www.silabs.com “Using Drop-in Opto Upgrade Devices to Improve System Reliability and Performance” October 2012 Agenda Opto Backgrounder A Close Look at Optos Common Opto Remedies Conclusion Upgrading to the Si87xx CMOS Digital Isolator A Close Look at Si87xx/826x Si87xx/826x vs. Optos Upgrading optos with Si87xx/826x Interactive Problem Solving Summary 2 Silicon Laboratories Confidential What You’re Going to See… FIRST: You’re going to see how hard it is to apply optos because of: Substantial internal parasitic coupling Key parameters that interact with one another Additional external BOM Parametric wander with temperature and current Internal wear-out mechanisms Mushy current thresholds NEXT: Experience the wonder of the Si87xx/826x The world’s one and only true opto upgrade • Enhanced performance • EASY to use 3 Silicon Laboratories Confidential Birth of the Optocoupler Optos have been around in various forms since the early 1970’s Early optos were called “Light Cells” A miniature incandescent bulb sandwiched between two photocells packaged in a heat shrink tube! Optos have evolved into the incumbent isolation device 30+ years in the market; highly diversified customer base! Optos outsell all other semiconductor isolation devices combined Multiple suppliers: Avago, Toshiba, Fairchild. IXYS, Sharp, etc. Large product offerings, BUT… Customers need for improved devices are driving CMOS isolators growth Wider temp ranges, greater performance, and improved reliability Silicon isolators are starting to supplant optos in many applications 4 Silicon Laboratories Confidential Si87xx/826x upgrade – That was easy! For most upgrading to Si87xx/826x couldn’t be easier: 1. 2. 3. 4. Find the proper cross reference part with the online selection guide Unsolder the optocoupler from the board Solder the compatible Si87xx/826x part onto the opto footprint Enjoy the superior performance and extended life of Si87xx/826x! Check out this demo of just how easy upgrading is… http://www.youtube.com/watch?v=0GQ5OyVSYao Drop-in isolator upgrade for legacy optocouplers 5 Silicon Laboratories Confidential Board with Competitor’s Optocoupler Installed 6 Silicon Laboratories Confidential Step 1: Desolder Competitor’s Optocoupler 7 Silicon Laboratories Confidential Step 2: Throw Competitor’s Optocoupler Away 8 Silicon Laboratories Confidential Step 3: Place Si87xx Optocoupler on Board 9 Silicon Laboratories Confidential Step 4: Solder-in the Si87xx 10 Silicon Laboratories Confidential Step 5: Be Sure the Si87xx is Soldered Correctly 11 Silicon Laboratories Confidential Step 6: Apply Power Better timing performance and reliability, easier to use, longer lifetime, wider operating temperature range, improved CMTI, 10 kV surge tolerant, lower input current, 2x to 3x lower internal parasitics vs. optocouplers, 60+ years TDDB…the FIRST and ONLY optocoupler upgrade!! 12 Silicon Laboratories Confidential Digging Deeper For most applications, you can simply swap with Si87xx/826x Find the compatible part, solder it in, and win the socket! Optimize your system with Si87xx/826x Optos often have lots of circuits around them to achieve acceptable performance Many of these components can be removed when using Si87xx/826x Other component values can be changed to further improve performance The next section will reveal the numerous problems with optocouplers Revealing the work you must perform to make optos work correctly, and How you can simplify your system using Si87xx/826x Hold your nose – optocouplers stink! 