Cell Management Electronics for Lithium-Ion Battery BEU8638-12 Independent Balancing for Two 12-Cell Batteries Cell Voltage Monitoring and Telemetry Cell Bypass Relay Drivers www.aeroflex.com/BEU March 21, 2008 Description The Aeroflex 8638-12 is a Lithium-Ion cell balancing system. It controls the balancing of one or two batteries, each consisting of a series stack of Lithium-Ion cells to ensure that each cell is precisely charged to its proper level of energy and to monitor each cell's operational voltage. The cell balancing circuitry uses a set of bilateral DC-DC converters which tie each cell of a battery to a common share bus. Cell charge is distributed among the multiple cells so that the charge of each cell is automatically matched to the average charge of the other cells. Features ● Cell Balancing to within ±5.0mV ● Cell Voltage Monitoring Accuracy ±10.0mV (±20.0mV Space Mission Life) ● Total Battery Voltage Monitoring Accuracy ±0.3% of Full Scale ● Supports up to 12 Lithium-Ion battery cells in series per stack ● Battery Drain Current at Balance 15mA Max for each 12 cell stack ● Discrete output lines for critical signaling with user definable thresholds: Overvoltage Protection 4.40V typ Cell Voltage High 4.20V typ Cell Voltage Low 3.20V typ ● MIL-STD-1553B telemetry for data logging and monitoring SCD8638 Rev D Safety The safety of Lithium-Ion battery technology requires that extreme care be taken in the provisions made for cell charging and cell monitoring. Precision measurements of each of the individual cell voltages in the battery stack and precise charge balancing to each individual cell are critical. The Aeroflex 8638-12 provides the necessary precision of control and monitoring to ensure that safety. Discrete logic outputs are provided for critical signaling, enabling the user to initiate load shedding and/or to halt charging. Low operating losses enable continuous operation. Continuous balancing provides maximum protection against any one cell becoming overcharged. CELL BALANCE BOARD CONTROL BOARD OVP A/D 12-BIT HIGH CELL LOW CELL 1553B Channel A 12 MUX SELECT XFMR 7 XCVR 1553B Channel B ON OFF +30 VDC VIN CONTROLLER XFMR BALANCING CIRCUIT CLOCK DRIVER RELAY +12VDC (ISOLATED) POWER SUPPLY +5VDC MUX BAL CLK MON CLK BALANCING CIRCUIT 1 + - BALANCING CIRCUIT 2 + - BALANCING CIRCUIT 3 + - BALANCING CIRCUIT 4 + - BALANCING CIRCUIT 12 + - PRECISION REFERENCE 4.000V 2 2 2 BATTERY VOLTAGE DIFF. AMPS -12VDC BATTERY RELAY DRIVER BOARD 12 CELLS & RELAYS BATTERY HI AND LO ( 3x ) +12VDC SHARE BUS RELAY DRIVER CONTROL SIGNALS BATTERY 12 CELLS & RELAYS CONTROL BOARD OVP A/D 12-BIT HIGH CELL LOW CELL 1553B Channel A 12 MUX SELECT XFMR 7 XCVR 1553B Channel B ON OFF +30 VDC VIN CONTROLLER XFMR BALANCING CIRCUIT CLOCK DRIVER RELAY POWER SUPPLY +12VDC (ISOLATED) +5VDC -12VDC MUX BAL CLK MON CLK BALANCING CIRCUIT 13 + - BALANCING CIRCUIT 14 2 + - BALANCING CIRCUIT 15 + - BALANCING CIRCUIT 16 + - BALANCING CIRCUIT 24 + - PRECISION REFERENCE 4.000V 2 2 2 BATTERY VOLTAGE DIFF. AMPS BATTERY HI AND LO ( 3x ) +12VDC SHARE BUS RELAY DRIVER CONTROL SIGNALS Block Diagram Aeroflex Plainview SCD8638 Rev D 3/21/08 2 8638-12 Operating Details Battery Cell