LT8312 Boost Controller with Power Factor Correction Features Description PFC Boost with Minimum Number of External Components nn V and V IN OUT Limited Only by External Components nn Active Power Factor Correction nn Low Harmonic Distortion nn Overvoltage Protection nn Energy Star Compliant (<0.5W No-Load Operation) nn 16-Lead MSOP Package The LT®8312 is a power factor correction (PFC) boost controller. A LT8312-based design can achieve a power factor of greater than 0.99 by actively modulating the input current, allowing compliance with most Harmonic Current Emission requirements. nn The LT8312 is well suited for a wide variety of off-line applications. The input range can be scaled up or down, depending mainly on the choice of external components. Efficiencies higher than 95% can be achieved with output power levels up to 250W. Applications L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Industrial nn Aviation nn Typical Application Universal Input 200W PFC Boost Converter B1 GBU404 0.1µF 499k 100k • 10µF 499k VOUT 400V 560µF 0.5A ×2 4.7pF 100k D3 2k 1M VIN_SENSE FB EN/UVLO 95.3k 9.53k LT8312 GATE VREF SENSE INTVCC OVP GND 100k 221k VC 98 1M DCM VIN 1M Efficiency 99 20Ω 97 EFFICIENCY (%) 90V TO 265V AC • D2 20Ω D4 CMR5H-06 4:1 115VAC 96 95 230VAC 50Hz 94 93 4.7µF 92 0.01Ω 91 2.2µF 0 20 40 60 80 100 120 140 160 POWER (W) 8312 G01 8312 TA01a 8312fa For more information www.linear.com/LT8312 1 LT8312 Absolute Maximum Ratings (Note 1) Pin Configuration EN/UVLO....................................................................30V VIN.............................................................................42V INTVCC.......................................................................18V FB................................................................................3V VC................................................................................5V VIN(SENSE).................................................................1mA OVP..............................................................................4V SENSE.......................................................................0.4V DCM........................................................................±3mA Operating Temperature Range (Note 2).....–40°C to 125°C Storage Temperature Range................... –65°C to 150°C TOP VIEW GND GND GND VREF OVP VC GND GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VIN_SENSE SENSE GATE INTVCC EN/UVLO VIN DCM FB MS PACKAGE 16-LEAD PLASTIC MSOP θJA = 125°C/W Order Information (http://www.linear.com/product/LT8312#orderinfo) LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8312EMS#PBF LT8312EMS#TRPBF 8312 16-Lead Plastic MSOP –40°C to 125°C LT8312IMS#PBF LT8312IMS#TRPBF 8312 16-Lead Plastic MSOP –40°C to 125°C LT8312HMS#PBF LT8312HMS#TRPBF 8312 16-Lead Plastic MSOP –40°C to 150°C LT8312MPMS#PBF LT8312MPMS#TRPBF 8312 16-Lead Plastic MSOP –55°C to 150°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 2 8312fa For more information www.linear.com/LT8312 LT8312 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN Input Voltage Range TYP MAX 38 V 60 70 70 µA µA 10 45 UNITS Quiescent Current VEN/UVLO = 0.2V Not Switching VIN Quiescent Current, INTVCC Overdriven VINTVCC = 11V 60 µA VIN Shunt Regulator Voltage I = 1mA 40 V VIN Shunt Regulator Current Limit 8 INTVCC Quiescent Current VEN/UVLO = 0.2V VEN/UVLO = 1.5V, Not Switching EN/UVLO Pin Threshold EN/UVLO Pin Voltage Rising EN/UVLO Pin Hysteresis Current EN/UVLO = 1V VREF Voltage 0µA Load 200µA Load l l l SENSE Current Limit Threshold 15.5 2.2 17.5 2.7 µA mA 1.21 1.25 1.29 V 8 10 12 μA 1.97 1.95 2.0 1.98 2.03 2.03 V V 96 102 107 Minimum SENSE Current Limit SENSE Input Bias Current mA 12.5 1.8 3 Current Out of Pin 15 Current Sense Blanking Time FB Voltage l mV mV µA 90 130 170 ns 1.22 1.25 1.28 V FB Voltage Line Regulation 10V < VIN < 35V 0.01 0.03 %/V FB Pin Bias Current (Note 3), FB = 1.25V, OVP = 1.35V 100 600 nA FB Error Amplifier Voltage Gain ΔVVC/ΔVFB 180 V/V FB Error Amplifier Transconductance ΔI = 5µA 170 µmhos 0.1 V FB Low Detection Voltage