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19-2849; Rev 0; 4/03
Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller
General Description
The MAX8533 is a single-port, 12V, InfinibandTM-compliant (IB) versatile hot-swap controller. The device can be implemented in both IB Class I (nonisolated) and Class II (isolated) power-topology applications. Additionally, the MAX8533 can be used as a reliable power controller on hot-swappable blade servers, RAID cards, and network switches or routers that are powered from a 12V bus. The MAX8533 integrates several features that allow reliable insertion and removal of the circuit card, as well as real-time monitoring of abnormal occurrences. The MAX8533 allows for an adjustable soft-start ramp during turn-on of the input voltage, while providing overcurrent protection. It also provides accurate and consistent current-regulated outputs for a programmable period of time to latch off and soft-start in the presence of overcurrent conditions (OC). Additionally, it provides a second level of severe overcurrent (SOC) protection by responding to a dead short in 100ns. The MAX8533 also includes adjustable overvoltage protection. The MAX8533 incorporates undervoltage lockout (UVLO) and a power-good (POK) signal to the DC-toDC converters to confirm the status of output voltage rails during operation. Two enable inputs EN (logic enable) and LPEN (local power enable) provide flexible sequencing. The MAX8533 is specified across the extended temperature range and has an absolute maximum rating of 16V to withstand inductive kickback during board removal. The MAX8533 is available in the space-saving 10-pin MAX package.
Features
o 12V Hot-Swap Controller for 25W or 50W Infiniband Ports o Programmable Overcurrent Protection Regulation Level o EN and LPEN Inputs for Flexible Sequencing o Power-Good Signal o 16V Absolute Maximum Rating Withstands Inductive Kickbacks o Soft-Start Overcurrent Protection During Turn-On o Timed Current Regulation Period (Adjustable) o 100ns IC Response Time to Output Dead Short o Adjustable Overvoltage Protection o Undervoltage Lockout o Adjustable Turn-On Ramp
MAX8533
Ordering Information
PART MAX8533EUB TEMP RANGE -40C to +85C PIN-PACKAGE 10 MAX
Typical Operating Circuit
VB_OUT
Applications
12V Hot-Swap Infiniband Bulk Power Hot-Swap/Plug/Dock Power Management Blade Servers RAID Network Routers and Switches
VBxEN LPEN VB_RET BACKPLANE VB_IN INFINIBAND MODULE 10V TO 14V
IN EN LPEN
ISET
GATE
OUT
OVP
MAX8533
VIN
Pin Configuration appears at end of data sheet. Infiniband is a trademark of InfinibandSM Trade Association.
CTIM
RET
POK
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller MAX8533
ABSOLUTE MAXIMUM RATINGS
IN, POK to RET .......................................................-0.3V to +16V GATE to RET ...................................................-0.3V to (VIN + 7V) OUT, ISET, CTIM to RET ..............................-0.3V to (VIN + 0.3V) EN, LPEN, OVP to RET .............................................-0.3V to +6V Continuous Power Dissipation (TA = +70C) 10-Pin Max (derate 5.6 mW/C above +70C) .......444.4 mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +12V, VEN = 0, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER VB BULK SUPPLY CONTROL IN Supply Voltage Range ISET Current Source Current-Limit Offset Voltage OUT Input Current Severe Overcurrent Threshold 25W OUT Current Regulation 50W OUT Current Regulation GATE PARAMETERS Gate Response Time to Severe Overcurrent Gate Response Time to Overcurrent Gate Turn-On Current Gate Pulldown Current Gate High Voltage IN PARAMETERS Quiescent Supply Current IN UVLO Threshold POK Undervoltage Threshold POK Delay POK Output Voltage POK Leakage Current EN Rising Threshold EN Pullup Voltage EN Pullup Current Hysteresis = 300mV Measured at OUT, rising edge, hysteresis = 300mV VPOK rising VOUT < 9.2V, IPOK = 1.6mA VOUT > 10V, VPOK = 14V Hysteresis = 120mV EN unconnected 1.3 4.5 12 7.5 9.2 100 1.5 8.4 9.6 220 0.1 0.1 1.65 5.5 20 28 3 9.0 10.0 350 0.25 1 2.0 mA V V s V A V V A Overcurrent, VRSENSE (current regulation threshold + 100mV) (Note 1) Severe overcurrent VRSENSE (150mV + current regulation threshold + 50mV) until VGATE begins to slew low (Note 1) VRSENSE current regulation threshold + 50mV until VGATE begins to slew low (Note 1) 8.4 100 600 10 2.7 350 VIN + 4 VIN + 5 V 11.6 ns ns A mA VISET - VIN VOUT = 12V With respect to current regulation threshold RISET = 3.09k 1%, RSENSE = 20m 1% RISET = 3.09k 1%, RSENSE = 10m 1% 2.6 5.2 10 18.5 -4 12 20 0 6 150 3.1 6.2 3.6 7.2 14 21.5 +4 12 V A mV A mV A A CONDITIONS MIN TYP MAX UNITS
2
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Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +12V, VEN = 0, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER LPEN Rising Threshold LPEN Pullup Voltage LPEN Pullup Current OVP Threshold Voltage OVP Fault Timeout CTIM PARAMETERS CTIM Charging Current CTIM Fault Pullup Current Current-Limit Timeout Threshold Voltage VCTIM < 1.5V VCTIM = 6V 16 6 1.5 20 8 1.8 24 12 2.1 A mA V Hysteresis = 10mV, VOVP rising Hysteresis = 120mV LPEN unconnected CONDITIONS MIN 1.3 4.5 12 1.96 TYP 1.65 5.5 20 2.00 1.5 28 2.04 MAX 2.0 UNITS V V A V ms
MAX8533
ELECTRICAL CHARACTERISTICS
(VIN = +12V, VEN = 0, TA = -40C to +85C, unless otherwise noted.) (Note 2)
PARAMETER VB BULK SUPPLY CONTROL IN Supply Voltage Range ISET Current Source Current-Limit Offset Voltage OUT Input Current 25W OUT Current Regulation 50W OUT Current Regulation GATE PARAMETERS Gate Turn-On Current Gate High Voltage IN PARAMETERS Quiescent Supply Current IN UVLO Threshold POK Undervoltage Threshold POK Delay POK Output Voltage POK Leakage Current EN Rising Threshold EN Pullup Voltage EN Pullup Current Hysteresis = 300mV Measured at OUT, rising edge, hysteresis = 300mV VPOK rising VOUT < 9.2V, IPOK = 1.6mA VOUT > 10V, VPOK = 14V Hysteresis = 120mV EN unconnected 1.3 4.5 12 28 7.5 9.0 100 3 9.0 10.2 350 0.25 1 2.0 mA V V s V A V V A 8 VIN + 4 12 A V Current regulation threshold = ISET x RISET VISET - VIN VOUT = 12V RISET = 3.09k 1%, RSENSE = 20m 1% RISET = 3.09k 1%, RSENSE = 10m 1% 2.5 5.0 10 18 -4 14 22 +4 12 3.7 7.4 V A mV A A A CONDITIONS MIN TYP MAX UNITS
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Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller MAX8533
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +12V, VEN = 0, TA = -40C to +85C, unless otherwise noted.) (Note 2)
PARAMETER LPEN Rising Threshold LPEN Pullup Voltage LPEN Pullup Current OVP Threshold Voltage CTIM PARAMETERS CTIM Charging Current CTIM Fault Pullup Current Current-Limit Timeout Threshold Voltage VCTIM < 1.5V VCTIM = 6V 15 6 1.4 25 12 2.2 A mA V Hysteresis = 10mV, VOVP rising Hysteresis = 120mV LPEN unconnected CONDITIONS MIN 1.3 4.5 12 1.96 28 2.04 TYP MAX 2.0 UNITS V V A V
Note 1: The current regulation threshold is set by R3 (Figure 2). It is equal to 20A x R3. Note 2: Specifications to -40C are guaranteed by design and not production tested.
Typical Operating Characteristics
(TA = +25C, unless otherwise noted.)
HOT PLUG WITH 10V INPUT INTO 50W LOAD
MAX8533 toc01
HOT PLUG WITH 14V INPUT INTO 65W LOAD
MAX8533 toc02
HOT PLUG INTO SHORT CIRCUIT
MAX8533 toc03
VIN
10V/div 0V
10V/div VIN 0V 10V/div VPOK 0V VPOK 10V/div VOUT 0V 5A/div 0A 20ms/div VIN
10V/div 0V
VPOK
10V/div 0V
0V 0V 5A/div 0A
VOUT IIN
10V/div 0V 5A/div 0A 20ms/div
VOUT IIN
IIN
20ms/div
ON/OFF CONTROL WITH EN TOGGLED
MAX8533 toc04
ON/OFF CONTROL WITH LPEN TOGGLED
MAX8533 toc05
VEN
10V/div 0V VLPEN
5V/div 0V 10V/div 0V 10V/div VOUT 0V 5A/div 0A
VPOK VOUT
10V/div 0V 10V/div 0V 5A/div 0A
VPOK
IIN
IIN
200ms/div
200ms/div
4
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Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller MAX8533
Typical Operating Characteristics (continued)
(TA = +25C, unless otherwise noted.)