Balancing Provides 12 individual continuous balancing circuits per stack. Cell Relay Bypass Incorporates one bypass relay for each cell to remove a malfunctioned cell from causing interference with the operation of the remaining cells. Maximum Cell Balancing Current Limit Each cell is provided with a 1Amp fuse for overload interrupt in the event of a shorted cell to protect the remaining cell balance functionality. Battery Cell Overvoltage Latch Output The status of the OVP latch is provided by telemetry as specified in Tables II, III & IV and also as a discrete output. Cell Balancing Accuracy When connected to a battery, the 8638-12 provides balancing currents into each of the battery's cells. The directions and the magnitudes of the individual currents are proportional to the deviations of the cell voltages from the average cell voltage. The transfer ratio of voltage to current is 1.0 Ohm nominal and is satisfied for cell voltages of up to 4.2V. Recovery from Cell Overvoltage Indication The OVP latch is reset by a 1553B reset command or by recycling the input power. Highest Battery Cell Voltage Telemetry Provides highest battery cell voltage telemetry as specified in Tables I & IV. Lowest Battery Cell Voltage Telemetry Provides lowest battery cell voltage telemetry as specified in Tables I & IV. Battery Cell Current Drawn in Off State In the off state, the differential mode battery cell current drawn by each cell balancing circuit is less than 50μA. Test Points Provides test points for total battery voltage, low cell indicator and high cell indicator. Access to the total battery voltage is provided to permit pre-charging before connection to the battery. Battery Cell Voltage Monitoring Measures cell voltages for up to two 12-cell batteries. 4V and 0V References for Calibration Provides 4V and 0V references for cell voltage telemetry calibration. Battery and Cell Protection Incorporates overvoltage protection (OVP) circuits. These circuits monitor all of the battery cell voltages and only register the highest of all cell voltages monitored. When a cell voltage threshold of 4.40V is reached, the protection circuit output changes state and latches within 50mS. Aeroflex Plainview SCD8638 Rev D 3/21/08 3 MIL-STD-1553B Telemetry & Commands (Each 12-cell battery) Analog or bi-level telemetry can be requested from either the primary or the redundant controller and reported over the dual redundant 1553B interface with the RT addresses configurable at the J1 and J4 connectors. Bi-Level Telemetry Bi-level telemetry can be requested on sub-addresses 18, 19 or 22. Analog Telemetry Each analog telemetry item can be requested individually on sub-addresses 18, 19 or 22. First a 1553B receive command with one data word as defined in Table II, which specifies the telemetry item being requested, must be issued. After a minimum delay of 1.2ms, the data can be retrieved by sending a 1553B transmit command for one data word on the same sub-address on which the request was initiated. First a 1553B receive command with one data word as defined in Table I, which specifies the telemetry item being requested, must be issued. After a minimum delay of 1.2ms, the data can