MAX9943_11

19-4433; Rev 3; 4/11 High-Voltage, Precision, Low-Power Op Amps General Description The MAX9943/MAX9944 is a family of high-voltage amplifiers that offers precision, low drift, and low-power consumption. The MAX9943 (single) and MAX9944 (dual) op amps offer 2.4MHz of gain-bandwidth product with only 550μA of supply current per amplifier. The MAX9943/MAX9944 family has a wide power supply range operating from ±3V to ±19V dual supplies or a 6V to 38V single supply. The MAX9943/MAX9944 is ideal for sensor signal conditioning, high-performance industrial instrumentation and loop-powered systems (e.g., 4mA–20mA transmitters). The MAX9943 is offered in a space-saving 6-pin TDFN or 8-pin μMAX® package. The MAX9944 is offered in an 8-pin SO or an 8-pin TDFN package. These devices are specified over the -40°C to +125°C automotive temperature range. o Wide 6V to 38V Supply Range o Low 100µV (max) Input Offset Voltage o Low 0.4µV/°C Offset Drift o Unity Gain Stable with 1nF Load Capacitance o 2.4MHz Gain-Bandwidth Product o 550µA Supply Current o 20mA Output Current o Rail-to-Rail Output o Package Options 3mm x 5mm, 8-Pin µMAX or 3mm x 3mm, 6-Pin TDFN Packages (Single) 5mm x 6mm, 8-Pin SO or 3mm x 3mm, 8-Pin TDFN Packages (Dual) Features MAX9943/MAX9944 Ordering Information PART MAX9943AUA+ MAX9943ATT+ MAX9944ASA+ MAX9944ATA+ TEMP RANGE -40°C to +125°C -40°C to +125°C -40°C to +125°C -40°C to +125°C PINPACKAGE 8 μMAX 6 TDFN-EP* 8 SO 8 TDFN-EP* TOP MARK AACA AUF — BLN Applications Sensor Interfaces Loop-Powered Systems Industrial Instrumentation High-Voltage ATE High-Performance ADC/DAC Input/Output Amplifiers μMAX is a registered trademark of Maxim Integrated Products, Inc. +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Capacitive Load vs. Resistive Load MAX9943 toc17 Package Detail TOP VIEW 100,000 MAX9943 OUT 1 *EP 6 VCC 10,000 CLOAD (pF) UNSTABLE VEE 2 5 N.C. 1000 STABLE IN+ 3 4 IN- 100 100 1000 10,000 RLOAD (Ω) 100,000 TOP VIEW 6 TDFN-EP *EP = EXPOSED PAD. Pin Configurations appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE) ..................................-0.3V to +40V All Other Pins (Note 1) .....................(VEE - 0.3V) to (VCC + 0.3V) OUT Short-Circuit Current Duration 8-Pin μMAX (VCC - VEE ≤ 20V)...............................................3s 8-Pin μMAX (VCC - VEE > 20V) ................................Momentary 6-Pin TDFN (VCC - VEE ≤ 20V) .............................................60s 6-Pin TDFN (VCC - VEE > 20V)...............................................2s 8-Pin SO (VCC - VEE ≤ 20V) .................................................60s 8-Pin SO (VCC - VEE > 20V)...................................................2s 8-Pin TDFN (VCC - VEE ≤ 20V) .............................................60s 8-Pin TDFN (VCC - VEE > 20V)...............................................2s Note 1: Operation is limited by thermal limits. 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. Continuous Input Current (Any Pins) ................................±20mA Thermal Limits (Note 2) Multiple Layer PCB Continuous Power Dissipation (TA = +70°C) 8-Pin μMAX (derate 4.8mW/°C above +70°C) ...........387.8mW 6-Pin TDFN-EP (derate 23.8mW/°C above +70°C) ..1904.8mW 8-Pin SO (derate 7.6mW/°C above +70°C)...................606.1W 8-Pin TDFN-EP (derate 24.4mW/°C above +70°C) ..1951.2mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature ......................................................