECTRICAL CHARACTERISTICS (Unless otherwise stated, these specifications apply TA=25°C; VCC=+3.3V and PVDD=+3.3V) maximum ratings are stress ratings only and functional device operation is not implied.(Note 1) Symbol Parameter Test Conditions CM8500A Unit Min. Typ. Max. 1.12 1.15 1.18 V VCCQ = 2.5V 1.22 1.25 1.28 V VCCQ = 2.7V 1.32 1.35 1.38 IOUT = VCCQ = 2.3V 1.09 1.15 1.21 V ±3A, VCCQ = 2.5V 1.19 1.25 1.31 V VCCQ = 2.7V 1.28 1.35 1.42 V VCCQ = 2.3V 1.139 1.15 1.162 V VCCQ = 2.5V 1.238 1.25 1.263 V VCCQ = 2.7V 1.337 1.35 1.364 V KΩ 660 KHz 3 A 6 A SWITCHING REGULATOR IOUT = 0, VCCQ = 2.3V VIN/2 = open Note 2 VL Output Voltage, SSTL_2 V VIN/2 = open Note 3 VIN/2 Internal Resistor Divider IOUT = 0 Note 2 Note 2 VCCQ = 0 50 ZIN VIN/2 Reference Pin Input Impedance fsw Switching Frequency CM8500A IOUT(RMS) Maximum Output RMS Current CM8500A IOUT(PEAK) Maximum Output Peak Current CM8500A Ilimit Current limit CM8500A 6 Drain to Source on-State Resistance PVDD=5V 150 480 A MOSFETs RDS(ON) 180 mΩ SUPPLY IVCCA Quiescent Current IPVDD VFB = 1.4V LC unconnected VFB = 1.4V LC unconnected 200 µA 500 µA Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions Note 2: VCC, PVDD = 3.3V ±10% Note 3: It’s not 100% test 2008/01/16 Champion Microelectronic Corporation Page 3 CM8500A 3A BUS TERMINATOR FUNCTIONAL DESCRIPTION The CM8500A is a switching regulator that is capable of Low Noise Current Limit: sinking and sourcing 3A of current without an external heat CM3708A’s current limit is a low noise current limit. It increase sink. CM8500A uses a standard surface mount PTSSOP the system loop noise immunity while it is doing the current limit and PSOP package with bottom metal exposed and the heat protection for the system. The current limit is around 6A for the can be piped through the bottom of the device and onto the normal 3A operation. PCB. INPUTS The CM8500A integrates power MOSFETs that are capable The input voltage pins (VCCQ or VIN/2) determine the output of source and sink 3A of current while maintaining excellent voltages (VL1 or VL2). In the default mode, when the VIN/2 pin voltage regulation. The output voltage can be regulated within is open, the output voltage is 50% of the VCCQ input. 3% or less by using the external feedback. Separate voltage If a specific voltage is forced at the VIN/2 pin, the output voltage supply inputs have been added to fit applications with various follows the voltage at the VIN/2 pin. VCCQ suggested power supplies for the databus and power buses. connecting to VCCQ of memory module for better tracking with memory VCCQ. VREF The reference voltage could be ranged from 0V to VIN. OTHER SUPPLY VOLTAGES Several inputs are provided for the supply voltages: PVDD1, OUPUTS PVDD2, VCC1, and VCC2. The output voltage pins (VL1, VL2) are tied to the databus, address, or clock lines via an external inductor. Output voltage The PVDD1 and PVDD2 provide the power supply to the power is determined by the VCCQ or VIN/2 inputs so it can be from MOSFETs. VCC1 and VCC2 provide the voltage supply to the 0V to VIN.. logic section and internal error amplifiers. Internal Power Switches: FEEDBACK CM3708A has been integrated 2 Power MOSFETs whose The VFB pin is an input that can be used for closed loop RDS(ON) is around 100m Ohm each. compensation. This input is derived from the voltage output. AGSEN pin is a contact node of internal resistor divider for remote sense. APPLICATIONS USING THE CM8500A FOR SSTL BUS TERMINATION Figure 1 is the typical schematic of the CM8500ATEVAL that Figure 4 shows the PCB layout of the CM8500ATEVAL. shows the recommended approach for bus terminating Table 1details the key parameters of SSTL_2 specification. solutions for SSTL-2 bus. This circuit can be used in PC Figure 5 shows two different approach of SSTL_2 Terminated memory and Graphics memory applications as shown in Output. (Refer to page 8 for detail description.) Figure 2 and Figure 3. 