be retrieved by sending a 1553B transmit command for one data word on the same sub-address on which the request was initiated. Table II – Bi-level Telemetry The 12-bit data reply is left justified in the 16-bit 1553B data word with the four LSBs set to "0". Item Telemetry Title Status Table I – Analog Telemetry (Each 12-cell battery) Item Telemetry Reply Scale Telemetry Title 1st Data Word of 1553B Receive Command (Hex) 1 Overvoltage Latch Status 2 Bypass Dev. 1 Arm Status 1 4V Reference -0.40V to 4.89V 0800 3 Bypass Dev. 2 Arm Status 2 0V Reference -0.40V to 4.89V 0803 4 Bypass Dev. 3 Arm Status 3 Total Battery Voltage 1 0V to 61.44V 0805 5 Bypass Dev. 4 Arm Status 4 Total Battery Voltage 2 0V to 61.44V 0806 6 Bypass Dev. 5 Arm Status 5 Total Battery Voltage 3 0V to 61.44V 0809 7 Bypass Dev. 6 Arm Status 6 Share Bus Voltage 0V to 5.12V 080A 8 Bypass Dev. 7 Arm Status 7 Bypass Device Driver Power 8 Cell 1 Voltage 9 Cell 2 Voltage 10 Cell 3 Voltage 11 Cell 4 Voltage 12 Cell 5 Voltage 13 Cell 6 Voltage 14 Cell 7 Voltage 15 Cell 8 Voltage 16 Cell 9 Voltage 17 Cell 10 Voltage 18 Cell 11 Voltage 19 Cell 12 Voltage 20 Cell 13 Voltage 21 Cell 14 Voltage 22 Cell 15 Voltage 23 Cell 16 Voltage 24 Cell 17 Voltage 25 Cell 18 Voltage 26 Cell 19 Voltage 27 Cell 20 Voltage 28 Cell 21 Voltage 29 Cell 22 Voltage 30 Cell 23 Voltage ⎫ ⎬ ⎭ ⎫ ⎬ ⎭ 1/ 2/ 0V to 51.2V 080C 0V to 5.12V 0811 0V to 5.12V 0812 0V to 5.12V 0814 0V to 5.12V 0817 0V to 5.12V 0818 0V to 5.12V 081B 0V to 5.12V 081D 0V to 5.12V 081E 0V to 5.12V 0821 Bypass Dev. 8 Arm Status Bypass Dev. 9 Arm Status 11 Bypass Dev. 10 Arm Status 12 Bypass Dev. 11 Arm Status 13 Bypass Dev. 12 Arm Status 14 Bypass Dev. 13 Arm Status 15 Bypass Dev. 14 Arm Status 16 Bypass Dev. 15 Arm Status 17 Bypass Dev. 16 Arm Status 18 Bypass Dev. 17 Arm Status 0V to 5.12V 0822 0V to 5.12V 0824 19 Bypass Dev. 18 Arm Status 0V to 5.12V 0827 20 Bypass Dev. 19 Arm Status 0V to 5.12V 0828 21 Bypass Dev. 20 Arm Status 0V to 5.12V 082B 22 Bypass Dev. 21 Arm Status 0V to 5.12V 082D 23 Bypass Dev. 22 Arm Status 0V to 5.12V 082E 24 Bypass Dev. 23 Arm Status 0V to 5.12V 0830 25 Bypass Dev. 24 Arm Status 0V to 5.12V 0833 0V to 5.12V 0835 0V to 5.12V 0836 0V to 5.12V 0839 0V to 5.12V 083A 0V to 5.12V 083C 0V to 5.12V 083F 31 Cell 24 Voltage 32 Lowest Cell Voltage 0V to 5.12V 0871 33 Highest Cell Voltage 0V to 5.12V 0872 1/ For Battery A. 9 10 ⎫ ⎬ ⎭ ⎫ ⎬ ⎭ 1/ For Battery A. 1/ 2/ 1st Data Word of Reply 1553B Bit Receive Command (Hex) 1 = Set D13 0C80 1 = Armed D15 0C83 1 = Armed D14 0C83 1 = Armed D13 0C83 1 = Armed D12 0C83 1 = Armed D11 0C83 1 = Armed D10 0C83 1 = Armed D9 0C83 1 = Armed D8 0C83 1 = Armed D15 0C85 1 = Armed D14 0C85 1 = Armed D13 0C85 1 = Armed D12 0C85 1 = Armed D11 0C85 1 = Armed D10 0C85 1 = Armed D9 0C85 1 = Armed D8 0C85 1 = Armed D15 0C86 1 = Armed D14 0C86 1 = Armed D13 0C86 1 = Armed D12 0C86 1 = Armed D11 0C86 1 = Armed D10 0C86 1 = Armed D9 0C86 1 = Armed D8 0C86 2/ For Battery B. 2/ For Battery B. Aeroflex Plainview SCD8638 Rev D 3/21/08 4 32-Word Telemetry To reduce data bus bandwidth usage, the 8638-12 supports a 32-word telemetry request on sub-address 20 as defined in Table III. 8-Word Telemetry To reduce data