13 Silicon Laboratories Confidential Use Grounded Cathode Topology (Best CMTI) NC RF VDD NC ANODE CLEDP RL IF VF CATHODE VO 0.1uF CLEDN NC GND Optocoupler VCM Parasitic capacitor CLEDN is typically much larger than CLEDP Grounded cathode directly shorts CLEDN across VCM; CLEDN is eliminated as a parasitic! • CLEDN can account for up to 90% of input/output parasitic capacitance CIO. CLEDP remains a smaller, but still an active parasitic coupling If VIN is high, CLEDP can steal current from IF, turning the LED OFF If VIN is low, CLEDP can inject current into the LED, turning it ON BOTH optos AND Si87xx/826x have internal parasitic coupling Si87xx/826x parasitics are much lower than those of optos! BOTH optos AND Si87xx/826x benefit from the use of the Grounded Cathode configuration All circuit examples in this presentation will be Grounded Cathode configurations 14 Silicon Laboratories Confidential Opto Flaw 1: Strong Internal Parasitic Coupling CLEDP can rob current from IF turning the LED OFF if VIN is high; or turn LED ON if VIN is low. NC RF VDD NC ANODE CLEDP VIN Shield RL IF CATHODE VO Cbypass CLEDN NC GND 1.5kV Optocoupler 0V 1µS VCM Parasitic coupling enables fast CMTs to occur on one side of the isolator These fast dv/dt pulses can turn the opto LED on or off causing data errors Key isolation parameter: Common Mode Transient Immunity (CMTI) • CMTI is the isolator’s ability to reject CMT and continue operating without errors Note that a low ohmic value RF helps CMTI! 15 Silicon Laboratories Confidential Opto Flaw 2: Unshielded Opto Offering NC VDD ANODE NC NC ANODE VDD NC CLEDP CATHODE VO CATHODE CLEDN NC NC GND Shielded Optocoupler CLEDP, CLEDN affects sensitive receive diode • Significantly degrades CMTI Receive diode no longer affected LED still affected by parasitic coupling • Small reduction in CMTI Example: HCPL-4502 Typical CMTI = 1 kV/µS at IF = 16 mA Positive and negative false triggers Positive CMT can turn receive diode OFF Negative CMT can turn receive diode ON Positive CMT can turn LED OFF Negative CMT can turn LED ON Takeaway: Unshielded optocouplers are useless in high CMT environments 16 VO CLEDN GND Unshielded Optocoupler • • • • Shield CLEDP Example: HCPL-4503 Typical CMTI = 30 kV/µS at IF = 16 mA Positive and negative false triggers • Positive CMT can turn LED OFF • Negative CMT can turn LED ON Takeaway: Shielded optocouplers are targets for Si87xx/826x! Silicon Laboratories Confidential Opto Flaw 3: “Wandering” CTR Current Transfer Ratio (CTR) is a gain term Typical values for CTR: 10% to 50% for devices with an output phototransistor Up to 2000% for devices with a Darlington transistor output pair Some optos remove CTR as a spec and instead add compensating circuits to the receive diode CTR Dependencies: Output transistor current gain (hfe), VDD supply voltage, forward current through the LED, operating temperature CTR varies with absolute current level: 17 Peaks at an LED current level of about 10 mA, and falls away at both higher and lower current levels Silicon Laboratories Confidential Current Thresholds? Unit 1 Opto Turn-On/Turn-off “Thresholds” Forward Current (mA) Forward Current (mA) Opto Flaw 4: “Mushy” Current Thresholds Current Thresholds? Unit 2 Opto Turn-On/Turn-off “Thresholds” Forward Voltage (V) Forward Voltage (V) Opto begin to turn on at “some point” Poor unit-to-unit current threshold value matching Sloping (Analog turn-on/turn-off) further muddles true turn-on threshold value Threshold value is temperature dependent Lab measurements have shown most optos begin turn on BELOW the specified threshold 18 Silicon Laboratories Confidential Forward Current Thresholds (mA) Opto Flaw 5: “Low Current” Thresholds i2 B LED ON Higher threshold current = higher CMTI iTH2 A A i1 iTH1 LED ON Lower threshold current = lower CMTI Forward Voltage (V) Turn-on Threshold affects spurious turn-on Higher threshold = more CMTI • The LED requires more requires more parasitic current to turn-on! Example: Opto “B” requires more parasitic current to cause a false turn-on 19 Silicon Laboratories Confidential Opto Flaw 6: False Output Turn-on/Turn-Off Negative dVCM: Negative glitch (false turn-on) on VOUT due to CLED01+CLED02 Positive dVCM: Positive glitch (false turn-off) on VOUT due to CLED01+CLED02 CMTI is degraded