DCM Current Turn-On Threshold Current Out of Pin Maximum Oscillator Frequency 80 µA 400 kHz Linear Regulator INTVCC Regulation Voltage 9.8 Dropout (VIN-INTVCC) IINTVCC = –10mA, VIN = 10V Current Limit INTVCC < 9.5V INTVCC > 9.5V 12 80 10 10.4 V 500 900 mV 25 120 mA mA Gate Driver tr GATE Driver Output Rise Time CL = 3300pF 18 ns tf GATE Driver Output Fall Time CL = 3300pF 18 ns GATE Output Low (VOL) 0.01 GATE Output High (VOH) V INTVCC – 50mV Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT8312E is guaranteed to meet specified performance from 0°C to 125°C junction temperature. Specification over the –40°C and 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT8312I is guaranteed to meet specified performance from –40°C to V 125°C operating junction temperature range. The LT8312H is guaranteed to meet performance specifications over the –40°C to 150°C operating junction temperature range. The LT8312MP is guaranteed to meet performance specifications over the –55°C to 150°C operating junction temperature range. High junction temperatures degrade operating lifetimes. Operating lifetime is derated for junction temperatures greater than 125°C. Note 3: Current flows out of the FB pin. 8312fa For more information www.linear.com/LT8312 3 LT8312 Typical Performance Characteristics EN/UVLO Threshold vs Temperature Input Voltage Hysteresis Current vs Temperature RISING 1.26 1.24 FALLING 1.22 1.2 –50 –25 0 11.5 11 40 20 10 2.05 0 0 –50 –25 25 50 75 100 125 150 TEMPERATURE (°C) 0 25 50 75 100 125 150 TEMPERATURE (°C) 8312 G03 SENSE Pin Threshold Current vs Temperature VREF vs VIN 120 2.04 SENSE CURRENT LIMIT (mV) 2.03 2.02 VIN = 24V WITH NO LOAD 2.000 1.975 VIN = 24V WITH 200µA LOAD 1.950 VREF (V) VREF (V) 50 8312 G02 VREF vs Temperature 2.025 2.01 NO LOAD 2 1.99 200µA LOAD 1.98 1.97 1.925 MAX ILIM 100 80 60 40 20 1.96 1.900 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 1.95 10 15 20 8312 G04 INTVCC vs Temperature 25 VIN (V) 30 VIN Shunt Voltage vs Temperature 42 10.2 25 50 75 100 125 150 TEMPERATURE (°C) 8312 G07 9 40 39.5 9.2 0 41 40.5 9.6 9.4 9.75 ISHUNT = 1mA 41.5 10 INTVCC (V) 10 25 50 75 100 125 150 TEMPERATURE (°C) 8312 G06 VIN SHUNT VOLTAGE (V) NO LOAD 10mA LOAD 25mA LOAD 0 8312 G05 9.8 9.5 –50 –25 0 –50 –25 40 35 INTVCC vs VIN 10.25 INTVCC (V) 60 30 10.5 25 50 75 100 125 150 TEMPERATURE (°C) 2.050 4 VIN = 12V 70 10 –50 –25 2.075 10.5 VIN = 24V 80 8312 G01 2.100 VIN IQ vs Temperature 90 IQ (µA) EN/UVLO HYSTERESIS CURRENT (µA) 1.28 EN/UVLO (V) 100 12 1.3 5 10 15 25 20 VIN (V) 30 40 35 39 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 8312 G09 8312 G08 8312fa For more information www.linear.com/LT8312 LT8312 Typical Performance Characteristics Maximum VIN Shunt Current vs Temperature THD vs Output Power 0.90 POWER FACTOR 40 THD 8 7 30 230VAC 50Hz 20 230VAC 50Hz 0.85 0.80 0.75 0.70 6 5 –50 –25 115VAC 0.95 50 9 SHUNT CURRENT (mA) Power Factor vs Output Power 1.00 60 10 10 0 25 50 75 100 125 150 TEMPERATURE (°C) 0 0.65 115VAC 0 20 40 60 80 100 120 140 160 POWER (W) 8312 G11 8312 G10 0.60 0 20 40 60 80 100 120 140 160 POWER (W) 8312 G12 Pin Functions GND (Pins 1, 2, 3, 7, 8): Ground. VREF (Pin 4): Voltage Reference Output Pin, Typically 2V. This pin drives a resistor divider for the OVP pin. Can supply up to 200μA. OVP (Pin 5): Overvoltage Protection. This pin accepts a DC voltage to compare to the voltage output information. When FB pin voltage is above the OVP, the part stops switching. This protects devices connected to the output. VC (Pin 6): Compensation Pin for Internal Error Amplifier. Connect a series RC from this pin to ground to compensate the switching regulator. A 100pF capacitor in parallel helps eliminate noise. FB (Pin 9): Voltage Loop Feedback Pin. FB is used to regulate the output voltage. DCM (Pin 10): Discontinuous Conduction Mode Detection Pin. Connect a capacitor and resistor in series with this pin to the auxiliary winding. VIN (Pin 11): Input Voltage. This pin supplies current to the internal start-up circuitry and to the INTVCC LDO. This pin must be locally bypassed with a