+150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C PACKAGE THERMAL CHARACTERISTICS (Note 2) 8 μMAX Junction-to-Ambient Thermal Resistance (θJA)......206.3°C/W Junction-to-Ambient Case Resistance (θJC) ...............42°C/W 6 TDFN-EP Junction-to-Ambient Thermal Resistance (θJA)...........42°C/W Junction-to-Ambient Case Resistance (θJC) .................9°C/W 8 SO Junction-to-Ambient Thermal Resistance (θJA).........132°C/W Junction-to-Ambient Case Resistance (θJC) ...............38°C/W 8 TDFN-EP Junction-to-Ambient Thermal Resistance (θJA)...........41°C/W Junction-to-Ambient Case Resistance (θJC) .................8°C/W Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (VCC = 15V, VEE = -15V, VCM = 0V, RL = 10kΩ to GND, VGND = 0V, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER DC CHARACTERISTICS Operating Supply Voltage Range Quiescent Supply Current per Amplifier Power-Supply Rejection Ratio Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Offset Current Input Voltage Range Common-Mode Rejection Ratio VSUPPLY ICC PSRR VOS TCVOS IBIAS IOS VIN+ , VINCMRR VEE + 0.3V ≤ VCM ≤ VCC - 1.8V VEE ≤ VCM ≤ VCC - 1.8V VEE ≤ VCM ≤ VCC - 1.8V Guaranteed by CMRR test, TA = -40°C to +125°C VEE + 0.3V ≤ VCM ≤ VCC - 1.8V VEE ≤ VCM ≤ VCC - 1.8V VEE 105 105 125 1 VS = ±3V to ±19V TA = +25°C TA = -40°C to +125°C 0.4 4 20 90 10 VCC 1.8 105 Guaranteed by PSRR test ±3 550 130 20 100 240 ±19 950 V μA dB μV μV/°C nA nA V dB SYMBOL CONDITIONS MIN TYP MAX UNITS 2 _______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps ELECTRICAL CHARACTERISTICS (continued) (VCC = 15V, VEE = -15V, VCM = 0V, RL = 10kΩ to GND, VGND = 0V, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL CONDITIONS -13.5V ≤ VO ≤ +13.5V, RL = 10kΩ, TA = +25°C -13.5V ≤ VO ≤ +13.5V, RL = 10kΩ, TA = -40°C to +125°C -12V ≤ VO ≤ +12V, RL = 600Ω, TA = +25°C -12V ≤ VO ≤ +12V, RL = 600Ω, TA = -40°C to +85°C RL = 10kΩ VOH RL = 600Ω Output Voltage Swing RL = 10kΩ VOL RL = 600Ω TA = -40°C to +85°C Short-Circuit Current AC CHARACTERISTICS Gain Bandwidth Product Slew Rate Input Voltage Noise Density Input Voltage Noise Input Current Noise Density Capacitive Loading GBWP SR en In CLOAD -5V ≤ VOUT ≤ +5V f = 1kHz f = 1kHz No sustained oscillation 2.4 0.35 17.6 500 0.18 1000 MHz V/μs nV/√Hz nVP-P pA/√Hz pF ISC TA = +25°C TA = -40°C to +125°C 60 100 TA = +25°C TA = +25°C TA = -40°C to +85°C MIN 115 100 dB 100 90 VCC 0.2 VCC 1.8 VCC - 2 VEE + 0.1 VEE + 1 VEE + 1.1 V 110 TYP 130 MAX UNITS MAX9943/MAX9944 Open-Loop Gain AVOL mA TOTAL NOISE 0.1Hz ≤ f ≤ 10Hz Note 3: All devices are 100% production tested at TA = +25°C. Temperature limits are guaranteed by design. _______________________________________________________________________________________ 3 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Typical Operating Characteristics (VCC = 15V, VEE = -15V, VCM = 0V, RL = 10kΩ to GND, VGND = 0V, TA = +25°C, unless otherwise noted.) INPUT VOLTAGE OFFSET DRIFT HISTOGRAM MAX9943 toc01 MAX9943 toc02 OFFSET VOLTAGE HISTOGRAM 25 70 60 50 40 30 20 5 10 0 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 OFFSET VOLTAGE (µV) SUPPLY CURRENT vs. SUPPLY VOLTAGE 650 SUPPLY CURRENT (µA) 600 550 500 450 400 350 MAX9943 toc03 700 20 FREQUENCY (%) 15 10 0 FREQUENCY (%) -0.3 -0.2 -0.1 0 0.1 0.2 0.3 -0.25 -0.15 -0.05 0.05 0.15 0.25 VOS DRIFT (µV/°C) 300 6 10 14 18 22 26 30 34 38 SUPPLY VOLTAGE (V) SUPPLY CURRENT vs. TEMPERATURE MAX9943 toc04 OFFSET VOLTAGE vs. SUPPLY VOLTAGE MAX9943 toc05 800 30 25 OFFSET VOLTAGE (µV) 20 15 10 5 0 700 SUPPLY CURRENT (µA) 600 500 400 300 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 6 10 14 18 22 26 30 34 38 SUPPLY VOLTAGE (V) OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE MAX9943 toc06 OFFSET VOLTAGE vs. TEMPERATURE MAX9943 toc07 30 25 OFFSET VOLTAGE (µV) 20 15 10 