2008/01/16 Champion Microelectronic Corporation Page 4 CM8500A 3A BUS TERMINATOR APPLICATION CIRCUIT NOTE: J3:referance output provided from Vtt J4:short :Demo kit on . open:off(into shutdown mode) J6:reference output provided from shunt regulator J5:pin1 ,pin2 short:Vtt = 1/2Vcc 1 2 C13 104 5 Vref -OUT J3 TP1 BNC When external voltage applied ,pin1,2 should be open R8 100 and pin2:connect to external voltage (+) 4 1 pin3:connect to external voltage (-) 3 Vtt=1/2 external voltage 2 D6 100uf /6.3V 100uf /6.3V 820uf /6.3V L1 3.3uH R6,R7(option circuit)forVttVOLTAGEADJUST SK12 Vtt=(Vcc*R6)/R6+R7 VTT J1 1 2 C12 C11 D5 SK12 C7 C3 104 C2 104 C15 10uf /6.3V VCC U1 CM8500A 1 VDD 2 2 1 C14 100uf /6.3V 3 C4 104 R5 100k 4 5 6 J4ON/OFF 2 7 2 R6 R7 C6 8 10k 10k 102 1 1 VCC1 VCC2 VDD1 VDD2 VL1 VL2 PGND1 PGND2 AGND1 AGND4 SD 2/VCC FB VCCQ G-sense AGND3 VCC R1 5R1 J2 DC-INPUT VDD 16 1 2 VDD 15 C16 14 C5 13 104 C1 104 C10 10uf /6.3V 470uf /6.3V C9 100uf /6.3V 12 11 10 J5 2 9 3 1 IN/EXT R3 200k 1 2 1 2 R4 1k C8 102 Figure 1 . CM8500A Typical Application (Schematic of CM8500A TEVAL) 2008/01/16 Champion Microelectronic Corporation Page 5 CM8500A 3A BUS TERMINATOR Figure 2. Termination Solution for PC Main Memory (Mother Boards) Figure 3. Termination Solution for Graphic Memory (AGP Graphics) 2008/01/16 Champion Microelectronic Corporation Page 6 CM8500A 3A BUS TERMINATOR CM8500ATEVAL PART LIST Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Q’ty Description Resistors 0805, 5Ω, 1/8W 1 0805, 100Ω, 1/8W 1 0805, 470Ω, 1/8W 1 0805, 1KΩ, 1/8W 1 0805, 100KΩ, 1/8W 2 Designator Manufacturer R1 R8 R9 (option) R4 R3, R5 Capacitors 1 0805, 1nF/ 16V (102) 6 0805, 0.1µF/ 16V (104) 1 0805, 1µF/ 16V (105) CE 10φ, 820uF/ 6.3V 1 2 B Size, Tant 10uF/ 6.3V 4 D Size, Tant 100uF/ 6.3V Magnetics 1 3.3uH 5A Inductor IC’s 1 CM8500AIT 1 CM431L Connectors 1 2-pin, 2.54mm 4 2-pin Jumper, 2.54mm 1 3-pin Jumper, 2.54mm PCBs 1 CM8500ATEVAL PCB C6, C8 C1, C2, C3, C4, C5 C13 C7 C10, C15 C9, C11, C12, C14 Sanyo OSCON L1 Bipolar Electronic Corp. U1 U2 (option) Champion Microelectronic Corp. Champion Microelectronic Corp. J2 J1, J3, J4, J6 (option) J5 Champion Microelectronic Corp. Vendor Information Bipolar Electronic Corp. Sanyo 2008/01/16 Phn: +886-3-360 8892 Champion Microelectronic Corporation Page 7 CM8500A 3A BUS TERMINATOR CM8500ATEVAL PCB LAYOUT Figure 4. CM8500AEVAL PCB Layout SSTL-2 SPECIFICATIONS SYMBOL PARAMETER MIN TYP MAX UNITS VDD Device Supply Voltage VDDQ N/A V VDDQ Output Supply Voltage 2.3 2.5 2.7 V VREF Input Reference Voltage 1.15 1.25 1.35 V VTT Termination Voltage VREF - 0.04 VREF VREF + 0.04 V INPUT DC LOGIC LEVELS VIH (DC) DC Input Logic High VREF + 0.18 VDDQ + 0.3 V VIL (DC) DC Input Logic Low - 0.3 VREF - 0.18 V INPUT AC LOGIC LEVELS VIH (AC) AC Input Logic High VIL (AC) AC Input Logic Low V VREF + 0.35 VREF - 0.35 V OUTPUT DC CURRENT DRIVE IOH (DC) Output Minimum Source DC Current IOL (DC) Output Minimum Sink DC Current Notes: - 15.2 mA 15.2 mA VREF and VTT must track variations in VDDQ Peak-to-peak AC noise on VREF may not exceed ±2% VREF (DC) VTT of transmitting device