when using an internal pull-up. Example: HCPL-4506: IF = 10 mA for 30 kV & external pull-up IF = 16 mA for 30 kV & internal pull-up 20 Silicon Laboratories Confidential Opto Flaw 7: Compound Coupling NC ANODE IF VDD DP CLE 01 CLED 20KΩ RL RF VF CMT CATHODE +V Output CLED CLED +1500V NC 02 N VO GND V 0V t VCM HCPL-4506 Circuit Model Parasitic caps CLED01/2, CLEDP combine to create unwanted effects CLED01/2 inject current into internal pull-up & collector causing output parasitic turn-off CLEDP can inject current into cathode causing LED parasitic turn-off 21 Silicon Laboratories Confidential VDD2 Opto Flaw 8: Performance Degradation Can’t take the Heat No Mo!! OPTO One key optocoupler wear-out mechanism is LED light output (LOP) LED to loses brightness over time Reduced LED emission decreases the photo detector output signal • Negatively impacts opto timing and output impedance characteristics LOP typically worsens with increasing temperature and LED current Manufacturer’s LOP data based on normalized light output over a period of 10,000 hours • Best case: nominal light falls by output by as much as 20% • Worst case: light output falls below the minimum value required for proper device operation. 22 Silicon Laboratories Confidential Opto Flaw 9: Current, Current and MORE Current! Issue Opto Solutions Si87xx/826x Solutions Improve CMTI: Spurious Turn-on Use higher threshold device Use clamping diode or switch Decrease value of RF (more current) Increase value of CL (more current) Decrease value of RL (more current) Use higher threshold device Decrease value of RF (more current) (Note 1) Remove CL Improve CMTI: Spurious Turn-off Decrease value of RF (more current) Decrease value of RF (more current) Increase value of RL Use higher threshold device Decrease value of RF (more current) (Note 1) Increase value of RL Decrease tPHL Decrease RF value (more current) Increase RL value Decrease CL value Add peaking cap across RF Non-issue Non-issue Non-issue Non-issue Decrease tPLH Decrease value of RL (more current) Decrease value of CL Add peaking cap across RF Decrease value of RL (more current) Remove CL Non-issue Address CTR Variation Use worst case # (more current) Non-Issue Address LED aging Decrease RF (more current) Non-Issue Notes 1. All “More Current” comments in RED refer to LED current only; not output current. All “More Current” comments in BLUE refer to output current. 2. Significant coupling through CLED01 and CLED02 can cause 87xx turn-on failures, which can be mitigated by reducing RL or increasing using CL a higher threshold device. These coupling mechanisms are minimal in Si87xx; usually < 1V 3. Increasing CL requires more current for same tPHL or tPLH . 4. Decreasing RL requires more LED current for the opto. 23 Silicon Laboratories Confidential Opto Flaw 10: Long Prop Delays NC VDD ANODE NC VBIAS Cp RL RF Opto VO CATHODE VF Peaking Cap: “Kick-starts” the LED, decreasing tPHL GND NC 150 B Cp Opto LED RLED ` D 100 Opto Prop Delay (nS) F E C A: 0.5mA to 1.0mA, Cp =20pF 0.5mA to 0.75mA, Cp = 20pF tPHL B: 0.5mA, Cp = 0pf C: 1.0mA, Cp = 0pf 50 A tPLH D: 0.5mA to 1.0mA Cp= 20pF 0.5mA to 0.75mA, Cp = 20pF E: 0.5mA, Cp=0pF F: 1.0mA, Cp=0pF OptoPro Si87xx/826x CL = 15pF all devices -60 -40 -20 0 20 40 60 80 Temperature (C) 24 Silicon Laboratories Confidential 100 120 No peaking cap needed! Common Optocoupler Remedies Optos need added “remedies” to “work” properly; i.e.: Prevent False turn-on Increase operating service life De-glitch output Lower power consumption Etc….. ER “opto-docs” routinely implement the following gimmicks… 25 Silicon Laboratories Confidential Propping-Up the Opto… Clamping diode: Keeps LED off by shorting RF in reverse direction RL: External pullup resistor Peaking capacitor: hastens LED turn-on/turn-off for faster propagation time VDD2 VDD NC RF Internal Pull-Up ANODE RL NC Optocoupler CATHODE VO CPK NC GND VF -V Shorting