5 0 -14 -10 -6 -2 2 6 10 100 80 OFFSET VOLTAGE (µV) 60 40 20 0 -20 -40 14 -50 -25 0 25 50 75 100 125 COMMON-MODE VOLTAGE (V) TEMPERATURE (°C) 4 _______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps Typical Operating Characteristics (continued) (VCC = 15V, VEE = -15V, VCM = 0V, RL = 10kΩ to GND, VGND = 0V, TA = +25°C, unless otherwise noted.) INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE MAX9943 toc08 MAX9943/MAX9944 INPUT BIAS CURRENT vs. SUPPLY VOLTAGE MAX9943 toc09 3.0 2.5 INPUT BIAS CURRENT (nA) 2.0 1.5 1.0 0.5 0 -14 -10 -6 -2 2 6 10 3.0 2.5 INPUT BIAS CURRENT (nA) 2.0 1.5 1.0 0.5 0 14 6 10 14 18 22 26 30 34 38 COMMON-MODE VOLTAGE (V) SUPPLY VOLTAGE (V) COMMON-MODE REJECTION RATIO vs. FREQUENCY MAX9943 toc10 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 140 120 PSRR (dB) 100 80 60 40 20 0 0.001 0.01 0.1 1 10 100 1000 10,000 MAX9943 toc11 140 130 120 CMRR (dB) 110 100 90 80 70 60 0.001 0.01 0.1 1 10 100 160 1000 10,000 FREQUENCY (kHz) FREQUENCY (kHz) VOH vs. OUTPUT CURRENT MAX9943 toc12 VOL vs. OUTPUT CURRENT MAX9943 toc13 16 -12 15 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) TA = -40°C TA = +25°C -13 TA = +85°C TA = +125°C 14 TA = +85°C 13 TA = +125°C -14 -15 TA = +25°C TA = -40°C 12 0 5 10 15 20 25 30 OUTPUT CURRENT (mA) -16 0 5 10 15 20 25 30 OUTPUT CURRENT (mA) _______________________________________________________________________________________ 5 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Typical Operating Characteristics (continued) (VCC = 15V, VEE = -15V, VCM = 0V, RL = 10kΩ to GND, VGND = 0V, TA = +25°C, unless otherwise noted.) INPUT VOLTAGE NOISE vs. FREQUENCY MAX9943 toc14 OUTPUT IMPEDANCE vs. FREQUENCY 1000 100 90 INPUT VOLTAGE NOISE (nV/√Hz) 80 70 60 50 40 30 20 10 0.01 0.1 1 10 100 1000 10,000 FREQUENCY (kHz) 0 1 OUTPUT IMPEDANCE (Ω) 100 10 1 0.1 10 100 1000 10,000 100,000 FREQUENCY (Hz) OPEN-LOOP GAIN vs. FREQUENCY MAX9943 toc16 CAPACITIVE LOAD vs. RESISTIVE LOAD MAX9943 toc17 140 120 OPEN-LOOP GAIN (dB) 100 100,000 60 40 20 0 -20 10 0.001 0.1 0.00001 1000 10,000 1 0.0001 100 0.01 FREQUENCY (kHz) CLOAD (pF) 80 10,000 UNSTABLE 1000 STABLE 100 100 1000 10,000 RLOAD (Ω) 100,000 SMALL SIGNAL-STEP RESPONSE LARGE SIGNAL-STEP RESPONSE MAX9943 toc19 MAX9943 toc18 20mV/div OUT 1μs/div OUT 10μs/div 6 _______________________________________________________________________________________ MAX9943 toc15 1V/div High-Voltage, Precision, Low-Power Op Amps Pin Description MAX9943 6 TDFN-EP 1 — — 2 3 — — 4 — — 5 6 — MAX9943 8 µMAX 6 — — 4 3 — — 2 — — 1, 5, 8 7 — MAX9944 8 SO/TDFN-EP — 1 7 4 — 3 5 — 2 6 — 8 — NAME OUT OUTA OUTB VEE IN+ INA+ INB+ ININAINBN.C. VCC EP Output Output A Output B Negative Power Supply. Bypass with a 0.1μF capacitor to ground. Positive Input Positive Input A Positive Input B Negative Input Negative Input A Negative Input B No Connection Positive Power Supply. Bypass with a 0.1μF capacitor to ground. Exposed Pad (TDFN Only). Connect to a large VEE plane to maximize thermal performance. Not intended as an electrical connection point. FUNCTION MAX9943/MAX9944 Detailed Description The MAX9943/MAX9944 are single/dual operational amplifiers designed for industrial applications. They operate from 6V to 38V supply range while maintaining excellent performance. These devices utilize a threestage architecture optimized for low offset voltage and low input noise with only 550μA supply current. The devices are unity gain stable with a 1nF capacitive load. These well-matched devices guarantee the high open-loop gain, CMRR, PSRR, and low voltage offset. The MAX9943/MAX9944 provide a wide input/output voltage range. The