CM8500A

CM8500A 3A BUS TERMINATOR GENERAL DESCRIPTION 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 default mode, when the VIN/2 pin is open, the output voltage is 50% of the VCCQ. The CM8500A can also be used to produce various user-defined voltages by forcing a voltage on the VIN/2 pin. In this case, the output voltage follows 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 those seen in high speed memory buses and distributed backplane designs. The voltage output of the regulator can be used as a termination voltage for other bus interface standards such as SSTL, CMOS, Rambus ™ ,GTL+, VME, LV-CMOS, LV-TTL, and PECL. ◆ ◆ ◆ ◆ ◆ ◆ ◆ Mother Board PCI / AGP Graphics Game / Play Station Set Top Box IPC SCSI-III Bus terminator Buck Converter 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 Separate voltages for VCCQ and PVDD V OUT of ±3% or less at 3A Minimum external components 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 APPLICATIONS PIN CONFIGURATION PSOP-16 (PS16)/PTSSOP-16 (PT16) Top View 1 2 3 4 5 6 7 8 VCC2 PVDD2 V L2 PGND2 AGND V FB VCCQ AGND 16 15 14 13 12 11 10 9 V CC 1 P V D D1 V L1 PGND1 AGND SD V IN / 2 AG SEN 2008/01/16 Champion Microelectronic Corporation Page 1 CM8500A 3A BUS TERMINATOR PIN DESCRIPTION Pin No. 1,16 2,15 3,14 Symbol VCC1,VCC2 PVDD1,PVDD2 VL1,VL2 Description Min. Voltage supply for internal circuits Voltage supply for output power transistors Output voltage/inductor connection (IDD1+IDD2, Output RMS current) 4,13 5,9,12 8 6 PGND1,PGND2 AGND Ground for output power transistors Ground for internal reference voltage divider Ground for remote sensing Shutdown active high. CMOS input level 0.75 X VCC 7 10 11 VIN/2 VCCQ VFB Input for external reference voltage Voltage reference for external voltage divider Feedback node for the VTT 0 VCC + 0.3V VIN 5 5 V V V V 2 2 -3 Operating Rating Typ. Max. 2.5 2.5 5 5 3 Unit V V A AGSEN SD BLOCK DIAGRAM VCCQ 10 VCC1 1 VCC2 16 SD 6 PVDD1 2 PVDD2 15 OSCILLATOR/ RAMP GENERATOR 3 VL1 14 S Q VL2 100K ERROR AMP R + RAMP AMP COMPARATOR Q VIN/2 7 5 100K + - AGND AGND 9 20PF AGND12 8 AGND 11 VFB 4 PGND1 13 PGND2 ORDERING INFORMATION Part Number CM8500AIT CM8500AIS CM8500AGIT* CM8500AGIS* CM8500ATEVAL *Note: G : Suffix for Pb Free Product Temperature Range -40℃ to 85 -40℃ to 85 -40℃ to 85 -40℃ to 85 16-Pin 16-Pin 16-Pin 16-Pin Package PTSSOP (PT16) PSOP (PS16) PTSSOP (PT16) PSOP (PS16) Evaluation Board (T16) 2008/01/16 Champion Microelectronic Corporation Page 2 CM8500A 3A BUS TERMINATOR ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the device could be permanently damaged. PVDD/VCC/VCCQ ......................................….......-0.3V to 6.0V Voltage on Any Other Pin ………... GND – 0.3V to VCC + 0.3V Output RMS Current, Source or Sink .....…………........…...3.0A Junction Temperature ...…………………… ……………150°C Storage Temperature ……................……. -65°C to 125°C Lead Temperature (Soldering, 5 sec)………………….. 260°C Thermal Resistance(θJA )….. …………..