or Reverse Bias switches: helps keep LED turned-off during CMT events 26 CL: Filters output glitches caused by CMT coupling to internal pullup resistor Silicon Laboratories Confidential CL Opto Remedy 1: Helping CMTI Clamp Diode Low forward-drop diode shorts RF in reverse direction Transistor Clamp Hard short across LED prevents LED turn-on 27 Silicon Laboratories Confidential Opto Remedy 2: Preventing False Turn-On/Off 28 Silicon Laboratories Confidential Opto Remedy 3: Deglitching Output CLOAD IMPACT COMMENTS Small Capacitive Value Higher speed output Large Capacitive Value Improved CMTI Less capacitive loading translates to faster output rise and fall times. More capacitive loading prevents CMT output glitches. CMT glitch is a "hump-like" waveform shape. Increased output capacitance filters the glitch by reducing its amplitude. 29 Silicon Laboratories Confidential Opto Remedy 4: When in Doubt, Increase Input Current Decreasing RF = higher LED emission and lower LED impedance VBIAS NC IF ANODE CLED01 RF VDD Opto Decreased RL: Increased current flow acts to oppose many parasitic effects RI NC RL CLEDP CATHODE VF VO CLEDN CLED02 NC GND Higher current flow decreases switch effective output impedance BUT…excessive input current shortens opto service life! 30 Silicon Laboratories Confidential Opto Remedy 5: Increase Opto Service Life Use less LED input current Typically operate at 85 ºC or less This tactic lowers CMTI • Compensate by applying more aggressive CMTI external component techniques to compensate • Flies in the face of previous slide Contact opto supplier for apps help? 31 Silicon Laboratories Confidential Opto Summary Opto vendors should ship a clothespin with each opto ’cause they stink! The evidence against optos is overwhelming!! Poor performance Questionable reliability Multiple/interdependent parasitic parameters Variable turn-on/turn-off thresholds Poor power efficiency Added BOM “fix-’em-up” circuits Poor unit-to-unit matching Narrow operating temperature range Intrinsic wear-out mechanisms, etc… No doubt…optos are REALLY lame 32 Silicon Laboratories Confidential Agenda Overview Opto Backgrounder Introduction A Close Look at Optos Common Opto Remedies Conclusion Si87xx/826x Training Introduction A Close Look at Si87xx/826x Si87xx/826x vs. Optos Upgrading Optos with Si87xx/826x Interactive Problem Solving Summary 33 Silicon Laboratories Confidential Si87xx/826x: Easy as Shootin’ Fish in a Barrel! “Si87xx/826x is what an opto wants to be when it grows-up!” Well behaved, intuitive and easy to apply A flexible, comprehensive solution Robust and rugged Solid performance over temperature and voltage DROP-IN compatibility with popular optos and optodrivers 34 Silicon Laboratories Confidential Rudye McGlothlin Si87xx/826x: Simple Yet Elegant Architecture Forward voltage VF provides input-side VDD VBIAS VBIAS Si87xx Digital Isolator NC VDD1 ANODE XMIT CATHODE NC INPUT DIE Forward voltage VF causes current flow IF determined by resistor RF - i.e: IF = [VF – 2]/RF RECV RF RECV e ENABLE XMIT CATHODE OUTPUT BUFFER GND2 OUTPUT DIE UVLO ANODE GND1 VOUT ISOLATION ENABLE ISOLATION e GND1 35 IF NC, VE or VL VDD VDD2 VDD1 VDD2 ISOLATION VF IF NC VDD ISOLATION RF Si826x Isolated Gate Driver GATE DRIVER V0 V0 OUTPUT OUTPUT GND NC GND INPUT DIE GND2 OUTPUT DIE Receiver energizes output buffer when sufficient inband energy is detected The transmitter is enabled when IF is at or above threshold value Silicon Laboratories Confidential Si826x operation is the largely the same as Si87xx Si87xx/826x Packages & Performance Grades DIP8 Gullwing SOIC8 SDIP6 LGA8 A-GRADE B-GRADE Input Input Isolation Data Isolation Current Data Rate Surge Current Surge Ratings Packages Comments Rate Ratings Packages Comment Threshold (Mbps) (kV) Threshold (kV) (kV) (Mbps) (kV) DEVICE (mA) (mA) Si8710xD-A-IS 3 1 5 10 SDIP6 Low Power 6 15 5 10 SDIP6 SO8, SO8, High CMTI Si8710xx-A-IS 3 