capacitor. A 42V shunt regulator is internally connected to this pin. EN/UVLO (Pin 12): Enable/Undervoltage Lockout. A resistor divider connected to VIN is tied to this pin to program the minimum input voltage at which the LT8312 will turn on. When below 1.25V, the part will draw 60μA with most of the internal circuitry disabled and a 10μA hysteresis current will be pulled out of the EN/UVLO pin. When above 1.25V, the part will be enabled and begin to switch and the 10μA hysteresis current is turned off. INTVCC (Pin 13): Regulated Supply for Internal Loads and GATE Driver. Supplied from VIN and regulates to 10V (typical). INTVCC must be bypassed with a 4.7μF capacitor placed close to the pin. GATE (Pin 14): N-Channel FET Gate Driver Output. Switches between INTVCC and GND. Driven to GND during shutdown state and stays high during low voltage states. SENSE (Pin 15): The Current Sense Input for the Control Loop. Kelvin connect this pin to the positive terminal of the switch current sense resistor, RSENSE, in the source of the NFET. The negative terminal of the current sense resistor should be connected to the GND plane close to the IC. VIN(SENSE) (Pin 16): Line Voltage Sense Pin. The pin is used for sensing the AC line voltage to perform power factor correction. Connect a resistor in series with the line voltage to this pin. 8312fa For more information www.linear.com/LT8312 5 LT8312 Block Diagram D2 R2 L2 C1 R1 L1 D1 10 12 16 EN/UVLO DCM 4 VREF VIN VIN(SENSE) R4 1.22V Q1 – + – + ONE SHOT A2 – V 600MV + 6 VC 13 C5 A1 DRIVER Q MASTER LATCH – INTVCC R11 S C4 M2 R10 S R + A7 CURRENT COMPARATOR A3 A8 R3 – + 1.22V C6 START-UP INTERNAL REG R9 FB VOUT 11 5 OVP 9 VIN C2 R14 R5 R8 C3 R13 A6 SENSE A4 MULTIPLIER GATE 14 M1 15 R6 GND 1, 2, 3, 7, 8 OSCILLATOR 8312 BD 6 8312fa For more information www.linear.com/LT8312 LT8312 Operation The LT8312 is a power factor correction boost controller IC. It provides high power factor and low harmonic distortion in applications with current mode control and critical conduction mode. Active power factor correction is becoming a requirement for offline power supplies. A power factor of one is achieved if the current drawn is proportional to the input voltage. The LT8312 modulates the peak current limit with a scaled version of the input voltage. This technique can provide power factors of 0.97 or greater. The Block Diagram shows an overall view of the system. The external components are in a boost topology configuration. The auxiliary winding supplies power to the part in steady-state operation. The VIN pin supplies power to an internal LDO that generates 10V at the INTVCC pin. The control circuitry consists of an error amplifier, a multiplier, a current comparator, and a master latch, which will be explained in the following sections. A comparator is used to detect discontinuous conduction mode (DCM) with a cap connected to the auxiliary winding. The part features a 1.9A gate driver. a rate proportional to the difference between the output voltage and the input voltage. When the current decreases to zero, the output diode turns off and the voltage on the drain of the MOSFET starts to oscillate from the parasitic capacitance and the inductor. The auxiliary winding has the same voltage across it as the main inductor and rings too. The capacitor connected to the DCM pin, C1, trips the comparator A2, which serves as a dv/dt detector, when the ringing occurs. The dv/dt detector waits for the ringing waveform to reach its minimum value and then the switch turns back on. This switching behavior is similar to zero volt switching and minimizes the amount of energy lost when the switch is turned back on and improves efficiency as much as 5%. Since this part operates on the edge of continuous conduction mode and discontinuous conduction mode, the operating mode is called critical conduction mode (or boundary conduction mode). The output voltage is regulated with a resistor divider connected to the FB pin. The output of the error amplifier is the VC pin. This node needs a capacitor to compensate the control