input terminals of the MAX9943/ MAX9944 are protected from excessive differential voltage with back-to-back diodes. The input signal current is also limited by an internal series resistor. With a 40V differential voltage, the input current is limited to 20mA. The output can swing to the negative rail while delivering 20mA of current, which is ideal for loop-powered system applications. The specifications and operation of the MAX9943/MAX9944 family is guaranteed over the -40°C to +125°C temperature range. Application Information Bias Current vs. Input Common Mode The MAX9943/MAX9944 use an internal bias current cancellation circuit to achieve very low bias current over a wide input common-mode range. For such a circuit to function properly, the input common mode must be at least 300mV away from the negative supply VEE. The input common mode can reach the negative supply VEE. However, in the region between VEE and VEE + 0.3V, there is an increase in bias current for both inputs. Capacitive Load Stability Driving large capacitive loads can cause instability in many op amps. The MAX9943/MAX9944 are stable with capacitive loads up to 1nF. The Capacitive Load vs. Resistive Load graph in the T ypical Operating Characteristics gives the stable operation region for capacitive versus resistive loads. Stability with higher capacitive loads can be improved by adding an isolation resistor in series with the op-amp output, as shown in Figure 1. This resistor improves the circuit’s phase margin by isolating the load capacitor from the amplifier’s output. _______________________________________________________________________________________ 7 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Power Supplies and Layout The MAX9943/MAX9944 can operate with dual supplies from ±3V to ±19V or with a single supply from +6V to +38V with respect to ground. When used with dual supplies, bypass both VCC and VEE with their own 0.1μF capacitor to ground. When used with a single supply, bypass VCC with a 0.1μF capacitor to ground. Careful layout technique helps optimize performance by decreasing the amount of stray capacitance at the op amp’s inputs and outputs. To decrease stray capacitance, minimize trace lengths by placing external components close to the op amp’s pins. RISO OUTPUT MAX9943 INPUT CL Figure 1. Capacitive Load Driving Circuit Output Current Capability The MAX9943/MAX9944 are capable of driving heavy loads such as the ones that can be found in loop-powered systems for remote sensors. The information is transmitted through ±20mA or 4mA–20mA current output across long lines that are terminated with low resistance loads (e.g., 600Ω). The Typical Application Circuit shows the MAX9944 used as a voltage-to-current converter with a current-sense amplifier in the feedback loop. Because of the high output current capability of the MAX9944, the device can be used to directly drive the current-loop. The specifications and operation of the MAX9943/ MAX9944 family is guaranteed over the -40°C to +125°C temperature range, However, when used in applications with ±15V supply voltage (see Figure 3), the capability of driving more than ±20mA of current is limited to the -40°C to +85°C temperature range. Use a lower supply voltage if this current must be delivered at a higher temperature range. 