bus bandwidth usage, the 8638-12 supports an 8-word telemetry request on sub-address 24 as defined in Table IV. First a 1553B receive command with one data word of AAAA(Hex) must be issued. After a minimum delay of 1.2ms, the data can be retrieved by sending a 1553B transmit command for 32 data words on sub-address 20. First a 1553B receive command with one data word of 5555(Hex) must be issued. After a minimum delay of 1.2ms, the data can be retrieved by sending a 1553B transmit command for 8 data words on sub-address 24. Reply word 31 is a modulo-16 message count. This counter increments by one for each valid telemetry request. The 12-bit analog data reply is left justified in the 16-bit 1553B data word with the four LSBs set to "0".. Reply word 8 is a modulo-16 message count. This counter increments by one for each valid telemetry request. The 12-bit analog data reply is left justified in the 16-bit 1553B data word with the four LSBs set to "0". Table III – 32-Word Telemetry Table IV – 8-Word Telemetry Item 1 2 Telemetry Reply Type Word Telemetry Title 4V Reference Analog Total Battery Voltage 1 1 Analog 2 Reply Bits Item Telemetry Title D(15:4) 1 Overvoltage Latch Status D(15:4) 2 Bypass Dev. 1 Arm Status Bypass Dev. 2 Arm Status 3 Total Battery Voltage 2 Analog 3 D(15:4) 3 4 Total Battery Voltage 3 Analog 4 D(15:4) 4 Bypass Dev. 3 Arm Status D(15:4) 5 Bypass Dev. 4 Arm Status D(15:4) 6 Bypass Dev. 5 Arm Status Bypass Dev. 6 Arm Status 5 6 Share Bus Voltage Master Bypass Power Status 7 Cell 1 Voltage 8 Cell 2 Voltage 9 Cell 3 Voltage 10 Cell 4 Voltage 11 Cell 5 Voltage 12 Cell 6 Voltage 13 14 Cell 7 Voltage Cell 8 Voltage 15 Cell 9 Voltage 16 Cell 10 Voltage 17 Cell 11 Voltage 18 Cell 12 Voltage 19 Cell 13 Voltage 20 Cell 14 Voltage 21 Cell 15 Voltage 22 Cell 16 Voltage 23 Cell 17 Voltage 24 Cell 18 Voltage 25 Cell 19 Voltage 26 Cell 20 Voltage 27 Cell 21 Voltage 28 Analog Cell 22 Voltage 29 Cell 23 Voltage 30 Cell 24 Voltage 31 Message Count 32 Overvoltage Latch Status 5 Analog ⎫ ⎬ ⎭ ⎫ ⎬ ⎭ 1/ For Battery A. 6 Analog 7 D(15:4) 7 Analog 8 D(15:4) 8 Bypass Dev. 7 Arm Status D(15:4) 9 Bypass Dev. 8 Arm Status Bypass Dev. 9 Arm Status Analog 1/ Analog 10 D(15:4) 10 Analog 11 D(15:4) 11 Bypass Dev. 10 Arm Status Analog 12 D(15:4) 12 Bypass Dev. 11 Arm Status D(15:4) 13 Bypass Dev. 12 Arm Status 14 D(15:4) 14 Bypass Dev. 13 Arm Status Analog 15 D(15:4) 15 Bypass Dev. 14 Arm Status Analog 16 D(15:4) 16 Bypass Dev. 15 Arm Status D(15:4) 17 Bypass Dev. 16 Arm Status 18 Bypass Dev. 17 Arm Status Analog Analog Analog 2/ 9 13 17 Analog 18 D(15:4) Analog 19 D(15:4) 19 Bypass Dev. 18 Arm Status 20 Bypass Dev. 19 Arm Status Analog 20 D(15:4) Analog 21 D(15:4) 21 Bypass Dev. 20 Arm Status Bypass Dev. 21 Arm Status Analog 22 D(15:4) 22 Analog 23 D(15:4) 23 Bypass Dev. 22 Arm Status D(15:4) 24 Bypass Dev. 23 Arm Status Bypass Dev. 24 Arm Status Analog 24 ⎫ ⎬ ⎭ ⎫ ⎬ ⎭ 1/ 2/ Telemetry Type Reply Word Reply Bits Bi-level 1 D13 Bi-level 2 D15 Bi-level 2 D14 Bi-level 2 D13 Bi-level 2 D12 Bi-level 2 D11 Bi-level 2 D10 Bi-level 2 D9 Bi-level 2 D8 Bi-level 3 D15 Bi-level 3 D14 Bi-level 3 D13 Bi-level 3 D12 Bi-level 3 D11 Bi-level 3 D10 Bi-level 3 D9 Bi-level 3 D8 