HOT PLUG INTO INPUT OVERVOLTAGE CONDITION
MAX8533 toc06
INPUT OVERVOLTAGE PROTECTION FAULT CONDITION
MAX8533 toc07
10V/div VIN 0V VGATE 10V/div 0V
VOUT
10V/div 0V
VGATE
10V/div 0V
IIN VOUT 10V/div 0V 0A 40ms/div 2ms/div 5V/div
SHORT-CIRCUIT CURRENT PROTECTION
MAX8533 toc08
OUTPUT-VOLTAGE RISE TIME AS A FUNCTION OF GATE CAPACITOR (C2)
MAX8533 toc09
0.047F 0.1F VOUT 10V/div 0.022F 0V VIN VGATE 12V 10V/div 0V IIN 2A/div 0A VOUT
0.22F
0.47F
5V/div 0V
10s/div
40ms/div
INPUT-CURRENT RISE TIME AS A FUNCTION OF GATE CAPACITOR (C2)
MAX8533 toc10
HOT UNPLUG
MAX8533 toc11
0.047F 0.1F 0.022F
0.22F
0.47F
VIN 2A/div
10V/div 0V
VOUT
10V/div 0V
IIN
0A
IIN
2A/div 0A
40ms/div
4ms/div
_______________________________________________________________________________________
5
Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller MAX8533
Pin Description
PIN 1 2 NAME ISET IN FUNCTION Current-Limit Threshold Programming Input. Connect to the low side of the current-limit threshold programming resistor. Bulk Power Supply. Connect to the input power supply and positive terminal of the current-sense resistor. External MOSFET-Gate-Drive Output. Connect to the gate of the external N-channel MOSFET. A series resistor and capacitor connected from GATE to RET sets the turn-on ramp rate. At turn-on, this capacitor is charged to VIN + 5V (typ) by an internal current source. GATE is pulled to RET when EN is high and/or LPEN is low. GATE is pulled to RET during a fault condition. Current Regulation Time Programming Input. Connect a capacitor from CTIM to RET. The capacitance at CTIM determines the time delay between an overcurrent event and chip output shutdown (current-limit timeout). CTIM is pulled low, resetting the fault latch when either EN is high or LPEN is low. Bulk Power Ground Overvoltage Protection Input. Connect to common point of a resistor-divider from OUT to RET. GATE pulls low when VOVP exceeds the 2V threshold for at least 1.5ms and the IC is latched off. Output Voltage. Connect to the output of the circuit. Power-Good Output. POK is an open-drain output that becomes high impedance when VOUT reaches 9.6V. Pull POK up to the supply rail using an external pullup resistor. POK is pulled to RET until the MAX8533 is enabled. Local Power-Enable Input. LPEN is a positive-assertion enable input to turn on the IC. Pull LPEN low to disable the output. LPEN has an internal pullup to 5V. Chip-Enable Input. EN is an active-low input that enables the IC.
3
GATE
4 5 6 7 8 9 10
CTIM RET OVP OUT POK LPEN EN
Detailed Description
The MAX8533 is a single-port, 12V, IB-compliant versatile hot-swap controller IC designed for applications where a line card is inserted into a live backplane. The MAX8533 can be implemented in both IB Class I (nonisolated) and Class II (isolated) power-topology applications. Normally, when a line card is plugged into a live backplane, the low impedance of the card's discharged filter capacitors can momentarily collapse the input supply voltage. The MAX8533 is designed to reside on the line card and to provide inrush currentlimiting and short-circuit protection. This is achieved using an external N-channel MOSFET, current-sense resistor, and current-limit set resistor, along with two on-chip comparators (Figure 1).
Once VIN exceeds the UVLO threshold and LPEN and EN are enabled, the capacitor on the gate of the external MOSFET is charged and the MOSFET turns on. The charging of this capacitor provides soft-start to prevent high inrush currents.
On/Off Control
The MAX8533 is enabled/disabled using LPEN and EN. Drive EN low and LPEN high to enable the device. LPEN can also be left unconnected as it is internally connected to 5V. Drive LPEN low or EN high to disable the output. Table 1 is the truth table for these inputs.
Table 1. Truth Table
EN 0 0 1 1 LPEN 0 1 0 1 OUTPUT OFF ON OFF OFF
UVLO and Startup
The MAX8533 has an undervoltage lockout protection circuit. The circuit is disabled when VIN is below 8.4V (typ). The gate of the MOSFET, CTIM, LPEN, and POK is pulled to RET until VIN exceeds the UVLO threshold.