loop. The LT8312 is designed for off-line applications. The EN/UVLO and a resistor divider are configured for a micropower hysteretic start-up. In the Block Diagram, R2 is used to stand off the high voltage supply voltage. The internal LDO starts to supply current to the INTVCC pin when VIN is above 2.5V. The VIN and INTVCC capacitor are charged by the current from R2. When VIN exceeds the turn-on threshold and INTVCC is in regulation at 10V, the part begins to switch. The VIN hysteresis is set by the EN/UVLO resistor divider. The auxiliary winding provides power to VIN when its voltage is higher than the VIN voltage. A voltage shunt is provided for fault protection and can sink 8mA of current when VIN is over 40V. Power Factor Correction During a typical cycle, the gate driver turns the external MOSFET on and a current flows through the inductor. This current increases at a rate proportional to the input voltage. The control loop determines the maximum current and the current comparator turns the switch off when the current level is reached. When the switch turns off, the inductor current begins to flow through the diode connected to the output capacitor. This current decreases at The LT8312 uses a hysteretic start-up to operate from high offline voltages. A resistor connected to the supply voltage protects the part from high voltages. This resistor is connected to the VIN pin on the part and bypassed with a capacitor. When the resistor charges the VIN pin to a turn-on voltage set with the EN/UVLO resistor divider and the INTVCC pin is at its regulation point, the part begins to switch. The resistor cannot provide power for the part in When the VIN(SENSE) pin is connected to the supply voltage with a resistor, the current limit is proportional to the supply voltage. If the LT8312 is configured with a fast control loop, the VC pin would adjust to the changes of the VIN(SENSE). The only way for the multiplier to function is to set the control loop to be an order of magnitude slower than the fundamental frequency of the VIN(SENSE) signal. In an offline application, the fundamental frequency of the supply voltage is 120Hz so the control loop unity gain frequency needs to be set less than approximately 12Hz. Start-Up 8312fa For more information www.linear.com/LT8312 7 LT8312 Operation steady state, but relies on the capacitor to start up the part, then the auxiliary winding begins to provide power to the VIN pin along with the resistor. An internal voltage clamp is attached to the VIN pin to prevent the resistor current from allowing VIN to go above the absolute maximum voltage of the pin. The internal clamp is set at 40V and is capable of 8mA (typical) of current at room temperature. Setting the VIN Turn-On and Turn-Off Voltages A large voltage difference between the VIN turn-on voltage and the VIN turn-off voltage is preferred to allow time for the auxiliary winding to power the part. The EN/UVLO sets these two voltages. The pin has a 10μA current sink when the pins voltage is below 1.25V and 0μA when above 1.25V. The VIN pin connects to a resistor divider as shown in Figure 1. The UVLO threshold for VIN rising is: VIN(UVLO,RISING) =1.25V • R1+R2 +10µA •R1 R2 The UVLO Threshold for VIN Falling is : VIN(UVLO, FALLING) =1.25V • R1+R2 R2 VIN R1 EN/UVLO LT8312 GND R2 8312 F01 Figure 1. Undervoltage Lockout (UVLO) 8 Programming Output Voltage The output voltage is set using a resistor divider from the output capacitor to the FB pin. From the Block Diagram the resistors R3 and R4 form a resistor divider from the output capacitor. The output voltage equation is: VOUT = VBG • R3+R4 R5 The VBG voltage is equal to FB Voltage in Electrical Specification Table. Setting VIN(SENSE) Resistor The VIN(SENSE) resistor sets the current feeding the internal multiplier that modulates the current limit for power factor correction. At the maximum line voltage, VMAX, the current is set to 360µA. Under this condition, the resistor value is equal to (VMAX/360µA). Critical Conduction Mode Operation Critical conduction mode is a variable frequency