Bi-level 4 D15 Bi-level 4 D14 Bi-level 4 D13 Bi-level 4 D12 Bi-level 4 D11 Bi-level 4 D10 Bi-level 4 D9 Bi-level 4 D8 5 D(15:4) D(15:4) Analog 25 D(15:4) 25 Analog 26 D(15:4) 26 0V Reference Analog Analog 27 D(15:4) 27 Lowest Cell Voltage Analog 6 D(15:4) 28 Highest Cell Voltage Analog 7 D(15:4) 29 Message Count Analog 8 D(15:0) Analog 28 Analog 29 D(15:4) Analog 30 D(15:4) Analog 31 D(15:0) Bi-level 32 D13 1/ For Battery A. 2/ For Battery B. 2/ For Battery B. Aeroflex Plainview SCD8638 Rev D 3/21/08 5 Additional Commands Data Load Command 1553B receive commands consist of 2 data words to the sub-address specified in Table V. Only the first data word is used. Table V – Commands Item Function Title 1st Data Word of 1553B Sub-Address Receive Command (Hex) 1 Bypass commands (multiple) 14 as req’d 2 Reset OVP Latch 15 0400 Telemetry Frame Sync Command 1553B broadcast command on sub-address 17 (any data word) commands the 8638-12 to refresh its RT address. Remote Terminal State Command 1553B transmit command on sub-address 21 for one data word. The reply word will be 4000(Hex), to indicate that the unit is ready to accept another command or 5000(Hex), to indicate that the unit is busy and cannot accept another command. 1553B Data Wrap Around Sub-address 30 is dedicated to data wrap around as specified in MIL-STD-1553B. Supported Mode Codes The 8638-12 supports the 1553B Mode Codes in Table VI. Table VI – 1553B Mode Codes Mode Code Name Mode Code Number Transmit Status Word 2 Transmitter Shutdown 4 Override Transmitter Shutdown 5 Reset Remote Terminal 8 1553B Status Flag Bits The 8638-12 supports the following 1553B status flag bits: 1. Message Error bit 2. Broadcast Message Received bit All other status bits are set to "0". Aeroflex Plainview SCD8638 Rev D 3/21/08 6 Connector P1 26 Pin Subminiature-D Plug Cell Sense Pin # Function Name 1/ Connector J2 for Control Board Connector J5 for Control Board Triaxial 1553B Bus A Pin # Function Name 2/ CHA_DATA_H CHA_DATA_L 23 CELL_12+ 17 CELL_24+ 9 CELL_11+ 7 CELL_23+ 3 CELL_10+ 14 CELL_22+ 19 CELL_9+ 1 CELL_21+ 10 CELL_8+ 20 CELL_20+ 13 CELL_7+ 12 CELL_19+ 16 CELL_6+ 18 CELL_18+ 26 CELL_5+ 8 CELL_17+ SHIELD 5 CELL_4+ 4 CELL_16+ Connector J3 for Control Board Connector J6 for Control Board Triaxial 1553B Bus B 2 CELL_3+ 21 CELL_15+ CHB_DATA_H 15 CELL_2+ 22 CELL_14+ CHB_DATA_L 24 CELL_1+ 6 CELL_13+ SHIELD 11 CELL_1- 25 CELL_13- 1/ For Battery A. 2/ For Battery B. Connector J1 for Control Board 2/ Connector J4 for Control Board 1/ 51 Pin Micro-D Receptacle Control & Test Points Pin # 1 Function 30V_RTN Pin # 18 Function V_BAT_3 Pin # 35 Function V_BAT_2 2 NC_ISOLATION 19 NC_ISOLATION 36 NC_ISOLATION 3 NC_ISOLATION 20 +30V_POWER 37 NC_ISOLATION 4 NC_ISOLATION 21 +30V_POWER 38 NC_ISOLATION 5 30V_RTN 22 NC_ISOLATION 39 SPARE 6 NC_ISOLATION 23 NC_ISOLATION 40 CHASSIS GND 7 CHASSIS GND 24 CHASSIS GND 41 CELL_CHG_24 8 CELL_CHG_12 25 LOW_CELL 42 SPARE 9 SPARE 26 RESERVED 43 BEU_ON_CMD_1 10 BEU_OFF_CMD_2 27 BAL_ON_1 44 BEU_ON_CMD_2 11 BEU_OFF_CMD_1 28 BAL_ON_2 45 HIGH_CELL 12 RTA_2 29 RTA_0 46 RTA_4 13 RTA_GND 30 RTA_GND 47 RTA_GND 14 RTA_GND 31 RTA_GND 48 RTA_GND 15 RTA_1 32 RTA_3 49 RTPTY 16 OV_PROT 33 V_BAT_TP 