Zero is a logic-low input, 1 is a logic-high input or unconnected input.
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Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller
Startup Into Load
The MAX8533 is intended to be used in a circuit where no load is applied until the POK signal is enabled. In an application where the load is applied during the outputvoltage ramp up, the RDS(ON) of the MOSFET is higher and the power dissipated by the MOSFET is larger. Repeated, rapid hot-swaps into a load can create sufficient heat to exceed the power-dissipation limits of the package causing failure of the MOSFET.
MAX8533
IN
GATE
ISET
IREG
I0A CHARGE PUMP OVERCURRENT COMPARATOR IN
CURRENT-REGULATION CONTROL LOGIC 5V LINEAR REGULATOR 2V REFERENCE (REF) UVLO COMPARATOR SEVERE OVERCURRENT COMPARATOR BIAS
IN 7.5k
Applications Information
Setting the Turn-On Ramp Rate
The MOSFET turn-on ramp rate is determined by the capacitor (C2) at GATE (Figure 2). An internal 10A current source charges C2 to bring GATE high. The soft-start rate is determined as follows: tSS = C2 x (VIN + 5)/(10 x 10-6) tSS may be longer than expected in the application depending on the gate capacitance of the external MOSFET. The necessary gate voltage is provided by an on-board charge pump that boosts the voltage at GATE to (VIN + 5V).
20A
IN
CURRENTREGULATION TIMER OVP COMPARATOR 2V POK COMPARATOR 2V
CTIM
OVP OUT
RET EN LPEN
20A 5V CLAMP
External Power MOSFET Selection
Select the N-channel MOSFET according to the application's current requirements. Table 2 lists some recommended components. The MOSFET's on-resistance (RDS(ON)) should be chosen low enough to have a minimal voltage drop at full load to limit the MOSFET power dissipation. High RDS(ON) can cause high output ripple if the board has pulsing loads, or trigger an external
5V CLAMP
MAX8533 20A POK IN N
Figure 1. MAX8533 Functional Diagram
BACKPLANE VIN 100F 10F
INFINIBAND MODULE 10V TO 14V
R1 10m
N1 R2 20 C2 0.1F ISET GATE OUT VIN R5 31.6k
VVB_OUT C1 470F
R3 3.09k
VBxEN LPEN VB_RET EN LPEN C4 0.22F CTIM C3 0.01F IN
MAX8533
RET POK
OVP R4 4.99k
R6 100k POK
Figure 2. Typical 50W Applications Circuit _______________________________________________________________________________________ 7
Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller
Table 2. External Component List for 50W Output
REF DESIGNATOR C1 C2 C3 C4 R1* R2 R3 R4 R5 N1 DESCRIPTION 470F, 25V aluminum electrolytic capacitor 0.1F 10%, 25V X5R ceramic capacitor 0.01F 20% X7R ceramic capacitor MANUFACTURER PART NO. Sanyo 25MV470HC Taiyo Yuden TMK107BJ104KA Kemet C0606C103M4RAC
0.22F 10%, 25V X5R TDK ceramic capacitor C1608X5R1A224K 10m 1%, 0.5W current-sense resistor 20 5% resistor 3.09k 1% resistor 4.99k 1% resistor 31.6k 1% resistor N-channel MOSFET, 30V, 6m Dale LRF1206-01-R010-F Panasonic Panasonic Panasonic Panasonic Siliconix Si4842DY
plus VILIM. As the load current increases, the voltage drop across R1 increases and reduces the voltage at ISET. Once VISET is lower than VIN, the overcurrent comparator (Figure 1) is tripped and the MAX8533 enters current regulation mode. During current regulation mode, the gate voltage of the MOSFET is decreased to limit the current to the output. The maximum time period for the current regulation mode is set by the external capacitor at CTIM (C3). This feature allows transient currents that exceed the current limit to pass without shutting down the circuit. The current regulation time period is determined as: tIREG = C3 x (1.8V/20A) If t IREG expires and the overcurrent condition still exists, the MOSFET is latched off. The severe overcurrent comparator (Figure 1) trips if the drop across the current-sense resistor (R1) is 150mV higher than the current-limit threshold (V IN exceeds VISET by 150mV). During a severe overcurrent event, the gate of the external MOSFET is pulled down with a 350mA current source and latched immediately. Toggle EN, LPEN, or input power to clear the latched fault condition.