1 3.75, 5 10 6 15 3.75, 5 10 LGA8, LGA8, Low Power PDIP PDIP8 Si8711xx-A-IS Si8712xx-A-IS 36 3 3 1 1 3.75, 5 3.75, 5 10 SO8, LGA8, PDIP Low Power, Integrated 20KΩ 10 SO8, LGA8, PDIP Low Power, VE (Output Enable) Silicon Laboratories Confidential 6 6 15 15 3.75, 5 3.75, 5 10 SO8, LGA8, PDIP8 10 SO8, LGA8, High CMTI PDIP8 High CMTI What Makes Si87xx/826x so Easy to Use? x/ x 87 6 x i S 2 8 Item Parasitics Si87xx/826x Less than half the parasitic coupling of optos; most parameters independent from each other Optocoupler High parasitic coupling with interdependent parameters No wear out mechanisms, 60+ year operating lifetime at 125 C at maximum VDD Intrinsic wear-out mechanisms; 10x lower lifetime Input Current Low parasitic coupling requires less current Requires higher input current to be competitive Ease-of-Use Fewer second order effects, tight unit-to-unit matching, no CTR Significant 1st and 2nd order effects, temperature dependencies, imprecise current thresholds, CTR Simple: Use Si87xx/826x B-grade (high threshold device) with IF = 6mA Make design trade-offs for optimum input current, CMTI performance, operating temperature, and operating lifetime Input Interface Precise thresholds, multiple threshold versions Ambiguous threshold often positioned below specifications Performance Fast prop time, better CMTI, stable over temp and voltage, -40 C to +125 C operating range Slow prop time, narrow temperature range, parametric change with temperature, input current and device age Reliability Opto Retrofit 37 Silicon Laboratories Confidential Si87xx/826x Virtue 1: Threshold Options Low Output CMTI (min, V/µS) Si871xB Improved CMTI Si871xA 50% lower current Forward Current (mA) Si871xA provides CMTI performance similar to the best optos with < ½ the forward current Si871xB provides superior CMTI performance with slightly less forward current Black points represent replaceable optos X-axis is the forward current used for specifying CMTI 38 Silicon Laboratories Confidential Si87xx/826x Virtue 2: Digital (vs. Analog) Behavior Optimum ON Current Optimum ON Current Output HI Minimum Current Required for Turn-On (B Grade) Maximum Operating Current OFF ON Minimum Current Required for Turn-On (Undetermined) Si87xx/826x Turn-On/Turn-Off Characteristics Opto Turn-On Characteristics Si87xx/826x: precise current thresholds with hysteresis Output is either high or low – no ambiguous output states Opto: Highly non-linear transfer function Ambiguous thresholds that vary unit-to-unit and wander with temperature LED turn-on typically begins below data sheet threshold specification 39 Silicon Laboratories Confidential xmA Maximum Opto Emulator Input Current 20mA 6.0mA 2.3mA Output LO 2.0mA 20mA Maximum Opto Emulator Input Current 3.0mA 1.2mA 1.1mA Minimum Current Required for Turn-On (A Grade) Start of LED turn-on? – Maybe! Datasheet Thresholds? Si87xx/826x Virtue 3: No CTR Guaranteed OFF 2.0mA A-Grade Digital operation and precision current thresholds eliminate the need for CTR The Si87xx/826x is either full-on or completely off! CTR???...we don’t need no stinking CTR! 40 Silicon Laboratories Confidential Guaranteed ON 2.3mA Guaranteed ON 1.2mA 1.1mA Guaranteed OFF B-Grade Si87xx/826x Virtue 4: Substantially Lower Parasitics It takes a substantially faster, higher amplitude CMT pulse to perturb Si87xx/826x NC VDD ANODE NC Disturbances are easily addressed using a higher threshold device and/or decreasing the value of RF CLEDP is a small parasitic capacitance CLEDN is eliminated (shorted) through VCM CLED01 is eliminated using external RL CLED02 is half that of opto parasitics CATHODE VCM • The parasitic effects of which are <1 volt CMTI-to-current ratio Tx RL ISOLATION e ISOLATION Si87xx/826x lower parasitic coupling: VDDO Rx CLED02 VO CL ED P NC GND VCM Si87xx • 16x (Silicon Labs) vs. 9x (optos) Measured CMTI: 41 Part # Threshold Measured Spurious Turn-on Common-Cathode (CLEDP) Spurious Turn-on Common-Anode (CLEDN) Si8712A 1.2 mA 19 kV/us (16:1) 6.9 kV/us Si8712B 2.3 mA 40 kV/us (17:1) 12 kV/us HCPL-4506 1.4 mA 12.5 kV/us (9:1) 3.3 kV/us Silicon Laboratories Confidential Example: Spurious Turn-on NC 1.5kV CMTI Pulse Si8712A Tfall = 120 ns Output ANODE Gradual turn-off (~350µS) External 20k pull-up Output HCPL-4506 Tfall = 80 ns VF = 0V VF RF CATHODE VDD2 NC CLEDP Shield Before VDD RPULL-UP VO 1.5kV CMTI Pulse Gradual turn-on Hard Turn-on CMT NC V GND -V 0V Turn off (~20nS) -1500V t After Si8710B Tfall = 120 nS VCM Negative-going CMT pulls down cathode, turning LED on and driving output low. Fixes: Opto Fix (Hard): Shorting switch? Lower RF value? Add CL? Si87xx/826x Fix (Simple): Use higher threshold Si870xB 42 Silicon Laboratories Confidential Example: Spurious Turn-off Resistive (20k) Pull-up 1.5kV CMTI Pulse Si8712A Trise = 40 ns HCPL-4506 Trise = 400 ns RF Gradual Turn-on Hard turn-on VF Gradual Turn-off Output Output ANODE IF CATHODE CLEDP Shield 1.5kV CMTI Pulse VDD RPULL-UP NC RL 1 D0 CLE CLE D0 2 V+ CLEDN CMT +1500V NC GND V 0V t VCM Positive-going CMT momentarily turns diode off, driving output high ACPL-4506 output goes high momentarily Si8712: ~500 mV parasitic rise with no logic state change Fix: Opto fix (Hard): Add CL? Decrease RF value? Add shorting switch? Decrease RL? Si87xx/826x Fix (Simple): No action required! 43 Silicon Laboratories Confidential VO VDD2 Si87xx/826x Virtue 5: No need for CL CL useful as a glitch filter in optos, but not necessarily in Si87xx/826x “Snappy” on-off action of Si87xx/826x eliminates need for CL CL acts only to slow Si87xx/826x performance 44 Silicon Laboratories Confidential Si87xx/826x Virtue 6: Stable Operation Over Temp CMOS process technology and careful design gives Si87xx/826x solid parametric consistency over the entire operating range Note the slope and linearity of the Si87xx/826x curve vs. competing optos! Si87xx/826x 45 Silicon Laboratories Confidential Si87xx/826x Virtue 7: No Wear-out Mechanisms Standard CMOS process technology instead of GaAs Mature and well understood • 40+ years of learning Substantially more reliable than GaAs • 5.5x lower FIT rate • TDDB = 60 years • MTTF = 87 years Other benefits of CMOS: Wider operating temp range Parametrically stable over voltage and temperature Product Low operating power Avago Economical Coupler Type Ta FITs (90%) MTTF GaAs – Optical 125 oC 7195 15 years Avago HCPL0900 GMR 125 oC 8722 13 years Silicon Labs Si8442 CMOS – Capacitive 125 oC 1310 87 years 6N135/136 46 Silicon Laboratories Confidential (1) Si87xx/826x Virtue 8: Drop-in Opto Upgrade! Step 2: Check the value of RF – If necessary, adjust its value to optimize input current range for Si87xx/826x. Do not exceed +20 mA ! Step 1: Use the on-line selection guide to find the correct Si87xx/826x part number, then remove and replace the opto with the Si87xx/826x device VDD NC VF RF Cp Sw R1 VDD RL ANODE NC Si87xx OptoPro /826x CATHODE Out VO Q1 CL NC GND GND1 Step 3: “Helper” components like this shorting switch can optionally be left in place or removed. (Note the Si87xx/826x can withstand reverse input current of -150 mA (max)) GND2 Step 4: Apply power and verify system operation! Typically a bullet-proof drop-in, regardless of application circuit 47 Silicon Laboratories Confidential Si87xx/826x Virtue 9: Comprehensive Solution NC 1 ANODE IF RF VF 2 CATHODE 3 VDD2 VDD2 NC 1 VDD ANODE 8 RF CMOS Inverter 8 UVLO VO 2 4 Q1 VO NC 3 6 7 NC GND 4 5 Output Si8261BCC VO 6 CBOOT 7 CATHODE Output VDD2 VDD ANODE NC HV VDD GND 5 RF VF 1 UVLO 6 NC VO 2 5 Q2 GND CATHODE 4 3 Si8261BCD Si87xx Digital Isolator Digital isolators and isolated gate drivers Both use the same technology Both enjoy the same drop-in replacement strategy The Si87xx, Si826x are 10 kV surge tolerant! 