switching scheme that always returns the inductor current to zero with every cycle. The DCM pin uses a fast current input comparator in combination with a small capacitor to detect dv/dt on the auxiliary winding. To eliminate false tripping, a blanking time of 200ns is applied after the switch turns off. The detector looks for 80μA of current through the DCM pin due to falling voltage on the auxiliary winding when the output diode turns off. This is not the optimal time to turn the switch on because the switch voltage is still close to VOUT and would waste all the energy stored in the parasitic capacitance on the switch node. Discontinuous ringing begins when the output diode current reaches zero 8312fa For more information www.linear.com/LT8312 LT8312 Operation and the energy in the parasitic capacitance on the switch node transfers to the input capacitor. This is a secondorder network composed of the parasitic capacitance on the switch node and the main inductor. The minimum voltage of the switch node during this discontinuous ring is 2VIN-VOUT. The LT8312 turns the switch back on at this time, during the discontinuous switch waveform, by sensing when the slope of the switch waveform goes from negative to positive using the dv/dt detector. This switching technique may increase efficiency by 5%. At low current limits, the frequency of critical conduction mode can become very high. The LT8312 features a maximum frequency clamp of 400kHz. The part operates in discontinuous conduction mode when the natural critical conduction mode frequency is higher than 400kHz. Sense Resistor Selection The resistor, RSENSE, between the source of the external N-channel MOSFET and GND should be selected to provide an adequate switch current to drive the application without exceeding the current limit threshold. Minimum Current Limit The LT8312 features a minimum current limit of approximately 3% of the peak current limit. This helps improve the harmonic distortion during the input supplies off-line crossover period. Universal Input The LT8312 operates over the universal input voltage range of 90V AC to 265V AC. Loop Compensation The feedback loop is a traditional gm error amplifier. The loop crossover frequency is set much lower than twice the line frequency for PFC to work properly. In a typical application, the compensation capacitor is 1µF. MOSFET and Diode Selection With a strong 1.9A gate driver, the LT8312 can effectively drive most high voltage MOSFETs. A low QG MOSFET is recommended to maximize efficiency. In most applications, the RDS(ON) should be chosen to limit the temperature rise of the MOSFET. The drain of the MOSFET is stressed to VOUT during the time the MOSFET is off and the diode is conducting current. The diode is stressed to VOUT when the switch is on. The average current through the diode is equal to the load current. Discontinuous Mode Detection The discontinuous mode detector uses AC-coupling to detect the ringing on the auxiliary winding. A 22pF capacitor with a 30k resistor in series is recommended in most designs. Power Factor Correction/Harmonic Content The LT8312 attains high power factor and low harmonic content by making the peak current of the main power switch proportional to the line voltage by using and internal multiplier. A power factor of >0.97 is easily attainable for most applications by following the design equations in this data sheet. With proper design, LT8312 applications can easily meet most harmonic standards. 