must track VREF of receiving device Table 1. Key Specifications for SSTL_2 2008/01/16 Champion Microelectronic Corporation Page 8 CM8500A 3A BUS TERMINATOR SSTL_2 TERMINATED OUTPUT Single Terminated Output Double Terminated Output Figure 5. SSTL_2 Terminated Output Note. The SSTL_2 specification requires adequate output current drive so that parallel termination schemes can be used. The use of parallel termination is important for high-speed signaling, since it allows proper termination of the bus transmission lines, which reduces signal reflections. The result will be improved settling, lower EMI emissions, and higher possible clock rates. A minimumtermination resistance of 23Ω to VTT can be used and still comply with the minimum output voltages and output currents of theSSTL_2 specification. Two choices for implementing the parallel termination are shown in Figure 5. Double Terminated Output The bus is terminated at both ends with a 50Ω resistor, for a combined parallel resistance of 25Ω. Single Terminated Output The bus is terminated at the far end from the controller with a single 25Ω resistor. It is strongly recommended that the single resistor termination scheme be used for best performance. The benefits of this approach include reduced cost, simpler signal routing, reduced reflections, and better signal bandwidth and settling. 2008/01/16 Champion Microelectronic Corporation Page 9 CM8500A 3A BUS TERMINATOR CM8500AEVAL TESTING DIAGRAM Figure 6. CM8500AEVAL Typical Testing Diagram TYPICAL CHARACTERISTICS CM8500 Temperature vs. VTT (VCC,VCCQ&VDD=3.3V) 1.350 VTT(V) 1.300 1A 2A 1.250 3A 1.200 1.150 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85 T(℃ ) Temperature vs. VTT VCC, VCCQ & VDD=3.3V 2008/01/16 Champion Microelectronic Corporation Page 10 CM8500A 3A BUS TERMINATOR CM8500 Temperature vs. VTT (VCC,VCCQ&VDD=2.5V) VTT(V) 1.350 1.300 1A 1.250 3A 2A 1.200 1.150 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85 T(℃ ) Temperature vs. VTT VCC, VCCQ & VDD=2.5V 2V INPUT 2008/01/16 LOAD: 0A - 3A 2.5V INPUT LOAD: 0A - 3A 3.3V INPUT LOAD: 0A - 3A 2V INPUT 2.5V INPUT 3.3V INPUT Champion Microelectronic Corporation LOAD: 3A - 0A LOAD: 3A - 0A LOAD: 3A - 0A Page 11 CM8500A 3A BUS TERMINATOR PACKAGE DIMENSION 16-PIN PTSSOP (PT16) 16-PIN PSOP (PS16) θ θ 2008/01/16 Champion Microelectronic Corporation Page 12 CM8500A 3A BUS TERMINATOR IMPORTANT NOTICE Champion Microelectronic Corporation (CMC) reserves the right to make changes to its products or to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current. A few applications using integrated circuit products may involve potential risks of death, personal injury, or severe property or environmental damage. CMC integrated circuit products are not designed, intended, authorized, or warranted to be suitable for use in life-support applications, devices or systems or other critical applications. Use of CMC products in such applications is understood to be fully at the risk of the customer. In order to minimize risks associated provide adequate design and with the customer’s applications, the customer operating safeguards. HsinChu Headquarter Sales & Marketing 5F, No. 11, Park Avenue II, Science-Based Industrial Park, HsinChu City, Taiwan 300 7F-6, No. 32, Sec. 1, Chenggong Rd., Nangang District , Taipei City 115 Taiwan T E L : +886-3-567 9979 F A X : +886-3-567 9909 http://www.champion-micro.com T E L : +886-2-2788 0558 F A X : +886-2-2788 2985 2008/01/16 should Champion Microelectronic Corporation Page 13