48 Silicon Laboratories Confidential Si826x Isolated Drivers Si87xx/826x Virtue 10: On-Line Design Tools High-side bootstrap and bypass capacitor values are calculated using five different equations: Occupies four-pages in application note AN677 • Not a complex calculation, but easily prone to error Silicon Labs will offer an on-line high-side bootstrap and bypass capacitor calculator: • User needs only the MOSFET datasheet QG vs. VGS curve • Plug in the operating point and the calculator provides the values for both capacitors, and required capacitor recharge current! 49 Silicon Laboratories Confidential Example: High-Side Bootstrap Calculator 50 Silicon Laboratories Confidential Si87xx/826x Virtue 11: Intuitive Behavior Si87xx/826x is more intuitive to use vs. optos Si87xx/826x is a digital device – it’s either on or off Operation is straight-forward and easy to understand and diagnose • Most key Si87xx/826x parameters are independent from each other High threshold, low CIO and few second-order effects You can hand someone a (high threshold) B-grade Si87xx/826x, tell them to use 6 mA for IF and be reasonably confident it will perform in most system configurations • Optos: complicated by compound parasitics, CTR and other variable parameters Si87xx/826x is for retrofit AND for new designs! Few key parameters: • Primary isolator design variables: IF, RL and input current threshold • Primary gate driver design variables: IF, peak output current and input current threshold 51 Silicon Laboratories Confidential Summary Here’s your chance to put optocouplers out of their misery for good! Si87xx/826x benefits: Higher timing performance and reliability Pin-compatible drop-ins – little or no PCB modifications Lower internal parasitic coupling Precision current thresholds Lower input current for greater operating efficiency Full -40 to +125 ºC operating range Easier system design On-line support tools Replaces both optos, signal isolators and opto-coupled gate drivers Supports 10 kV surge and isolation ratings of 2.5 kV, 3.75 kV and 5.0 kV …And Silicon Labs is the only place you can get ’em! 52 Silicon Laboratories Confidential Isolation Support Tools Isolation support tools Application notes Evaluation Boards (EVBs) Turnkey reference designs • ISOvolt, ISOlinear, Class D Audio, and more… Website isolation product design utilities Discrete ISOvolt Reference Design • Isolator power calculator, high-side bootstrap calculator, and more… Technical Support • Expert guidance from the best team in the business! 9-Bit Version (Circuit #3) 10-Bit Version (Circuit #2) 12-Bit Version (Circuit #1) ISOlinear Reference Design 53 Silicon Laboratories Confidential Si890x EVB Turnkey Tools Get You Started Today Evaluation kits streamline testing directly in your system Si84xxISO-KIT • Quick evaluation of 6 different isolators from the Si84xx family Si86xxISO-KIT • Quick evaluation of 6 different isolators from the Si86xx family Si82xx-KIT • Quick evaluation of 4 different isolated drivers from the Si82xx family Reference designs explore new applications Si86ISOLIN-KIT • Three cost and performance optimized analog isolation circuits ISOVOLT35-KIT • Isolated DC/DC converter and isolated digital channels SI890xPWR-KIT • Isolated power line monitoring with analog or digital output You Silicon Laboratories Confidential 54 can find more at: http://www.silabs.com/products/power/isolators/Pages/DevelopmentTools.aspx Isolator Product Support & Tools Competitor Cross-Reference Search Parametric Search Tool Digital Isolator Resources Isolation Products Brochure 55 Isolator White Papers Silicon Laboratories Confidential Summary Si87xx/826x: great opportunity! Drop-in upgrades for opto-based devices Considerable value add Easy to use Increased performance, reliability Outstanding product mix Digital isolators and isolated gate drivers Drop-ins for Avago and others On-line design resources in the works 56 Silicon Laboratories Confidential www.silabs.com Thank you! www.silabs.com/isolation