1.5kΩ 1.5kΩ Figure 2. Input Protection Circuit Input Differential Voltage Protection During normal op-amp operation, the inverting and noninverting inputs of the MAX9943/MAX9944 are at essentially the same voltage. However, either due to fast input voltage transients or due to other fault conditions, these pins can be forced to be at two different voltages. Internal back-to-back diodes and series resistors protect the inputs from an excessive differential voltage (see Figure 2). Therefore, IN+ and IN- can be any voltage within the range shown in the absolute maximum rating. Note the protection time is still dependent on the package thermal limits. Input Common Mode and Output Swing The MAX9943/MAX9944 input common-mode range can swing to the negative rail VEE. The output voltage can swing to both the positive VCC and the negative VEE rails if the output stage is not heavily loaded. These two features are very important for applications where the MAX9943/ MAX9944 are used with a single-supply (VEE connected to ground). One of the applications that can benefit from these features is when the single-supply op amp is driving an ADC. Chip Information PROCESS: BiCMOS 8 _______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 +15V -15V VREF RSENSE DAC MAX9944 RLOAD -15V Figure 3. Typical ±20mA Current-Source in Loop-Powered Systems _______________________________________________________________________________________ 9 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Pin Configurations TOP VIEW MAX9943 + N.C. ININ+ 1 2 3 8 7 6 5 N.C. VCC OUT N.C. OUTA 1 + 8 7 6 5 VCC OUTB INBINB+ MAX9944 INA- 2 INA+ 3 VEE 4 VEE 4 8 μMAX 8 SO TOP VIEW MAX9943 + OUT 1 *EP 6 VCC OUTA 1 8 7 6 5 VCC OUTB INBINB+ MAX9944 INA- 2 VEE 2 5 N.C. INA+ 3 IN+ 3 4 IN- VEE 4 *EP TOP VIEW 6 TDFN NOT TO SCALE. *EP = EXPOSED PAD. TOP VIEW 8 TDFN 10 ______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps Package Information For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 8 μMAX 6 TDFN-EP 8 SO 8 TDFN-EP PACKAGE CODE U8+1 T633+2 S8+4 T833+2 OUTLINE NO. 21-0036 21-0137 21-0041 21-0137 LAND PATTERN NO. 90-0092 90-0058 90-0096 90-0059 MAX9943/MAX9944 α α ______________________________________________________________________________________ 11 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 12 ______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. MAX9943/MAX9944 COMMON DIMENSIONS SYMBOL A D E A1 L k A2 MIN. 0.70 2.90 2.90 0.00 0.20 MAX. 0.80 3.10 3.10 0.05 0.40 PACKAGE VARIATIONS PKG. CODE T633-2 T833-2 T833-3 T1033-1 T1033MK-1 T1033-2 T1433-1 N 6 8 8 10 10 10 14 14 14 D2 1.50±0.10 1.50±0.10 1.50±0.10 1.50±0.10 1.50±0.10 1.50±0.10 1.70±0.10 1.70±0.10 1.70±0.10 E2 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 2.30±0.10 e 0.95 BSC 0.65 BSC 0.65 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.40 BSC 0.40 BSC 0.40 BSC JEDEC SPEC MO229 / WEEA MO229 / WEEC MO229 / WEEC MO229 / WEED-3 MO229 / WEED-3 MO229 / WEED-3 ---------- b 0.40±0.05 0.30±0.05 0.30±0.05 0.25±0.05 0.25±0.05 0.25±0.05 0.20±0.05 0.20±0.05 0.20±0.05 [(N/2)-1] x e 1.90 REF 1.95 REF 1.95 REF 2.00 REF 2.00 REF 2.00 REF 2.40 REF 2.40 REF 2.40 REF 0.25 MIN. 0.20 REF. T1433-2 T1433-3F ______________________________________________________________________________________ 13 High-Voltage, Precision, Low-Power Op Amps MAX9943/MAX9944 Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 14 ______________________________________________________________________________________ High-Voltage, Precision, Low-Power Op Amps Revision History REVISION NUMBER 0 1 2 3 REVISION DATE 3/09 4/09 6/09 4/11 Initial release Removed future product reference for the MAX9944, updated EC table Corrected TOC 13 and added rail-to-rail output feature Updated Pin Description section DESCRIPTION PAGES CHANGED — 1, 2 1, 3, 5, 8 7 MAX9943/MAX9944 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15 © 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.