MAX8533
*Use a 20m 1%, 0.25W current-sense resistor for 25W applications.
Overvoltage Protection
The MAX8533 has an adjustable overvoltage protection feature that latches the IC off in case of an overvoltage event. An external resistor-divider (R4 and R5, Figure 2) from OUT to RET with OVP connected to the center, sets the overvoltage threshold. Use 4.99k for R4. R5 is determined using the following equation: R5 = 4.99 x 103 x ((VOVT / VOVP) - 1) VOVT is the desired overvoltage threshold and VOVP is 2V (typ). OVP latches off the MAX8533 if an overvoltage condition exists for 1.5ms. Toggle EN, LPEN, or input power to clear the latched fault condition.
undervoltage reset monitor at full load. The maximum gate voltage (VGS) rating must be at least 20V. Low MOSFET gate capacitance is not necessary for the inrush current limiting because it is achieved by limiting the GATE dV/dt. However, higher gate capacitance increases the turn-off time of the MOSFET under fault conditions.
Current-Limit and Overload Protection
The MAX8533 features a dual overcurrent protection circuit that turns off the MOSFET in overcurrent situations. When an overload event is sensed, the IC limits the current to a level set by ISET. Continuous overload for a period set by the user (t CTIM ) latches off the MOSFET. The severe overcurrent protection immediately shuts down the external MOSFET and latches it off. R3 sets the current-limit threshold voltage. This voltage is generated from an internal 20A source driven through R3. Therefore: VILIM = R3 x 20A The current-sense signal is sensed across resistor R1. With no load, the voltage at ISET is the input voltage
Fault Reset
Overcurrent, severe overcurrent, and overvoltage conditions result in the MAX8533 entering a latched fault condition. Toggle LPEN, EN, or input power to reset the latched fault condition and return to normal operation.
Power-Good Output (POK)
POK is an open-drain output used to enable the onboard DC-to-DC converter. The POK output turns high impedance when the output rail reaches 9.6V. POK must be pulled up to the user's logic level using a pullup resistor.
8
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Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller
_______PC Board Layout Guidelines
To take advantage of the switch response time to an output fault condition, keep all traces as short as possible and maximize the high-current trace width to reduce the effect of undesirable parasitic inductance. The MOSFET dissipates a fair amount of heat due to the high currents involved, especially during an overcurrent condition. In order to dissipate the heat generated by the MOSFET, make the power traces very wide with a large amount of copper area. A more efficient way to achieve good power dissipation on a surfacemount package is to lay out two copper pads directly under the MOSFET package on both sides of the board. Connect the two pads to the ground plane through vias, and use enlarged copper mounting pads on the top side of the board. Minimize the current-sense resistor trace length (<10mm), and ensure accurate current sensing with Kelvin connections. Place capacitor CTIM as close as possible to the IC. The traces from the current-sense resistor to IN and ISET should be as short as possible for accurate current sensing. Place the MAX8533 circuit as close as possible to the backplane connector. A sample PC board layout is available in the MAX8533 Evaluation Kit.
TOP VIEW
ISET 1 IN GATE CTIM RET 2 3 4 5 10 EN 9 LPEN POK OUT OVP
Pin Configuration
MAX8533
MAX8533
8 7 6
MAX
Chip Information
TRANSISTOR COUNT: 2541 PROCESS: BiCMOS
_______________________________________________________________________________________
9
Smallest, Most Reliable, 12V, InfinibandCompliant Hot-Swap Controller MAX8533
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
e
10
4X S
10
INCHES MAX DIM MIN 0.043 A 0.006 A1 0.002 A2 0.030 0.037 0.120 D1 0.116 0.118 0.114 D2 0.116 0.120 E1 E2 0.114 0.118 H 0.187 0.199 L 0.0157 0.0275 L1 0.037 REF b 0.007 0.0106 e 0.0197 BSC c 0.0035 0.0078 0.0196 REF S 0 6
MILLIMETERS MAX MIN 1.10 0.15 0.05 0.75 0.95 3.05 2.95 3.00 2.89 3.05 2.95 2.89 3.00 4.75 5.05 0.40 0.70 0.940 REF 0.177 0.270 0.500 BSC 0.090 0.200 0.498 REF 0 6
H y 0.500.1 0.60.1
1
1
0.60.1
TOP VIEW
BOTTOM VIEW
D2 GAGE PLANE A2 A b A1 D1
E2
c
E1 L1
L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, 10L uMAX/uSOP
APPROVAL DOCUMENT CONTROL NO. REV.
21-0061
1 1
I
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
10LUMAX.EPS

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