8312fa For more information www.linear.com/LT8312 9 10 2 3 For more information www.linear.com/LT8312 1 2 Z1 C1 0.22µF • •1 4 L N 90-265VAC J1 4 L1 15mH F1 3.15A 2 3 B1 GBU404 C2 0.47µF L4 300µH C12 1µF C13 1nF R18 75k R5 24.9k 1% R4 11.8k 1% R3 301k 1% R7 150k 1% 1206 R2 499k 1% 1206 C3 100pF R8 2.4M 1% D1 BAV20W R6 150k 1% 1206 R1 499k 1% 1206 3 2 1 5 4 12 16 11 VIN C5 680nF GND R26 10k 1% C14 4.7µF 6 GND GND INTVCC SENSE GATE FB GND VC LT8312 DCM 10 C6 4.7nF GND OVP VREF EN/UVLO VIN_SENSE + C4 10µF, 50V D2 BAV20W D3 CMZ5934B R9 47Ω 1206 7 8 13 15 14 9 R10 2k 6 R11 10Ω 1% R13 1M 1206 C9 100pF 50V R14 100Ω Q1 IPA50R190CE C15 100pF L3 760802122 450µH 10:1 D4 1N4005 R19 0Ω 12 R12 9.53k • D6 1N4148W • C8 4.7µF 16V INTVCC C7 27pF 7 3 Universal Input 150W PFC Boost Converter R15 0.015Ω 1206 R16 1M 1206 + D5 CMR5H-06 C10 100µF 450V R17 1M 1206 J2 + – 8312 TA02 400V/0.375A 1 2 LT8312 Typical Applications 8312fa 2 3 For more information www.linear.com/LT8312 1 2 Z1 4 •1 C1 47nF • L1 27mH 4 L N 97~134VAC 400Hz J1 F1 2.5A 2 3 B1 KBP204G C12 100nF L4 1mH C12 220nF C13 1nF R18 75k R5 24.9k 1% R4 11.8k 1% R3 301k 1% R7 100k 1% 1206 R2 499k 1% 1206 C3 100pF R8 2.4M 1% D1 BAV20W R6 100k 1% 1206 R1 499k 1% 1206 3 2 1 5 4 12 16 11 VIN C5 27nF R26 82.5k 1% C14 470nF 6 GND GND GND INTVCC SENSE GATE FB GND VC LT8312 DCM 10 C6 4.7nF GND OVP VREF EN/UVLO VIN_SENSE + C4 10µF, 50V D2 BAV20W D3 CMZ5934B R9 47Ω 1206 7 8 13 15 14 9 R10 2k 6 R11 10Ω 1% R13 1M 1206 C9 100pF 50V R14 100Ω Q1 IPA50R190CE C15 100pF L3 760801130 750µH D4 1N4005 R19 0Ω 12 R12 9.53k • D6 1N4148W • C8 4.7µF 16V INTVCC C7 27pF 7 3 Avionics Input 60W PFC Boost Converter R15 0.04Ω 1206 R16 1M 1206 + D5 CMR2U-06 C10 47µF 450V R17 1M 1206 J2 + – 8312 TA03 400V/0.15A 1 2 LT8312 Typical Applications 8312fa 11 LT8312 Package Description Please refer to http://www.linear.com/product/LT8312#packaging for the most recent package drawings. MS Package 16-Lead Plastic MSOP (Reference LTC DWG # 05-08-1669 Rev A) MS Package 16-Lead Plastic MSOP (Reference LTC DWG # 05-08-1669 Rev A) 0.889 ±0.127 (.035 ±.005) 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 4.039 ±0.102 (.159 ±.004) (NOTE 3) 0.50 (.0197) BSC 0.305 ±0.038 (.0120 ±.0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) DETAIL “A” 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.006) 0° – 6° TYP 0.280 ±0.076 (.011 ±.003) REF 16151413121110 9 GAUGE PLANE 0.53 ±0.152 (.021 ±.006) DETAIL “A” 0.18 (.007) SEATING PLANE 1.10 (.043) MAX 0.17 – 0.27 (.007 – .011) TYP 1234567 8 0.50 (.0197) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 12 0.86 (.034) REF 0.1016 ±0.0508 (.004 ±.002) MSOP (MS16) 0213 REV A 8312fa For more information www.linear.com/LT8312 LT8312 Revision History REV DATE DESCRIPTION A 2/16 Modified schematics. PAGE NUMBER 1, 14 Changed minimum current limit for INTVCC. 3 Changed OVP pin description. 6 8312fa Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. For more information www.linear.com/LT8312 13 LT8312 Typical Application Universal Input 200W PFC Boost Converter 90V TO 265V AC 0.1µF 499k • D2 20Ω 100k VOUT 400V 560µF 0.5A ×2 • 10µF 499k D4 4:1 4.7pF 100k D3 2k 1M VIN 1M 1M DCM VIN_SENSE FB EN/UVLO 95.3k 9.53k LT8312 GATE VREF SENSE INTVCC OVP GND 100k 221k VC 20Ω 4.7µF 0.01Ω 2.2µF 8312 TA04 Related Parts PART NUMBER DESCRIPTION COMMENTS LT3798 Off-Line Isolated No Opto Flyback Controller with Active PFC VIN and VOUT Limited Only By External Components LT3752/ LT3752-1 Active Clamp Synchronous Forward Controllers with Internal Input Voltage Range: LT3752: 6.5V to 100V, LT3752-1: Limited Only By Housekeeping Controller Eternal Components LT3753 Active Clamp Synchronous Forward Controller Input Voltage Range: 8.5V to 100V LT8311 Synchronous Rectifier Controller with Opto-Coupler Driver for Forward Converters Optimized for Use with Primary-Side LT3752/LT3752-1, LT3753 and LT8310 Controllers LT3748 100V Isolated Flyback Controller 5V ≤ VIN ≤ 100V, No Opto Flyback, MSOP-16 with High Voltage Spacing LTC 3765/ LTC3766 Synchronous No Opto Forward Controller Chip Set with Active Clamp Reset Direct Flux Limit, Supports Self Starting Secondary Forward Control LTC3723-1/ LTC3723-2 Synchronous Push-Pull and Full-Bridge Controllers High Efficiency with On-Chip MOSFET Drivers, Adjustable Synchronous Rectification Timing LTC3722/ LTC3722-2 Synchronous Full Bridge Controllers Adaptive or Manual Delay Control for Zero Voltage Switching, Adjustable Synchronous Rectification Timing ® 14 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LT8312 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT8312 8312fa LT 0216 REV A • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2015