50 V_BAT_RTN1 17 V_BAT_RTN3 34 V_BAT_RTN2 51 V_BAT_1 1/ For Battery A. 2/ For Battery B. Aeroflex Plainview SCD8638 Rev D 3/21/08 7 Connector P2 78 Pin Subminiature-D Plug Bypass Relay Driver Pin # Function Pin # Function Pin # Function KDH1 27 RESERVED 53 2 KDH5 28 RESERVED 54 KDL13 3 KDH9 29 ISO_1MEG 55 KDL10 4 ISO_1MEG 30 KDL23 56 ISO_1MEG 5 RESERVED 31 KDL2 57 KDH16 6 ISO_1MEG 32 KDL22 58 KDH20 7 ISO_1MEG 33 KDL9 59 KDH24 8 RESERVED 34 KDL19 60 KDH4 9 ISO_1MEG 35 KDL4 61 KDH8 10 KDL1 36 ISO_1MEG 62 KDH12 11 KDL8 37 KDH13 63 RELAY_CURRENT_MON 1 KDL6 12 KDL17 38 KDH17 64 ISO_1MEG 13 KDL3 39 KDH21 65 ISO_1MEG 14 KDL16 40 KDH2 66 ISO_1MEG 15 KDL11 41 KDH6 67 ISO_1MEG 16 KDL20 42 KDH10 68 RESERVED 17 ISO_1MEG 43 ISO_1MEG 69 ISO_1MEG 18 KDL24 KDH15 44 ISO_1MEG 70 19 KDH19 45 RESERVED 71 KDL14 20 KDH23 46 RESERVED 72 KDL21 21 KDH3 47 ISO_1MEG 73 KDL12 22 KDH7 48 RESERVED 74 KDL5 23 KDH11 49 ISO_1MEG 75 ISO_1MEG 24 ISO_1MEG 50 KDL18 76 KDH14 25 ISO_1MEG 51 KDL7 77 KDH18 26 RESERVED 52 KDL15 78 KDH22 Aeroflex Plainview SCD8638 Rev D 3/21/08 8 3D View NOTES - UNLESS OTHERWISE SPECIFIED 1. DIMENSIONS ARE IN INCHES. TOLERANCE: .XXX ±.010 .XX = .03 2x 3.465 2x .425 J3 J6 J2 J5 5.25 MAX. P2 P1 2x 4.010 3.703 2x 3.250 3.147 J1 J4 2x 2.110 1.835 1.297 2x .895 2x .441 2x 1.464 2x 2.424 2x 3.481 10.715 .785 10x .200 5.25 MAX. 2x 1.125 4.940 4.015 2x 3.526 2x 2.423 2x 1.000 2x.403 5x.250 5x 11.000 11.500 Outline Aeroflex Plainview SCD8638 Rev D 3/21/08 9 Standard Configuration Power Dissipation 14 Watts from 30V Supply 1.5 Watts from battery Operating Base Plate Temperature BEU8638-12-S -34°C to +71°C BEU8638-12 0°C to +70°C Storage Temperature -34°C to +71°C Dimensions 11.5'' L x 5.250'' W x 5.250'' H Weight 7.40 lbs (3.36 kg) Ordering Information MODEL NUMBER SCREENING BEU8638-12-S High Reliablilty Space Grade BEU8638-12 Commerical Flow EXPORT CONTROL: EXPORT WARNING: This product is controlled for export under the International Traffic in Arms Regulations (ITAR). A license from the U.S. Department of State is required prior to the export of this product from the United States. Aeroflex’s military and space products are controlled for export under the International Traffic in Arms Regulations (ITAR) and may not be sold or proposed or offered for sale to certain countries. (See ITAR 126.1 for complete information.) PLAINVIEW, NEW YORK Toll Free: 800-THE-1553 Fax: 516-694-6715 INTERNATIONAL Tel: 805-778-9229 Fax: 805-778-1980 NORTHEAST Tel: 603-888-3975 Fax: 603-888-4585 SE AND MID-ATLANTIC Tel: 321-951-4164 Fax: 321-951-4254 WEST COAST Tel: 949-362-2260 Fax: 949-362-2266 CENTRAL Tel: 719-594-8017 Fax: 719-594-8468 www.aeroflex.com [email protected] Aeroflex Microelectronic Solutions reserves the right to change at any time without notice the specifications, design, function, or form of its products described herein. All parameters must be validated for each customer's application by engineering. No liability is assumed as a result of use of this product. No patent licenses are implied. Our passion for performance is defined by three attributes represented by these three icons: solution-minded, performance-driven and customer-focused SCD8638 Rev D 3/21/08 10