…………….. .40°C/W OPERATING CONDITIONS Temperature Range ............................. -40°C to 85°C PVDD Operating Range .........................2.0V to 5.0V (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) CM8500A Min. 1.12 1.22 1.32 1.09 1.19 1.28 1.139 1.238 1.337 480 Typ. 1.15 1.25 1.35 1.15 1.25 1.35 1.15 1.25 1.35 50 660 3 6 6 150 180 Max. 1.18 1.28 1.38 1.21 1.31 1.42 1.162 1.263 1.364 ELECTRICAL CHARACTERISTICS Symbol SWITCHING REGULATOR Parameter Test Conditions Unit IOUT = 0, VCCQ = 2.3V VIN/2 = open Note 2 VL Output Voltage, SSTL_2 IOUT = ±3A, VIN/2 = open Note 3 VIN/2 ZIN fsw IOUT(RMS) IOUT(PEAK) Ilimit MOSFETs RDS(ON) SUPPLY IVCCA IPVDD Quiescent Current VFB = 1.4V LC unconnected VFB = 1.4V LC unconnected Drain to Source on-State Resistance PVDD=5V Internal Resistor Divider VIN/2 Reference Pin Input Impedance Switching Frequency Maximum Output RMS Current Maximum Output Peak Current Current limit IOUT = 0 Note 2 Note 2 VCCQ = 2.3V VCCQ = 2.5V VCCQ = 2.7V VCCQ = 0 VCCQ = 2.7V VCCQ = 2.5V VCCQ = 2.7V VCCQ = 2.3V VCCQ = 2.5V V V V V V V V V V KΩ KHz A A A mΩ CM8500A CM8500A CM8500A CM8500A 200 500 µA 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 sinking and sourcing 3A of current without an external heat sink. CM8500A uses a standard surface mount PTSSOP Low Noise Current Limit: CM3708A’s current limit is a low noise current limit. It increase the system loop noise immunity while it is doing the current limit protection for the system. The current limit is around 6A for the normal 3A operation. and PSOP package with bottom metal exposed and the heat can be piped through the bottom of the device and onto the PCB. INPUTS The CM8500A integrates power MOSFETs that are capable of source and sink 3A of current while maintaining excellent voltage regulation. The output voltage can be regulated within 3% or less by using the external feedback. Separate voltage supply inputs have been added to fit applications with various power supplies for the databus and power buses. The input voltage pins (VCCQ or VIN/2) determine the output voltages (VL1 or VL2). In the default mode, when the VIN/2 pin is open, the output voltage is 50% of the VCCQ input. If a specific voltage is forced at the VIN/2 pin, the output voltage follows the voltage at the VIN/2 pin. VCCQ suggested 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, PVDD2, VCC1, and VCC2. OUPUTS 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 0V to VIN.. MOSFETs. VCC1 and VCC2 provide the voltage supply to the logic section and internal error amplifiers. Internal Power Switches: CM3708A has been integrated 2 Power MOSFETs whose RDS(ON) is around 100m Ohm each. FEEDBACK The VFB pin is an input that can be used for closed loop 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 shows the recommended approach for bus terminating solutions for SSTL-2 bus. This circuit can be used in PC memory and Graphics memory applications as shown in Figure 2 and Figure 3. Figure 4 shows the PCB layout of the CM8500ATEVAL. Table 1details the key parameters of SSTL_2 specification. Figure 5 shows two different approach of SSTL_2 Terminated Output. (Refer to page 8 for detail description.) 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 Vref -OUT J3 1 2 5 J5:pin1 ,pin2 short:Vtt = 1/2Vcc C13 104 1 When external voltage applied ,pin1,2 should be open R8 100 and pin2:connect to external voltage (+) pin3:connect to external voltage (-) Vtt=1/2 external voltage D6 TP1 BNC 4 3 L1 3.3uH 100uf /6.3V 100uf /6.3V 820uf /6.3V SK12 R6,R7(option circuit)forVttVOLTAGEADJUST Vtt=(Vcc*R6)/R6+R7 2 VTT J1 1 2 C12 C3 104 C11 C7 C2 104 C15 10uf /6.3V VDD D5 SK12 VCC U1 CM8500A 1 2 2 C14 100uf /6.3V R5 100k C4 104 3 4 5 6 J4ON/OFF 2 R6 10k 1 R7 10k 1 2 7 C6 8 102 VCC1 VDD1 VL1 VCC2 VDD2 VL2 16 VDD 15 C16 14 13 12 11 10 9 2 J5 3 1 C5 104 C1 104 C9 100uf /6.3V C10 10uf /6.3V 470uf /6.3V VCC R1 5R1 VDD J2 DC-INPUT 1 2 PGND1 PGND2 AGND1 AGND4 SD 2/VCC FB VCCQ 1 G-sense AGND3 IN/EXT R3 200k 1 2 1 R4 1k 2 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 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 Designator R1 R8 R9 (option) R4 R3, R5 C6, C8 C1, C2, C3, C4, C5 C13 C7 C10, C15 C9, C11, C12, C14 L1 U1 U2 (option) J2 J1, J3, J4, J6 (option) J5 Champion Microelectronic Corp. Manufacturer Sanyo OSCON Bipolar Electronic Corp. Champion Microelectronic Corp. Champion Microelectronic Corp. Vendor Information Bipolar Electronic Corp. Sanyo Phn: +886-3-360 8892 2008/01/16 Champion Microelectronic Corporation Page 7 CM8500A 3A BUS TERMINATOR CM8500ATEVAL PCB LAYOUT Figure 4. CM8500AEVAL PCB Layout SSTL-2 SPECIFICATIONS SYMBOL VDD VDDQ VREF VTT VIH (DC) VIL (DC) VIH (AC) VIL (AC) IOH (DC) IOL (DC) Notes: PARAMETER Device Supply Voltage Output Supply Voltage Input Reference Voltage Termination Voltage DC Input Logic High DC Input Logic Low AC Input Logic High AC Input Logic Low Output Minimum Source DC Current Output Minimum Sink DC Current - 15.2 15.2 MIN VDDQ 2.3 1.15 VREF - 0.04 VREF + 0.18 - 0.3 VREF + 0.35 VREF - 0.35 2.5 1.25 VREF TYP MAX N/A 2.7 1.35 VREF + 0.04 VDDQ + 0.3 VREF - 0.18 UNITS V V V V V V V V mA mA INPUT DC LOGIC LEVELS INPUT AC LOGIC LEVELS OUTPUT DC CURRENT DRIVE 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 1.300 VTT(V) 1.250 1.200 1.150 -40 -30 -20 -10 0 10 20 30 T(℃ ) 40 50 60 70 80 85 1A 2A 3A 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) 1.350 1.300 VTT(V) 1.250 1.200 1.150 -40 -30 -20 -10 0 10 20 30 T(℃ ) 40 50 60 70 80 85 1A 2A 3A Temperature vs. VTT VCC, VCCQ & VDD=2.5V 2V INPUT LOAD: 0A - 3A 2V INPUT LOAD: 3A - 0A 2.5V INPUT LOAD: 0A - 3A 2.5V INPUT LOAD: 3A - 0A 3.3V INPUT LOAD: 0A - 3A 3.3V INPUT LOAD: 3A - 0A 2008/01/16 Champion Microelectronic Corporation 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. provide Use of CMC products in such applications is understood to be fully at the risk of the customer. with the customer’s applications, the customer should design and operating safeguards. In order to minimize risks associated adequate HsinChu Headquarter 5F, No. 11, Park Avenue II, Science-Based Industrial Park, HsinChu City, Taiwan 300 T E L : +886-3-567 9979 F A X : +886-3-567 9909 http://www.champion-micro.com Sales & Marketing 7F-6, No. 32, Sec. 1, Chenggong Rd., Nangang District , Taipei City 115 Taiwan T E L : +886-2-2788 0558 F A X : +886-2-2788 2985 2008/01/16 Champion Microelectronic Corporation Page 13